Ultraviolet-resistant dye as well as preparation method and application thereof

Abstract

The invention relates to the technical field of functional dyes, and particularly discloses an ultraviolet-light-resistant dye and a preparation method and application thereof.The preparation method of the ultraviolet-light-resistant dye comprises the following steps that S1, 4, 5-quinoline diamine, 4-amino-1, 8-naphthalic anhydride, glacial acetic acid and an organic solvent are mixed and then heated and stirred for a reaction, a solid is obtained through filtering, and the solid is dried; washing with water and ethanol, and drying to obtain a dye intermediate A; and S2, stirring the dye intermediate A with 4-chloro-3 ', 5'-dimethyl-4 '-methoxybenzophenone, an organic solvent and a catalyst at room temperature to react, pouring the reaction liquid into water after the reaction is ended, separating, filtering to obtain a solid, recrystallizing, and drying to obtain the ultraviolet-resistant dye. The problems of migration and compatibility of the dye are solved, and meanwhile, excellent coloring performance and light stability are kept.

Description

Technical Field

[0001] This application relates to the field of functional dye technology, and in particular to a UV-resistant dye, its preparation method, and its application. Background Technology

[0002] Organic dyes, as important colorants, are widely used in plastics, coatings, textiles, printing, and other fields. However, traditional organic dyes are susceptible to photodegradation under ultraviolet light when used outdoors, leading to fading, discoloration, and other problems that severely affect the appearance and lifespan of products. This issue is particularly prominent in high-end applications such as automotive coatings, outdoor building materials, and packaging materials.

[0003] Currently, the main method to improve the lightfastness of dyes is to add UV absorbers or light stabilizers to the product. Commonly used UV absorbers include benzophenones, benzotriazoles, and triazines. However, this physical blending method has significant drawbacks: firstly, the lack of chemical bonds between dye molecules and UV absorbers makes phase separation easy, leading to uneven dispersion; secondly, small-molecule UV absorbers are prone to migration and volatilization during processing and use, which not only reduces the protective effect but may also pollute the environment; finally, the protective efficiency of physical blending systems is limited, making it difficult to meet the stringent requirements for color durability in high-end applications. To overcome these shortcomings, researchers have begun to explore chemically linking UV absorbing groups to dye molecules. Some attempts have been made, such as introducing UV absorbing groups into the dye structure through diazotization and esterification reactions. However, these methods often suffer from harsh reaction conditions, low yields, and low product purity, and the resulting dyes often fall short in terms of color brightness and tinting strength. Especially in the field of red dyes, although some research has been conducted to improve lightfastness, most of it remains at the stage of physical blending, or the chemical modification methods used have limited effects. Currently, there is still a lack of red dye products on the market that can maintain vibrant color while possessing excellent UV resistance. This is mainly because there are significant challenges in molecular structure design: on the one hand, it is necessary to maintain the optical properties of the dye chromophores; on the other hand, it is necessary to ensure that the introduced UV-absorbing groups do not affect the dye's coloring properties, while also ensuring that the entire molecule has good thermal stability and processability.

[0004] Therefore, developing a novel UV-resistant red dye that can solve migration and compatibility issues through chemical bonding while maintaining excellent coloring performance and photostability has become a pressing technical challenge in this field. Such a dye would not only meet the color durability requirements of high-end applications but also provide downstream products with longer lifespans and better user experiences, possessing significant market value and application prospects. Summary of the Invention

[0005] To address the issues of dye migration and compatibility while maintaining excellent coloring performance and photostability, this application provides a UV-resistant dye, its preparation method, and its application. This involves using 4-chloro-3... ' 5 ' -dimethyl-4 ' -The methoxybenzophenone UV absorption unit is covalently bonded to the quinolinonaphthalimide chromophore via a nucleophilic substitution reaction to form a single molecular structure. This dye is red and can not only meet the requirements of high-end applications for color durability, but also provide downstream products with a longer service life and a better user experience, thus having significant market value and application prospects.

[0006] In a first aspect, this application provides a UV-resistant dye, employing the following technical solution: A UV-resistant dye has the following structural formula: .

[0007] Optionally, the UV-resistant dye is prepared by the following reaction: , .

[0008] By employing the above technical solution, using 4,5-quinolinediamine and 4-amino-1,8-naphthalenedicarboxylic anhydride as chromophore backbone materials, a red chromophore parent with a quinoline-naphthalimide structure is constructed through a condensation reaction. Then, the active amino group in this parent molecule is combined with 4-chloro-3-amino(2 ... ' 5 ' -dimethyl-4 ' -Methoxybenzophenone UV absorbers undergo nucleophilic substitution reactions, permanently bonding the benzophenone UV absorber unit to the chromophore through the formation of stable CN covalent bonds, ultimately yielding a composite dye with a single molecular structure.

[0009] Secondly, this application provides a method for preparing a UV-resistant dye, which adopts the following technical solution: A method for preparing a UV-resistant dye includes the following steps: S1. 4,5-Quinolinediamine, 4-amino-1,8-naphthalenedicarboxylic anhydride, glacial acetic acid and organic solvent are mixed, heated and stirred to react, filtered to obtain a solid, washed with water and ethanol, and dried to obtain dye intermediate A. S2. Dye intermediate A is reacted with 4-chloro-3 ' 5 ' -dimethyl-4 '-Methoxybenzophenone, organic solvent, and catalyst were stirred and reacted at room temperature. After the reaction was completed, the reaction solution was poured into water for separation, filtered to obtain a solid, recrystallized, and dried to obtain the UV-resistant dye.

[0010] By employing the above technical solution, using 4,5-quinolinediamine and 4-amino-1,8-naphthalenedicarboxylic anhydride as the chromophore backbone, a quinolinediamine chromophore matrix is ​​constructed through a condensation reaction under the catalysis of glacial acetic acid. Then, through the catalytic action in step S2, the active amino group in this matrix reacts with the 4-chloro-3-amino-1,8-naphthalenedicarboxylic anhydride containing an active chlorine atom. ' 5 ' -dimethyl-4 ' -Methoxybenzophenone-based UV absorbers undergo nucleophilic substitution reactions to obtain red dyes with photostability and weather resistance.

[0011] Optionally, in step S1, the molar ratio of 4,5-quinolinediamine and 4-amino-1,8-naphthalenedicarboxylic anhydride is (1-1.2):1.

[0012] Optionally, in step S1, the heating temperature is 80-120℃ and the reaction time is 4-6 hours.

[0013] Optionally, in step S1, the organic solvent is one or more of dichloromethane, DMF, and chlorobenzene.

[0014] Optionally, in step S2, dye intermediate A and 4-chloro-3 ' 5 ' -dimethyl-4 ' The molar ratio of 1-methoxybenzophenone is 1:(1-1.2).

[0015] Optionally, in step S2, the catalyst is potassium carbonate or cesium carbonate or a mixture of both.

[0016] Optionally, in step S2, the organic solvent is one or more of dichloromethane, DMF, and chlorobenzene.

[0017] Thirdly, this application provides an application of a UV-resistant dye, employing the following technical solution: An application of a UV-resistant dye involves melting, granulating, and molding the UV-resistant dye with a plastic resin to obtain colored plastic products.

[0018] Specifically, the molding process includes blown film and cast film stretching, and the plastic resin includes polyethylene terephthalate, polyethylene, and polypropylene.

[0019] By adopting the above technical solution, this dye can be widely used in fields with strict requirements for lightfastness, such as high-performance engineering plastics, advanced automotive coatings, outdoor protective coatings, chemical fibers, and special printing inks.

[0020] In summary, this application includes at least one of the following beneficial technical effects: 1. Using 4,5-quinolinediamine and 4-amino-1,8-naphthalenedicarboxylic anhydride as the chromophore skeleton, a red chromophore parent with a quinoline-naphthalimide structure is constructed via a condensation reaction. Then, the active amino group in this parent molecule is combined with 4-chloro-3-amino(2, ... ' 5 ' -dimethyl-4 ' -Methoxybenzophenone UV absorbers undergo nucleophilic substitution reactions, permanently bonding the benzophenone UV absorber unit to the chromogenic matrix by forming stable CN covalent bonds, ultimately obtaining a composite dye with a single molecular structure. 2. This dye can be widely used in high-performance engineering plastics, advanced automotive coatings, outdoor protective coatings, chemical fibers, and special printing inks, as well as in fields with strict requirements for lightfastness. Attached Figure Description

[0021] Figure 1 This is the nuclear magnetic resonance spectrum of a UV-resistant dye in Example 1.

[0022] Figure 2 The thermogravimetric analysis diagram is shown for the UV-resistant dye prepared in Example 1.

[0023] Figure 3 The images show a sample of a UV-resistant dye from Example 1, and samples of red masterbatch and red PET film from Application Example 1.

[0024] Figure 4 The image shows a comparison of the fading of the red PET films in Application Example 1 and Comparative Example 1 after 500 hours of QUV accelerated aging test. Detailed Implementation

[0025] Example

[0026] This application discloses an ultraviolet-resistant dye.

[0027] Example 1

[0028] A UV-resistant dye is prepared by the following steps: S1. In a 5L three-necked flask equipped with a stirrer, condenser, and thermometer, add 175g of 4,5-quinolinediamine, 213g of 4-amino-1,8-naphthalenedicarboxylic anhydride, 50mL of glacial acetic acid, and 3L of DMF. Under nitrogen protection, heat the mixture to 100°C and stir at this temperature for 5 hours. After the reaction is complete, cool to 25°C at room temperature, pour the reaction solution into a large amount of ice water to precipitate the solid, filter, and wash the solid thoroughly with water and ethanol successively. Dry the solid product under vacuum at 80°C for 12 hours to obtain a dark red solid powder dye intermediate A.

[0029] S2. In a 5L round-bottom flask, add 100g of dye intermediate A and 94g of 4-chloro-3 ' 5 ' -dimethyl-4 ' A mixture of 41 g of methoxybenzophenone and 2 L of potassium carbonate and DMF was prepared. The mixture was stirred at 400 rpm for 7 hours at room temperature (25 °C). After the reaction was complete as monitored by TLC, the reaction solution was slowly poured into 8 L of ice water and stirred until the product was completely separated. The product was filtered, washed with water until neutral, and the crude product was recrystallized with a mixture of ethanol and N,N-dimethylformamide to obtain deep red crystals with a metallic luster. The product was then vacuum dried at 80 °C for 12 hours to obtain the final product, a UV-resistant dye.

[0030] The above preparation method involves the following reaction formula: , .

[0031] like Figure 1 As shown, this proves that the substance actually exists.

[0032] The yield of Example 1 was found to be 88%.

[0033] Example 2

[0034] The difference between Example 2 and Example 1 is that in step S1, the mass of 4,5-quinolinediamine is 168g, the mass of 4-amino-1,8-naphthalenedicarboxylic anhydride is 213g, the solvent is 3L of chlorobenzene, the reaction temperature is 110℃, and the reaction time is 4.5 hours. In step S2, 4-chloro-3 ' 5 ' -dimethyl-4 ' The mass of 1-methoxybenzophenone was 90.7 g, the catalyst was 41 g of cesium carbonate, and the reaction time was 6 hours.

[0035] Example 3

[0036] The difference between Example 3 and Example 1 is that in step S1, the mass of 4,5-quinolinediamine is 159g, the mass of 4-amino-1,8-naphthalenedicarboxylic anhydride is 213g, the solvent is 3L of dichloromethane, and the reaction is carried out at a reflux temperature of 40°C for 6 hours. In step S2, the solvent is 1.5 L of dichloromethane, and the reaction time is 8 hours.

[0037] Example 4

[0038] The difference between Example 4 and Example 1 is that in step S1, the reaction temperature is 80°C and the reaction time is 6 hours. In step S2, 4-chloro-3 ' 5 ' -dimethyl-4 ' The mass of 98g of methoxybenzophenone was used, the catalyst was a mixture of 20.5g potassium carbonate and 20.5g cesium carbonate, and the reaction time was 6.5 hours.

[0039] Example 5

[0040] The difference between Example 5 and Example 1 is that in step S1, the reaction temperature is 120°C and the reaction time is 4 hours.

[0041] Example 6

[0042] The difference between Example 6 and Example 1 is that in step S1, the mass of 4,5-quinolinediamine is 191g and the mass of 4-amino-1,8-naphthalenedicarboxylic anhydride is 213g. In step S2, the solvent is 150 mL of chlorobenzene, the reaction temperature is 40 °C, and the reaction time is 7 hours.

[0043] Example 7

[0044] The difference between Example 7 and Example 1 is that in step S2, 4-chloro-3 ' 5 ' -dimethyl-4 ' The mass of 1-methoxybenzophenone is 82.4 g.

[0045] Example 8

[0046] The difference between Example 8 and Example 1 is that the reaction time in step S2 is 10 hours.

[0047] The reaction conditions and the yield of dye intermediate A in step S1 of Examples 1-8 are shown in Table 1 below: Table 1

[0048] The reaction conditions for step S2 in Examples 1-8 are shown in Table 2 below: Table 2

[0049] The performance test results of the UV-resistant dyes obtained in Examples 1-8 are shown in Table 3 below: Table 3

[0050] Application examples

[0051] Application Example 1 0.05g of the UV-resistant dye prepared in Example 1 was mixed with 1000g of polyethylene terephthalate chips, and then melt-blended and granulated using a twin-screw extruder at 285°C to obtain a coloring masterbatch. The masterbatch was then formed into a film using a casting and stretching mechanism. Figure 3 and Figure 4 As shown, the film has a bright color and after 600 hours of QUV accelerated aging test (340nm, 0.68W / m², 60℃), the color difference ΔE < 1.8.

[0052] Application Example 2 0.05g of the UV-resistant dye prepared in Example 2 was mixed with 1000g of polyethylene chips, and then melt-blended and granulated using a twin-screw extruder at 285°C to obtain a coloring masterbatch. The masterbatch was then blow-molded into a film. This film exhibited good dispersibility in a flexible matrix, no migration, and excellent weather resistance. After 600 hours of QUV accelerated aging testing (340nm, 0.68W / m², 60°C), the color difference ΔE < 1.8.

[0053] Application Example 3 0.05g of the UV-resistant dye prepared in Example 3 was mixed with 1000g of polyethylene terephthalate chips, and then melt-blended and granulated using a twin-screw extruder at 285°C to obtain a coloring masterbatch. The masterbatch was then cast into a film using a casting and stretching mechanism. The film exhibited a bright color, and after 600 hours of QUV accelerated aging testing (340nm, 0.68W / m², 60°C), the color difference ΔE < 2.0.

[0054] Application Example 4 0.05g of the UV-resistant dye prepared in Example 4 was mixed with 1000g of polypropylene chips, and then melt-blended and granulated using a twin-screw extruder at 285°C to obtain a coloring masterbatch. The masterbatch was then injection molded into a sample. This sample exhibited strong coloring power and good heat and weather resistance among highly crystalline plastics. After 600 hours of QUV accelerated aging testing (340nm, 0.68W / m², 60°C), the color difference ΔE was <1.8.

[0055] Application Example 5 0.05g of the UV-resistant dye prepared in Example 5 was mixed with 1000g of polyethylene terephthalate chips, and then melt-blended and granulated using a twin-screw extruder at 285°C to obtain a coloring masterbatch. The masterbatch was then cast into a film using a casting and stretching mechanism. The film had a bright color, and after 600 hours of QUV accelerated aging testing (340nm, 0.68W / m², 60°C), the color difference ΔE < 1.8.

[0056] Application Example 6 0.05g of the UV-resistant dye prepared in Example 6 was mixed with 1000g of polyethylene terephthalate chips, and then melt-blended and granulated using a twin-screw extruder at 285°C to obtain a coloring masterbatch. The masterbatch was then cast into a film using a casting and stretching mechanism. The film had a bright color, and after 600 hours of QUV accelerated aging testing (340nm, 0.68W / m², 60°C), the color difference ΔE < 1.8.

[0057] Application Example 7 0.05g of the UV-resistant dye prepared in Example 7 was mixed with 1000g of polyethylene terephthalate chips, and then melt-blended and granulated using a twin-screw extruder at 285°C to obtain a coloring masterbatch. The masterbatch was then cast into a film using a casting and stretching mechanism. The film exhibited a bright color, and after 600 hours of QUV accelerated aging testing (340nm, 0.68W / m², 60°C), the color difference ΔE < 1.9.

[0058] Application Example 8 0.05g of the UV-resistant dye prepared in Example 8 was mixed with 1000g of polyethylene terephthalate chips, and then melt-blended and granulated using a twin-screw extruder at 285°C to obtain a coloring masterbatch. The masterbatch was then cast into a film using a casting and stretching mechanism. The film exhibited a bright color, and after 600 hours of QUV accelerated aging testing (340nm, 0.68W / m², 60°C), the color difference ΔE < 1.8.

[0059] The processing methods and performance of the final products obtained in Examples 1-8 (i.e., Application Examples 1-8) are shown in Table 4 below: Table 4

[0060] As can be seen from Examples 1-8 and Application Examples 1-8, and Tables 1-4, the UV-resistant dyes prepared in this application have excellent coloring properties and light stability. After being prepared into colored plastic products, they have good weather resistance, thus solving the problems of dye migration and compatibility.

[0061] Comparative Example

[0062] Comparative Example 1 100g of dye intermediate A obtained in step S1 of Example 1 was physically mixed with an equal mass of commercial UV absorber UV-12 and then added to PET resin.

[0063] Comparative Example 2 The difference between Comparative Example 2 and Comparative Example 1 is that the amount of UV absorber UV-12 added is twice the mass of dye intermediate A, i.e., 200g.

[0064] Comparative Example 3 PET is colored using only dye intermediate A, without adding any UV absorbers.

[0065] Performance testing and data comparison The samples from Comparative Examples 1-3 and Example 1 were fabricated into PET films and subjected to QUV accelerated aging tests (conditions: UVA-340 lamp, irradiance 0.68 W / m² @ 340nm, 60℃ illumination, 50℃ condensation cycle). Color changes (ΔE*) were periodically monitored. Migration resistance tests were also conducted, and the results are shown in Table 5 below.

[0066] Table 5

[0067] As can be seen from Examples 1 and Comparative Examples 1-3, and in conjunction with Table 5, the ΔE value of the dye in Example 1 is much lower than that of all the comparative examples, indicating that physical blending is prone to failure. In contrast, the UV-resistant dye prepared by chemical bonding exhibits photostability and weather resistance. The dye prepared in this application achieves efficient and stable UV protection through intramolecular energy transfer, surpassing traditional physical blending techniques in terms of lightfastness, long-term product appearance stability, and safety.

[0068] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A UV-resistant dye, characterized in that, It has the following structural formula: 。 2. The UV-resistant dye according to claim 1, characterized in that, It is prepared by the following reaction: ， 。 3. A method for preparing a UV-resistant dye according to any one of claims 1-2, characterized in that, Includes the following steps: S1. 4,5-Quinolinediamine, 4-amino-1,8-naphthalenedicarboxylic anhydride, glacial acetic acid and organic solvent are mixed, heated and stirred to react, filtered to obtain a solid, washed with water and ethanol, and dried to obtain dye intermediate A. S2. Dye intermediate A is reacted with 4-chloro-3 ' 5 ' -dimethyl-4 ' -Methoxybenzophenone, organic solvent, and catalyst were stirred and reacted at room temperature. After the reaction was completed, the reaction solution was poured into water for separation, filtered to obtain a solid, recrystallized, and dried to obtain the UV-resistant dye.

4. The method for preparing a UV-resistant dye according to claim 3, characterized in that: In step S1, the molar ratio of 4,5-quinolinediamine and 4-amino-1,8-naphthalenedicarboxylic anhydride is (1-1.2):

1.

5. The method for preparing a UV-resistant dye according to claim 3, characterized in that: In step S1, the heating temperature is 80-120℃ and the reaction time is 4-6 hours.

6. The method for preparing a UV-resistant dye according to claim 3, characterized in that: In step S1, the organic solvent is one or more of dichloromethane, DMF, and chlorobenzene.

7. The method for preparing a UV-resistant dye according to claim 3, characterized in that: In step S2, dye intermediate A and 4-chloro-3 ' 5 ' -dimethyl-4 ' The molar ratio of 1-methoxybenzophenone is 1:(1-1.2).

8. The method for preparing a UV-resistant dye according to claim 3, characterized in that: In step S2, the catalyst is potassium carbonate, cesium carbonate, or a mixture of both.

9. The method for preparing a UV-resistant dye according to claim 3, characterized in that: In step S2, the organic solvent is one or more of dichloromethane, DMF, and chlorobenzene.

10. The application of the UV-resistant dye according to any one of claims 1-2, characterized in that: Colored plastic products are obtained by melt mixing, granulation, and molding of the UV-resistant dye and plastic resin.

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