Preparation method of anthraquinone colored soft aramid fiber

Abstract

The invention discloses a preparation method of anthraquinone colored soft aramid fibers, and belongs to the field of high-performance aromatic polyamide materials. Monomers containing aryl ether and having an anthraquinone structure with a color development effect are introduced into a molecular chain to prepare the modified aramid fiber, and the viscosity of a spinning stock solution is 300-500 Po. According to the aromatic polyamide polymer disclosed by the invention, the molecular structure is optimized on the basis of the original polyisophthaloyl metaphenylene diamine, so that the aromatic polyamide polymer has the characteristics of low modulus, high strength and high elongation at break and also keeps excellent flame retardant property, and the color range covers a full chromatogram of 400-700nm. According to the method, the problems of rigidity and brittleness of traditional aramid fibers in processing are solved, and polyamide can obtain different colors according to requirements.

Description

Technical Field

[0001] This invention belongs to the field of high-performance aromatic polyamide materials, specifically relating to a method for preparing anthraquinone-based colored soft aramid. Background Technology

[0002] Aramid fibers are widely used in aerospace, military, transportation, and communications fields due to their excellent flame retardancy, mechanical properties, chemical stability, and electrical insulation. However, the regular stacking structure of benzene rings and the highly oriented intermolecular hydrogen bonds in aramid molecules lead to the rigidity of the molecular chains and the brittleness of the material, affecting the processing and practical applications. Two key issues need to be considered when modifying aramid fibers to improve their flexibility: mechanical strength and thermal stability. Generally, breaking strength decreases as the elastic modulus decreases, and improving material strength always contradicts improving flexibility. On the other hand, modified aramid fibers, by weakening the benzene ring stacking effect and disrupting the regularity between molecular chains, experience a decrease in thermal stability.

[0003] Furthermore, aramid fibers have a compact molecular structure and a glass transition temperature of 270℃, making it difficult to obtain color through dyeing. Conventional dyeing methods are difficult to apply dyes to, and industrially, colored aromatic polyamides are mostly prepared using high-temperature, high-pressure dyeing or solution dyeing methods. However, high-temperature, high-pressure dyeing requires sophisticated equipment and consumes a lot of energy, while solution dyeing also has some problems, such as inflexibility in production, complex processes when changing fiber colors, and unstable product colors in small-scale production. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a method for preparing anthraquinone-based colored soft aramid fibers, thereby solving the rigidity and brittleness issues of aromatic polyamides during processing and imparting color to the polyamides. This method involves copolymerizing aromatic ethers and anthraquinone monomers, followed by a wet spinning process to prepare colored soft aramid fibers.

[0005] To achieve the above objectives, the present invention provides an anthraquinone-based colored soft aramid fiber, wherein the aramid fiber has the following structural formula I:

[0006]

[0007] Wherein, 85≤x≤94, 5.5≤y≤13, 0.5≤z≤2;

[0008] The structure of Ar1 in Formula I includes:

[0009]

[0010]

[0011] The structure of Ar2 in Formula I includes:

[0012]

[0013] Among them, R1, R2, R3, R4, R5, and R6 are selected from hydrogen, halogen, ether, alkyl, nitro, cyano, thioalkyl, alkoxy, phenoxy, or alkylamine, and R7 is selected from ether, alcohol, ester, or alkyl.

[0014] Furthermore, in Equation I, 88≤x≤94, 5.5≤y≤10, and 0.5≤z≤1.5.

[0015] Furthermore, the structure of Ar1 in Formula I can be any of the following structures:

[0016]

[0017] Furthermore, the structure of Ar2 in Formula I can be any of the following:

[0018]

[0019] Among them, R1, R2, R3, R4, R5, and R6 are selected from hydrogen, alkoxy, and nitro, and R7 is selected from alkyl and ether.

[0020] This invention also provides a method for preparing anthraquinone-based colored soft aramid fibers, the method comprising the following steps:

[0021] (1) Add m-phenylenediamine, Br1 and Br2 to an organic solvent, cool to 0-5℃, add isophthaloyl chloride and react for 1-2 hours, heat to 55-65℃ and add neutralizing agent and react for 10-20 minutes to obtain colored soft aramid spinning solution.

[0022] (2) The spinning solution is formed by coagulation bath, washed, dried and heat-set to obtain colored soft aramid.

[0023] In one embodiment of the present invention, the structural formula of Br1 in step (1) is shown in Formula II as follows:

[0024] H2N-Ar1-NH2 type II

[0025] The structure of Ar1 in Formula II includes:

[0026]

[0027] In one embodiment of the present invention, the structural formula of Br2 in step (1) is shown in Formula III:

[0028] H2N-Ar2-NH2 type III

[0029] The structure of Ar2 in Formula III includes:

[0030]

[0031] R1, R2, R3, R4, R5, and R6 are selected from hydrogen, halogen, ether, alkyl, nitro, cyano, thioalkyl, alkoxy, phenoxy, or alkylamine, and R7 is selected from ether, alcohol, ester, or alkyl.

[0032] In one embodiment of the present invention, the structure of Ar1 in Formula II is any one of the following structures:

[0033]

[0034] In one embodiment of the present invention, the Ar2 in Formula III has any of the following structures:

[0035]

[0036] Among them, R1, R2, R3, R4, R5, and R6 are selected from hydrogen, alkoxy, and nitro, and R7 is selected from alkyl and ether.

[0037] In one embodiment of the present invention, Br2 in step (1) is a colored monomer with a color development wavelength range of 400 to 700 nm.

[0038] In one embodiment of the present invention, the molar ratio of intermediate phenylenediamine to Br1 in step (1) is 10:0.8 to 1.2.

[0039] In one embodiment of the present invention, the molar ratio of intermediate phenylenediamine to Br2 in step (1) is 90:0.4 to 1.8.

[0040] In one embodiment of the present invention, the organic solvent in step (1) is one or more of N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide.

[0041] In one embodiment of the present invention, the concentration of intermediate phenylenediamine in the organic solvent in step (1) is 0.5 to 1.5 mol / L.

[0042] In one embodiment of the present invention, the molar ratio of intermediate phenylenediamine and phthaloyl chloride in step (1) is 1:1 to 1.2.

[0043] In one embodiment of the present invention, phthaloyl chloride in step (1) needs to be added in two parts; the amount of phthaloyl chloride added in the first part is 70-80% of the total molar amount of phthaloyl chloride, and the remaining phthaloyl chloride is added in the second part; the time interval between the two additions of phthaloyl chloride is 10-30 minutes.

[0044] In one embodiment of the present invention, the neutralizing agent in step (1) is one of calcium oxide, calcium hydroxide or triethylamine.

[0045] In one embodiment of the present invention, the molar ratio of intermediate phenylenediamine and neutralizing agent in step (1) is 1:1 to 1.2.

[0046] In one embodiment of the present invention, the reaction in step (1) is carried out in a nitrogen atmosphere.

[0047] In one embodiment of the present invention, the reaction in step (1) is carried out under stirring; the stirring speed is 400-500 r / min.

[0048] In one embodiment of the present invention, the coagulation liquid in the coagulation bath in step (2) is a mixture of organic solvent and water; the organic solvent includes N,N-dimethylacetamide; the organic solvent accounts for 20% to 40% of the mass fraction of the coagulation liquid.

[0049] In one embodiment of the present invention, the stretching ratio during the solidification bath forming process in step (2) is 1.5 to 3.5.

[0050] In one embodiment of the present invention, the drying temperature in step (2) is 80-160°C.

[0051] In one embodiment of the present invention, the heat setting temperature in step (2) is 200-350°C, and the heat setting draw ratio is 1.2-2.

[0052] This invention provides anthraquinone-based colored soft aramid fibers prepared according to the above method.

[0053] The present invention provides the application of anthraquinone-based colored soft aramid fibers in the fields of textiles, clothing, composite material preparation, building materials, and electronic equipment.

[0054] The present invention has the following beneficial effects:

[0055] 1. This invention, based on the original meta-aramid, enhances the flexibility of the molecular chain by introducing an aromatic ether structure, while retaining the inherent strength of meta-aramid. The prepared aromatic polyamide has the characteristics of low modulus, high strength, and high elongation at break, which can greatly improve the rigidity and brittleness of meta-aramid, thus making it easier to process and mold.

[0056] 2. This invention imparts color to meta-aramid fibers by introducing colored monomers into the molecular chain, and the color of the aramid fibers can be controlled by adjusting the monomer ratio, exhibiting good operability. Because the color of the aramid fibers is altered at the molecular structure level, it possesses excellent colorfastness.

[0057] 3. The colored soft aramid provided by this invention has excellent flame retardancy and thermal stability, and can be used for a long time under high temperature conditions. Attached Figure Description

[0058] Figure 1The GPC curves are for Examples 1-5 and Comparative Example 1.

[0059] Figure 2 The color reflectance curves are for Examples 1, 2, and 3. Detailed Implementation

[0060] The present invention will be further illustrated below with specific examples. These examples are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0061] Example 1

[0062] A colored, soft aramid fiber of the anthraquinone class, with the following molecular structure:

[0063]

[0064] Where x = 90, y = 9, z = 1;

[0065] The preparation steps are as follows:

[0066] (1) Under a nitrogen-drying environment below 0℃, 4.5 mol m-phenylenediamine, 0.45 mol 4,4'-diaminodiphenyl ether and 0.05 mol 1,4-diamino-9,10-anthraquinone were dissolved in 4.5 L N,N-dimethylacetamide, then 4 mol isophthaloyl chloride was added and reacted for 20 min, then 1 mol isophthaloyl chloride was added and reacted at 0℃ for 1.5 h, then the temperature was raised to 60℃, and then 5 mol calcium hydroxide was added and reacted for another 15 min to obtain a colored soft aramid spinning solution with a solid content of 22% and a viscosity of 450 Po.

[0067] (2) The spinning solution is stretched and shaped in a coagulation bath containing 30% N,N-dimethylacetamide with a draw ratio of 3. After washing with water, it is dried at 100℃ and then heat-set at 280℃ with a draw ratio of 2. After oiling, crimping and cutting, the strength of the short fibers obtained can reach more than 3.0 cN / dtex, the elongation at break is more than 20%, and the color wavelength range is 610~700nm and 400~425nm.

[0068] Example 2

[0069] A colored, soft aramid fiber of the anthraquinone class, with the following molecular structure:

[0070]

[0071] Where x = 90, y = 9, z = 1;

[0072] The preparation steps are as follows:

[0073] (1) Under a nitrogen-drying environment below 0℃, 4.5 mol m-phenylenediamine, 0.45 mol 1,4-bis(4-aminophenoxy)benzene and 0.05 mol 1,4-diamino-2-methoxy-9,10-anthraquinone were dissolved in 4.5 L N,N-dimethylacetamide, and then 4 mol isophthaloyl chloride was added and reacted for 20 min. Then 1 mol isophthaloyl chloride was added and reacted at 0℃ for 1.5 h. After that, the temperature was raised to 60℃ and 5 mol calcium hydroxide was added and the reaction was continued for 15 min to obtain a colored soft aramid spinning solution with a solid content of 20% and a viscosity of 400 Po.

[0074] (2) The spinning solution is stretched and shaped in a coagulation bath containing 30% N,N-dimethylacetamide with a draw ratio of 2.5. After washing with water, it is dried at 100℃ and then heat-set at 280℃ with a draw ratio of 1.5. After oiling, crimping and cutting, the strength of the short fibers obtained can reach more than 3.0 cN / dtex, the elongation at break is more than 15%, and the color wavelength range is 550-700nm.

[0075] Example 3

[0076] A colored, soft aramid fiber of the anthraquinone class, with the following molecular structure:

[0077]

[0078] Where x = 90, y = 9, z = 1;

[0079] The preparation steps are as follows:

[0080] (1) Under nitrogen-drying conditions below 0℃, 4.5 mol m-phenylenediamine, 0.45 mol 1,4-bis(4-aminophenoxy)benzene and 0.05 mol 2-butyl-1H-cyclopentano[b]anthracene-1,3,5,10(2H)-tetraone were dissolved in 4.5 L N,N-dimethylacetamide, then 4 mol isophthaloyl chloride was added and reacted for 30 min, then 1 mol isophthaloyl chloride was added and reacted at 0℃ for 1.5 h, then the temperature was raised to 60℃, and then 5 mol calcium hydroxide was added and reacted for another 15 min to obtain a colored soft aramid spinning solution with a solid content of 20% and a viscosity of 420 Po.

[0081] (2) The spinning solution is stretched and shaped in a coagulation bath containing 30% N,N-dimethylacetamide with a draw ratio of 1.5. After washing with water, it is dried at 120°C and then heat-set at 300°C with a draw ratio of 2. After oiling, crimping and cutting, the strength of the short fibers obtained can reach more than 3.0 cN / dtex, the elongation at break is more than 20%, and the color wavelength range is 400-550nm.

[0082] Example 4

[0083] A colored, soft aramid fiber of the anthraquinone class, with the following molecular structure:

[0084]

[0085] Where x = 90, y = 9, z = 1;

[0086] The preparation steps are as follows:

[0087] (1) Under a nitrogen-drying environment below 0℃, 4.5 mol m-phenylenediamine, 0.45 mol 1,3-bis(4'-aminophenoxy)benzene and 0.05 mol 1,4-diamino-2,3-dichloroanthraquinone were dissolved in 4.5 L N,N-dimethylacetamide, then 4 mol isophthaloyl chloride was added and reacted for 20 min, then 1 mol isophthaloyl chloride was added and reacted at 0℃ for 1.5 h, then the temperature was raised to 60℃, and then 5 mol calcium hydroxide was added and reacted for another 15 min to obtain a colored soft aramid spinning solution with a solid content of 22% and a viscosity of 380 Po.

[0088] (2) The spinning solution is stretched and shaped in a coagulation bath containing 30% N-methylpyrrolidone with a draw ratio of 2.5. After washing with water, it is dried at 100℃ and then heat-set at 280℃ with a draw ratio of 1.5. After oiling, crimping and cutting, the strength of the short fibers obtained can reach more than 3.0 cN / dtex, the elongation at break is more than 20%, and the color wavelength range is 600-700nm and 400-450nm.

[0089] Example 5

[0090] A colored, soft aramid fiber of the anthraquinone class, with the following molecular structure:

[0091]

[0092] Where x = 90, y = 9, z = 1;

[0093] The preparation steps are as follows:

[0094] (1) Under a nitrogen-drying environment below 0℃, 4.5 mol of m-phenylenediamine, 0.45 mol of 1,3-bis(4'-aminophenoxy)benzene and 0.05 mol of 2-(3-methoxypropyl)-1H-cyclopentano[b]anthracene-1,3,5,10(2H)-tetraone were dissolved in 4.5 L of N,N-dimethylacetamide, and then 4 mol of isophthaloyl chloride was added and reacted for 20 min. Then 1 mol of isophthaloyl chloride was added and reacted at 0℃ for 1.5 h. After that, the temperature was raised to 60℃ and 5 mol of calcium hydroxide was added and the reaction was continued for 15 min to obtain a colored soft aramid spinning solution with a solid content of 20% and a viscosity of 350 Po.

[0095] (2) The spinning solution is stretched and shaped in a coagulation bath containing 30% N,N-dimethylformamide with a draw ratio of 2.5. After washing with water, it is dried at 100℃ and then heat-set at 280℃ with a draw ratio of 1.5. After oiling, crimping and cutting, the strength of the short fibers obtained can reach more than 3.0 cN / dtex, the elongation at break is more than 20%, and the color wavelength range is 400-525nm.

[0096] Compare with Example 1

[0097] The preparation steps are as follows:

[0098] (1) At 0℃ or below, 5 mol of m-phenylenediamine was dissolved in 4.5 L of N,N-dimethylacetamide, and then 4 mol of isophthaloyl chloride was added and reacted for 20 min. Then 1 mol of isophthaloyl chloride was added and reacted at 0℃ for 1.5 h. After that, the temperature was raised to 60℃ and 5 mol of calcium hydroxide was added and the reaction was continued for 15 min to obtain aramid spinning solution with a solid content of 22% and a viscosity of 400 Po.

[0099] (2) The spinning method is the same as in Example 1. The strength of the short fibers obtained by testing can reach more than 3.0 cN / dtex and the breaking elongation is less than 10%.

[0100] Compare with Example 2

[0101] A colored, soft aramid fiber of the anthraquinone class, with the following molecular structure:

[0102]

[0103] Where x = 98, y = 1, z = 1;

[0104] The preparation steps are as follows:

[0105] (1) Except for dissolving 4.9 mol m-phenylenediamine, 0.05 mol 4,4'-diaminodiphenyl ether and 0.05 mol 1,4-diamino-9,10-anthraquinone in 4.5 L N,N-dimethylacetamide, the other reaction conditions were the same as in Example 1, and a colored soft aramid spinning solution with a solid content of 22% and a viscosity of 450 Po was obtained.

[0106] (2) The spinning method is the same as in Example 1. The strength of the short fibers obtained by testing can reach more than 3.0 cN / dtex, the breaking elongation is less than 10%, and the color wavelength range is 610-700nm and 400-425nm.

[0107] Compare with Example 3

[0108] A colored, soft aramid fiber of the anthraquinone class, with the following molecular structure:

[0109]

[0110] Where x = 85, y = 10, z = 5;

[0111] The preparation steps are as follows:

[0112] (1) Except for dissolving 4.25 mol m-phenylenediamine, 0.5 mol 4,4'-diaminodiphenyl ether and 0.25 mol 1,4-diamino-9,10-anthraquinone in 4.5 L N,N-dimethylacetamide, the other reaction conditions were the same as in Example 1, and a colored soft aramid spinning solution with a solid content of 22% and a viscosity of 150 Po was obtained.

[0113] (2) The spinning method is the same as in Example 1. The strength of the short fibers obtained by testing can reach below 3.0 cN / dtex, the breaking elongation is below 10%, and the color wavelength range is 610-700 nm and 400-425 nm.

[0114] Table 1 Comparison of fiber parameters between the examples and the control examples.

[0115]

[0116] As can be seen from the data in Table 1, the colored soft aramid prepared by the method of the present invention has the characteristics of low modulus, high strength and high elongation at break, and also maintains excellent flame retardant properties, making it a high-performance soft material.

[0117] Compared to Comparative Example 1, the elastic modulus of the embodiment is significantly reduced, while the elongation at break is greatly increased, thus solving the rigidity and brittleness problems of aramid. Furthermore, the aramid in the embodiment can be colored according to requirements, covering the full spectrum of 400–700 nm, and exhibits excellent color fastness. This can improve actual production and processing efficiency and broaden the application areas of aromatic polyamides.

[0118] Compared with Comparative Examples 2 and 3 and Example 1, it can be found that after adjusting the amount of raw materials, the elastic modulus of the comparative examples increased and the elongation at break decreased, indicating that in the aramid structure of the present invention, each group must exist in a certain proportion to achieve high performance.

[0119] Table 2 Color fastness of fibers in the examples

[0120]

[0121] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A colored, soft aramid fiber of anthraquinone type, characterized in that, The structural formula of the aramid is shown in Formula I below: Wherein, 85≤x≤94, 5.5≤y≤13, 0.5≤z≤2; The structure of Ar1 in Formula I includes: The structure of Ar2 in Formula I includes: Among them, R1, R2, R3, R4, R5, and R6 are selected from hydrogen, halogen, ether, alkyl, nitro, cyano, thioalkyl, alkoxy, phenoxy, or alkylamine, and R7 is selected from ether, alcohol, ester, or alkyl.

2. A method for preparing anthraquinone-based colored soft aramid fiber as described in claim 1, characterized in that, The method includes the following steps: (1) Add m-phenylenediamine, Br1 and Br2 to an organic solvent, cool to 0-5℃, add isophthaloyl chloride and react for 1-2 hours, heat to 55-65℃ and add neutralizing agent and react for 10-20 minutes to obtain colored soft aramid spinning solution. (2) The spinning solution is formed by coagulation bath, washed, dried and heat-set to obtain colored soft aramid.

3. The method according to claim 2, characterized in that, The structural formula of Br1 in step (1) is shown in Formula II below: H2N—Ar1—NH2 Formula II The structure of Ar1 in Formula II includes:

4. The method according to claim 2, characterized in that, The structural formula of Br2 in step (1) is shown in formula III below: H2N—Ar2—NH2 Formula III The structure of Ar2 in Formula III includes: R1, R2, R3, R4, R5, and R6 are selected from hydrogen, halogen, ether, alkyl, nitro, cyano, thioalkyl, alkoxy, phenoxy, or alkylamine, and R7 is selected from ether, alcohol, ester, or alkyl.

5. The method according to claim 2, characterized in that, In step (1), the molar ratio of m-phenylenediamine to Br1 is 10:0.8 to 1.2; the molar ratio of m-phenylenediamine to Br2 is 90:0.4 to 1.

8.

6. The method according to claim 2, characterized in that, In step (1), the organic solvent is one or more of N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide; the concentration of m-phenylenediamine in the organic solvent is 0.5 to 1.5 mol / L.

7. The method according to claim 2, characterized in that, In step (1), the molar ratio of m-phenylenediamine to phthaloyl chloride is 1:1 to 1.2; phthaloyl chloride needs to be added in two parts; the amount of phthaloyl chloride added in the first part is 70 to 80% of the total molar amount of phthaloyl chloride, and the remaining phthaloyl chloride is added in the second part; the time interval between the two additions of phthaloyl chloride is 10 to 30 minutes.

8. The method according to claim 2, characterized in that, In step (1), the neutralizing agent is one of calcium oxide, calcium hydroxide or triethylamine; the molar ratio of m-phenylenediamine to the neutralizing agent is 1:1 to 1.

2.

9. The method according to claim 2, characterized in that, In step (2), the coagulation liquid in the coagulation bath is a mixture of organic solvent and water; the organic solvent includes N,N-dimethylacetamide; the organic solvent accounts for 20% to 40% of the mass fraction of the coagulation liquid; the stretching ratio during the coagulation bath forming process is 1.5 to 3.5; the heat setting temperature is 200 to 350°C, and the heat setting stretching ratio is 1.2 to 2.

10. The application of anthraquinone-based colored soft aramid fibers prepared by the methods described in claim 1 and any one of claims 2 to 9 in the fields of textiles, clothing, composite material preparation, building materials, and electronic equipment.

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