Benzotriazole-modified Anti-sagging resin and preparation method therefor, and coating

Abstract

A benzotriazole-modified anti-sagging resin, a preparation method therefor, and a coating. The raw materials of the modified anti-sagging resin, calculated by parts by weight, comprise the following components: 60-80 parts of a polymer resin; 5-20 parts of a solvent; 1-3 parts of one or more mixed diisocyanates; and 1-4 parts of benzotriazole containing a primary amine group. The preparation method comprises: S1: mixing a primary amine diphenylmethanol with a portion of the solvent, to prepare a primary amine diphenylmethanol solution of a preset concentration; S2: mixing the polymer resin and the remaining solvent uniformly in a reaction kettle with continuous stirring, maintaining the reaction system temperature at 0-40°C, dispersing the primary amine diphenylmethanol solution prepared in step S1 into the reaction system, adding the diisocyanate(s), and stirring, to obtain the modified anti-sagging resin. By means of a benzotriazole-based UV absorber present in the form of polyurea crystals, the risk of volatilization and incompatibility with a coating are avoided, and this can also enhance the aging resistance of the anti-sagging resin.

Description

A benzotriazole-modified anti-sagging resin and its preparation method, coatings Technical Field

[0001] This invention belongs to the field of coating additives technology, and particularly relates to a benzotriazole modified anti-sagging resin, its preparation method, and coatings. Background Technology

[0002] Resin materials are widely used in coatings, composite materials, electronic packaging, and construction. These applications require high aging resistance from the resin to ensure the long-term stability and service life of the product. However, during long-term use, resins are affected by environmental factors (such as ultraviolet radiation, temperature, and humidity), leading to a gradual decline in performance and problems such as embrittlement, color changes, and reduced mechanical properties.

[0003] To improve the aging performance of resins, anti-aging agents, modifiers, or other functional additives are typically added. However, these additives may pose a risk of incompatibility with the coating resin matrix, potentially leading to performance instability, such as layering or precipitation. Furthermore, the introduction of additives can affect the resin's processing properties, such as flowability and curing speed, thereby impacting production efficiency and product quality. Since many anti-aging agents and modifiers are small-molecule compounds and volatile, their use may have potential negative impacts on the environment or human health, requiring careful consideration. In addition, the addition of new additives or modifiers may necessitate adjustments to the coating production process, increasing process complexity and management difficulty. Therefore, researching and introducing novel functional materials to replace traditional anti-aging agents and modifiers has become an urgent problem to be solved.

[0004] Anti-sagging coatings are a class of coatings with added anti-sagging additives to modify their rheological properties. The main function of such coatings is to prevent paint from flowing during application to vertical or sloping surfaces, thus preventing uneven coating thickness or buildup. The main principle behind anti-sagging additives is to modify the resin matrix in the coating with polyurea compounds. The molecular structure of polyurea compounds readily forms hydrogen bonds, resulting in higher viscosity of the coating when not subjected to or under minimal external force (such as slight gravity on a vertical surface), thereby reducing sagging. When a certain shear force is applied (such as during transport or spraying), the hydrogen bonds are broken, and the resin exhibits lower viscosity, making it easier to flow. Anti-sagging resins are mainly used for spraying large areas of vertical surfaces or other applications requiring anti-sagging properties. However, currently available anti-sagging resins offer limited performance; while initial performance may be improved, long-term use may lead to aging, discoloration, or performance degradation, affecting their long-term stability.

[0005] In summary, traditional anti-sagging resins suffer from limitations such as limited performance and poor long-term stability. Directly adding anti-aging agents to coatings to improve their aging resistance can lead to incompatibility issues, compromise anti-sagging properties, and negative impacts on the environment and health.

[0006] Summary of the Invention

[0007] To address the aforementioned technical problems, this invention offers a novel approach by using benzotriazole-based anti-aging additives as raw materials for the synthesis of anti-sagging resins, i.e., polyurea compounds. This allows the benzotriazole-based anti-aging additives to exist in the form of polyurea crystals, avoiding the risk of volatilization and incompatibility with coatings, while also enhancing the aging resistance of the anti-sagging resin. Therefore, this invention provides a benzotriazole-modified anti-sagging resin, its preparation method, and a coating.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows:

[0009] A benzotriazole-modified anti-sagging resin, comprising the following components by weight:

[0010] Preferably, the chemical structure of the primary aminobenzotriazole is as follows:

[0011] Where R 1 —R 8 It can be any one of the structures -H, -OH, -OCH3, -C4H9, -Cl, and -OCH2CHOCH2, or any combination thereof; n = 0-10.

[0012] Preferably, the chemical structure of the primary aminobenzotriazole is as follows:

[0013] That is, R1-R8 are all -H; or

[0014] That is, R8 = -NH2, and R1-R7 are all -H.

[0015] Preferably, the solvent is any one or more of xylene, S-100A high-boiling-point solvent, or S-150 aromatic solvent.

[0016] Preferably, when the solvent is any two of xylene, S-100A high-boiling-point solvent or S-150 aromatic solvent, the blending ratio is 1:0-10.

[0017] Preferably, the polymer resin is polyacrylic acid resin (PA) or / and polyester resin (PE).

[0018] Preferably, the isocyanate is any one of hexamethylene diisocyanate (HDI), diphenylmethane-4,4'-diisocyanate (MDI) or 4,4'-dicyclohexylmethane diisocyanate (HMDI) or a mixture thereof.

[0019] Based on the same inventive concept, the present invention also provides a method for preparing the benzotriazole-modified anti-sagging resin, comprising the following steps:

[0020] S1: Prepare a primary aminodiphenylmethanol solution of a predetermined concentration by mixing primary aminodiphenylmethanol with a portion of the solvent;

[0021] S2: Mix the polymer resin and the remaining solvent evenly in the reactor and stir continuously, keeping the temperature of the reaction system at 0-40℃. Disperse the primary aminodiphenylmethanol solution prepared in step S1 into the reaction system, add diisocyanate and stir to obtain the modified anti-sagging resin.

[0022] Based on the same inventive concept, the present invention also provides a coating comprising the benzotriazole modified anti-sagging resin.

[0023] Because the present invention adopts the above technical solution, it has the following advantages and positive effects compared with the prior art:

[0024] The modified anti-sagging resin provided by this invention includes a polymer resin, a solvent, multiple or one mixed diisocyanate, and a primary amino benzotriazole. Using the primary amino benzotriazole as a polyurea raw material, the primary amine and primary amino groups in the molecular structure react with the diisocyanate to generate polyurea crystals, thus achieving the resin's anti-sagging function. This allows the benzotriazole UV absorber to exist in the form of polyurea crystals, making the benzotriazole UV absorber an integral part of the polyurea structure. This avoids the volatility problem of small molecule compounds in the benzotriazole UV absorber, thereby preventing environmental pollution and health hazards. Compared to existing technologies, this is more environmentally friendly and safer.

[0025] In addition, benzotriazole UV absorber exists in the form of polyurea crystals and is composed of polymer resin to form polyurea resin. When added to coatings, it is evenly dispersed with the coating due to the principle of similar compatibility, thus avoiding problems such as separation and precipitation between the anti-aging agent and the coating.

[0026] Meanwhile, this invention introduces benzotriazole into polyurea resin in the form of chemical bonds, making benzotriazole a group in the polyurea molecule. This not only does not affect the resin's anti-sagging properties, but also significantly enhances the resin's aging resistance and extends its service life. This makes the anti-sagging resin possess both anti-sagging and aging resistance. When added to coatings as an additive, it provides the same function to the coating while avoiding the delamination and volatility problems of traditional aging-resistant additives. At the same time, it simplifies the coating production process. Compared with existing technologies, it reduces the complexity of the coating process and improves production efficiency and product quality.

[0027] The modified anti-sagging resin preparation method provided by the present invention involves adding a solution containing primary aminobenzotriazole to a reaction system composed of polymer resin and solvent, and then adding diisocyanate to the reaction system and stirring to react. This process improves the resin synthesis process and enhances the consistency and stability of the product. Attached Figure Description

[0028] Figure 1 shows the rheological properties test results of the resin in Example 1 of the present invention;

[0029] Figure 2 shows the rheological properties test results of the resin in Example 2 of the present invention;

[0030] Figure 3 shows the rheological properties test results of the resin in Example 3 of the present invention;

[0031] Figure 4 shows the rheological properties test results of the resin of Comparative Example 1 of the present invention.

[0032] Figure 5 shows the rheological properties test results of the resin of Comparative Example 2 of the present invention;

[0033] Figure 6 shows the rheological properties test results of the resin of Comparative Example 3 of the present invention. Detailed Implementation

[0034] Benzotriazole-based anti-aging additives have become an important choice for improving the weather resistance of resin materials due to their excellent ultraviolet absorption properties. These additives effectively prevent photo-oxidation damage to resins by absorbing ultraviolet light and converting it into harmless heat energy, thereby delaying material aging. Because benzotriazole compounds can effectively absorb ultraviolet light in both the UV-A and UV-B bands, they are widely used in coatings, composite materials, electronic packaging, and building materials to significantly improve product durability and service life.

[0035] This invention selects benzotriazole-based anti-aging additives. Since polyurea is a polymerization reaction between amino groups and isocyanates, benzotriazole containing a primary amino group is chosen to react with isocyanates to synthesize polyurea, making benzotriazole a functional group in the polyurea molecule. Furthermore, the high symmetry of the benzotriazole molecular structure and the presence of a rigid aromatic ring facilitate the formation of regular chain segment arrangements, thereby increasing the crystallinity of the polyurea. Consequently, the benzotriazole molecular group does not affect the polyurea crystals and even improves their crystallinity. Therefore, this invention selects benzotriazole containing a primary amino group, which allows the anti-aging agent to be introduced into the anti-sagging resin matrix in a chemically bonded manner. This overcomes the volatility and compatibility issues of anti-aging agents without affecting the anti-sagging performance, thus improving the anti-aging resistance of the anti-sagging resin.

[0036] It is important to note that benzotriazole-based anti-aging additives currently on the market are generally added externally, leading to insufficient compatibility between the additive and the resin matrix. This can cause phenomena such as layering and precipitation, affecting the performance and quality of the coating. Furthermore, traditional addition methods often require adjustments to the production process, increasing process complexity and management difficulty. This invention, by using benzotriazole containing primary amine groups as raw materials, directly introduces benzotriazole additives into the synthesis process of anti-sagging resins, ensuring high compatibility between the additive and the resin matrix, simplifying the production process, and improving product consistency and stability.

[0037] Currently used benzotriazole additives are typically volatile organic compounds (VOCs), which release harmful substances during use, causing environmental pollution and posing potential health risks. Furthermore, the presence of volatile substances can affect the long-term stability of the resin, leading to performance degradation. This invention introduces a benzotriazole UV absorber into polyurea resin via chemical bonding, making benzotriazole a functional group in the polyurea molecule. This effectively reduces volatility, providing a more environmentally friendly and safer solution, while significantly improving the resin's durability and aging resistance.

[0038] Existing anti-sagging resins can effectively reduce sagging in the initial stage of use, but they are prone to aging, discoloration, and performance degradation during long-term use, thus affecting the service life of coating products. This invention introduces a primary amine benzotriazole into the polyurea structure, which not only effectively improves anti-sagging performance in the initial stage but also significantly enhances the resin's aging resistance and long-term stability, extending its service life and overcoming the shortcomings of existing technologies.

[0039] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a benzotriazole-modified anti-sagging resin, its preparation method, and coatings based on the present invention. The advantages and features of the present invention will become clearer from the following description.

[0040] Example 1: Bz-A compound + HDI + HMDI in PA resin

[0041] In a 1000 mL dispersion jar equipped with a high-speed dispersion disc and a thermometer, 447.50 g of PA (solid content: 70.00%) and 72.83 g of xylene were added sequentially. Nitrogen gas was introduced, and the mixture was stirred at 1000 rpm until homogeneous. At 23°C, a mixture of 16.45 g (77.55 mmol) of Bz-A compound and 15 g of xylene was rapidly added dropwise to the dispersion jar, and the mixture was stirred at 4000 rpm for 1 minute. Then, 6.38 g (37.93 mmol) of HDI was added to the dispersion jar, the stirring speed was increased to 4000 rpm, and the mixture was dispersed for 2 minutes. Finally, 4.97 g (18.96 mmol) of HMDI was added, and the mixture was dispersed at 4000 rpm for 40 minutes to obtain an opaque thixotropic resin R1 with a fineness ≤10 μm. After sealing a portion of R1 resin, it was placed in a 50℃ water bath and stored under a 20W UVA-340 lamp for 10 days. Then it was taken out and marked as heat-stored resin R1' with a fineness ≤10μm.

[0042] The high shear rate (1000 s⁻¹) of resins R1 and R1' after 10 days of thermal storage (50℃) and light exposure (20W UVA-340) was measured using a rotational rheometer. -1 ) and low shear viscosity (1s -1 The changes were measured to determine the shear factor.

[0043] Example 2: Bz-A compound + HDI + HMDI in PE resin

[0044] In a 1000 mL dispersion jar equipped with a high-speed dispersion disc and a thermometer, 423.30 g of PE (solid content: 72.00%) and 97.16 g of xylene were added sequentially. Nitrogen gas was introduced, and the mixture was stirred at 1000 rpm until homogeneous. At 23°C, a mixture of 16.45 g (77.55 mmol) of Bz-A compound and 15 g of xylene was rapidly added dropwise to the dispersion jar, and the mixture was stirred at 4000 rpm for 1 minute. Then, 6.38 g (37.93 mmol) of HDI was added to the dispersion jar, the stirring speed was increased to 4000 rpm, and the mixture was dispersed for 2 minutes. Finally, 4.97 g (18.96 mmol) of HMDI was added, and the mixture was dispersed at 4000 rpm for 40 minutes to obtain an opaque resin R2 with a fineness ≤10 μm. After sealing a portion of R2 resin, it was placed in a 50℃ water bath and stored under 20W UVA-340 lamp for 10 days. This was marked as heat-stored resin R2' with a fineness ≤10μm.

[0045] The high shear rate (1000 s⁻¹) of resins R2 and R2' after 10 days of thermal storage (50℃) and light irradiation (20W UVA-340) was determined using a rotational rheometer. -1) and low shear viscosity (1s -1 The changes were measured to determine the shear factor.

[0046] Example 3: Bz-B compound in PA + MDI + HMDI

[0047] In a 1000 mL dispersion jar equipped with a high-speed dispersion disc and a thermometer, 447.50 g of PA (solid content: 70.00%) and 72.83 g of xylene were added sequentially. Nitrogen gas was introduced, and the mixture was stirred at 1000 rpm until homogeneous. At 23°C, a mixture of 17.60 g (77.55 mmol) of Bz-B compound and 15 g of xylene was rapidly added dropwise to the dispersion jar, and the mixture was stirred at 4000 rpm for 1 minute. Then, 9.49 g (37.93 mmol) of MDI was added to the dispersion jar, the stirring speed was increased to 4000 rpm, and the mixture was dispersed for 2 minutes. Finally, 4.97 g (18.96 mmol) of HMDI was added, and the mixture was dispersed at 4000 rpm for 40 minutes to obtain an opaque thixotropic resin R3 with a fineness ≤10 μm. After sealing a portion of R3 resin, it was placed in a 50℃ water bath and stored under a 20W UVA-340 lamp for 10 days. Then it was taken out and marked as heat-stored resin R3' with a fineness ≤10μm.

[0048] The high shear rate (1000 s⁻¹) of resins R3 and R3' after 10 days of thermal storage (50℃) and light irradiation (20W UVA-340) was determined using a rotational rheometer. -1 ) and low shear viscosity (1s -1 The changes were measured to determine the shear factor.

[0049] Comparative Example 1: Benzylamine + HDI + HMDI in PA

[0050] In a 1000 mL dispersion jar equipped with a high-speed dispersion disc and a thermometer, 447.50 g of PA (solid content: 70.00%) and 87.83 g of xylene were added sequentially. Nitrogen gas was introduced, and the mixture was stirred at 1000 rpm until homogeneous. At a temperature of 23°C, 8.31 g (77.55 mmol) of benzylamine was rapidly added dropwise to the dispersion jar, and the mixture was stirred at 4000 rpm for 1 minute to disperse. Then, 6.38 g (37.93 mmol) of HDI was added to the dispersion vessel, the stirring speed was increased to 4000 rpm, and the mixture was dispersed for 2 minutes. Then, 4.97 g (18.96 mmol) of HMDI was added, and the mixture was dispersed at 4000 rpm for 40 minutes to obtain an opaque thixotropic resin R4 with a fineness ≤10 μm. A portion of the R4 resin was sealed and stored in a 50°C water bath under irradiation with a 20W UVA-340 lamp for 10 days. The resin was then removed and labeled as heat-stored resin R4', and its fineness was measured to be ≤10 μm.

[0051] The high shear rate (1000 s⁻¹) of resins R4 and R4' after 10 days of thermal storage (50℃) and light irradiation (20W UVA-340) was determined using a rotational rheometer. -1 ) and low shear viscosity (1s -1 The changes were measured to determine the shear factor.

[0052] Comparative Example 2: Benzylamine + HDI + HMDI in PE

[0053] In a 1000 mL dispersion jar equipped with a high-speed dispersion disc and a thermometer, 423.30 g of PE (solid content: 72.00%) and 112.16 g of xylene were added sequentially. Nitrogen gas was introduced, and the mixture was stirred at 1000 rpm until homogeneous. At a temperature of 23°C, 8.31 g (77.55 mmol) of benzylamine was rapidly added dropwise to the dispersion jar, and the mixture was stirred at 4000 rpm for 1 minute to disperse. Then, 6.38 g (37.93 mmol) of HDI was added to the dispersion vessel, the stirring speed was increased to 4000 rpm, and the mixture was dispersed for 2 minutes. Then, 4.97 g (18.96 mmol) of HMDI was added, and the mixture was dispersed at 4000 rpm for 40 minutes to obtain opaque resin R5 with a fineness ≤10 μm. A portion of the R5 resin was sealed and stored in a 50°C water bath under irradiation with a 20W UVA-340 lamp for 10 days. The resin was then removed and labeled as heat-stored resin R5', and its fineness was measured to be ≤10 μm.

[0054] The high shear rate (1000 s⁻¹) of resins R5 and R5' after 10 days of thermal storage (50℃) and light irradiation (20WUVA-340) was determined using a rotational rheometer. -1 ) and low shear viscosity (1s -1 The changes were measured to determine the shear factor.

[0055] Comparative Example 3: Benzylamine + MDI + HMDI in PA

[0056] In a 1000 mL dispersion jar equipped with a high-speed dispersion disc and a thermometer, 447.50 g of PA (solid content: 70.00%) and 87.83 g of xylene were added sequentially. Nitrogen gas was introduced, and the mixture was stirred at 1000 rpm until homogeneous. At a temperature of 23°C, 8.31 g (77.55 mmol) of benzylamine was rapidly added dropwise to the dispersion jar, and the mixture was stirred at 4000 rpm for 1 minute to disperse. Then, 9.49 g (37.93 mmol) of MDI was added to the dispersion vessel, the stirring speed was increased to 4000 rpm, and the mixture was dispersed for 2 minutes. Then, 4.97 g (18.96 mmol) of HMDI was added, and the mixture was dispersed at 4000 rpm for 40 minutes to obtain an opaque thixotropic resin R6 with a fineness ≤10 μm. A portion of the R6 resin was sealed and stored in a 50°C water bath under irradiation with a 20W UVA-340 lamp for 10 days. The resin was then removed and labeled as heat-stored resin R6', and its fineness was measured to be ≤10 μm.

[0057] The high shear rate (1000 s⁻¹) of resins R6 and R6' after 10 days of thermal storage (50℃) and light irradiation (20W UVA-340) was determined using a rotational rheometer. -1 ) and low shear viscosity (1s -1 The changes were measured to determine the shear factor.

[0058] The fineness test described above was conducted in accordance with the national standard GB / T 1724-2019.

[0059] The rheological behavior of the above resin was tested according to conventional testing methods in the field.

[0060] Test instrument model: Test conditions: 10# rotor, temperature: 25℃, speed divided into two segments, first segment: 1000s -1 Cutting time: 5 minutes; Second segment: 1 second -1 Cutting time: 9 minutes.

[0061] Shear factor: Calculated using the following formula: X = A0 / A1. Where A0 is the sample rotation speed (in 1 second). -1 The viscosity at which the sample rotates at a speed of 1000 s is given by A1. -1 Viscosity at that time.

[0062] The shear viscosity test results of the resins in Examples 1-3 and Comparative Examples 1-3 before and after heat storage are shown in Figures 1-6, and the rheological property test results are shown in Table 1. It can be seen from Figures 1-3 that the obtained resins have anti-sagging properties before and after heat storage, indicating that polyurea synthesized from primary aminobenzotriazole can also have anti-sagging properties. In addition, it can be seen from the comparison of Figures 1-6 that the shear viscosity of the resins in Examples 1-3 before and after heat storage is basically unchanged, while the shear viscosity of Comparative Examples 1-3 is reduced after heat storage.

[0063] Table 1. Test results of resin viscosity and shear factor before and after thermal storage in Examples 1-3 and Comparative Examples 1-3.

[0064] By comparing the low-shear viscosity and shear factor before and after thermal storage, it can be seen that the viscosity of Examples 1-3 did not change much after thermal storage and light irradiation, indicating that the storage stability was good under high temperature and light irradiation. However, the viscosity of Comparative Examples 1-3 decreased significantly, indicating poor storage stability.

[0065] As can be seen from the rheological results of the embodiments and comparative examples before and after thermal storage and light irradiation in the attached figures and Table 1, the low-shear viscosity and shear factor of the comparative example show significant changes, while the viscosity of the examples remains basically unchanged, indicating good storage stability under high temperature and light irradiation. The shear factor change after 10 days under 50℃ water bath and UVA-340 lamp irradiation is <±5%. This further demonstrates that the polyurea resin provided by this invention, which uses primary aminobenzotriazole as a raw material and diisocyanate to synthesize polyurea crystals, not only effectively improves the anti-sagging properties in the initial stage but also significantly enhances the resin's aging resistance and extends its long-term service life.

[0066] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they shall still fall within the protection scope of the present invention.

Claims

1. A benzotriazole-modified anti-sagging resin, characterized in that, Based on parts by weight, it includes the following components:

2. The benzotriazole-modified anti-sagging resin according to claim 1, characterized in that, The chemical structure of the primary amino benzotriazole is as follows: Where R 1 —R 8 It can be any one of the following structures: -H, -OH, -OCH3, -C4H9, -Cl, -CH2NH2, -CH(CH3)3, and -OCH2CHOCH2, or any combination thereof.

3. The benzotriazole-modified anti-sagging resin according to claim 2, characterized in that, The chemical structure of the primary amino benzotriazole is as follows:

4. The benzotriazole-modified anti-sagging resin according to claim 1, characterized in that, The solvent is any one or more of xylene, S-100A high-boiling-point solvent, or S-150 aromatic solvent.

5. The benzotriazole-modified anti-sagging resin according to claim 4, characterized in that, When the solvent is any two of xylene, S-100A high-boiling-point solvent or S-150 aromatic solvent, the blending ratio is 1:0-10.

6. The benzotriazole-modified anti-sagging resin according to claim 1, characterized in that, The polymer resin is polyacrylic acid resin and / or polyester resin.

7. The benzotriazole-modified anti-sagging resin according to claim 1, characterized in that, The diisocyanate is any one or a mixture of several of hexamethylene diisocyanate, diphenylmethane-4,4'-diisocyanate, or 4,4'-dicyclohexylmethane diisocyanate.

8. A method for preparing a benzotriazole-modified anti-sagging resin as described in any one of claims 1-7, characterized in that, Includes the following steps: S1: Prepare a primary aminobenzotriazole solution of a predetermined concentration by mixing primary aminobenzotriazole with a portion of the solvent; S2: Mix the polymer resin and the remaining solvent evenly in the reactor and stir continuously, keeping the temperature of the reaction system at 0-40℃. Disperse the primary aminobenzotriazole solution prepared in step S1 into the reaction system, add diisocyanate and stir to obtain the modified anti-sagging resin.

9. A coating, characterized in that, Includes the benzotriazole-modified anti-sagging resin according to any one of claims 1-7.

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