Application of sulfonated polyaromatic oxadiazole as fiber dyeing auxiliary agent, spinning solution, modified fiber and dyeing method of modified fiber

Abstract

The invention discloses application of sulfonated polyaromatic oxadiazole as a fiber dyeing auxiliary agent, a spinning solution, a modified fiber and a dyeing method of the modified fiber. On the basis of the dyeing mechanism of cationic dye, sulfonated polyaromatic oxadiazole is adopted as a modified dyeing assistant, and the sulfonated polyaromatic oxadiazole dyeing assistant is added into a fiber spinning stock solution through a solution blending method, so that the high-performance fiber easy to dye is obtained. The preparation process of the cationic dyeable modified high-performance fiber is realized by taking the sulfonate anion of the sulfonated polyaromatic oxadiazole polymer as the dyeing site of the cationic dye, and the preparation process is simple, low in cost, small in environmental harm and wide in industrial application prospect.

Description

Technical Field

[0001] The invention relates to the field of textile technology, and in particular to application of sulfonated polyaromatic oxadiazole as a fiber dyeing auxiliary, spinning solution, modified fiber and a dyeing method for the modified fiber. Background Art

[0002] High-performance fibers are a type of special fiber that has developed rapidly in the field of polymer fiber materials in recent years. High-performance fibers refer to chemical fibers with special physical and chemical structures, properties and uses, or with special functions. Generally speaking, high-performance fibers refer to high-modulus, high-strength fibers and high-heat and chemical-resistant fibers, such as aramid, PBO fibers, carbon fibers, Technora fibers, and ultra-high molecular weight polyethylene fibers. These fibers have fireproof, bulletproof and corrosion-resistant functions and are mainly used in aerospace, national defense science and technology, military engineering, construction industry, transportation, medical protection, civil industry, and electronic communications. However, with the expansion of the application fields of high-performance fibers, the preparation of colored high-performance fibers has been challenged.

[0003] High-performance fibers have completely different physical properties, aggregate structures, and morphological structures from conventional synthetic fibers such as polyester. For example, the strong interaction between polymer chains, high fiber crystallinity, and strong chemical inertness on the fiber surface make it difficult for dye molecules to enter the fiber or combine with the fiber, resulting in difficulty in constructing the color of high-performance fibers and difficulty in obtaining the desired color depth. In order to break through the technical bottleneck of high-performance fiber color construction, a large number of studies have been conducted on the structural characteristics and physical and chemical properties of high-performance fibers, and innovative surface modification methods and dyeing processes for high-performance fibers have been developed. Attempts have been made to give high-performance fibers color from aspects such as fiber raw materials, forming processing, and surface modification. However, the currently reported processes damage the surface structure of the fibers and increase the process flow. On the other hand, most of the chemical additives used are toxic and harmful, and their industrial applications are limited.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The purpose of the present invention is to provide the use of sulfonated polyarylene oxadiazole as a fiber dyeing auxiliary, a spinning solution, a modified fiber and a dyeing method for the modified fiber. The present invention introduces sulfonated polyarylene oxadiazole as a fiber dyeing auxiliary in the fiber preparation process, which is beneficial to improving the dyeing rate and fastness of the fiber.

[0006] The present invention is achieved in that:

[0007] In a first aspect, the present invention provides a use of a sulfonated polyaromatic oxadiazole as a fiber dyeing auxiliary agent.

[0008] In an optional embodiment, the fiber includes at least one of para-aramid, polybenzimidazole and polybenzoxazole;

[0009] And / or, the grafting rate of the sulfonic acid groups in the sulfonated polyaromatic oxadiazole is 50%-100%.

[0010] In a second aspect, the present invention provides a spinning solution, comprising a fiber monomer and a sulfonated polyarylene oxadiazole, wherein the mass ratio of the sulfonated polyarylene oxadiazole to the fiber monomer is 0.5%-8%.

[0011] In a third aspect, the present invention provides a modified fiber obtained by dry-wet spinning the spinning solution described in the above embodiment.

[0012] In a fourth aspect, the present invention provides a method for dyeing the modified fiber described in the aforementioned embodiment, comprising: placing the modified fiber in a dyeing bath for dyeing, followed by washing, soap boiling and drying to obtain the dyed modified fiber.

[0013] In an alternative embodiment, the dye in the dye bath is a cationic dye;

[0014] And / or, the dye is used in an amount of 1% owf to 5% owf.

[0015] In an optional embodiment, the bath ratio of the dyeing step is 1:10 to 1:15.

[0016] In an optional embodiment, the dyeing bath further comprises an inorganic salt, and the concentration of the inorganic salt is less than 30 g / L.

[0017] In an optional embodiment, the dyeing bath has a pH of 4-5.

[0018] In an optional embodiment, the temperature of the dyeing step is 100°C to 140°C, and the holding time is 50min-70min;

[0019] and / or, the heating rate of the dyeing step is 1°C / min-3°C / min;

[0020] And / or, the dyeing step is performed in a high pressure dyeing machine.

[0021] The present invention has the following beneficial effects:

[0022] Based on the dyeing mechanism of cationic dyes, the present application adopts sulfonated polyarylene oxadiazole as a modified dyeing auxiliary, and adds the sulfonated polyarylene oxadiazole dyeing auxiliary to the fiber spinning solution by a solution blending method to obtain a high-performance fiber that is easy to dye. The sulfonate anion of the sulfonated polyarylene oxadiazole polymer is used as a dyeing site for cationic dyes to realize a preparation process for cationic dyeable modified high-performance fibers, which has a simple process, low cost, low environmental harm, and broad prospects for industrial application. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0024] The embodiment of the present invention provides a use of a sulfonated polyaromatic oxadiazole as a fiber dyeing auxiliary agent.

[0025] The five-membered oxadiazole heterocycle in the sulfonic acid polyaromatic oxadiazole molecular chain contains 2 N atoms and 1 O atom, and the lone pair of electrons on the sp2 hybridized N atom does not participate in the conjugation of the aromatic heterocycle, so it can be complexed with protons, and at the same time, because the relatively strong electronegativity of the O atom will reduce the electron cloud density on the N atom, the binding strength of the N atom and the proton is low, and the proton is easy to leave. Therefore, the oxadiazole group has a weak Lewis alkalinity and is easily combined with the cations in the solution. Therefore, the present application is based on the dyeing mechanism of cationic dyes, using sulfonated polyaromatic oxadiazole as a modified dyeing auxiliary, and adding a sulfonated polyaromatic oxadiazole dyeing auxiliary to the fiber spinning solution by a solution blending method to obtain a high-performance fiber that is easy to dye. Using the sulfonate anion of the sulfonated polyaromatic oxadiazole polymer as a dyeing site for cationic dyes, to realize the preparation process of cationic dyeable modified high-performance fibers, its process is simple, the cost is low, the environmental hazard is small, and the industrial application prospect is broad.

[0026] In an optional embodiment, the fiber includes at least one of para-aramid, polybenzimidazole and polybenzoxazole.

[0027] It is difficult to dye high-performance fibers such as para-aramid, polybenzimidazole and polybenzoxazole, and it is difficult to obtain an ideal color depth. Therefore, the effect of sulfonated polyaromatic oxadiazole in improving the dyeing performance of para-aramid, polybenzimidazole (aromatic III) and polybenzoxazole (PBO) is more obvious.

[0028] In an optional embodiment, the grafting rate of the sulfonic acid groups in the sulfonated polyaromatic oxadiazole is 50%-100%.

[0029] The higher the grafting rate of the sulfonic acid group, the more dyeing sites there are under the premise of the same amount of dyeing auxiliaries added, which is conducive to the binding of more cationic dyes.

[0030] In some embodiments, the preparation method of the sulfonated polyarylene oxadiazole comprises: dissolving hydrazine sulfate and a reaction monomer in fuming sulfuric acid, then heating and sequentially performing prepolymerization and polycondensation to obtain a reaction liquid, and removing air and free SO in the reaction liquid. 3 , to obtain the polyaromatic oxadiazole;

[0031] Preferably, the reactive monomer is at least one of terephthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, 4,4'-biphenyl ether dicarboxylic acid and 4,4'-biphenyl dicarboxylic acid.

[0032] Among them, only one benzene ring of 2,6-naphthalene dicarboxylic acid and 4,4'-biphenyl dicarboxylic acid is sulfonated, both benzene rings of 4,4'-biphenyl ether dicarboxylic acid are sulfonated, and the benzene rings of terephthalic acid and isophthalic acid cannot be sulfonated. In some embodiments, the sulfonated polyaromatic oxadiazole can be synthesized by 2,6-naphthalene dicarboxylic acid, 4,4'-biphenyl ether dicarboxylic acid and 4,4'-biphenyl dicarboxylic acid and hydrazine sulfate in fuming sulfuric acid, which is obtained due to the strong dehydration ability and sulfonation of fuming sulfuric acid.

[0033] A. the total molar ratio of the hydrazine sulfate to the reaction monomer is 1-1.1:1;

[0034] B. The prepolymerization temperature is 80-90°C and the time is 2.5-3.5h;

[0035] C. The temperature of polycondensation is 115-125°C and the time is 1.5-2.5h.

[0036] The embodiment of the present invention further provides a spinning solution, comprising a fiber monomer and a sulfonated polyarylene oxadiazole, wherein the mass ratio of the sulfonated polyarylene oxadiazole to the fiber monomer is 0.5%-8%.

[0037] The sulfonate anions of the sulfonated poly(arylene oxadiazole) polymer are used as dyeing sites for cationic dyes. To ensure the dyeing effect, there need to be enough dyeing sites to combine with the cationic dyes. At the same time, the proportion of the sulfonated poly(arylene oxadiazole) should not be too high to avoid significantly reducing the performance of the fiber itself.

[0038] The embodiment of the present invention further provides a modified fiber, which is obtained by dry-wet spinning the spinning solution described in the above embodiment.

[0039] The modified fiber prepared in the present application does not require any other treatment and can be directly dyed. Compared with the existing dyeing methods, it is more conducive to simplifying the process and reducing production costs.

[0040] The embodiment of the present invention further provides a dyeing method for the modified fiber described in the aforementioned embodiment, comprising: placing the modified fiber in a dyeing bath for dyeing, followed by washing, soap boiling and drying to obtain the dyed modified fiber.

[0041] In an alternative embodiment, the dye in the dye bath is a cationic dye;

[0042] And / or, the dye is used in an amount of 1% owf to 5% owf.

[0043] In an optional embodiment, the bath ratio of the dyeing step is 1:10 to 1:15.

[0044] In an optional embodiment, the dyeing bath further comprises an inorganic salt, and the concentration of the inorganic salt is less than 30 g / L.

[0045] In an optional embodiment, the dyeing bath has a pH of 4-5.

[0046] In an optional embodiment, the temperature of the dyeing step is 100°C to 140°C, and the holding time is 50min-70min;

[0047] and / or, the heating rate of the dyeing step is 1°C / min-3°C / min;

[0048] And / or, the dyeing step is performed in a high pressure dyeing machine.

[0049] The features and properties of the present invention are further described in detail below in conjunction with the examples, wherein the para-aramid liquid crystal spinning solution, aramid III liquid crystal spinning solution and PBO spinning solution involved in each example and comparative example are all purchased from Zhonglan Chenguang Chemical Research and Design Institute.

[0050] Embodiment 1:

[0051] This embodiment provides a method for dyeing modified para-aramid fiber, which specifically includes the following steps:

[0052] A. Preparation of sulfonated polyoxadiazole

[0053] A one-step three-stage polycondensation method was used. 21.63 g of hydrazine sulfate, 10.53 g of terephthalic acid, and 24.54 g of 4'4-biphenyl ether dicarboxylic acid were dissolved in 150 mL of fuming sulfuric acid in a 250 mL three-necked bottle equipped with a mechanical stirrer, and the temperature was raised to the prepolymerization temperature of 85°C, and the reaction was carried out for 3 hours, and then the temperature was raised to the polycondensation temperature of 120°C, and the reaction was continued for 2 hours. The reaction was terminated, and the original solution was vacuum degassed and set aside.

[0054] B. Preparation of spinning solution

[0055] 500g of para-aramid liquid crystal spinning stock solution was placed in a reaction kettle, and the sulfonated polyarylene oxadiazole prepared above was added, the mass of which was 2% of the para-aramid liquid crystal spinning stock solution, i.e., 10g, and then stirred for 4h to allow the sulfonated polyarylene oxadiazole to be evenly dispersed in the stock solution. The spinning stock solution was then transferred to the spinning equipment, and the modified para-aramid fiber was prepared by a dry-wet spinning process.

[0056] C. Dyeing process of modified para-aramid fiber

[0057] The fiber was dyed with cationic brilliant red dye. The bath ratio of the dye bath was 1:15, the dye dosage was 4% owf, the NaCl concentration was 20g / L, the pH was 4-5, and then stirred evenly. 3g of the modified para-aramid fiber prepared above was placed in a high-pressure dyeing machine, heated to 140°C at a heating rate of 2°C / min, maintained for 1h, and then taken out for water washing, soap boiling and drying. The dyeing rate and fastness of the modified para-aramid fiber were then measured.

[0058] Embodiment 2:

[0059] This embodiment provides a dyeing method for modified para-aramid fiber, which is different from Embodiment 1 mainly in that the amount of reaction monomer is different, and specifically includes the following steps:

[0060] A. Preparation of sulfonated polyoxadiazole

[0061] A one-step three-stage polycondensation method was used. 21.63g of hydrazine sulfate, 7.9g of terephthalic acid, and 28.64g of 4'4-biphenyl ether dicarboxylic acid were dissolved in 150mL of fuming sulfuric acid in a 250mL three-necked bottle equipped with a mechanical stirrer, and the temperature was raised to the prepolymerization temperature of 85°C, and the reaction was carried out for 3h, and then the temperature was raised to the polycondensation temperature of 120°C, and the reaction was continued for 2h, and the reaction was terminated. The original solution was vacuum degassed and set aside for use.

[0062] B. Preparation of spinning solution

[0063] 500g of para-aramid liquid crystal spinning stock solution was placed in a reaction kettle, and the sulfonated polyarylene oxadiazole prepared above was added, the mass of which was 2% of the para-aramid liquid crystal spinning stock solution, and then stirred for 4 hours to allow the sulfonated polyarylene oxadiazole to be evenly dispersed in the stock solution. The spinning stock solution was then transferred to the spinning equipment, and the modified para-aramid fiber was prepared by a dry-wet spinning process.

[0064] C. Dyeing process of modified para-aramid fiber

[0065] The fiber was dyed with cationic brilliant red dye. The bath ratio of the dye bath was 1:15, the dye dosage was 4% owf, the NaCl concentration was 20g / L, the pH was 4-5, and then stirred evenly. 3g of the modified para-aramid fiber prepared above was placed in a high-pressure dyeing machine, heated to 140°C at a heating rate of 2°C / min, maintained for 1h, and then taken out for water washing, soap boiling and drying. The dyeing rate and fastness of the modified para-aramid fiber were then measured.

[0066] Embodiment 3:

[0067] This embodiment provides a method for dyeing modified para-aramid fiber, which is different from Embodiment 1 mainly in that the reactive monomer terephthalic acid is replaced by isophthalic acid, and specifically comprises the following steps:

[0068] Preparation of sulfonated polyoxadiazole

[0069] A one-step three-stage polycondensation method was used. 21.63g of hydrazine sulfate, 10.53g of isophthalic acid, and 24.54g of 4,4'-biphenyl ether dicarboxylic acid were dissolved in 150mL of fuming sulfuric acid in a 250mL three-necked bottle equipped with a mechanical stirrer, and the temperature was raised to the prepolymerization temperature of 85°C, and the reaction was carried out for 3h, and then the temperature was raised to the polycondensation temperature of 120°C, and the reaction was continued for 2h, and the reaction was terminated. The original solution was vacuum degassed and set aside.

[0070] B. Preparation of spinning solution

[0071] 500g of para-aramid liquid crystal spinning stock solution was placed in a reaction kettle, and the sulfonated polyarylene oxadiazole prepared above was added, the mass of which was 2% of the para-aramid liquid crystal spinning stock solution, and then stirred for 4 hours to allow the sulfonated polyarylene oxadiazole to be evenly dispersed in the stock solution. The spinning stock solution was then transferred to the spinning equipment, and the modified para-aramid fiber was prepared by a dry-wet spinning process.

[0072] C. Dyeing process of modified para-aramid fiber

[0073] The fiber was dyed with cationic brilliant red dye. The bath ratio of the dye bath was 1:15, the dye dosage was 4% owf, the NaCl concentration was 20g / L, the pH was 4-5, and then stirred evenly. 3g of the modified para-aramid fiber prepared above was placed in a high-pressure dyeing machine, heated to 140°C at a heating rate of 2°C / min, maintained for 1h, and then taken out for water washing, soap boiling and drying. The dyeing rate and fastness of the modified para-aramid fiber were then measured.

[0074] Example 4

[0075] This embodiment provides a method for dyeing modified para-aramid fiber, which is different from Embodiment 2 mainly in that the reactive monomer terephthalic acid is replaced by isophthalic acid, and specifically comprises the following steps:

[0076] A. Preparation of sulfonated polyoxadiazole

[0077] A one-step three-stage polycondensation method was used. 21.63g of hydrazine sulfate, 7.9g of isophthalic acid, and 28.64g of 4,4'-biphenyl ether dicarboxylic acid were dissolved in 150mL of fuming sulfuric acid in a 250mL three-necked bottle equipped with a mechanical stirrer, and the temperature was raised to the prepolymerization temperature of 85°C, and the reaction was carried out for 3h, and then the temperature was raised to the polycondensation temperature of 120°C, and the reaction was continued for 2h, and the reaction was terminated. The original solution was vacuum degassed and set aside for use.

[0078] B. Preparation of spinning solution

[0079] 500g of para-aramid liquid crystal spinning stock solution was placed in a reaction kettle, and the sulfonated polyarylene oxadiazole prepared above was added, the mass of which was 2% of the para-aramid liquid crystal spinning stock solution, and then stirred for 4 hours to allow the sulfonated polyarylene oxadiazole to be evenly dispersed in the stock solution. The spinning stock solution was then transferred to the spinning equipment, and the modified para-aramid fiber was prepared by a dry-wet spinning process.

[0080] C. Dyeing process of modified para-aramid fiber

[0081] The fiber was dyed with cationic brilliant red dye. The bath ratio of the dye bath was 1:15, the dye dosage was 4% owf, the NaCl concentration was 20g / L, the pH was 4-5, and then stirred evenly. 3g of the modified para-aramid fiber prepared above was placed in a high-pressure dyeing machine, heated to 140°C at a heating rate of 2°C / min, maintained for 1h, and then taken out for water washing, soap boiling and drying. The dyeing rate and fastness of the modified para-aramid fiber were then measured.

[0082] Example 5

[0083] This embodiment provides a dyeing method for modified para-aramid fiber, which is different from Embodiment 1 mainly in that the reaction monomers are different, and specifically includes the following steps:

[0084] A. Preparation of sulfonated polyoxadiazole

[0085] A one-step three-stage polycondensation method was used. 21.63g of hydrazine sulfate, 11.51g of 4,4'biphenyl dicarboxylic acid, and 28.64g of 4,4'biphenyl ether dicarboxylic acid were dissolved in 150mL of fuming sulfuric acid in a 250mL three-necked bottle equipped with a mechanical stirrer, and the temperature was raised to the prepolymerization temperature of 85°C, and the reaction was carried out for 3h, and then the temperature was raised to the polycondensation temperature of 120°C, and the reaction was continued for 2h, and the reaction was terminated. The original solution was vacuum degassed and set aside.

[0086] B. Preparation of spinning solution

[0087] 500g of para-aramid liquid crystal spinning stock solution was placed in a reaction kettle, and the sulfonated polyarylene oxadiazole prepared above was added, the mass of which was 2% of the para-aramid liquid crystal spinning stock solution, and then stirred for 4 hours to allow the sulfonated polyarylene oxadiazole to be evenly dispersed in the stock solution. The spinning stock solution was then transferred to the spinning equipment, and the modified para-aramid fiber was prepared by a dry-wet spinning process.

[0088] C. Dyeing process of modified para-aramid fiber

[0089] The fiber was dyed with cationic brilliant red dye. The bath ratio of the dye bath was 1:15, the dye dosage was 4% owf, the NaCl concentration was 20g / L, the pH was 4-5, and then stirred evenly. 3g of the modified para-aramid fiber prepared above was placed in a high-pressure dyeing machine, heated to 140°C at a heating rate of 2°C / min, maintained for 1h, and then taken out for water washing, soap boiling and drying. The dyeing rate and fastness of the modified para-aramid fiber were then measured.

[0090] Example 6

[0091] This embodiment provides a dyeing method for modified para-aramid fiber, which is different from Embodiment 5 mainly in that the reaction monomers are different, and specifically includes the following steps:

[0092] A. Preparation of sulfonated polyoxadiazole

[0093] A one-step three-stage polycondensation method was used. 21.63g of hydrazine sulfate, 15.35g of 4,4'biphenyl dicarboxylic acid, and 24.54g of 4,4'biphenyl ether dicarboxylic acid were dissolved in 150mL of fuming sulfuric acid in a 250mL three-necked bottle equipped with a mechanical stirrer, and the temperature was raised to the prepolymerization temperature of 85°C, and the reaction was carried out for 3h, and then the temperature was raised to the polycondensation temperature of 120°C, and the reaction was continued for 2h, and the reaction was terminated. The original solution was vacuum degassed and set aside.

[0094] B. Preparation of spinning solution

[0095] 500g of para-aramid liquid crystal spinning stock solution was placed in a reaction kettle, and the sulfonated polyarylene oxadiazole prepared above was added, the mass of which was 2% of the para-aramid liquid crystal spinning stock solution, and then stirred for 4 hours to allow the sulfonated polyarylene oxadiazole to be evenly dispersed in the stock solution. The spinning stock solution was then transferred to the spinning equipment, and the modified para-aramid fiber was prepared by a dry-wet spinning process.

[0096] C. Dyeing process of modified para-aramid fiber

[0097] The fiber was dyed with cationic brilliant red dye. The bath ratio of the dye bath was 1:15, the dye dosage was 4% owf, the NaCl concentration was 20g / L, the pH was 4-5, and then stirred evenly. 3g of the modified para-aramid fiber prepared above was placed in a high-pressure dyeing machine, heated to 140°C at a heating rate of 2°C / min, maintained for 1h, and then taken out for water washing, soap boiling and drying. The dyeing rate and fastness of the modified para-aramid fiber were then measured.

[0098] Example 7

[0099] This embodiment provides a dyeing method for modified para-aramid fiber, which is different from Embodiment 1 mainly in that the reaction monomers are different, and specifically includes the following steps:

[0100] A. Preparation of sulfonated polyoxadiazole

[0101] A one-step three-stage polycondensation method was used. 21.63g of hydrazine sulfate, 13.7g of 2,6-naphthalene dicarboxylic acid, and 24.54g of 4,4'-biphenyl ether dicarboxylic acid were dissolved in 150mL of fuming sulfuric acid in a 250mL three-necked bottle equipped with a mechanical stirrer, and the temperature was raised to the prepolymerization temperature of 85°C, and the reaction was carried out for 3h, and then the temperature was raised to the polycondensation temperature of 120°C, and the reaction was continued for 2h, and the reaction was terminated. The original solution was vacuum degassed and set aside.

[0102] B. Preparation of spinning solution

[0103] 500g of para-aramid liquid crystal spinning stock solution was placed in a reaction kettle, and the sulfonated polyarylene oxadiazole prepared above was added, the mass of which was 2% of the para-aramid liquid crystal spinning stock solution, and then stirred for 4 hours to allow the sulfonated polyarylene oxadiazole to be evenly dispersed in the stock solution. The spinning stock solution was then transferred to the spinning equipment, and the modified para-aramid fiber was prepared by a dry-wet spinning process.

[0104] C. Dyeing process of modified para-aramid fiber

[0105] The fiber was dyed with cationic brilliant red dye. The bath ratio of the dye bath was 1:15, the dye dosage was 4% owf, the NaCl concentration was 20g / L, the pH was 4-5, and then stirred evenly. 3g of the modified para-aramid fiber prepared above was placed in a high-pressure dyeing machine, heated to 140°C at a heating rate of 2°C / min, maintained for 1h, and then taken out for water washing, soap boiling and drying. The dyeing rate and fastness of the modified para-aramid fiber were then measured.

[0106] Example 8

[0107] This embodiment provides a dyeing method for modified para-aramid fiber, which is different from Embodiment 7 mainly in that the reaction monomers are different, and specifically includes the following steps:

[0108] A. Preparation of sulfonated polyoxadiazole

[0109] A one-step three-stage polycondensation method was used. 21.63g of hydrazine sulfate, 10.27g of 2,6-naphthalene dicarboxylic acid, and 28.64g of 4,4'-biphenyl ether dicarboxylic acid were dissolved in 150mL of fuming sulfuric acid in a 250mL three-necked bottle equipped with a mechanical stirrer, and the temperature was raised to the prepolymerization temperature of 85°C, and the reaction was carried out for 3h, and then the temperature was raised to the polycondensation temperature of 120°C, and the reaction was continued for 2h, and the reaction was terminated. The original solution was vacuum degassed and set aside.

[0110] B. Preparation of spinning solution

[0111] 500g of para-aramid liquid crystal spinning stock solution was placed in a reaction kettle, and the sulfonated polyarylene oxadiazole prepared above was added, the mass of which was 2% of the para-aramid liquid crystal spinning stock solution, and then stirred for 4 hours to allow the sulfonated polyarylene oxadiazole to be evenly dispersed in the stock solution. The spinning stock solution was then transferred to the spinning equipment, and the modified para-aramid fiber was prepared by a dry-wet spinning process.

[0112] C. Dyeing process of modified para-aramid fiber

[0113] The fiber was dyed with cationic brilliant red dye. The bath ratio of the dye bath was 1:15, the dye dosage was 4% owf, the NaCl concentration was 20g / L, the pH was 4-5, and then stirred evenly. 3g of the modified para-aramid fiber prepared above was placed in a high-pressure dyeing machine, heated to 140°C at a heating rate of 2°C / min, maintained for 1h, and then taken out for water washing, soap boiling and drying. The dyeing rate and fastness of the modified para-aramid fiber were then measured.

[0114] Example 9

[0115] This embodiment provides a dyeing method for modified polybenzimidazole fibers, which is different from Embodiment 1 mainly in that the para-aramid liquid crystal spinning solution is replaced by aramid III liquid crystal spinning solution.

[0116] Example 10

[0117] This embodiment provides a method for dyeing modified polybenzoxazole fibers, which is different from Embodiment 1 mainly in that the para-aramid liquid crystal spinning solution is replaced by a PBO spinning solution.

[0118] Comparative Example 1

[0119] This comparative example provides a method for dyeing modified para-aramid fiber, which is different from Example 1 mainly in that the para-aramid fiber is not modified, specifically: step A is omitted, and in step B no sulfonated polyaromatic oxadiazole is added to the spinning solution.

[0120] Comparative Example 2

[0121] This comparative example provides a method for dyeing modified para-aramid fiber, which is different from Example 9 mainly in that the para-aramid fiber is not modified, specifically: step A is omitted, and no sulfonated polyoxadiazole is added to the spinning solution in step B.

[0122] Comparative Example 3

[0123] This comparative example provides a method for dyeing modified para-aramid fiber, which is different from Example 10 mainly in that the para-aramid fiber is not modified, specifically: step A is omitted, and no sulfonated polyaromatic oxadiazole is added to the spinning solution in step B.

[0124] Comparative Example 4

[0125] This comparative example provides a method for dyeing modified para-aramid fiber, which is different from Example 1 mainly in that 10 g of unsulfonated polyaromatic oxadiazole is added to the spinning solution in step B.

[0126] Comparative Example 5

[0127] This comparative example provides a method for dyeing modified para-aramid fiber, which is different from Example 1 mainly in that the amount of sulfonated polyaromatic oxadiazole added to the spinning solution in step B is too small, namely, 0.5 g.

[0128] Comparative Example 6

[0129] This comparative example provides a method for dyeing modified para-aramid fiber, which is different from Example 1 mainly in that the amount of sulfonated polyaromatic oxadiazole added to the spinning solution in step B is too much, i.e., 100 g.

[0130] The grafting rate of the sulfonic acid groups in the sulfonated polyoxadiazole obtained by the above-mentioned examples and comparative examples and the fiber properties after dyeing were tested. The results are shown in Table 1.

[0131] Table 1

[0132]

[0133]

[0134] By comparing the above embodiments with the comparative examples, it can be seen that the use of sulfonated polyaromatic oxadiazole as a dyeing auxiliary can effectively improve the dyeing effect of high-performance fibers represented by para-aramid, polybenzimidazole and polybenzoxazole, and the dyeing effect (including dyeing rate, K / S value and fatigue resistance) is related to the amount of sulfonated polyaromatic oxadiazole added and the number of sulfonic acid groups in the sulfonated polyaromatic oxadiazole. Under the same conditions, the higher the amount of sulfonated polyaromatic oxadiazole, the more dyeing sites combined with the dye, and the better the dyeing effect. At the same time, the content of sulfonated polyaromatic oxadiazole in the prepared modified fiber is lower, so that the damage to the high-performance fiber by dyeing is lower. However, if too much sulfonated polyaromatic oxadiazole is added, the performance of the high-performance fiber itself will be reduced. For example, compared with the modified para-aramid fiber prepared in Example 1, the mechanical properties of the modified para-aramid fiber prepared in Comparative Example 6 are reduced by 30%, which seriously affects the application of the fiber in special fields.

[0135] It can be seen from Example 1 and Comparative Example 4 that if the sulfonic acid group is not introduced, the dyeing effect of polyaromatic oxadiazole on para-aramid is not significantly improved.

[0136] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. Application of sulfonated polyaromatic oxadiazole as a fiber dyeing auxiliary.

2. The use of the sulfonated polyaromatic oxadiazole as a fiber dyeing auxiliary according to claim 1, characterized in that: The fiber comprises at least one of para-aramid, polybenzimidazole and polybenzoxazole; And / or, the grafting rate of the sulfonic acid groups in the sulfonated polyaromatic oxadiazole is 50%-100%.

3. A spinning solution, characterized in that: The invention comprises a fiber monomer and a sulfonated polyaromatic oxadiazole, wherein the mass ratio of the sulfonated polyaromatic oxadiazole to the fiber monomer is 0.5%-8%.

4. A modified fiber, characterized in that: The spinning solution according to claim 3 is subjected to dry-wet spinning.

5. A method for dyeing modified fibers according to claim 4, characterized in that: include: The modified fiber is placed in a dyeing bath for dyeing, followed by washing, soap boiling and drying to obtain the dyed modified fiber.

6. The method for dyeing modified fibers according to claim 5, characterized in that: The dye in the dye bath is a cationic dye; And / or, the dye is used in an amount of 1% owf to 5% owf.

7. The method for dyeing modified fibers according to claim 5, characterized in that: The bath ratio of the dyeing step is 1:10 to 1:

15.

8. The method for dyeing modified fibers according to claim 5, characterized in that: The dyeing bath also includes inorganic salts, and the concentration of the inorganic salts is less than 30 g / L.

9. The method for dyeing modified fibers according to claim 5, characterized in that: The pH of the dyeing bath is 4-5.

10. The method for dyeing modified fibers according to claim 5, characterized in that: The temperature of the dyeing step is 100°C to 140°C, and the holding time is 50min-70min; and / or, the heating rate of the dyeing step is 1°C / min-3°C / min; And / or, the dyeing step is performed in a high pressure dyeing machine.

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