High-weather-resistance anthraquinone dye and preparation method thereof

Abstract

The invention relates to the technical field of dyes, and particularly discloses a high-weather-resistance anthraquinone dye and a preparation method thereof. The method comprises the following steps: by taking a structural formula I and an amine compound as reaction raw materials, reacting in a mixed solvent system of an organic solvent, a catalyst I and a surfactant, separating, filtering and washing to obtain the amino-anthraquinone dye, the preparation method comprises the following steps: dropwise adding an amino-anthraquinone dye into a polyurethane prepolymer, and preparing anthraquinone dye particles with bright colors through an interfacial polymerization method. The particle size of the anthraquinone dye particles can be controlled to be 300-450 nm, the anthraquinone dye particles are well dispersed in a plastic base material, and the color generation effect of the plastic base material is good. According to the anthraquinone dye particles, the double 85 anti-aging performance can be detected for more than 300 hours, and the QUV (Quality Ultraviolet) resistance can be detected for more than 200 hours.

Description

Technical Field

[0001] The present invention relates to the technical field of dyes, and more particularly to a highly weather-resistant anthraquinone dye and a preparation method thereof. Background Art

[0002] Anthraquinone dyes are based on the anthraquinone structure, primarily containing amino or hydroxyl groups. Currently available, the more stable anthraquinone dyes are 1,4-dihydroxyanthraquinone, 1-chloroanthraquinone, 1,8-dichloroanthraquinone, and 1,5-dichloroanthraquinone. Anthraquinone dyes offer vibrant colors, but they suffer from poor weather resistance. Hydroxyl groups and halogens can easily lead to oxidation and deterioration, resulting in rapid fading. Summary of the Invention

[0003] In order to solve the problem of poor weather resistance of traditional anthraquinone dyes, the present application provides a highly weather-resistant anthraquinone dye and a preparation method thereof.

[0004] In a first aspect, the present application provides a highly weather-resistant anthraquinone dye, which adopts the following technical solution: A method for preparing a highly weather-resistant anthraquinone dye comprises the following steps: S1 using a structural formula and an amine compound as a reaction raw material, the reaction in an organic solvent, a catalyst, a surfactant mixed solvent system, after separation, filtration, washing, to obtain an aminoanthraquinone dye; Among them, structural formula 1 is as follows: ; R1, R2, R3 and R4 are hydroxyl or chlorine; when one substituent appears in Structural Formula 1, the substituent is located at R2; when two substituents appear in Structural Formula 1, one substituent is located at R2 and the other substituent is located at R1, R3 or R4; The amine compound is selected from one or two of cyclohexylamine, p-acetamidoaniline, 2,6-di-sec-butylaniline, 2,6-dimethyl-4-ethylaniline, p-butylaniline, p-tert-amylaniline, 2,4,6-trimethylaniline, 2,4,6-ethylaniline, 2,4,6-tri-tert-butylaniline, 2,6-dibromo-p-methylaniline, 4-aminobiphenyl, 4'-amino-4-phenylbenzophenone, 2-ethyl-6-sec-butylaniline and 2-methyl-6-sec-butylaniline; S2. Aminoanthraquinone dyes are dissolved in an organic solvent, catalyst 2 and emulsifier are added to the organic solvent, and the solution is added dropwise to a polyurethane prepolymer. The temperature is raised to 70-90°C under an inert atmosphere, and the solution is stirred and dispersed at a speed of 400-2000 rpm. The solution is kept warm for 1-3 hours. During the reaction, an organic solvent is added to adjust the viscosity of the system. The reaction product is precipitated in water, dried, and washed to obtain a highly weather-resistant anthraquinone dye.

[0005] Furthermore, the reaction molar ratio of the structural formula 1 and the amine compound is 1:(1.1-3.2).

[0006] Furthermore, the reaction temperature of the structural formula 1 and the amine compound is 110-200°C.

[0007] Furthermore, the reaction temperature of the structural formula 1 and the amine compound is 125-180°C.

[0008] Furthermore, the surfactant used in the reaction between the compound of structural formula 1 and the amine compound is fatty alcohol polyoxyethylene ether, fatty amine polyoxyethylene ether, alkylphenol polyoxyethylene ether or polyethylene glycol.

[0009] Furthermore, the catalyst is boric acid or anhydrous sodium acetate.

[0010] Furthermore, the amine compound is cyclohexylamine.

[0011] Furthermore, the raw materials of the polyurethane prepolymer are polyethylene glycol and isophorone diisocyanate, and the molar ratio of polyethylene glycol, isophorone diisocyanate and aminoanthraquinone dye is 1:(1-1.2):(0.1-2).

[0012] Furthermore, the emulsifier is sodium dodecylbenzenesulfonate.

[0013] Furthermore, the weight of the emulsifier is 2.5-4.5% of the weight of the organic solvent.

[0014] Furthermore, the stirring and dispersing speed is 400 to 800 rpm.

[0015] Furthermore, the number average molecular weight of the polyethylene glycol used in the polyurethane prepolymer is 600-800.

[0016] Furthermore, the second catalyst is organotin.

[0017] Furthermore, the average particle size of the highly weather-resistant anthraquinone dye is in the range of 300 to 450 nm.

[0018] In a second aspect, the present application provides a highly weather-resistant anthraquinone dye, which adopts the following technical solution: A highly weather-resistant anthraquinone dye is prepared by the above-mentioned preparation method of the highly weather-resistant anthraquinone dye.

[0019] This application has at least the following advantages: First, the present application adopts an aqueous phase method to use traditional hydroxyanthraquinone or halogenated anthraquinone as raw materials, and the modifier contains a primary amine. The primary amine is condensed with the hydroxyl group or halogen to obtain an aminoanthraquinone dye; the chromophore of the aminoanthraquinone dye is fixed on the polyurethane main material, giving the dye particles the following properties: First, aminoanthraquinone dyes contain amino groups, which are prepolymerized with one of the isocyanate groups of a diisocyanate, and the other isocyanate group can react with polyethylene glycol, so that the chromophore of the aminoanthraquinone dye is fixed in the polyurethane material. The present application connects aromatic hydrocarbons or cycloalkanes to the amino groups. Aromatic hydrocarbons, cycloalkanes, and long-chain polyurethanes are bulky, and these substituents, through steric hindrance, make it difficult for nitrogen oxides and sulfur oxides in the atmosphere to act on the anthraquinone dye, thereby improving the weather resistance of the anthraquinone dye. Second, the present application utilizes interfacial polymerization to produce polyurethane / aminoanthraquinone dye particles with inherent color. The polyurethane / aminoanthraquinone dye particles have a small particle size and excellent color rendering effect. Compared with conventional polyurethane-coated anthraquinone dye microcapsule particles, the chromophores are embedded in the polyurethane chain segments, and the polyurethane has no color-blocking effect on the chromophores, resulting in a more vivid color and excellent color rendering effect. Furthermore, the polyurethane / aminoanthraquinone dye particles have higher transparency and clarity, which facilitates color matching of the dye particles. After color matching, the color is uniform and stable, and it is also convenient to adjust the ratio between the dye particles of different colors and adjust the color light. Third, the main material of the dye particles is polyurethane. Polyurethane has a certain degree of compatibility with materials such as polyamide (PA), polyethylene (PE), polyethylene terephthalate (PET), polystyrene (PS) and polyvinyl chloride (PVC). The dye particles can be directly added to the above main materials and then melt-extruded and drawn to form an optical film of the target color. It can also be used as a polymer dye and dyed using a solvent method. The dyeing methods are flexible and diverse. Fourth, the polyurethane of the dye particles is entangled with the base plastic. Compared with small molecule dyes, it has excellent anti-migration properties and can maintain the integrity and clarity of the pattern.

[0020] Secondly, the present application optimizes the structure of aminoanthraquinone dyes. Although these dyes contain rigid benzene rings, allowing the dye particles to serve as hard segments in polyurethane materials, their introduction has little effect on the phase separation of the hard and soft segments of the polyurethane. The side chain functional groups of aminoanthraquinone dyes affect the ease with which the isocyanate groups react with the amino groups of the aminoanthraquinone dyes, thus affecting the color depth of the dye particles.

[0021] Furthermore, in this application, the weight ratio between polyethylene glycol, diisocyanate and aminoanthraquinone dyes, emulsification speed, emulsifier type, emulsifier dosage and other related parameters are optimized. The particle size distribution range of the dye particles is narrow, and the average particle size is controlled at 300-450nm; the dye particles have excellent color rendering effect, and the color depth of the dye particles is uniform, which helps to improve the dyeing effect of the dye.

[0022] In summary, after being modified with polyurethane, aminoanthraquinone dyes can not only retain their original bright colors, but also maintain excellent weather resistance and achieve better color matching effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is the structural formula of the aminoanthraquinone dye of Example 1; Figure 2 is the structural formula of the aminoanthraquinone dye of Example 2; Figure 3 is the structural formula of the aminoanthraquinone dye of Example 3; Figure 4 is the structural formula of the aminoanthraquinone dye of Example 4. DETAILED DESCRIPTION

[0024] Unless otherwise specified, the raw materials used in the examples of this application are from the following sources: Organic tin: dibutyltin dilaurate, analytical grade.

[0025] Example 1

[0026] A highly weather-resistant anthraquinone dye is prepared according to the following steps: S1. 1,4-dihydroxyanthraquinone and p-acetamidoaniline were used as the reaction materials, n-butanol was used as the organic solvent, and N,N-dimethylformamide and polyethylene glycol 1000 were used as surfactants; n-Butanol, N,N-dimethylformamide, and polyethylene glycol 1000 are blended in a weight ratio of 24:6:1, and 1,4-dihydroxyanthraquinone, leuco form of 1,4-dihydroxyanthraquinone, boric acid, and para-acetamidoaniline are added in sequence under stirring, wherein the molar ratio of 1,4-dihydroxyanthraquinone, leuco form of 1,4-dihydroxyanthraquinone, boric acid, and para-acetamidoaniline is 1:0.248:1.36:2.72; after the addition, the temperature is raised to 105° C., kept for dehydration for 1 hour, then raised to 125° C., kept for 24 hours, and the midpoint is measured by chromatography. After the midpoint is reached, the temperature is lowered to 80° C., methanol is slowly added dropwise, kept for stirring for 1 hour, and then the temperature is lowered to 45° C., filtered, washed with methanol, then washed with hot water, and finally rinsed with cold water, and then dried in an 80° C. oven to obtain a bluish-green aminoanthraquinone dye; S2. Polyethylene glycol 800 was heated to 70°C and, under N2 protection, isophorone diisocyanate was added at a molar ratio of polyethylene glycol 800 to isophorone diisocyanate of 1:1. After mechanical stirring at 150 rpm for 30 min, dibutyltin dilaurate was added at a molar ratio of dibutyltin dilaurate to polyethylene glycol 800 of 0.001:1. The mixture was kept warm for 1.5 h to obtain a polyurethane prepolymer. Dissolve the aminoanthraquinone dye in tetrahydrofuran at a molar ratio of 0.1:1 to polyethylene glycol 800 and a volume ratio of 1:2.5 to tetrahydrofuran. Add sodium dodecylbenzenesulfonate at a weight of 2.5% of the weight of tetrahydrofuran. After dissolution, add the solution dropwise to the polyurethane prepolymer. Under nitrogen protection, heat to 70°C, stir and disperse at 400 rpm, and allow to react for 2 hours. During the reaction, add tetrahydrofuran to maintain the viscosity of the system. The reaction product is precipitated in distilled water, dried, placed in a tetrafluoroethylene mold, and thermoformed in a vacuum environment at 110° C. for 12 hours; finally, it is placed in a mixed solution of distilled water and ethanol with a mixing ratio of 1:1, washed and removed to obtain a highly weather-resistant anthraquinone dye.

[0027] Example 2

[0028] A highly weather-resistant anthraquinone dye is prepared according to the following steps: S1. 1,4-dihydroxyanthraquinone and 4-aminobiphenyl were used as the reaction materials, n-butanol was used as the organic solvent, and N-methylpyrrolidone and polyethylene glycol 600 were used as surfactants; n-Butanol, N-methylpyrrolidone, and polyethylene glycol 600 are blended in a weight ratio of 18:12:1, and 1,4-dihydroxyanthraquinone, leuco form of 1,4-dihydroxyanthraquinone, boric acid, and 4-aminobiphenyl are added sequentially under stirring, wherein the molar ratio of 1,4-dihydroxyanthraquinone, leuco form of 1,4-dihydroxyanthraquinone, boric acid, and para-acetamidoaniline is 1:0.248:1.55:2.83; after the addition, the temperature is raised to 110° C., kept at this temperature for dehydration for 1 hour, then raised to 150° C., kept at this temperature for 20 hours, and the midpoint is measured by chromatography. After the midpoint is reached, the temperature is lowered to 80° C., methanol is slowly added dropwise, kept at this temperature for stirring for 1 hour, and then the temperature is lowered to 50° C., filtered, washed with methanol, then washed with hot water, and finally rinsed with cold water, and then dried in an 80° C. oven to obtain a brilliant blue aminoanthraquinone dye; S2. Polyethylene glycol 800 was heated to 70°C and, under N2 protection, isophorone diisocyanate was added at a molar ratio of polyethylene glycol 800 to isophorone diisocyanate of 1:1. After mechanical stirring at 150 rpm for 30 min, dibutyltin dilaurate was added at a molar ratio of dibutyltin dilaurate to polyethylene glycol 800 of 0.001:1. The mixture was kept warm for 1.5 h to obtain a polyurethane prepolymer. Dissolve the aminoanthraquinone dye in tetrahydrofuran at a molar ratio of 0.1:1 to polyethylene glycol 800 and a volume ratio of 1:2.5 to tetrahydrofuran. Add sodium dodecylbenzenesulfonate at a weight of 2.5% of the weight of tetrahydrofuran. After dissolution, add the solution dropwise to the polyurethane prepolymer. Under nitrogen protection, heat to 70°C, stir and disperse at 400 rpm, and allow to react for 2 hours. During the reaction, add tetrahydrofuran to maintain the viscosity of the system. The reaction product is precipitated in distilled water, dried, placed in a tetrafluoroethylene mold, and thermoformed in a vacuum environment at 110° C. for 12 hours; finally, it is placed in a mixed solution of distilled water and ethanol with a mixing ratio of 1:1, washed and removed to obtain a highly weather-resistant anthraquinone dye.

[0029] Example 3

[0030] A highly weather-resistant anthraquinone dye is prepared according to the following steps: S1. 1,5-dichloroanthraquinone and cyclohexylamine were used as the reaction materials, n-butanol was used as the organic solvent, and N,N-dimethylformamide and polyethylene glycol 400 were used as surfactants; n-Butanol, N,N-dimethylformamide, and polyethylene glycol 400 are blended in a weight ratio of 10:20:1, and 1,5-dichloroanthraquinone, anhydrous sodium acetate, and cyclohexylamine are added sequentially under stirring, with a molar ratio of 1,5-dichloroanthraquinone, anhydrous sodium acetate, and cyclohexylamine being 1:3.02:2.10. After the addition, the temperature is raised to 155° C. and maintained for 15 hours. The midpoint is measured by chromatography. After the midpoint is reached, the temperature is lowered to 80° C., methanol is slowly added dropwise, and the mixture is maintained with stirring for 1 hour. The temperature is then lowered to 50° C., filtered, washed with methanol, then with hot water, and finally rinsed with cold water, and then dried in an 80° C. oven to obtain a bluish-red aminoanthraquinone dye. S2. Polyethylene glycol 800 was heated to 70°C and, under N2 protection, isophorone diisocyanate was added at a molar ratio of polyethylene glycol 800 to isophorone diisocyanate of 1:1. After mechanical stirring at 150 rpm for 30 min, dibutyltin dilaurate was added at a molar ratio of dibutyltin dilaurate to polyethylene glycol 800 of 0.001:1. The mixture was kept warm for 1.5 h to obtain a polyurethane prepolymer. Dissolve an aminoanthraquinone dye in tetrahydrofuran at a molar ratio of 0.1:1 to polyethylene glycol 800 and a volume ratio of 1:2.5 to tetrahydrofuran. Add sodium dodecylbenzenesulfonate at a weight of 2.5% of the weight of tetrahydrofuran. After complete dissolution, add dropwise to a polyurethane prepolymer. Under nitrogen protection, heat to 70°C, stir and disperse at 400 rpm, and maintain the temperature for 2 hours. During the reaction, add tetrahydrofuran to maintain the viscosity of the system. The reaction product is precipitated in distilled water, dried, placed in a tetrafluoroethylene mold, and thermoformed in a vacuum environment at 110° C. for 12 hours; finally, it is placed in a mixed solution of distilled water and ethanol with a mixing ratio of 1:1, washed and removed to obtain a highly weather-resistant anthraquinone dye.

[0031] Example 4

[0032] A highly weather-resistant anthraquinone dye is prepared according to the following steps: S1. 1-chloroanthraquinone and 4'-amino-4-phenylbenzophenone were used as the reaction materials, n-butanol was used as the organic solvent, and N,N-dimethylformamide and polyethylene glycol 200 were used as surfactants; n-Butanol, N,N-dimethylformamide, and polyethylene glycol 200 were blended in a weight ratio of 15:15:1, and 1-chloroanthraquinone, anhydrous sodium acetate, and 4'-amino-4-phenylbenzophenone (from Debye Technologies, Inc., No. DB-160972) were added sequentially under stirring, with a molar ratio of 1-chloroanthraquinone, anhydrous sodium acetate, and 4'-amino-4-phenylbenzophenone of 1:0.248:1.1. After the addition, the temperature was raised to 110° C., kept for dehydration for 1 hour, then raised to 200° C., kept for 8 hours, and the midpoint was measured by chromatography. After the midpoint was reached, the temperature was lowered to 80° C., methanol was slowly added dropwise, kept for stirring for 1 hour, and then lowered to 50° C., filtered, washed with methanol, then washed with hot water, and finally rinsed with cold water, and then dried in an 80° C. oven to obtain a bluish-red aminoanthraquinone dye. S2. Polyethylene glycol 800 was heated to 70°C and, under N2 protection, isophorone diisocyanate was added at a molar ratio of polyethylene glycol 800 to isophorone diisocyanate of 1:1. After mechanical stirring at 150 rpm for 30 min, dibutyltin dilaurate was added at a molar ratio of dibutyltin dilaurate to polyethylene glycol 800 of 0.001:1. The mixture was kept warm for 1.5 h to obtain a polyurethane prepolymer. Dissolve the aminoanthraquinone dye in tetrahydrofuran at a molar ratio of 0.1:1 to polyethylene glycol 800 and a volume ratio of 1:2.5 to tetrahydrofuran. Add sodium dodecylbenzenesulfonate at a weight of 2.5% of the weight of tetrahydrofuran. After dissolution, add the solution dropwise to the polyurethane prepolymer. Under nitrogen protection, heat to 70°C, stir and disperse at 400 rpm, and allow to react for 2 hours. During the reaction, add tetrahydrofuran to maintain the viscosity of the system. The reaction product is precipitated in distilled water, dried, placed in a tetrafluoroethylene mold, and thermoformed in a vacuum environment at 110° C. for 12 hours; finally, it is placed in a mixed solution of distilled water and ethanol with a mixing ratio of 1:1, washed and removed to obtain a highly weather-resistant anthraquinone dye.

[0033] Examples 5-8 A high weather resistant anthraquinone dye, based on example 3, the difference between example 3 and example 4 is the molar ratio of polyethylene glycol, isophorone diisocyanate and amino anthraquinone dye in step S2, and the number average molecular weight of polyethylene glycol is different, as follows: In example 5, the molar ratio of polyethylene glycol 800, isophorone diisocyanate and amino anthraquinone dye is 1:1.1:0.6; In example 6, the molar ratio of polyethylene glycol 800, isophorone diisocyanate and amino anthraquinone dye is 1:1.2:2; In example 7, equal molar amount of polyethylene glycol 600 is used instead of polyethylene glycol 800; In example 8, equal molar amount of polyethylene glycol 2000 is used instead of polyethylene glycol 800.

[0034] Examples 9-12 A high weather resistant anthraquinone dye, based on example 5, the difference between example 5 and example 9 is the amount and type of emulsifier in step S2, as follows: In example 9, the emulsifier is polyethylene glycol 200, and the weight of polyethylene glycol 200 is 2.5% of the weight of tetrahydrofuran; In example 10, the emulsifier is emulsifier OP-10 (from Macklin), and the weight of emulsifier OP-10 is 2.5% of the weight of tetrahydrofuran; In example 11, the emulsifier is sodium dodecyl benzene sulfonate, and the weight of sodium dodecyl benzene sulfonate is 3.0% of the weight of tetrahydrofuran; In example 12, the emulsifier is sodium dodecyl benzene sulfonate, and the weight of sodium dodecyl benzene sulfonate is 4.5% of the weight of tetrahydrofuran.

[0035] Examples 13-14 A high weather resistant anthraquinone dye, based on example 11, the difference between example 11 and example 13 is the stirring and dispersing speed in step S2, as follows: In example 13, the stirring and dispersing speed is 800 rpm; In example 14, the stirring and dispersing speed is 2000 rpm.

[0036] Examples 15-16 A high weather resistant anthraquinone dye, based on example 13, the difference between example 13 and example 15 is the reaction temperature and holding time after stirring and dispersing of amino anthraquinone dye in step S2, as follows: In example 15, the amino anthraquinone dye is added dropwise into the polyurethane prepolymer, under N2 protection, the temperature is raised to 80℃, and the stirring and dispersing speed is 800 rpm, the holding time is 3h, and tetrahydrofuran is added during the reaction to maintain the viscosity of the system; In Example 16, aminoanthraquinone dyes were added dropwise to the polyurethane prepolymer. Under N2 protection, the temperature was raised to 90°C, and the mixture was stirred and dispersed at 800 rpm. The mixture was kept warm for 1 hour. Tetrahydrofuran was added during the reaction to maintain the viscosity of the system.

[0037] Comparative Example 1 An anthraquinone dye is prepared according to the following steps: 1,4-Dihydroxyanthraquinone, polyethylene glycol 800, and isophorone diisocyanate were emulsified in deionized water at a molar ratio of 1:0.34:0.1. Sodium dodecylbenzenesulfonate was used as the emulsifier. The mixture was kept warm at 60°C for 1 hour. 1,4-Butanediol was added dropwise at a constant pressure with a molar ratio of 1,4-Butanediol to isophorone diisocyanate of 0.66:1. After the addition was completed, the mixture was kept warm for 3 hours. The prepared microsphere emulsion was filtered to remove unreacted dyes and impurities. The water was then removed by rotary evaporation. The microspheres were then washed with dichloromethane and centrifuged three times at 10,000 rpm for 5 minutes each time. The microspheres were finally freeze-dried at -50°C for 24 hours to obtain polyurethane-coated anthraquinone dyes.

[0038] Detection data Color vividness: 1.1 Test the K / S value of the aminoanthraquinone dye prepared in Example 1, and then test the K / S value of the high-weather-resistant anthraquinone dye prepared in Example 1. Color brightness = (K / S value of high-weather-resistant anthraquinone dye) / (K / S value of aminoanthraquinone dye)×100%; 1.2 Test the K / S value of the aminoanthraquinone dye prepared in Example 2, and then test the K / S value of the high-weather-resistant anthraquinone dye prepared in Example 2. Color vividness = (K / S value of high-weather-resistant anthraquinone dye) / (K / S value of aminoanthraquinone dye)×100%; 1.3 Test the K / S value of the aminoanthraquinone dye prepared in Example 3, and then test the K / S value of the high-weather-resistant anthraquinone dye prepared in Example 3. Color vividness = (K / S value of high-weather-resistant anthraquinone dye) / (K / S value of aminoanthraquinone dye)×100%; 1.4 Test the K / S value of the aminoanthraquinone dye prepared in Example 4, and then test the K / S value of the high weather-resistant anthraquinone dye prepared in Example 4. Color brightness = (high weather-resistant anthraquinone dye K / S value) / (aminoanthraquinone dye K / S value) × 100%.

[0039] 1.5 Test the K / S value of the 1,4-dihydroxyanthraquinone dye used in Comparative Example 1, and then test the K / S value of the high weather-resistant anthraquinone dye prepared in Comparative Example 1. Color brightness = (K / S value of high weather-resistant anthraquinone dye) / (K / S value of 1,4-dihydroxyanthraquinone dye) × 100%.

[0040] Table 1. Color vividness of Examples 1-4 and Comparative Example 1

[0041] Table 1 shows that while Examples 1-4 have different colors, their color vividness is similar. After polyurethane modification and self-polymerization, the color vividness is retained by 80-90%, resulting in vibrant colors. Comparative Example 1, which uses polyurethane as the shell material to encapsulate the 1,4-dihydroxyanthraquinone dye, exhibits a color vividness of only 8%, indicating that the microcapsule structure can lead to color shading issues. However, Examples 1-4 utilize a self-crosslinking method to directly embed the dye into the polyurethane segments, maintaining the vibrant color.

[0042] Particle size distribution The particle size distribution of Examples 1-16 and Comparative Example 1 was tested.

[0043] Weather resistance testing The fading time of Examples 1-16 and Comparative Example 1 was tested using double 85 testing and QUV resistance.

[0044] Table 2. Particle size distribution and weathering time of Examples 1-16 and Comparative Example 1

[0045] According to Table 2, although the aminoanthraquinone dyes of Examples 1-4 have different structures, their particle size distribution ranges are similar, indicating that the structure of the dye has little effect on the particle size. At the same time, there are differences in the weathering time of Examples 1-4, indicating that the dye structure has an impact on its weathering resistance. The addition of a rigid benzene ring helps to improve the weathering resistance of the dye.

[0046] Examples 5-8 modify the same aminoanthraquinone dye using different polyurethane prepolymers, with varying reaction ratios of the aminoanthraquinone dye to the polyurethane prepolymer. Increasing the proportion of the aminoanthraquinone dye helps reduce the particle size distribution of the highly weather-resistant anthraquinone dye, while increasing the proportion of the aminoanthraquinone dye has little effect on the dye's weather resistance. Increasing the number-average molecular weight of polyethylene glycol in the polyurethane prepolymer tends to widen the particle size distribution of the highly weather-resistant anthraquinone dye particles, but improves the dye's weather resistance. Therefore, optimizing the number-average molecular weight and proportion of polyethylene glycol in the polyurethane prepolymer optimizes both the dye's weather resistance and color rendering.

[0047] Examples 9-14 optimized the type and dosage of emulsifiers. The use of polyethylene glycol as an emulsifier significantly broadened the particle size distribution of highly weather-resistant anthraquinone dye particles. This may be due to the polyethylene glycol's participation in the reaction, which simultaneously improved both weather resistance and particle size distribution. Increasing the dispersion speed significantly reduced the particle size distribution of the dye particles within a certain limit, but when the dispersion speed reached a certain level, the particle size distribution of the dye particles actually increased.

[0048] Examples 15-16 changed the reaction temperature and reaction time of the polyurethane prepolymer and the aminoanthraquinone dye. The changes in the reaction temperature and reaction time had little effect on the particle size distribution range of the high-weather-resistant anthraquinone dye, but could significantly improve the weather resistance of the high-weather-resistant anthraquinone dye. The reason for this may be that the increase in the reaction temperature increased the reactivity of the high-weather-resistant anthraquinone dye, thereby increasing the grafting rate of the aminoanthraquinone dye, increasing the cross-linking density of the dye, and improving the weather resistance.

[0049] Comparative Example 1, in which 1,4-dihydroxyanthraquinone was coated with a polyurethane shell, exhibited a relatively large particle size range. Furthermore, data from the double 85 and QUV tests showed that the core-shell coating structure improved the weatherability of the dye. Examples 13-16 exhibited similar weatherability to Comparative Example 1, with the highly weatherable anthraquinone dyes of Examples 13-16 exhibiting superior weatherability.

[0050] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0051] Furthermore, the above-described embodiments merely represent several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent. It should be noted that a person of ordinary skill in the art can make a number of variations and improvements without departing from the concept of the present invention, and these variations and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be based on the appended claims.

Claims

1. A method for preparing a highly weather-resistant anthraquinone dye, characterized in that: The steps include: S1 using a structural formula and an amine compound as a reaction raw material, the reaction in an organic solvent, a catalyst, a surfactant mixed solvent system, after separation, filtration, washing, to obtain an aminoanthraquinone dye; Among them, structural formula 1 is as follows: ； R1, R2, R3 and R4 are hydroxyl or chlorine; when one substituent appears in Structural Formula 1, the substituent is located at R2; when two substituents appear in Structural Formula 1, one substituent is located at R2 and the other substituent is located at R1, R3 or R4; The amine compound is selected from one or two of cyclohexylamine, p-acetamidoaniline, 2,6-di-sec-butylaniline, 2,6-dimethyl-4-ethylaniline, p-butylaniline, p-tert-amylaniline, 2,4,6-trimethylaniline, 2,4,6-ethylaniline, 2,4,6-tri-tert-butylaniline, 2,6-dibromo-p-methylaniline, 4-aminobiphenyl, 4'-amino-4-phenylbenzophenone, 2-ethyl-6-sec-butylaniline and 2-methyl-6-sec-butylaniline; S2. Aminoanthraquinone dye is dissolved in an organic solvent, catalyst 2 and emulsifier are added to the organic solvent, and the solvent is added dropwise to a polyurethane prepolymer, wherein the raw materials of the polyurethane prepolymer are polyethylene glycol and isophorone diisocyanate, and the molar ratio of polyethylene glycol, isophorone diisocyanate and aminoanthraquinone dye is 1:(1-1.2):(0.1-2), and the number average molecular weight of polyethylene glycol used in the polyurethane prepolymer is 600-800. The temperature is raised to 70-90°C under an inert atmosphere, and the mixture is stirred and dispersed at a speed of 400-2000 rpm. The reaction is kept warm for 1-3 hours, and an organic solvent is added during the reaction to adjust the viscosity of the system. The reaction product is precipitated with water, dried, and washed to obtain a highly weather-resistant anthraquinone dye.

2. The method for preparing a highly weather-resistant anthraquinone dye according to claim 1, wherein: The reaction molar ratio of the structural formula 1 and the amine compound is 1:(1.1-3.2).

3. The method for preparing a highly weather-resistant anthraquinone dye according to claim 1, wherein: The reaction temperature of the structural formula 1 and the amine compound is 110-200°C.

4. The method for preparing a highly weather-resistant anthraquinone dye according to claim 1, wherein: The surfactant used in the reaction between the structural formula 1 and the amine compound is fatty alcohol polyoxyethylene ether, fatty amine polyoxyethylene ether, alkylphenol polyoxyethylene ether or polyethylene glycol.

5. The method for preparing a highly weather-resistant anthraquinone dye according to claim 1, wherein: The first catalyst is boric acid or anhydrous sodium acetate.

6. The method for preparing a highly weather-resistant anthraquinone dye according to claim 1, wherein: The amine compound is cyclohexylamine.

7. The method for preparing a highly weather-resistant anthraquinone dye according to claim 1, wherein: The weight of the emulsifier is 2.5-4.5% of the weight of the organic solvent.

8. The method for preparing a highly weather-resistant anthraquinone dye according to claim 1, wherein: The stirring and dispersing speed is 400-800 rpm.

9. A highly weather-resistant anthraquinone dye, characterized in that: The dye is prepared by the preparation method of a highly weather-resistant anthraquinone dye according to any one of claims 1 to 8.

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