A method for preparing bio-based aromatic polyamide fiber

Abstract

The present invention belongs to the field of fiber technology and specifically discloses a method for preparing bio-based aromatic polyamide fibers, as well as the resulting fiber products and their applications. The method for preparing bio-based aromatic polyamide fibers provided by the present invention utilizes solution polymerization to directly polycondense a dibasic acid containing a furan ring structure with an aromatic diamine to form a polymer stock solution, which is then directly wet-spun to form a fiber sample having good flexibility, high water absorption, and easy dyeing. The fibers prepared by the present invention not only possess the physical strength of aramid fibers but also have good dyeing and moisture absorption properties, thereby expanding the application range of aramid fibers.

Description

Technical Field

[0001] The present invention belongs to the field of fiber technology, and particularly relates to a method for preparing bio-based aromatic polyamide fiber, and also relates to the prepared fiber product and application thereof. Background Art

[0002] Aramid fiber, also known as aromatic polyamide fiber, has been widely used in various fields of life and production due to its many excellent properties such as ultra-high strength, high modulus, high temperature resistance, acid and alkali resistance, light weight, insulation, anti-aging, and long life cycle.

[0003] With the rapid development of society and economy, the demand for green energy and environmentally friendly resources is increasing rapidly. The production of environmentally friendly bio-based chemicals and green energy is the only way for human development, but it is also a difficult problem in current scientific research.

[0004] Therefore, the development of new bio-based aromatic polyamide fibers, namely aramid fibers, not only meets the requirements of eco-friendly development, but also has important significance for the development of my country's aramid industry. Summary of the Invention

[0005] The present invention provides a method for preparing bio-based aromatic polyamide fibers and also provides applications for the resulting fiber products. The fibers produced by the method not only possess the physical strength of aramid fibers but also exhibit excellent dyeing and moisture absorption properties, thereby expanding the application range of aramid fibers.

[0006] To achieve this object, the present invention adopts the following technical solutions.

[0007] In a first aspect, the present invention provides a method for preparing bio-based aromatic polyamide fibers, comprising: using a bio-based furan dicarboxylic acid represented by general formula (I) and an aromatic diamine represented by general formula (II) as raw materials, and performing solution polymerization to prepare a bio-based aromatic polyamide polymerization stock solution; and spinning the polymerization stock solution to produce a bio-based aromatic polyamide fiber product;

[0008] HOOC-X-COOH (I);

[0009] H2N-Y-NH2 (Ⅱ);

[0010] Wherein, X is a furan ring and its derivative structure;

[0011] Y is a furan ring and its derivative structure or a benzene ring and its derivative structure.

[0012] As an embodiment of the present invention, in the general formula (I), X is a furyl group or a dimethylene furyl group. Preferably, X is a furyl group.

[0013] As an embodiment of the present invention, in the general formula (II), Y is selected from phenyl, dimethylphenyl, furyl and dimethylfuryl. Preferably, Y is selected from phenyl and dimethylfuryl.

[0014] As a preferred embodiment of the present invention, the bio-based furandicarboxylic acid is 2,5-furandicarboxylic acid and / or 3,4-furandicarboxylic acid. The raw materials for preparing furandicarboxylic acid are non-food crops, such as Jerusalem artichoke, chicory, burdock, cassava, etc.

[0015] As a preferred embodiment of the present invention, the aromatic diamine is selected from any one or more of p-phenylenediamine, o-phenylenediamine, m-phenylenediamine, 2,5-furandimethylamine, p-phenylenediamine, and o-phenylenediamine. Further preferably, the aromatic diamine is selected from any one or more of p-phenylenediamine, m-phenylenediamine, and 2,5-furandimethylamine.

[0016] As one embodiment of the present invention, the present invention provides a method for preparing bio-based aromatic polyamide fibers, wherein the preparation of the polymer solution comprises the following steps:

[0017] (1) Under the protection of an inert gas, a polar solvent, a bio-based furan dicarboxylic acid represented by the general formula (I), and a cosolvent are mixed to obtain a first solution;

[0018] (2) mixing the first solution with an aromatic diamine represented by general formula (II), an organic base, and a catalyst to obtain a second solution;

[0019] (3) The second solution is subjected to solution polymerization at 130°C to 150°C to obtain a polymerization stock solution.

[0020] As a preferred embodiment of the present invention, in step (1), the polar solvent is either N,N-dimethylacetamide (DMAC) or N-methyl-2-pyrrolidone (NMP), or a mixture of the two. Further preferably, the polar solvent is N,N-dimethylacetamide or N-methyl-2-pyrrolidone.

[0021] In a preferred embodiment of the present invention, the cosolvent is calcium chloride and / or lithium chloride. Further preferably, the cosolvent is a mixture of calcium chloride and lithium chloride. The calcium chloride and lithium chloride are preferably mixed in a mass ratio of 3-5:1, more preferably in a mass ratio of 4:1.

[0022] Preferably, the concentration of the bio-based furan dicarboxylic acid represented by general formula (I) in the first solution is 0.7-1.3 mol / L.

[0023] Preferably, the amount of the co-solvent added is 40-85 g per liter of polar solvent, more preferably 40-70 g per liter of polar solvent, and even more preferably 50 g per liter of polar solvent.

[0024] As a preferred embodiment of the present invention, in step (2), the organic base is selected from one or more of triethylamine, pyridine, and sodium methoxide; more preferably, the organic base is triethylamine or pyridine.

[0025] As a preferred embodiment of the present invention, the catalyst is triphenyl phosphite and / or tetrabutyl titanate; more preferably, the catalyst is triphenyl phosphite or tetrabutyl titanate.

[0026] Preferably, the molar ratio of the bio-based furan dicarboxylic acid represented by general formula (I) to the aromatic diamine represented by general formula (II) is (1-1.2):(1-1.2); further preferably, the molar ratio of the bio-based furan dicarboxylic acid represented by general formula (I) to the aromatic diamine represented by general formula (II) is 1:(1-1.1).

[0027] Preferably, the molar ratio of the organic base to the bio-based furan dicarboxylic acid represented by the general formula (I) is (0.5-1.5):1; further preferably, the molar ratio of the organic base to the bio-based furan dicarboxylic acid represented by the general formula (I) is (0.65-1.35):1.

[0028] Preferably, the amount of the catalyst is 1-10% of the volume of the polar solvent, more preferably 3-7% of the volume of the polar solvent, and even more preferably 5% of the volume of the polar solvent.

[0029] As one embodiment of the present invention, the present invention provides a method for preparing bio-based aromatic polyamide fibers, wherein the polymer solution spinning comprises: extruding the polymer solution through a spinneret, coagulating and forming, and then stretching the solution through hot water and heat setting to obtain a bio-based aromatic polyamide fiber product.

[0030] As a preferred embodiment of the present invention, the pore size of the spinneret is 50-90 μm.

[0031] As a preferred embodiment of the present invention, the coagulation bath used for coagulation forming comprises active ingredients of CaCl2 and one of N,N-dimethylacetamide and N-methyl-2-pyrrolidone. Further preferably, the coagulation bath comprises active ingredients of CaCl2 and N,N-dimethylacetamide. Even more preferably, the coagulation bath comprises an aqueous solution containing CaCl2 and DMAC, wherein the mass concentration of CaCl2 is 3-5%, and the volume ratio of water to DMAC is (60-80):(20-40). As a specific preferred embodiment, the coagulation bath comprises an aqueous solution containing CaCl2 and DMAC, wherein the mass concentration of CaCl2 is 4%, and the volume ratio of water to DMAC is 70:30. Preferably, the coagulation bath temperature is 50-65°C.

[0032] As a preferred embodiment of the present invention, the stretching ratio of the hot water stretching is 2 to 4 times, preferably 2.5 to 3 times.

[0033] Preferably, the water temperature for hot water stretching is 50-65°C.

[0034] As a preferred embodiment of the present invention, the stretching ratio of the heat setting stretching is 1 to 1.5 times.

[0035] Preferably, the temperature of heat setting and stretching is 170-190°C, more preferably 180°C.

[0036] In a second aspect, the present invention provides a bio-based aromatic polyamide fiber, which is prepared using the preparation method of the present invention.

[0037] In a third aspect, the present invention also provides an application of bio-based aromatic polyamide fiber, preferably the application of bio-based aromatic polyamide fiber in textiles, further preferably the application in high-performance textiles, and more preferably the application in industrial protective clothing, racing suits, space suits, tire cord fabrics, and automotive hoses.

[0038] The bio-based aromatic polyamide fiber preparation method provided by the present invention utilizes solution polymerization to directly polycondense a furan ring-containing dibasic acid with an aromatic diamine. The resulting polymer solution, or polymer stock solution, is formed in a non-protonated polar solvent. Direct wet spinning then produces fiber samples with excellent flexibility, high water absorption, and easy dyeing. The polyamide fiber products provided by the present invention exhibit a regular surface morphology, uniform thickness, and excellent physical properties.

[0039] The present invention uses biomass-derived furan dicarboxylic acid as a monomer, and its molecular structure is aromatic. The presence of "-O-" can give the polymer fiber good moisture absorption properties. The asymmetric molecular structure and the presence of terminal amino groups make the fiber product easier to combine with cationic dyes through strong ionic bonds or electrostatic effects, thereby obtaining a bright color with excellent color fastness. At the same time, the specific molecular structure also gives the fiber excellent thermal stability and flame retardant properties.

[0040] The present invention prepares a polymerization solution with excellent performance by regulating process parameters such as reaction temperature, monomer concentration and the amount of each material in the polymerization reaction system. At the same time, through wet spinning and heat setting and stretching, the prepared fiber not only has the physical strength of aramid fiber and excellent mechanical properties, but also has good dyeing performance and moisture absorption performance, thereby improving the application range of aramid fiber.

[0041] The bio-based aromatic polyamide fiber monomers of this invention are derived from biomass, meeting the needs of environmentally friendly social development and the national goal of carbon neutrality. For example, 2,5-furandicarboxylic acid (FDCA) is a stable biomass monomer. Using FDCA as a dibasic acid raw material can eliminate dependence on petroleum-based raw materials, achieving low carbon and environmental protection, in line with sustainable and carbon neutral development strategies. Furthermore, wet spinning directly after obtaining the polymer stock solution offers a simple, low-carbon and environmentally friendly spinning process. The resulting fibers possess excellent comprehensive physical properties and are widely used in various industries, including textiles and apparel, with broad market prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is the GPC spectrum of the polymerization stock solution obtained in Example 1 of the present invention. DETAILED DESCRIPTION

[0043] The technical solution of the present invention is described in further detail below. It should be understood by those skilled in the art that the specific embodiments described are only for the purpose of helping to understand the present invention and should not be regarded as specific limitations of the present invention.

[0044] It should be noted that, unless otherwise specified, the technical means used in the following examples are conventional means well known to those skilled in the art, and the raw materials used are all commercially available conventional products.

[0045] The present invention provides a method for preparing bio-based aromatic polyamide fibers, which uses a bio-based furan dicarboxylic acid represented by general formula (I) and an aromatic diamine represented by general formula (II) as raw materials, and prepares a bio-based aromatic polyamide polymerization stock solution through solution polymerization; and spins the polymerization stock solution to produce a bio-based aromatic polyamide fiber product;

[0046] HOOC-X-COOH (I);

[0047] H2N-Y-NH2 (Ⅱ).

[0048] The bio-based furan dicarboxylic acid may be 2,5-furan dicarboxylic acid and / or 3,4-furan dicarboxylic acid. The aromatic diamine may be selected from any one or more of p-phenylenediamine, m-phenylenediamine, and 2,5-furandimethylamine.

[0049] The method for preparing bio-based aromatic polyamide fibers provided by the present invention comprises the following steps:

[0050] (1) placing bio-based furan dicarboxylic acid, a cosolvent, and a polar solvent into a reactor, sealing the reactor after the addition of the materials, then introducing high-purity nitrogen into the reactor for inert gas protection, and stirring at 70-80° C. until the liquid is mixed and clarified to obtain a first solution;

[0051] (2) adding an aromatic diamine, an organic base, and a catalyst to the first solution and mixing to obtain a second solution;

[0052] (3) The second solution is heated and polymerized at 130°C to 150°C for 3-8 hours to obtain a viscous polymer solution, i.e., a polymerization stock solution; the polymerization stock solution is naturally cooled to room temperature for use;

[0053] (4) The polymerized raw liquid is first filtered and degassed, then extruded through a spinneret and sprayed into a coagulation bath for coagulation to obtain nascent fibers. The nascent fibers are washed with water, then stretched in hot water, and then dried. After drying, they are heat-set and stretched to obtain bio-based aromatic polyamide fiber products.

[0054] Wherein, in step (1), the polar solvent is N,N-dimethylacetamide or N-methyl-2-pyrrolidone;

[0055] The cosolvent is calcium chloride and / or lithium chloride, preferably a mixture of calcium chloride and lithium chloride, more preferably a mixture of calcium chloride and lithium chloride in a mass ratio of (3-5):1, more preferably a mixture in a mass ratio of 4:1;

[0056] The concentration of bio-based furandicarboxylic acid in the first solution is 0.7-1.3 mol / L;

[0057] The amount of co-solvent added is 40-60 g per liter of polar solvent.

[0058] Wherein, in step (2), the organic base is triethylamine or pyridine;

[0059] The catalyst is triphenyl phosphite or tetrabutyl titanate;

[0060] The molar ratio of bio-based furan dicarboxylic acid to aromatic diamine is 1:(1-1.1);

[0061] The molar ratio of the organic base to the bio-based furan dicarboxylic acid is (0.5-1.5):1;

[0062] The amount of catalyst used is 1-10% of the volume of the polar solvent.

[0063] Wherein, in step (4), the pore size of the spinneret is 50-90 μm;

[0064] The coagulation bath effective components used in the coagulation forming include CaCl2 and one of N,N-dimethylacetamide and N-methyl-2-pyrrolidone. Preferably, the coagulation bath effective components include CaCl2 and N,N-dimethylacetamide;

[0065] The stretching ratio of hot water stretching is 2~4 times;

[0066] The stretching ratio of heat setting stretching is 1~1.5 times.

[0067] The following is a detailed explanation through examples.

[0068] Example 1

[0069] The preparation method of the bio-based aromatic polyamide fiber provided in this embodiment comprises the following steps:

[0070] (a) Synthesis of bio-based aromatic polyamide polymers

[0071] 3000 g of 2,5-furandicarboxylic acid, 800 g of anhydrous calcium chloride, 200 g of anhydrous lithium chloride, and 20.0 L of N,N-dimethylacetamide (DMAC) were added to a 50 L double-layer glass reactor. After the addition was completed, the reactor was sealed and high-purity nitrogen was introduced into the reactor. This process was repeated three times to expel the air in the reactor and then maintained at normal pressure. The reaction mixture was stirred at 70° C. until the solution became clear, thereby obtaining a first solution.

[0072] 2077 g of p-phenylenediamine, 2.0 L of pyridine, and 1.0 L of triphenyl phosphite were added to the first solution and mixed to obtain a second solution;

[0073] Keeping nitrogen flowing, the second solution was heated to 140°C, and then kept warm for 6 hours to obtain a viscous polymer solution, i.e., the polymerization stock solution, which was naturally cooled to room temperature for use;

[0074] (b) Preparation of bio-based aromatic polyamide fibers

[0075] The polymerization solution is filtered and deaerated to obtain the spinning solution;

[0076] The spinning solution was sprayed through a spinneret with a 75μm pore size into a 60°C coagulation bath containing an aqueous solution of CaCl2 and DMAC, with a CaCl2 concentration of 4% by mass and a water-to-DMAC ratio of 70:30 by volume. The spun fibers were then stretched in the coagulation bath to form fibers. The fibers were then washed in 65°C water and stretched 3.0 times in a 65°C hot water bath (i.e., hot water stretching). The fibers were then dried at 120°C and heat-set at 180°C, stretching them 1.5 times to obtain the fiber product.

[0077] Example 2

[0078] The preparation method of the bio-based aromatic polyamide fiber provided in this embodiment comprises the following steps:

[0079] (a) Synthesis of bio-based aromatic polyamide polymers

[0080] 3000 g of 2,5-furandicarboxylic acid, 800 g of anhydrous calcium chloride, 200 g of anhydrous lithium chloride, and 20.0 L of N,N-dimethylacetamide (DMAC) were added to a 50 L double-layer glass reactor. After the addition was completed, the reactor was sealed and high-purity nitrogen was introduced into the reactor. This process was repeated three times to expel the air in the reactor and then maintained at normal pressure. The reaction mixture was stirred at 70° C. until the solution became clear, thereby obtaining a first solution.

[0081] 2077 g of m-phenylenediamine, 2.0 L of pyridine, and 1.0 L of triphenyl phosphite were added to the first solution and mixed to obtain a second solution;

[0082] Keeping nitrogen flowing, the second solution was heated to 140°C, and then kept warm for 6 hours to obtain a viscous polymer solution, i.e., the polymerization stock solution, which was naturally cooled to room temperature for use;

[0083] (b) Preparation of bio-based aromatic polyamide fibers

[0084] The steps of preparing the finished fiber product using the polymerization solution are the same as those in Example 1, to obtain the fiber product.

[0085] Example 3

[0086] The preparation method of the bio-based aromatic polyamide fiber provided in this embodiment comprises the following steps:

[0087] (a) Synthesis of bio-based aromatic polyamide polymers

[0088] 3000 g of 2,5-furandicarboxylic acid, 800 g of anhydrous calcium chloride, 200 g of anhydrous lithium chloride, and 20.0 L of N,N-dimethylacetamide (DMAC) were added to a 50 L double-layer glass reactor. After the addition was completed, the reactor was sealed and high-purity nitrogen was introduced into the reactor. This process was repeated three times to expel the air in the reactor and then maintained at normal pressure. The reaction mixture was stirred at 70° C. until the solution became clear, thereby obtaining a first solution.

[0089] 2426 g of 2,5-furandimethylamine, 2.0 L of pyridine, and 1.0 L of triphenyl phosphite were added to the first solution and mixed to obtain a second solution;

[0090] Keeping nitrogen flowing, the second solution was heated to 140°C, and then kept warm for 6 hours to obtain a viscous polymer solution, i.e., the polymerization stock solution, which was naturally cooled to room temperature for use;

[0091] (b) Preparation of bio-based aromatic polyamide fibers

[0092] The steps of preparing the finished fiber product using the polymerization solution are the same as those in Example 1, to obtain the fiber product.

[0093] Example 4

[0094] The preparation method of the bio-based aromatic polyamide fiber provided in this embodiment comprises the following steps:

[0095] (a) Synthesis of bio-based aromatic polyamide polymers

[0096] 3000 g of 3,4-furandicarboxylic acid, 800 g of anhydrous calcium chloride, 200 g of anhydrous lithium chloride, and 20.0 L of N,N-dimethylacetamide (DMAC) were added to a 50 L double-layer glass reactor. After the addition was completed, the reactor was sealed and high-purity nitrogen was introduced into the reactor. This process was repeated three times to expel the air in the reactor and then maintained at normal pressure. The reaction mixture was stirred at 70° C. until the solution became clear, thereby obtaining a first solution.

[0097] 2077 g of p-phenylenediamine, 2.0 L of pyridine, and 1.0 L of triphenyl phosphite were added to the first solution and mixed to obtain a second solution;

[0098] Keeping nitrogen flowing, the second solution was heated to 140°C, and then kept warm for 6 hours to obtain a viscous polymer solution, i.e., the polymerization stock solution, which was naturally cooled to room temperature for use;

[0099] (b) Preparation of bio-based aromatic polyamide fibers

[0100] The steps of preparing the finished fiber product using the polymerization solution are the same as those in Example 1, to obtain the fiber product.

[0101] Example 5

[0102] The preparation method of the bio-based aromatic polyamide fiber provided in this embodiment comprises the following steps:

[0103] (a) Synthesis of bio-based aromatic polyamide polymers

[0104] 3000 g of 2,5-furandicarboxylic acid, 800 g of anhydrous calcium chloride, 200 g of anhydrous lithium chloride, and 20.0 L of N-methyl-2-pyrrolidone (NMP) were added to a 50 L double-layer glass reactor. After the addition was completed, the reactor was sealed and high-purity nitrogen was introduced into the reactor. This process was repeated three times to expel the air in the reactor and then maintained at normal pressure. The reaction mixture was stirred at 70° C. until the solution became clear, thereby obtaining a first solution.

[0105] 2077 g of p-phenylenediamine, 2.0 L of pyridine, and 1.0 L of triphenyl phosphite were added to the first solution and mixed to obtain a second solution;

[0106] Keeping nitrogen flowing, the second solution was heated to 140°C, and then kept warm for 6 hours to obtain a viscous polymer solution, i.e., the polymerization stock solution, which was naturally cooled to room temperature for use;

[0107] (b) Preparation of bio-based aromatic polyamide fibers

[0108] The steps of preparing the finished fiber product using the polymerization stock solution are the same as those in Example 1, to obtain the fiber product.

[0109] Example 6

[0110] The preparation method of the bio-based aromatic polyamide fiber provided in this embodiment comprises the following steps:

[0111] (a) Synthesis of bio-based aromatic polyamide polymers

[0112] 3000 g of 2,5-furandicarboxylic acid, 1000 g of anhydrous calcium chloride, and 20.0 L of N,N-dimethylacetamide (DMAC) were added to a 50 L double-layer glass reactor. After the addition was completed, the reactor was sealed and high-purity nitrogen was introduced into the reactor. This process was repeated three times to expel the air in the reactor and then maintained at normal pressure. The reaction mixture was stirred at 70° C. until the solution became clear, thereby obtaining a first solution.

[0113] 2077 g of p-phenylenediamine, 2.0 L of pyridine, and 1.0 L of triphenyl phosphite were added to the first solution and mixed to obtain a second solution;

[0114] Keeping nitrogen flowing, the second solution was heated to 140°C, and then kept warm for 6 hours to obtain a viscous polymer solution, i.e., the polymerization stock solution, which was naturally cooled to room temperature for use;

[0115] (b) Preparation of bio-based aromatic polyamide fibers

[0116] The steps of preparing the finished fiber product using the polymerization stock solution are the same as those in Example 1, to obtain the fiber product.

[0117] Example 7

[0118] The preparation method of the bio-based aromatic polyamide fiber provided in this embodiment comprises the following steps:

[0119] (a) Synthesis of bio-based aromatic polyamide polymers

[0120] 3000 g of 2,5-furandicarboxylic acid, 800 g of anhydrous calcium chloride, 200 g of anhydrous lithium chloride, and 20.0 L of N,N-dimethylacetamide (DMAC) were added to a 50 L double-layer glass reactor. After the addition was completed, the reactor was sealed and high-purity nitrogen was introduced into the reactor. This process was repeated three times to expel the air in the reactor and then maintained at normal pressure. The reaction mixture was stirred at 70° C. until the solution became clear, thereby obtaining a first solution.

[0121] 2077 g of p-phenylenediamine, 2.0 L of triethylamine, and 1.0 L of triphenyl phosphite were added to the first solution and mixed to obtain a second solution;

[0122] Keeping nitrogen flowing, the second solution was heated to 140°C, and then kept warm for 6 hours to obtain a viscous polymer solution, i.e., the polymerization stock solution, which was naturally cooled to room temperature for use;

[0123] (b) Preparation of bio-based aromatic polyamide fibers

[0124] The steps of preparing the finished fiber product using the polymerization stock solution are the same as those in Example 1, to obtain the fiber product.

[0125] Example 8

[0126] The preparation method of the bio-based aromatic polyamide fiber provided in this embodiment comprises the following steps:

[0127] (a) Synthesis of bio-based aromatic polyamide polymers

[0128] 3000 g of 2,5-furandicarboxylic acid, 800 g of anhydrous calcium chloride, 200 g of anhydrous lithium chloride, and 20.0 L of N,N-dimethylacetamide (DMAC) were added to a 50 L double-layer glass reactor. After the addition was completed, the reactor was sealed and high-purity nitrogen was introduced into the reactor. This process was repeated three times to expel the air in the reactor and then maintained at normal pressure. The reaction mixture was stirred at 70° C. until the solution became clear, thereby obtaining a first solution.

[0129] 2077 g of p-phenylenediamine, 2.0 L of pyridine, and 1.0 L of tetrabutyl titanate were added to the first solution and mixed to obtain a second solution;

[0130] Keeping nitrogen flowing, the second solution was heated to 140°C, and then kept warm for 6 hours to obtain a viscous polymer solution, i.e., the polymerization stock solution, which was naturally cooled to room temperature for use;

[0131] (b) Preparation of bio-based aromatic polyamide fibers

[0132] The steps of preparing the finished fiber product using the polymerization solution are the same as those in Example 1, to obtain the fiber product.

[0133] Example 9

[0134] The preparation method of the bio-based aromatic polyamide fiber provided in this embodiment comprises the following steps:

[0135] (a) Synthesis of bio-based aromatic polyamide polymers

[0136] The preparation of the polymerization stock solution was the same as in Example 1. After the polymerization stock solution was obtained, it was naturally cooled to room temperature for use;

[0137] (b) Preparation of bio-based aromatic polyamide fibers

[0138] The polymerization solution is filtered and deaerated to obtain the spinning solution;

[0139] The spinning solution is sprayed through a spinneret with a 75μm pore size into a 60°C coagulation bath containing an aqueous solution of CaCl2 and N-methyl-2-pyrrolidone (NMP), with a CaCl2 concentration of 4% by mass and a water-to-NMP ratio of 70:30 by volume. The spun fibers are then stretched in the coagulation bath to form fibers. The fibers are then washed in 65°C water and stretched 3.0 times in a 65°C hot water bath. The fibers are then dried at 120°C and heat-set at 180°C, where they are stretched 1.5 times to produce the fiber product.

[0140] Example 10

[0141] The preparation method of the bio-based aromatic polyamide fiber provided in this embodiment comprises the following steps:

[0142] (a) Synthesis of bio-based aromatic polyamide polymers

[0143] The preparation of the polymerization stock solution was the same as in Example 1. After the polymerization stock solution was obtained, it was naturally cooled to room temperature for use;

[0144] (b) Preparation of bio-based aromatic polyamide fibers

[0145] The polymerization solution is filtered and deaerated to obtain the spinning solution;

[0146] The spinning solution was sprayed through a spinneret with a 75 μm pore size into a 60°C coagulation bath containing an aqueous solution of DMAC in a volume ratio of 70:30. The spun fibers were then stretched in the coagulation bath to form fibers. The fibers were then washed in 65°C water and stretched 3.0 times in a 65°C hot water bath. The fibers were then dried at 120°C and heat-set at 180°C, stretching them 1.5 times to obtain the fiber product.

[0147] Example 11

[0148] The preparation method of the bio-based aromatic polyamide fiber provided in this embodiment comprises the following steps:

[0149] (a) Synthesis of bio-based aromatic polyamide polymers

[0150] The preparation of the polymerization stock solution was the same as in Example 1. After the polymerization stock solution was obtained, it was naturally cooled to room temperature for use;

[0151] (b) Preparation of bio-based aromatic polyamide fibers

[0152] The polymerization solution is filtered and deaerated to obtain the spinning solution;

[0153] The spinning solution was sprayed through a spinneret with a 75μm pore size into a 60°C coagulation bath containing an aqueous solution of CaCl2 and DMAC, with a CaCl2 concentration of 4% by mass and a water-to-DMAC ratio of 70:30 by volume. The spun fibers were then stretched in the coagulation bath to form fibers. The fibers were then washed in 65°C water and stretched 2.5 times in a 65°C hot water bath. The fibers were then dried at 120°C and heat-set at 180°C, where they were stretched 1.5 times to obtain the fiber product.

[0154] Example 12

[0155] The preparation method of the bio-based aromatic polyamide fiber provided in this embodiment comprises the following steps:

[0156] (a) Synthesis of bio-based aromatic polyamide polymers

[0157] The preparation of the polymerization stock solution was the same as in Example 1. After the polymerization stock solution was obtained, it was naturally cooled to room temperature for use;

[0158] (b) Preparation of bio-based aromatic polyamide fibers

[0159] The polymerization solution is filtered and deaerated to obtain the spinning solution;

[0160] The spinning solution was sprayed through a spinneret with a 75μm pore size into a 60°C coagulation bath containing an aqueous solution of CaCl2 and DMAC, with a CaCl2 concentration of 4% by mass and a water-to-DMAC ratio of 70:30 by volume. The spun fibers were then stretched in the coagulation bath to form fibers. The fibers were then washed in 65°C water and stretched 3.0 times in a 65°C hot water bath. The fibers were then dried at 120°C and heat-set at 180°C, where they were stretched 1.0 times to obtain a fiber product.

[0161] Comparative Example 1

[0162] This comparative example provides a method for preparing aromatic polyamide fibers, comprising the following steps:

[0163] (a) Synthesis of aromatic polyamide polymers

[0164] 3000 g of isophthaloyl chloride and 15 L of N,N-dimethylacetamide were added to a 50 L double-layer glass reactor. After the addition was completed, the reactor was sealed and high-purity nitrogen was introduced into the reactor. This process was repeated three times to expel the air in the reactor and then maintained at normal pressure. After stirring at 0°C until the solution became clear, 1620 g of m-phenylenediamine and 810 g of calcium hydroxide were added. The nitrogen flow was maintained, and the temperature was raised to 60°C and the reaction was carried out for 6 hours to obtain a viscous polymer solution, i.e., a polymerization stock solution. The solution was then naturally cooled to room temperature for use.

[0165] (b) Preparation of aromatic polyamide fibers

[0166] The steps of preparing the finished fiber product using the polymerization solution are the same as those in Example 1, to obtain the fiber product.

[0167] Comparative Example 2

[0168] This comparative example provides a method for preparing aromatic polyamide fiber, and the preparation steps are as follows:

[0169] (a) Synthesis of aromatic polyamide polymers

[0170] 3000 g of 2,5-furandicarboxylic acid, 800 g of anhydrous calcium chloride, 200 g of anhydrous lithium chloride, and 20.0 L of N,N-dimethylacetamide (DMAC) were added to a 50 L double-layer glass reactor. After the addition was completed, the reactor was sealed and high-purity nitrogen was introduced into the reactor. This process was repeated three times to expel the air in the reactor and then maintained at normal pressure. The reactor was stirred at 50° C. until the solution became clear, thereby obtaining a first solution.

[0171] 2077 g of p-phenylenediamine, 2.0 L of pyridine, and 1.0 L of triphenyl phosphite were added to the first solution and mixed to obtain a second solution;

[0172] Keeping nitrogen flowing, the second solution was kept at 50°C for 6 hours to react to obtain a polymer solution with low viscosity, i.e., the polymerization stock solution, which was naturally cooled to room temperature for use;

[0173] (b) Preparation of aromatic polyamide fibers

[0174] After testing, it was found that the viscosity of the polymerization solution was low and normal spinning was not possible.

[0175] Comparative Example 3

[0176] This comparative example provides a method for preparing aromatic polyamide fiber, the steps are as follows:

[0177] (a) Synthesis of aromatic polyamide polymers

[0178] 3000 g of 2,5-furandicarboxylic acid, 800 g of anhydrous calcium chloride, 200 g of anhydrous lithium chloride, and 20.0 L of N,N-dimethylformamide (DMF) were added to a 50 L double-layer glass reactor. After the addition was completed, the reactor was sealed and high-purity nitrogen was introduced into the reactor. This process was repeated three times to expel the air in the reactor and then maintained at normal pressure. The reactor was stirred at 90° C. until the solution became clear, thereby obtaining a first solution.

[0179] 2077 g of p-phenylenediamine, 2.0 L of pyridine, and 1.0 L of triphenyl phosphite were added to the first solution and mixed to obtain a second solution;

[0180] Keeping nitrogen flowing, the second solution was heated to 150°C and kept to react for 6 hours to obtain a polymer solution with low viscosity, i.e., the polymerization stock solution, which was naturally cooled to room temperature for use;

[0181] (b) Preparation of aromatic polyamide fibers

[0182] The steps of preparing the finished fiber product using the polymerization solution are the same as those in Example 1, to obtain the fiber product.

[0183] Performance testing

[0184] The fiber products obtained in the above examples and comparative examples were subjected to performance tests, and the test items and methods are as follows.

[0185] Relative viscosity is determined according to GB / T 38138-2019;

[0186] Fiber moisture regain is determined according to GB / T 6503-2008;

[0187] Mechanical properties include breaking strength, elongation at break and initial modulus, measured in accordance with GB / T 19975-2005;

[0188] The cationic dyeing process is carried out according to GB / T 2399-2003. The absorbance of the residual dyeing solution and the original dyeing solution after dyeing is measured by UV-2600 ultraviolet spectrophotometer. The dye uptake is calculated based on the difference in absorbance. The dye uptake calculation formula is:

[0189] ;

[0190] in, Aa is the absorbance of the residual dye solution, A 0 is the absorbance of the dye stock solution.

[0191] The performance test results of the fiber products obtained in the above Examples 1-12 and Comparative Examples 1-3 are shown in Table 1.

[0192] Table 1

[0193]

[0194] As shown in Table 1, the bio-based aromatic polyamide fiber produced using the bio-based monomer furandicarboxylic acid exhibits superior mechanical strength compared to petroleum-based meta-aramid, with a lower initial modulus, high moisture regain, and high cationic dye uptake. Fabrics made from bio-based aramid fiber offer a smoother texture, excellent moisture wicking properties, and vibrant colors, promising broader applications in the textile industry.

[0195] Specifically, Examples 1-4 prepared bio-based aramid fibers with different repeating structural units, mainly including poly-2,5-furandicarboxamide-p-phenylenediamine (Example 1), poly-2,5-furandicarboxamide-m-phenylenediamine (Example 2), poly-2,5-furandicarboxamide-furandimethylamine (Example 3), and poly-3,4-furandicarboxamide-p-phenylenediamine (Example 4). The relative viscosity shows that poly-2,5-furandicarboxamide-p-phenylenediamine has a relatively high relative viscosity, and its GPC test results are as follows. Figure 1 As shown, the weight average molecular weight M w >100,000, with a molecular weight distribution index of 1.5. Paraphenylenediamine possesses optimal molecular symmetry, which facilitates the growth of polyamide macromolecular chains. Furthermore, other aromatic diamines also exhibit high reactivity with furandicarboxylic acid, enabling direct solution polymerization to achieve the desired molecular weight, meeting direct spinning processing requirements.

[0196] In Example 5, Example 7, and Example 8, the polar solvent, organic base, and catalyst in Example 1 were replaced respectively. The test results of bio-based aramid showed that the same good effects were achieved, and the prepared polymers and fibers had excellent physical properties.

[0197] In Example 6, when preparing the polymerization stock solution, only calcium chloride was used as the cosolvent. As can be seen from Table 1, the prepared poly-2,5-furandicarboxamide has a relatively low viscosity and a relatively low fiber strength. Therefore, the use of a composite cosolvent of calcium chloride and lithium chloride has a better polymerization effect on bio-based aromatic polyamide.

[0198] Examples 9-12 investigated the solution spinning process for bio-based polyamide, focusing on the coagulation bath composition, hot water stretching, and heat setting stretching. Table 1 shows that a coagulation bath containing DMAC-CaCl2 and a hot water stretching ratio of 3.0x are the preferred processes for preparing bio-based polyamide fibers.

[0199] In Comparative Example 2, polymerization was attempted at a lower reaction temperature, and the diacid was directly used as a reaction monomer. Its reaction activity with diamine was low, and a high molecular weight could not be obtained, so it was not spinnable. In Comparative Example 3, the solvent was N,N-dimethylformamide (DMF), which has poor solubility in monomers. Therefore, the reaction temperature of the first solution needed to be increased. At the same time, the final polymer had a low relative viscosity and poor fiber mechanical properties. Therefore, DMF is not suitable for high-temperature solution polymerization to prepare furan-based aromatic polyamide.

[0200] In summary, the test data from the above examples and comparative examples demonstrate that the bio-based aramid fibers prepared by the present invention have stable performance and are suitable for large-scale development. The present invention begins with polymer preparation, then produces a high-quality polymer solution, which is then wet-spinned to produce uniform bio-based aramid fibers with good flexibility, high hygroscopicity, and easy dyeing. This preparation process is simple, with stable fiber properties and high production efficiency.

[0201] Although the present invention has been described in detail above using general explanations, specific embodiments, and experiments, it will be apparent to those skilled in the art that modifications and improvements may be made based on the present invention. Therefore, such modifications and improvements, which do not depart from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. Application of bio-based aromatic polyamide fiber in textile preparation, characterized in that: The preparation method of the bio-based aromatic polyamide fiber comprises: using a bio-based furan dicarboxylic acid represented by general formula (I) and an aromatic diamine represented by general formula (II) as raw materials, performing solution polymerization to prepare a bio-based aromatic polyamide polymerization stock solution; and spinning the polymerization stock solution to obtain a bio-based aromatic polyamide fiber product; HOOC-X-COOH (I); H2N-Y-NH2 (Ⅱ); The bio-based furandicarboxylic acid is 2,5-furandicarboxylic acid and / or 3,4-furandicarboxylic acid; The aromatic diamine is selected from any one or more of p-phenylenediamine, m-phenylenediamine, and 2,5-furandimethylamine; The preparation of the polymerization stock solution comprises the following steps: (1) Under inert gas protection, a polar solvent, a bio-based furan dicarboxylic acid represented by the general formula (I), and a cosolvent are mixed at 70° C. to obtain a first solution; (2) the first solution is mixed with an aromatic diamine represented by the general formula (II), an organic base, and a catalyst to obtain a second solution; the molar ratio of the bio-based furan dicarboxylic acid represented by the general formula (I) to the aromatic diamine represented by the general formula (II) is 1:1; the molar ratio of the organic base to the bio-based furan dicarboxylic acid represented by the general formula (I) is 1.3:1; the organic base is selected from one or more of triethylamine, pyridine, and sodium methoxide; (3) subjecting the second solution to solution polymerization at 140° C. to obtain a polymerization stock solution; The polymer solution spinning comprises: extruding the polymer solution through a spinneret, solidifying and forming the solution, and then stretching the solution with hot water and heat setting to obtain a bio-based aromatic polyamide fiber product; Wherein, the pore size of the spinneret is 50~90μm; The coagulation bath effective ingredients used in the coagulation forming include CaCl2 and N,N-dimethylacetamide; The cosolvent is a mixture of calcium chloride and lithium chloride in a mass ratio of 4:1; the stretching ratio of the hot water stretching is 3 times; The stretching ratio of the heat setting stretching is 1 to 1.5 times.

2. The use according to claim 1, characterized in that The polar solvent is any one of N,N-dimethylacetamide and N-methyl-2-pyrrolidone or a mixture of the two; and / or, The concentration of the bio-based furan dicarboxylic acid represented by general formula (I) in the first solution is 0.7-1.3 mol / L; and / or, The amount of the co-solvent added is 40-85 g per liter of polar solvent.

3. The use according to claim 1, characterized in that The catalyst is triphenyl phosphite and / or tetrabutyl titanate; and / or, The amount of the catalyst used is 1-10% of the volume of the polar solvent.

4. The use according to claim 1, characterized in that Application in the preparation of industrial protective clothing, racing suits, space suits, and tire cord fabrics.

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