Monomer for blue polyester fiber and preparation method thereof

Abstract

The invention relates to the technical field of polymer dye synthesis, and discloses a monomer for a blue polyester fiber and a preparation method thereof.According to the monomer for the blue polyester fiber, 1, 4-arylamino substituted anthraquinone serves as a color development mother nucleus, a benzoate group is introduced to aryl of the 1, 4-arylamino substituted anthraquinone mother nucleus, and the monomer for the blue polyester fiber is obtained; the benzoate group is connected with the chromophoric parent nucleus through a carbon-carbon bond; the molecular terminal of the monomer for the blue polyester fiber is connected with an exposed ester group through an aryl group, and the exposed ester group is used for transesterification with dihydric alcohol under the melt polycondensation condition of polyester. The novel monomer for the blue polyester fiber, provided by the invention, has excellent color development performance and thermal stability, can be directly used for in-situ synthesis of blue polyester and can be directly used for melt spinning, and the color fastness and coloring uniformity of a product are improved; meanwhile, the monomer for the blue polyester fiber, provided by the invention, is simple in preparation method, low in cost and easy for large-scale production.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high molecular dye synthesis, in particular to a blue polyester fiber monomer and a preparation method thereof. BACKGROUND

[0002] High molecular dye is a kind of functional polymer material in which chromophore is connected to the main chain or side chain of polymer by covalent bond. Compared with traditional coloring technology, high molecular dye has revolutionary advantages in essence. Traditional coloring method mainly relies on physical blending, which can be divided into two categories: small molecule dye and pigment. Although small molecule dye can achieve molecular dispersion and bright color, its binding force with the matrix is weak, and there are serious migration, extraction and volatilization problems, which lead to discoloration, staining of the product, and significant plasticization and degradation of the crystallinity and mechanical properties of the polymer. Compared with small molecule dye, organic or inorganic pigment is dispersed in the matrix by physical particles, and the migration is improved, but the dispersion is uneven, which may cause aggregation, affect the uniformity of color, and damage the mechanical properties and transparency of the material.

[0003] High molecular dye firmly anchors chromophore to the polymer skeleton by covalent bond, realizing coloring at molecular level. This structure brings multiple fundamental advantages: first, it completely solves the migration and extraction problems of small molecule dye, and gives the product excellent color fastness; second, it avoids the damage of external small molecules or aggregated particles to the intrinsic structure of the polymer, and can maximize the excellent mechanical properties and thermal stability of the matrix; third, its homogeneous molecular dispersion state ensures the high uniformity and transparency of color; in addition, this structure gives the material excellent heat and solvent resistance, and can withstand the high temperature and harsh processing environment of polyester polycondensation without decomposition or discoloration; finally, this design concept improves the coloring from the post-process to the molecular construction level, providing unprecedented freedom for the integration of color and other functions, and laying a foundation for the development of a new generation of high-performance, multifunctional colored fibers.

[0004] However, the performance of high molecular dye is highly dependent on the properties of its key structural unit, chromophoric monomer. In addition to bright color, an ideal blue high molecular dye monomer must meet the following requirements: excellent polymerization reactivity, good compatibility with polyester matrix, and thermal stability and chromophore stability that can withstand the high temperature and harsh environment of polyester melt polycondensation process. Currently, blue anthraquinone monomers face challenges such as insufficient reactivity and poor thermal stability, which makes it difficult to meet the process requirements in the preparation of polyester fibers, restricting the development of high-performance blue polyester fibers; therefore, it is urgent to develop a new type of blue polyester fiber monomer to prepare blue polyester fibers with high color fastness, excellent thermal stability and outstanding comprehensive performance.

[0005] The prior art has not yet proposed an effective solution to the problems in the related art. SUMMARY

[0006] In view of the problems in the related art, the present application provides a monomer for blue polyester fiber and a preparation method thereof to overcome the above technical problems existing in the prior art.

[0007] To this end, the present application adopts the following specific technical solutions: According to one aspect of the present application, a monomer for blue polyester fiber is provided, which has 1,4-arylamino-substituted anthraquinone as a chromophore mother nucleus, and a benzoate group is introduced on the aryl group of the 1,4-arylamino-substituted anthraquinone mother nucleus, the benzoate group being connected to the chromophore mother nucleus through a carbon-carbon bond; the molecular terminal of the monomer for blue polyester fiber is connected to expose an ester group through an aryl group, and the exposed ester group is used for ester exchange reaction with dihydric alcohol under polyester melt polycondensation conditions; The chemical structural formula of the monomer for blue polyester fiber is: ; In the formula, R 1 represents an aryl ring substituent selected from methyl, ethyl, or isopropyl; R 2 represents a hydrogen atom or an alkyl group selected from methyl, ethyl, isopropyl, or tert-butyl.

[0008] Further, the molecular structure of the monomer contains an anthraquinone mother nucleus, two arylamine substituents, and two terminal ester groups, the terminal ester groups being methoxycarbonyl, ethoxycarbonyl, or isopropoxycarbonyl.

[0009] According to another aspect of the present application, a preparation method of a monomer for blue polyester fiber is also provided, which includes: a halogenation reaction, specifically including: adding a solvent blue dye A and a halogenated solvent into a reaction kettle, stirring and dissolving, then adding halogenated reagents in batches to perform halogenation reaction, to obtain a dihalogenated intermediate B; a coupling reaction, specifically including: adding the dihalogenated intermediate B, a coupling solvent, an aryl boronic acid, a base, and a palladium catalyst into a reaction kettle, and heating to make the dihalogenated intermediate B and the aryl boronic acid containing an ester group perform coupling reaction under the action of the palladium catalyst and the base, and after the reaction is completed, recrystallization is performed to obtain the target monomer C; The synthesis expression of the halogenation reaction and the coupling reaction is: ; In the formula, R 1 represents an aryl ring substituent selected from methyl, ethyl, or isopropyl; R 2 represents a hydrogen atom or an alkyl group selected from methyl, ethyl, isopropyl, or tert-butyl; and X represents halogen selected from bromine or iodine.

[0010] Furthermore, the halogenation reaction includes at least one of the following characteristics: the halogenation reaction temperature is 0℃~25℃; the halogenation reaction pressure is atmospheric pressure; the halogenation reaction time is 10h~20h; the halogenation reagent is added in batches in small amounts multiple times; the halogenation solvent is selected from at least one of dichloromethane, dichloroethane, chloroform, and carbon tetrachloride; the weight of the halogenation solvent is 4 to 5 times that of solvent blue dye A; the amount of halogenation solvent added is 50%~60% of the reaction vessel volume; the halogenation reagent is selected from at least one of dibromohydantoin, N-bromosuccinimide, bromine, dibromoisocyanuric acid, tribromoisocyanuric acid, tetrabutylammonium tribromide, N-iodosuccinimide, and elemental iodine; the molar amount of the halogenation reagent is 2 to 2.5 times that of solvent blue dye A.

[0011] Furthermore, the post-treatment methods after the halogenation reaction include: adding a reducing agent to the reaction solution after the halogenation reaction to quench the reaction; distilling and concentrating the reaction solution to precipitate the product; filtering and washing successively with a saturated reducing agent solution and water; and recrystallizing the product with an organic solvent to obtain the dihalogenated intermediate B.

[0012] Further, the coupling reaction includes at least one of the following characteristics: the coupling reaction temperature is 60℃~130℃; the coupling reaction time is 15h~24h; the arylboronic acid is selected from at least one of m-alkoxycarbonylphenylboronic acid and p-alkoxycarbonylphenylboronic acid; the molar amount of arylboronic acid is 2 to 2.4 times that of the dihalogenated intermediate B; the palladium catalyst is selected from at least one of palladium chloride, palladium acetate, tetrakis(triphenylphosphine)palladium, and dibenzylpyridinium acetone; the amount of palladium catalyst added is 0% of the amount of dihalogenated intermediate B. 0.1 mol%~3 mol%; the base is selected from at least one of potassium carbonate, potassium hydroxide, potassium fluoride and potassium phosphate; the molar amount of the base is 3 to 4 times that of the dihalogenated intermediate B; the coupling solvent is selected from at least one of N-methylpyrrolidone, 1,4-dioxane, hexamethylphosphoramide, diethylene glycol dimethyl ether, diethylene glycol diethyl ether and dimethyl sulfoxide; the weight of the coupling solvent is 5 to 6 times that of the dihalogenated intermediate B; the amount of coupling solvent added is 40% to 50% of the reactor volume.

[0013] Furthermore, in the halogenation reaction, the molar ratio of the added solvent blue dye A to the halogenation reagent is 1:2 to 1:2.5, and the weight ratio of the added solvent blue dye A to the halogenation solvent is 1:4 to 1:10.

[0014] Furthermore, in the coupling reaction, the molar ratio of the added dihalogenated intermediate B to arylboronic acid is 1:2 to 1:4, and the molar ratio of the added dihalogenated intermediate B to the base is 1:2 to 1:6.

[0015] The beneficial effects of this invention are as follows: (1) The blue polyester fiber monomer provided by the present invention uses 1,4-arylamino group to replace anthraquinone as the color-developing core, which can bring a bright blue color to the polyester fiber. The color-developing core has a stable structure, which not only gives the fiber excellent light fastness, but also can withstand the high temperature processing environment of polyester melt polycondensation, and the color is long-lasting and stable.

[0016] (2) The present invention effectively regulates the polarity of the monomer by introducing benzoic acid ester groups on the aryl group, so as to achieve good polarity matching with the polyester raw material; this prevents phase separation in the polymerization process from the root, and ultimately achieves uniform molecular-level dispersion of chromophores in the polymer matrix, ensuring uniform color.

[0017] (3) The monomers for blue polyester fibers provided by the present invention have exposed ester groups at the molecular ends by aryl linkages. These exposed ester groups have low steric hindrance characteristics, which makes them exhibit high reactivity in the transesterification reaction under polyester melt polycondensation conditions. This not only ensures that the anthraquinone chromophores are efficiently and stably integrated into the polyester molecular chain, but also significantly reduces the residue of unreacted monomers, maximizing the macromolecularization of the monomers and thus ensuring fiber strength.

[0018] (4) Based on the principle of copolymer coloring, the blue polyester fiber obtained by this invention has excellent migration resistance and color fastness. At the same time, since the chromophore is anchored on the polymer skeleton through covalent bonds, the damage of small molecule dyes to the intrinsic structure of the polymer is avoided. The mechanical properties and thermal stability of the fiber are well maintained, and the overall quality reaches the high-end application standard. It is especially suitable for fields with demanding performance requirements such as automotive interiors and outdoor clothing. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic flowchart of a method for preparing monomers for blue polyester fibers according to an embodiment of the present invention; Figure 2 This is a detailed embodiment of Example 1 of a method for preparing monomers for blue polyester fibers according to an embodiment of the present invention; Figure 3 This is a detailed embodiment of Example 2 of a method for preparing monomers for blue polyester fibers according to an embodiment of the present invention; Figure 4 This is a detailed embodiment of Example 3 of a method for preparing monomers for blue polyester fibers according to an embodiment of the present invention. Detailed Implementation

[0021] To further illustrate the various embodiments, the present invention provides accompanying drawings, which are part of the disclosure of the present invention. These drawings are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these drawings, those skilled in the art should be able to understand other possible implementation methods and the advantages of the present invention. The components in the drawings are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0022] According to an embodiment of the present invention, a monomer for blue polyester fiber and a method for preparing the same are provided.

[0023] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments. According to one embodiment of the present invention, a monomer for blue polyester fiber is provided, wherein the monomer for blue polyester fiber uses 1,4-arylamine-substituted anthraquinone as the color-developing core and introduces benzoic acid ester groups on the aryl group of the 1,4-arylamine-substituted anthraquinone core, and the benzoic acid ester groups are connected to the color-developing core through carbon-carbon bonds. Blue polyester fibers use monomers with exposed ester groups at the molecular ends via aryl linkages. These exposed ester groups have low steric hindrance and are used for transesterification reactions with diols under polyester melt polycondensation conditions. The chemical structural formula of the monomer used in blue polyester fiber is: ; In the formula, R 1 Indicates an aromatic ring substituent, selected from methyl, ethyl, or isopropyl; R 2 It represents a hydrogen atom or an alkyl group, wherein the alkyl group is selected from methyl, ethyl, isopropyl or tert-butyl.

[0024] In one embodiment, the monomer has an anthraquinone core, two aromatic amino substituents, and two terminal ester groups, wherein the terminal ester groups are methoxycarbonyl, ethoxycarbonyl, or isopropoxycarbonyl.

[0025] It should be noted that this invention provides a blue anthraquinone monomer for use in high-molecular-weight polyester fibers. This monomer uses a 1,4-arylamino group replacing anthraquinone as the core color-developing nucleus, and incorporates two key structural improvements: First, a benzoate group was introduced onto the aryl group of the 1,4-arylamine-substituted anthraquinone core. This group is connected to the chromophore via a stable carbon-carbon bond, which not only ensures the stability of the overall structure at high temperatures but also significantly improves the solubility of the monomer in glycols (such as ethylene glycol), thereby ensuring its uniform dispersion during polymerization and smooth participation in subsequent reactions.

[0026] Secondly, a low-steric-hindrance exposed ester group (-COOR2) is attached to the molecule's end via an aryl group. This ester group serves as an active reactive site, capable of undergoing efficient transesterification with the diol under polyester melt polycondensation conditions, thereby directly integrating the anthraquinone chromophore into the polyester molecular backbone via covalent bonds. This "terminal exposed ester group" molecular design effectively avoids the steric hindrance shielding of the ester group by the large chromophore, significantly improving the polymerization reactivity of the monomer and enabling it to be smoothly and efficiently embedded into the polyester chain, achieving a stable combination of color and material properties.

[0027] like Figure 1 As shown, according to another embodiment of the present invention, a method for preparing a monomer for blue polyester fiber is also provided, the method comprising: Step 1, halogenation reaction, specifically includes: Solvent blue dye A and halogenated solvent were added to a reaction vessel and stirred to dissolve. After stirring, halogenated reagent was added in batches to carry out halogenation reaction to obtain dihalogenated intermediate B. Step 2, coupling reaction, specifically includes: Dihalogenated intermediate B, coupling solvent, arylboronic acid, base and palladium catalyst were added to the reaction vessel. The dihalogenated intermediate B and ester-containing arylboronic acid were coupled under the action of palladium catalyst and base by heating. After the reaction was completed, the target monomer C was obtained by recrystallization. The synthetic expression for the halogenation reaction and coupling reaction is as follows: ; In the formula, R 1 Indicates an aromatic ring substituent, selected from methyl, ethyl, or isopropyl; R 2 X represents a hydrogen atom or an alkyl group, wherein the alkyl group is selected from methyl, ethyl, isopropyl or tert-butyl; X represents a halogen, selected from bromine or iodine.

[0028] In one embodiment, the halogenation reaction includes at least one of the following characteristics: Feature 1: The halogenation reaction temperature is 0℃~25℃; Feature 2: The halogenation reaction is carried out at atmospheric pressure; Feature 3: The reaction time for halogenation is 10-20 hours; Feature 4: The halogenated reagent is added in batches, in small amounts, and multiple times; Feature 5: The halogenated solvent is selected from at least one of dichloromethane, dichloroethane, chloroform, and carbon tetrachloride; Feature 6: The weight of the halogenated solvent is 4 to 5 times that of solvent blue dye A; the amount of halogenated solvent added is 50% to 60% of the reactor volume; Feature 7: The halogenated reagent is selected from at least one of dibromohydantoin, N-bromosuccinimide, bromine, dibromoisocyanuric acid, tribromoisocyanuric acid, tetrabutylammonium tribromide, N-iodosuccinimide and elemental iodine; Feature 8: The molar amount of the halogenated reagent is 2 to 2.5 times that of the solvent blue dye A.

[0029] In one embodiment, the post-treatment after the halogenation reaction includes: adding a reducing agent to the reaction solution after the halogenation reaction to quench the reaction; distilling and concentrating the reaction solution to precipitate the product; filtering and washing with a saturated reducing agent solution and water in sequence; and recrystallizing the product with an organic solvent to obtain the dihalogenated intermediate B.

[0030] In one embodiment, the coupling reaction includes at least one of the following features: Feature 9: The coupling reaction temperature is 60℃~130℃; Feature 10: The reaction time of the coupling reaction is 15h~24h; Feature 11: The arylboronic acid is selected from at least one of m-alkoxycarbonylphenylboronic acid and p-alkoxycarbonylphenylboronic acid; Feature 12: The molar amount of arylboronic acid is 2 to 2.4 times that of dihalogenated intermediate B; Feature 13: The palladium catalyst is selected from at least one of palladium chloride, palladium acetate, tetraphenylphosphine palladium, and dibenzylpyridinium acetone; Feature 14: The amount of palladium catalyst added is 0.1 mol% to 3 mol% of the dihalogenated intermediate B. Feature 15: The base is selected from at least one of potassium carbonate, potassium hydroxide, potassium fluoride and potassium phosphate; Feature 16: The molar amount of alkali added is 3 to 4 times that of dihalogenated intermediate B; Feature 17: The coupling solvent is selected from at least one of N-methylpyrrolidone, 1,4-dioxane, hexamethylphosphoramide, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and dimethyl sulfoxide; Feature 18: The weight of the coupling solvent is 5 to 6 times that of the dihalogenated intermediate B; the amount of coupling solvent added is 40% to 50% of the reactor volume.

[0031] In one embodiment, in the halogenation reaction, the molar ratio of the added solvent blue dye A to the halogenation reagent is 1:2 to 1:2.5, and the weight ratio of the added solvent blue dye A to the halogenation solvent is 1:4 to 1:10.

[0032] In one embodiment, in the coupling reaction, the molar ratio of the added dihalogenated intermediate B to arylboronic acid is 1:2 to 1:4, and the molar ratio of the added dihalogenated intermediate B to the base is 1:2 to 1:6.

[0033] It should also be noted that this invention proposes a novel monomer for blue polyester fibers and its preparation method. The chemical structural formula of the monomer for blue polyester fibers is as follows: ; In the formula, R 1 Indicates an aromatic ring substituent, which can be methyl, ethyl, or isopropyl; R 2 It represents a hydrogen atom or an alkyl group, wherein the alkyl group can be methyl, ethyl, or isopropyl tert-butyl.

[0034] Specifically, the method for preparing the blue polyester fiber using monomers includes the following steps: (1) Halogenation: Add solvent blue dye A and solvent to the reaction vessel, stir to dissolve, and then add halogenation reagent in batches to react and generate B; (2) Coupling: The dihalogenated intermediate B is coupled with arylboronic acid containing ester group under palladium catalyst and base action. After the reaction is completed, the target monomer C is obtained by recrystallization.

[0035] Specifically, the expression for the above synthesis route is: ; In the formula, R 1 Indicates an aromatic ring substituent, which can be methyl, ethyl, or isopropyl; R 2 X represents a hydrogen atom or an alkyl group, where the alkyl group can be methyl, ethyl, or isopropyl tert-butyl; X represents a halogen, which can be bromine or iodine. Specifically, in step (1), the molar ratio of anthraquinone raw material A to halogenated reagent is 1:2 to 1:2.5, more preferably 1:2 to 1:2.2.

[0036] Specifically, in step (1), the weight ratio of anthraquinone raw material A to solvent is 1:4 to 1:10, more preferably 1:4 to 1:5.

[0037] Specifically, in step (1), the reaction temperature is 0-25℃, more preferably 0-10℃.

[0038] Specifically, in step (1), the post-processing method is quenching with a reducing agent, concentration, crystallization, etc., and more preferably quenching with sodium sulfite, concentration, and crystallization.

[0039] Specifically, in step (2), the molar ratio of the halogenated intermediate to the alkoxycarbonyl-substituted arylboronic acid is 1:2 to 1:4, more preferably 1:2 to 1:3.

[0040] Specifically, in step (2), the molar ratio of the halogenated intermediate C to the alkali is 1:2 to 1:6, more preferably 1:2 to 1:4.

[0041] Specifically, in step (2), the solvent includes any one or more of N-methylpyrrolidone, 1,4-dioxane, hexamethylphosphoramide, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and xylene, more preferably 1,4-dioxane and xylene.

[0042] To better understand the above-mentioned technical solutions of the present invention, the following three specific embodiments are provided in detail: Example 1 A method for preparing a monomer (monomer 1) for blue polyester fibers, such as... Figure 2 As shown, the steps are as follows: (1) Under an ice-water bath, dichloromethane (halogenated solvent) was added to the reaction vessel, with a volume of 50% of the total volume of the vessel; then Blue 1 (solvent blue dye A) was dissolved in it (the weight of dichloromethane was 4 times that of Blue 1), and N-bromosuccinimide (halogenated reagent) (twice the molar amount of Blue 1) was added in small batches. The reaction was stirred at this temperature (20℃) for 18 h. After the reaction was completed, the product was concentrated by distillation, filtered, and washed successively with saturated sodium sulfite solution (reducing agent solution) and water. The corresponding dihalogenated intermediate (denoted as intermediate 1, i.e., dihalogenated intermediate B) could be obtained by recrystallization with dimethylformamide (organic solvent).

[0043] (2) Intermediate 1, 4-ethoxycarbonylphenylboronic acid (arylboronic acid), potassium carbonate (base), and tetrakis(triphenylphosphine) palladium (palladium catalyst) were added to a reaction vessel in a molar ratio of 1:2.4:3.0:0.005. Subsequently, 1,4-dioxane (coupling solvent) was added, with a weight of 5 times that of intermediate 1. Under nitrogen protection, the reaction was carried out at 110°C for 18 h. The insoluble matter was removed by filtration, water was added to precipitate the product, and crystallization with dimethylformamide yielded a blue monomer (denoted as monomer 1, i.e., target monomer C).

[0044] Example 2 A method for preparing a monomer (monomer 2) for blue polyester fibers, such as... Figure 3 As shown, the steps are as follows: (1) Under an ice-water bath, dichloroethane (halogenated solvent) was added to the reaction vessel, with a volume of 50% of the total volume of the vessel; then Blue 2 (solvent blue dye A) was dissolved in it (the weight of dichloroethane was 4 times that of Blue 2), and N-iodosuccinimide (halogenated reagent) (1.1 molar amounts of Blue 2) was added in small batches. The reaction was stirred at this temperature (20℃) for 18 hours. After the reaction was completed, the product was concentrated by distillation, filtered, and washed successively with saturated sodium bisulfite solution (reducing agent solution) and water. Recrystallization with acetone (organic solvent) yielded the corresponding dihalogenated intermediate (denoted as intermediate 2, i.e., dihalogenated intermediate B).

[0045] (2) Intermediate 2, 4-ethoxycarbonylphenylboronic acid (arylboronic acid), potassium phosphate (base), and tetrakis(triphenylphosphine) palladium (palladium catalyst) were added to a reaction vessel in a molar ratio of 1:2.2:3.0:0.01. Then, diethylene glycol dimethyl ether (coupling solvent) was added, with a weight of 6 times that of intermediate 2. Under nitrogen protection, the reaction was carried out at 80°C for 15 h. The insoluble matter was removed by filtration, water was added to precipitate the product, and crystallization with ethanol was used to obtain a blue monomer (denoted as monomer 2, i.e., target monomer C).

[0046] Example 3 A method for preparing a monomer (monomer 3) for blue polyester fiber, such as Figure 4 As shown, the steps are as follows: (1) Under an ice-water bath, dichloromethane (halogenated solvent) was added to the reaction vessel, with a volume of 50% of the total volume of the vessel; then Blue 1 (solvent blue dye A) was dissolved in it (the weight of dichloromethane was 4 times that of Blue 1), and dibromohydantoin (halogenated reagent) (1.2 times the molar amount of Blue 1) was added in small batches. The reaction was stirred at this temperature (20℃) for 18 hours. After the reaction was completed, the product was concentrated by distillation, filtered, and washed successively with saturated sodium sulfite solution (reducing agent solution) and water. The corresponding dihalogenated intermediate (denoted as intermediate 3, i.e., dihalogenated intermediate B) could be obtained by recrystallization with dimethylacetamide (organic solvent).

[0047] (2) Intermediate 3, 3-ethoxycarbonylphenylboronic acid (arylboronic acid), potassium carbonate (base), and palladium dibenzyl acetone (palladium catalyst) were added to a reaction vessel in a molar ratio of 1:2.4:4.0:0.02. Then, N-methylpyrrolidone (coupling solvent) was added, with a weight of 5 times that of intermediate 3. The reaction was carried out at 110°C for 18 hours under nitrogen protection. The insoluble matter was removed by filtration, and water was added to precipitate the product. The product was then crystallized with dimethylformamide to obtain a blue monomer (denoted as monomer 3, i.e., target monomer C).

[0048] To verify the performance and application effect of the monomer for blue polyester fiber prepared by this invention, the following three effect experiments are used to comprehensively evaluate the performance of the monomer prepared in the above embodiments: I. Determination of the UV-Vis absorption spectrum of a blue anthraquinone monomer molecule for use in high molecular weight polyester fibers The anthraquinone dyes prepared in Examples 1-3 and the comparative examples were formulated into 50 μmol / L solutions using dichloromethane as the solvent, and their absorption spectra were measured using a UV-Vis spectrophotometer. The molar extinction coefficient of the dyes was calculated using the following formula: A = εcl; In the formula, A is the absorption intensity; ε is the molar extinction coefficient, L / (mol·cm); c is the concentration, mol / L; and l is the thickness of the absorption layer, cm.

[0049] The UV-Vis absorption spectra of the anthraquinone dye molecules prepared in Examples 1-3 and Comparative Example 1 are shown in Table 1.

[0050] Table 1. Results of UV-Vis absorption spectroscopy measurements of anthraquinone dye molecules prepared in Examples 1-3 and Comparative Example 1. As shown in Table 1, the anthraquinone dye molecules prepared in Examples 1, 2 and 3 show little change compared to Comparative Example 1, and the anthraquinone dye molecules prepared in Example 1 have the highest molar absorptivity.

[0051] II. Thermal stability test of anthraquinone dye molecules The processing temperature of polyester fibers exceeds 280℃, therefore, the dye monomer molecules must exhibit good thermal stability at this temperature. Thermogravimetric analysis (TGA) was used to evaluate the thermal stability of the synthesized monomers. Under nitrogen protection, the monomers were heated from room temperature to 400℃ at a rate of 10℃ / min to determine their thermal decomposition temperature (Td).

[0052] The thermal stability test results of the anthraquinone dye molecules prepared in Examples 1-3 and Comparative Example 1 are shown in Table 2.

[0053] Table 2. Thermal stability test results of anthraquinone dye molecules prepared in Examples 1-3 and Comparative Example 1. As shown in Table 2, the Td values ​​of the anthraquinone dye molecules prepared in Examples 1-3 are all greater than 300℃, indicating that the above dye molecules have good thermal stability and can withstand the processing temperature of polyester fibers.

[0054] III. Melt Polycondensation of Blue Polyester and its Fiber Preparation 1. Polymerization formulation To verify the practical application performance of the blue monomer of this invention, the following formulation was used to synthesize the copolymer-modified polyester: Terephthalic acid (PTA): 100 parts by weight Ethylene glycol (EG): 45 parts by weight The blue anthraquinone monomer of this invention (prepared in Example 1): 0.005 parts by weight Catalyst (antimony glycol): 250 ppm (based on elemental antimony) 2. Polymerization process The above materials were sequentially added to a polymerization reactor equipped with a fractionating column. Esterification and polycondensation reactions were carried out under nitrogen protection. Esterification stage: Slowly raise the temperature to 240-260℃ and carry out the esterification reaction under normal pressure until the amount of distilled water reaches more than 95% of the theoretical value, marking the completion of esterification.

[0055] Polycondensation stage: After esterification, the catalyst is added to the system. The system temperature is then raised to 275-285°C, and the pressure is gradually reduced to less than 100 Pa. Melt polycondensation is carried out under these high-temperature, high-vacuum conditions, with continuous stirring for approximately 2 hours, until the reaction torque reaches a predetermined value, indicating that the intrinsic viscosity of the polymer has reached approximately 0.65 dL / g.

[0056] 3. Performance observation and sampling Throughout the polymerization process, the melt was uniformly colored and transparent, with no colored substances precipitated or charring observed, indicating that the monomer of this invention possesses excellent thermal stability and compatibility under harsh polycondensation conditions. After the reaction, the material was discharged, water-cooled, and pelletized to obtain blue polyester chips.

[0057] 4. Fiber preparation The resulting blue polyester chips can be directly fed into the melt spinning equipment without additional drying and dyeing processes. Melting: Melt the slices at 285-290℃.

[0058] Spinning: The melt is precisely delivered by a metering pump and extruded through a spinneret to form nascent fibers.

[0059] Stretching and heat setting: The nascent fiber is stretched on a hot roller at 85°C for the first time, and then stretched and heat-set at 125°C for the second time to finally produce blue polyester filament with a specification of 150D / 36F.

[0060] 5. Fiber property characterization The performance of the obtained blue polyester fiber was tested, and the results are as follows: Hue: The fibers exhibit a pure, vibrant blue color, with uniform color throughout.

[0061] Color fastness: Tested in accordance with the national standard GB / T3920-2008, its rubbing color fastness (dry rubbing and wet rubbing) reaches level 4-5, and its soap washing color fastness reaches level 4 or above, which is significantly better than traditional dyed fibers.

[0062] Mechanical properties: The fiber has a breaking strength ≥3.5cN / dtex and a breaking elongation between 25% and 30%. Its comprehensive mechanical properties are comparable to those of uncolored polyester fiber, proving that the introduction of the monomer of this invention does not have an adverse plasticizing or damaging effect on the polyester matrix.

[0063] The blue anthraquinone monomers prepared in Examples 2 and 3 of this invention were used to repeat the polymerization and melt spinning process described in Application Example 1. The resulting blue polyester fibers all exhibited excellent properties similar to those of the product in Example 1: pure color, uniform distribution, and both high color fastness and excellent mechanical properties, fully verifying the universality and reliability of the monomers described in this invention in the preparation of high-end colored polyester fibers.

[0064] In summary, this invention designs a novel type of monomer for blue polyester fibers, which is particularly suitable for high-molecular-weight polyester fibers. Anthraquinone dye molecules exhibit excellent color performance and thermal stability. Regarding the preparation process, the process developed in this invention is simple and efficient, with significant advantages in production cost, making it highly suitable for large-scale industrial production.

[0065] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A monomer for blue polyester fiber, characterized in that, The blue polyester fiber uses a monomer with 1,4-arylamine-substituted anthraquinone as the color-developing core, and introduces benzoate groups on the aryl group of the 1,4-arylamine-substituted anthraquinone core, which are connected to the color-developing core through carbon-carbon bonds. The blue polyester fiber uses monomers with exposed ester groups at the molecular ends via aryl linkages. These exposed ester groups are used to undergo transesterification with diols under polyester melt polycondensation conditions. The chemical structural formula of the monomer used in the blue polyester fiber is: ； In the formula, R 1 Indicates an aromatic ring substituent, selected from methyl, ethyl, or isopropyl; R 2 It represents a hydrogen atom or an alkyl group, wherein the alkyl group is selected from methyl, ethyl, isopropyl or tert-butyl.

2. The monomer for blue polyester fiber according to claim 1, characterized in that, The monomer contains an anthraquinone core, two aromatic amino substituents, and two terminal ester groups, wherein the terminal ester groups are methoxycarbonyl, ethoxycarbonyl, or isopropoxycarbonyl.

3. A method for preparing monomers for blue polyester fibers, characterized in that, include: Halogenation reactions, specifically including: Solvent blue dye A and halogenated solvent were added to a reaction vessel and stirred to dissolve. After stirring, halogenated reagent was added in batches to carry out halogenation reaction to obtain dihalogenated intermediate B. Coupling reactions, specifically including: Dihalogenated intermediate B, coupling solvent, arylboronic acid, base and palladium catalyst were added to the reaction vessel. The dihalogenated intermediate B and ester-containing arylboronic acid were coupled under the action of palladium catalyst and base by heating. After the reaction was completed, the target monomer C was obtained by recrystallization. The synthetic expression for the halogenation reaction and coupling reaction is as follows: ； In the formula, R 1 Indicates an aromatic ring substituent, selected from methyl, ethyl, or isopropyl; R 2 X represents a hydrogen atom or an alkyl group, wherein the alkyl group is selected from methyl, ethyl, isopropyl or tert-butyl; X represents a halogen, selected from bromine or iodine.

4. The method for preparing a monomer for blue polyester fiber according to claim 3, characterized in that, The halogenation reaction includes at least one of the following characteristics: The halogenation reaction is carried out at a temperature of 0°C to 25°C. The halogenation reaction was carried out at atmospheric pressure. The halogenation reaction takes 10-20 hours. The halogenated reagent is added in batches, in small amounts, and multiple times.

5. The method for preparing a monomer for blue polyester fiber according to claim 4, characterized in that, The halogenation reaction further includes at least one of the following features: The halogenated solvent is selected from at least one of dichloromethane, dichloroethane, chloroform, and carbon tetrachloride; The weight of the halogenated solvent is 4 to 5 times that of solvent blue dye A; the amount of the halogenated solvent added is 50% to 60% of the reactor volume; The halogenated reagent is selected from at least one of dibromohydantoin, N-bromosuccinimide, bromine, dibromoisocyanuric acid, tribromoisocyanuric acid, tetrabutylammonium tribromide, N-iodosuccinimide, and elemental iodine. The molar amount of the halogenated reagent is 2 to 2.5 times that of solvent blue dye A.

6. The method for preparing a monomer for blue polyester fiber according to claim 3, characterized in that, The post-processing methods after the halogenation reaction include: A reducing agent is added to the reaction solution after the halogenation reaction is completed to quench the reaction. The reaction solution is concentrated by distillation, causing the product to precipitate. Filter and wash successively with saturated reducing agent solution and water; The product was recrystallized using an organic solvent to obtain dihalogenated intermediate B.

7. The method for preparing a monomer for blue polyester fiber according to claim 3, characterized in that, The coupling reaction includes at least one of the following characteristics: The coupling reaction is carried out at a temperature of 60℃~130℃; The reaction time for the coupling reaction is 15h~24h; The arylboronic acid is selected from at least one of m-alkoxycarbonylphenylboronic acid and p-alkoxycarbonylphenylboronic acid; The molar amount of the arylboronic acid is 2 to 2.4 times that of the dihalogenated intermediate B; The palladium catalyst is selected from at least one of palladium chloride, palladium acetate, tetraphenylphosphine palladium, and dibenzylpyridinium acetone; The amount of palladium catalyst added is 0.1 mol% to 3 mol of the dihalogenated intermediate B.

8. The method for preparing a monomer for blue polyester fiber according to claim 7, characterized in that, The coupling reaction further includes at least one of the following features: The alkali is selected from at least one of potassium carbonate, potassium hydroxide, potassium fluoride, and potassium phosphate; The molar amount of the base added is 3 to 4 times that of the dihalogenated intermediate B; The coupling solvent is selected from at least one of N-methylpyrrolidone, 1,4-dioxane, hexamethylphosphoramide, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and dimethyl sulfoxide; The weight of the coupling solvent is 5 to 6 times that of the dihalogenated intermediate B; the amount of the coupling solvent added is 40% to 50% of the reactor volume.

9. A method for preparing a monomer for blue polyester fiber according to claim 3, characterized in that, In the halogenation reaction, the molar ratio of the added solvent blue dye A to the halogenation reagent is 1:2 to 1:2.5, and the weight ratio of the added solvent blue dye A to the halogenation solvent is 1:4 to 1:

10.

10. A method for preparing a monomer for blue polyester fiber according to claim 3, characterized in that, In the coupling reaction, the molar ratio of the added dihalogenated intermediate B to arylboronic acid is 1:2 to 1:4, and the molar ratio of the added dihalogenated intermediate B to the base is 1:2 to 1:6.

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