Metaparamylon filament, its preparation method and application

Abstract

The application discloses a meta-aramid filament and a preparation method and application thereof, and comprises the following steps: mixing m-phenylenediamine, isophthaloyl chloride and N,N-dimethylacetamide, and then performing a polymerization reaction to obtain a meta-aramid spinning solution; performing a spinning forming treatment on the meta-aramid spinning solution to obtain a fiber filament; sequentially performing two-stage coagulation forming treatment on the fiber filament to obtain a coagulation forming product; and performing washing and drying treatment on the coagulation forming product to obtain the meta-aramid filament. The application obtains a meta-aramid fiber filament with a uniform and compact structure by regulating the coagulation bath temperature and concentration in the coagulation forming process. The prepared meta-aramid filament is uniform in size, smooth and flat in surface, has a uniform and compact structure, and exhibits excellent flexibility and mechanical strength, and can be applied to high-performance fiber filter materials and flexible fabrics.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aramid fiber preparation, and particularly relates to a meta-aramid filament and a preparation method and application thereof. BACKGROUND

[0002] The meta-aramid has excellent flame retardance, thermal stability and radiation resistance, and thus is one of the most widely used high-performance fibers; the meta-aramid includes meta-aramid short fibers and meta-aramid filaments, wherein the meta-aramid filaments are widely used in thermal protective clothing, filter materials and flame-retardant decorative fabrics; at present, the meta-aramid filaments are generally obtained by wet spinning; however, in the existing wet spinning process, the fiber surface firstly contacts the coagulation bath and coagulates to form a dense structure, which hinders the coagulation bath solution from further penetrating into the fiber; under the same drawing speed, since the coagulation degree inside the fiber is lower than that of the fiber surface, the outer layer structure of the fiber is easy to be compact, and the inside is loose and porous, which seriously affects the quality and application of the fiber. SUMMARY

[0003] In view of the technical problems in the prior art, the application provides a meta-aramid filament and a preparation method and application thereof, so as to solve the technical problem that the existing wet spinning process is easy to cause the outer layer structure of the fiber to be compact, the inside to be loose and porous, and the quality and application of the fiber to be seriously affected.

[0004] To achieve the above-mentioned purposes, the technical scheme adopted by the application is as follows:

[0005] The application provides a preparation method of a meta-aramid filament, comprising the following steps:

[0006] Step 1, mixing m-phenylenediamine, isophthaloyl chloride and N,N-dimethylacetamide, and then performing a polymerization reaction to obtain a meta-aramid spinning stock solution;

[0007] Step 2, performing a spinning forming treatment on the meta-aramid spinning stock solution to obtain a fiber filament;

[0008] Step 3, sequentially performing two-stage coagulation forming treatments on the fiber filament to obtain a coagulation forming product;

[0009] In the first-stage coagulation forming treatment, the coagulation forming is completed in a first-stage coagulation bath, the coagulation forming temperature is 20-45 DEG C, and the coagulation forming time is 25-40 s; the first-stage coagulation bath is an aqueous solution of N,N-dimethylacetamide, and the mass concentration of the aqueous solution of N,N-dimethylacetamide is 25%-45%;

[0010] In the second-stage coagulation forming process, the coagulation forming temperature is 30-65℃, and the coagulation forming time is 5-20s; the second-stage coagulation bath is an aqueous solution of N,N-dimethylacetamide, and the mass concentration of the aqueous solution of N,N-dimethylacetamide is 30%-65%; after the second-stage coagulation forming process, an alkali solution is added to adjust the pH value of the second-stage coagulation bath to neutralize the hydrogen chloride generated in the polymerization process.

[0011] In step 4, the coagulation forming product is subjected to washing and drying treatment to obtain the meta-aramid filament.

[0012] Further, in step 1, the m-phenylenediamine, isophthaloyl chloride and N,N-dimethylacetamide are mixed in a mass ratio of (30-45):(70-90):(400-550).

[0013] Further, in step 1, the temperature of the polymerization reaction is -20℃-0℃.

[0014] Further, in step 2, the meta-aramid spinning dope is subjected to jet forming treatment to obtain the fiber filament, and the process is as follows:

[0015] The meta-aramid spinning dope is subjected to temperature raising treatment to obtain the temperature-raised spinning dope.

[0016] The temperature-raised spinning dope is subjected to spinning forming treatment to obtain the fiber filament.

[0017] Further, in step 3, the fiber filament is subjected to drawing and is sequentially introduced into two-stage coagulation baths for coagulation forming treatment; wherein the drawing speed is 2-5m / min.

[0018] Further, after the alkali solution is added, the pH value of the second-stage coagulation bath is adjusted to 5.5-7.5.

[0019] Further, in step 4, the coagulation forming product is sequentially subjected to two-stage washing treatment; wherein in the first-stage washing treatment, a low-temperature DMAc aqueous solution is used, the mass concentration of the low-temperature DMAc aqueous solution is 10%-15%, and the temperature is 20-40℃; in the second-stage washing treatment, a high-temperature DMAc aqueous solution is used, the mass concentration of the high-temperature DMAc aqueous solution is 2%-7%, and the temperature is 70-90℃.

[0020] Further, the coagulation forming product is drawn and is sequentially introduced into the low-temperature DMAc aqueous solution and the high-temperature DMAc aqueous solution for washing; wherein the drawing speed is 2-5m / min.

[0021] The application further provides a meta-aramid filament prepared by the preparation method of the meta-aramid filament.

[0022] The application further provides an application of the meta-aramid filament, which is used for preparing a fiber filter material or a flexible fabric.

[0023] Compared with the prior art, the application has the following beneficial effects:

[0024] The application provides a meta-aramid filament and a preparation method and application thereof, two-stage coagulation forming processes are sequentially completed in a primary coagulation bath and a secondary coagulation bath; the primary coagulation bath is a low-temperature and low-concentration coagulation bath, and the coagulation time is relatively long, which is beneficial to the penetration of water molecules from the surface of the fiber filament into the interior, and the gradual reduction of the DMAc concentration in the filament dope, and promotes the coagulation of the filament; the secondary coagulation bath is a high-temperature and high-concentration coagulation bath, and the coagulation time is relatively short, and the hydrogen chloride generated in the neutralization of the alkali and the polymerization process is passed through, so as to stabilize the salt content in the filament, promote the formation of smaller holes in the interior of the filament, and the holes are uniformly distributed, effectively improving the mechanical strength and insulation performance of the meta-aramid filament; the prepared meta-aramid filament has uniform size, smooth surface, and uniform and dense structure, and the fiber filament exhibits excellent flexibility and mechanical strength, and can be applied to high-performance fiber filter materials and flexible fabrics. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 A surface SEM image of the meta-aramid filament prepared in Example 1. DETAILED DESCRIPTION

[0026] In order to make the technical problems solved by the application, the technical solutions and beneficial effects clearer, the following specific embodiments are used to further illustrate the application. It should be understood that the specific embodiments described herein are only used to explain the application, and are not used to limit the application.

[0027] The application provides a preparation method of a meta-aramid filament, including the following steps:

[0028] Step 1, after mixing meta-phenylenediamine (MPD), isophthaloyl chloride (IPC) and N,N-dimethylacetamide (DMAc), a polymerization reaction is performed to obtain a meta-aramid spinning dope; specifically, the meta-phenylenediamine and the isophthaloyl chloride are sequentially dissolved in the N,N-dimethylacetamide, and after mixing, a polymerization reaction is performed to prepare the meta-aramid spinning dope; wherein the mass ratio of the meta-phenylenediamine, the isophthaloyl chloride and the N,N-dimethylacetamide is (30-45):(70-90):(400-550); the temperature of the polymerization reaction is-20℃-0℃.

[0029] Step 2, the meta-aramid spinning dope is subjected to jet forming treatment to obtain fiber filaments; wherein, the specific process is as follows:

[0030] The meta-aramid spinning dope is subjected to temperature raising treatment to obtain a temperature-raised spinning dope; wherein, the temperature of the temperature-raised spinning dope is 30-40℃; the temperature-raised spinning dope is subjected to spinning forming treatment by using a jet device to obtain fiber filaments; wherein, the aperture of the jet device is 0.08-0.4mm.

[0031] Step 3, the fiber filaments are subjected to two-stage coagulation forming treatment in sequence to obtain coagulation forming products; specifically, the fiber filaments are drawn and introduced into two-stage coagulation baths in sequence for coagulation forming treatment; wherein, the drawing speed is 2-5m / min;

[0032] In step 3 of the present application, the first-stage coagulation forming treatment is completed in a first-stage coagulation bath, the coagulation forming temperature is 20-45℃, and the coagulation forming time is 25-40s; the first-stage coagulation bath is an aqueous solution of N,N-dimethylacetamide, and the mass concentration of the aqueous solution of N,N-dimethylacetamide is 25%-45%.

[0033] In step 3 of the present application, the second-stage coagulation forming treatment is completed in a second-stage coagulation bath, the coagulation forming temperature is 30-65℃, and the coagulation forming time is 5-20s; the second-stage coagulation bath is an aqueous solution of N,N-dimethylacetamide, and the mass concentration of the aqueous solution of N,N-dimethylacetamide is 30%-65%; after the second-stage coagulation forming treatment, an alkali liquor is added to adjust the pH value of the second-stage coagulation bath to neutralize hydrogen chloride generated in the polymerization process; wherein, after the addition of the alkali liquor, the pH value of the second-stage coagulation bath is adjusted to 5.5-7.5; preferably, the alkali liquor is prepared by using one of sodium hydroxide (NaOH), calcium hydroxide (CaOH) and potassium hydroxide (KOH) and water.

[0034] Step 4, the coagulation forming products are subjected to washing and drying treatment to obtain the meta-aramid filaments; wherein, during the washing process, the coagulation forming products are drawn and introduced into low-temperature DMAc aqueous solution and high-temperature DMAc aqueous solution in sequence for washing; specifically, during the first-stage washing treatment, low-temperature DMAc aqueous solution is used to complete the treatment, the mass concentration of the low-temperature DMAc aqueous solution is 10%-15%, and the temperature is 20-40℃; during the second-stage washing treatment, high-temperature DMAc aqueous solution is used to complete the treatment, the mass concentration of the high-temperature DMAc aqueous solution is 2%-7%, and the temperature is 70-90℃; vacuum drying is used during drying, and the drying temperature is 90-120℃.

[0035] Preparation principle:

[0036] The preparation method of the meta-aramid filament provided by the application sequentially passes through two coagulation baths in the coagulation forming process, and the two coagulation baths are divided into a first-stage coagulation bath and a second-stage coagulation bath; the first-stage coagulation bath is a low-temperature and low-concentration coagulation bath, has a relatively long coagulation time, is beneficial to the penetration of water molecules from the surface of the filament into the interior, gradually reduces the DMAc concentration in the filament dope, and promotes the coagulation of the filament; the second-stage coagulation bath is a high-temperature and high-concentration coagulation bath, has a relatively short coagulation time, and is adjusted by an alkali solution to have a pH value, which is beneficial to the neutralization of hydrogen chloride generated in the polymerization process, further stabilizes the salt content in the filament, promotes the formation of small holes in the interior of the filament and the uniform distribution of the hole diameters, and is beneficial to the improvement of the mechanical strength and insulation performance of the filament; the meta-aramid filament prepared by the application has uniform size, smooth and flat surface, uniform and dense structure, and excellent flexibility and mechanical strength, and can be applied to high-performance fiber filter materials and flexible fabrics.

[0037] Embodiment 1

[0038] The embodiment 1 provides a preparation method of a meta-aramid filament, which comprises the following steps:

[0039] Step 1: interdiaminobenzene (MPD) and isophthaloyl chloride (IPC) are sequentially dissolved in N,N-dimethylacetamide (DMAc) to perform a low-temperature polymerization reaction, so as to prepare a meta-aramid spinning dope; wherein the mass of MPD is 38 g, the mass of IPC is 70 g, and the mass of DMAc is 450 g; the temperature of the low-temperature polymerization reaction is -20℃.

[0040] Step 2: the meta-aramid spinning dope in step 1 is heated to 30℃, and then is sent into a spinning device to perform a spinning forming treatment, so as to obtain a fiber filament; wherein the pore diameter of the spinning device is 0.08 mm.

[0041] Step 3: the meta-aramid filament is pulled by a pulling device, and is sequentially introduced into two-stage coagulation baths to perform two-stage coagulation forming treatments, so as to obtain a coagulation forming product; wherein the pulling speed is 2.5 m / min; the first-stage coagulation forming treatment is completed in a first-stage coagulation bath, the coagulation forming temperature is 25℃, and the coagulation forming time is 40 s; the first-stage coagulation bath is an aqueous solution of N,N-dimethylacetamide, and the mass concentration of the aqueous solution of N,N-dimethylacetamide is 25%; the second-stage coagulation forming treatment is completed in a second-stage coagulation bath, the coagulation forming temperature is 50℃, and the coagulation forming time is 10 s; the second-stage coagulation bath is an aqueous solution of N,N-dimethylacetamide, and the mass concentration of the aqueous solution of N,N-dimethylacetamide is 40%; after the second-stage coagulation forming treatment, an alkali solution is added to adjust the pH value of the second-stage coagulation bath to 6.0, so as to neutralize hydrogen chloride generated in the polymerization process; wherein the alkali solution is prepared by mixing calcium hydroxide (CaOH) and water.

[0042] Step 4, using the traction device to pull the solidification molding product, in turn, into two levels of washing liquid for washing to obtain a washing product; wherein the pulling speed is 2.5 m / min; wherein the first stage of washing treatment is completed by using low-temperature DMAc aqueous solution, the mass concentration of the low-temperature DMAc aqueous solution is 15%, and the temperature is 25℃; the second stage of washing treatment is completed by using high-temperature DMAc aqueous solution, the mass concentration of the high-temperature DMAc aqueous solution is 5%, and the temperature is 70℃.

[0043] Step 5, drying the washing product to obtain the meta-aramid filament; wherein the drying process uses vacuum drying, and the drying temperature is 100℃.

[0044] Performance detection:

[0045] The meta-aramid filament prepared in this embodiment 1 is subjected to performance detection, and the detection result is that the breaking strength of the meta-aramid filament is 2.332 cN·dtex -1 , and the mechanical property is good.

[0046] As shown in the accompanying Figure 1 , the surface SME diagram of the meta-aramid filament prepared in this embodiment 1 is given in the accompanying Figure 1 ; it can be seen from the accompanying Figure 1 that the surface of the meta-aramid filament is smooth, the size is uniform, the diameter is about 10-20 μm, and the fiber surface is regular without obvious holes, the structure is dense, and the surface drawing is less.

[0047] Embodiment 2

[0048] This embodiment 2 provides a preparation method of meta-aramid filament, comprising the following steps:

[0049] Step 1, dissolving m-phenylenediamine (MPD) and isophthaloyl chloride (IPC) in N,N-dimethylacetamide (DMAc) in turn for low-temperature polymerization reaction to prepare a meta-aramid spinning solution; wherein the mass of MPD is 40 g, the mass of IPC is 75 g, and the mass of DMAc is 500 g; the temperature of the low-temperature polymerization reaction is -15℃.

[0050] Step 2, the meta-aramid spinning solution in step 1 is heated to 30℃, and then sent into a spinning device for spinning forming treatment to obtain a fiber filament; wherein the pore size of the spinning device is 0.2 mm.

[0051] Step 3, the limiting filament is pulled by using a traction device, and is sequentially introduced into two-stage coagulation baths to perform two-stage coagulation forming treatment, so as to obtain a coagulation forming product; wherein, the pulling speed is 3.5 m / min; the first-stage coagulation forming treatment is completed in a first-stage coagulation bath, the coagulation forming temperature is 25℃, and the coagulation forming time is 40 s; the first-stage coagulation bath is an aqueous solution of N,N-dimethylacetamide, and the mass concentration of the aqueous solution of N,N-dimethylacetamide is 40%; the second-stage coagulation forming treatment is completed in a second-stage coagulation bath, the coagulation forming temperature is 50℃, and the coagulation forming time is 10 s; the second-stage coagulation bath is an aqueous solution of N,N-dimethylacetamide, and the mass concentration of the aqueous solution of N,N-dimethylacetamide is 40%; after the second-stage coagulation forming treatment, an alkali liquor is added to adjust the pH value of the second-stage coagulation bath to 6.5, so as to neutralize hydrogen chloride generated in the polymerization process; wherein, the alkali liquor is prepared by using sodium hydroxide (NaOH) and water.

[0052] Step 4, the coagulation forming product is pulled by using a traction device, and is sequentially introduced into two-stage washing liquids to perform washing, so as to obtain a washing product; wherein, the pulling speed is 3.5 m / min; wherein, the first-stage washing treatment is completed by using a low-temperature DMAc aqueous solution, the mass concentration of the low-temperature DMAc aqueous solution is 10%, and the temperature is 20℃; the second-stage washing treatment is completed by using a high-temperature DMAc aqueous solution, the mass concentration of the high-temperature DMAc aqueous solution is 2%, and the temperature is 80℃.

[0053] Step 5, the washing product is subjected to drying treatment, so as to obtain the meta-aramid filament; wherein, the drying process adopts vacuum drying, and the drying temperature is 100℃.

[0054] Performance detection:

[0055] The meta-aramid filament prepared in this embodiment 2 is subjected to performance detection, and the detection result is that the breaking strength of the meta-aramid filament is 3.066 cN·dtex -1 , and the mechanical property is good.

[0056] Embodiment 3

[0057] This embodiment 3 provides a preparation method of a meta-aramid filament, which comprises the following steps:

[0058] Step 1, m-phenylenediamine (MPD) and isophthaloyl chloride (IPC) are sequentially dissolved in N,N-dimethylacetamide (DMAc) to perform low-temperature polymerization reaction, so as to prepare a meta-aramid spinning stock solution; wherein, the mass of MPD is 40 g, the mass of IPC is 70 g, and the mass of DMAc is 500 g; the temperature of the low-temperature polymerization reaction is 0℃.

[0059] Step 2, the meta-aramid spinning dope in step 1 is heated to 35℃, and then sent to a spinning device for spinning forming treatment to obtain a fiber filament; wherein the pore size of the spinning device is 0.3mm.

[0060] Step 3, the limiting filament is drawn by a traction device and sequentially introduced into two-stage coagulation baths for two-stage coagulation forming treatment to obtain a coagulation forming product; wherein the drawing speed is 5.0m / min; the first-stage coagulation forming treatment is completed in a first-stage coagulation bath, the coagulation forming temperature is 30℃, and the coagulation forming time is 30s; the first-stage coagulation bath is an aqueous solution of N,N-dimethylacetamide, and the mass concentration of the aqueous solution of N,N-dimethylacetamide is 30%; the second-stage coagulation forming treatment is completed in a second-stage coagulation bath, the coagulation forming temperature is 45℃, and the coagulation forming time is 15s; the second-stage coagulation bath is an aqueous solution of N,N-dimethylacetamide, and the mass concentration of the aqueous solution of N,N-dimethylacetamide is 50%; after the second-stage coagulation forming treatment, an alkali liquor is added to adjust the pH value of the second-stage coagulation bath to 5.5 to neutralize hydrogen chloride generated in the polymerization process; wherein the alkali liquor is prepared by mixing calcium hydroxide (CaOH) with water.

[0061] Step 4, the coagulation forming product is drawn by a traction device and sequentially introduced into two-stage washing liquids for washing to obtain a washing product; wherein the drawing speed is 5.0m / min; wherein the first-stage washing treatment is completed by using a low-temperature DMAc aqueous solution, the mass concentration of the low-temperature DMAc aqueous solution is 10%, and the temperature is 30℃; the second-stage washing treatment is completed by using a high-temperature DMAc aqueous solution, the mass concentration of the high-temperature DMAc aqueous solution is 5%, and the temperature is 85℃.

[0062] Step 5, the washing product is dried to obtain the meta-aramid filament; wherein the drying process adopts vacuum drying, and the drying temperature is 120℃.

[0063] Performance detection:

[0064] The meta-aramid filament prepared in this embodiment 3 is subjected to performance detection, and the detection result is that the breaking strength of the meta-aramid filament is 3.495cN·dtex -1 , and the mechanical property is good.

[0065] Embodiment 4

[0066] This embodiment 4 provides a preparation method of a meta-aramid filament, which comprises the following steps:

[0067] Step 1, meta-aramid spinning dope is prepared by sequentially dissolving meta-phenylenediamine (MPD) and isophthaloyl chloride (IPC) in N, N-dimethylacetamide (DMAc) for low-temperature polymerization reaction; wherein the mass of MPD is 45 g, the mass of IPC is 70 g, and the mass of DMAc is 450 g; the temperature of the low-temperature polymerization reaction is -5℃.

[0068] Step 2, the meta-aramid spinning dope in step 1 is warmed to 35℃, and then sent to a spinning device for spinning forming treatment to obtain a fiber filament; wherein the pore size of the spinning device is 0.08 mm.

[0069] Step 3, the long filament is drawn by a traction device and sequentially introduced into two-stage coagulation baths for two-stage coagulation forming treatment to obtain a coagulation forming product; wherein the drawing speed is 2.0 m / min; the first-stage coagulation forming treatment is completed in a first-stage coagulation bath, the coagulation forming temperature is 25℃, and the coagulation forming time is 40 s; the first-stage coagulation bath is an aqueous solution of N, N-dimethylacetamide, and the mass concentration of the aqueous solution of N, N-dimethylacetamide is 55%; the second-stage coagulation forming treatment is completed in a second-stage coagulation bath, the coagulation forming temperature is 60℃, and the coagulation forming time is 5 s; the second-stage coagulation bath is an aqueous solution of N, N-dimethylacetamide, and the mass concentration of the aqueous solution of N, N-dimethylacetamide is 55%; after the second-stage coagulation forming treatment, an alkali solution is added to adjust the pH value of the second-stage coagulation bath to 7.5 to neutralize hydrogen chloride generated in the polymerization process; wherein the alkali solution is prepared by mixing potassium hydroxide (KOH) and water.

[0070] Step 4, the coagulation forming product is drawn by a traction device and sequentially introduced into two-stage washing liquids for washing to obtain a washing product; wherein the drawing speed is 2.0 m / min; wherein the first-stage washing treatment is completed by using a low-temperature DMAc aqueous solution, the mass concentration of the low-temperature DMAc aqueous solution is 12%, and the temperature is 25℃; the second-stage washing treatment is completed by using a high-temperature DMAc aqueous solution, the mass concentration of the high-temperature DMAc aqueous solution is 6%, and the temperature is 90℃.

[0071] Step 5, the washing product is dried to obtain the meta-aramid filament; wherein the drying process adopts vacuum drying, and the drying temperature is 90℃.

[0072] Performance detection:

[0073] The meta-aramid filament prepared in this embodiment 4 is subjected to performance detection, and the detection result is that the breaking strength of the meta-aramid filament is 2.045 cN·dtex -1 , and the mechanical property is good.

[0074] Example 5

[0075] The present example 5 provides a preparation method of meta-aramid filament, comprising the following steps:

[0076] Step 1, meta-phenylenediamine (MPD) and isophthaloyl chloride (IPC) are sequentially dissolved in N, N-dimethylacetamide (DMAc) for low-temperature polymerization reaction to prepare a meta-aramid spinning solution; wherein the mass of MPD is 40 g, the mass of IPC is 75 g, and the mass of DMAc is 500 g; the temperature of low-temperature polymerization reaction is -10℃.

[0077] Step 2, the meta-aramid spinning solution in step 1 is warmed to 40℃, and then sent into a spinning device for spinning forming treatment to obtain a fiber filament; wherein the pore size of the spinning device is 0.15 mm.

[0078] Step 3, the meta-aramid filament is drawn by a drawing device and sequentially introduced into two-stage coagulation baths for two-stage coagulation forming treatment to obtain a coagulation forming product; wherein the drawing speed is 4.0 m / min; the first-stage coagulation forming treatment is completed in a first-stage coagulation bath, the coagulation forming temperature is 35℃, and the coagulation forming time is 40 s; the first-stage coagulation bath is an aqueous solution of N, N-dimethylacetamide, and the mass concentration of the aqueous solution of N, N-dimethylacetamide is 25%; the second-stage coagulation forming treatment is completed in a second-stage coagulation bath, the coagulation forming temperature is 50℃, and the coagulation forming time is 15 s; the second-stage coagulation bath is an aqueous solution of N, N-dimethylacetamide, and the mass concentration of the aqueous solution of N, N-dimethylacetamide is 50%; after the second-stage coagulation forming treatment, an alkali solution is added to adjust the pH value of the second-stage coagulation bath to 6.5 to neutralize hydrogen chloride generated in the polymerization process; wherein the alkali solution is prepared by mixing calcium hydroxide (CaOH) and water.

[0079] Step 4, the coagulation forming product is drawn by a drawing device and sequentially introduced into two-stage washing liquids for washing to obtain a washing product; wherein the drawing speed is 4.0 m / min; wherein the first-stage washing treatment is completed by using a low-temperature DMAc aqueous solution, the mass concentration of the low-temperature DMAc aqueous solution is 13%, and the temperature is 40℃; the second-stage washing treatment is completed by using a high-temperature DMAc aqueous solution, the mass concentration of the high-temperature DMAc aqueous solution is 4%, and the temperature is 75℃.

[0080] Step 5, the washing product is dried to obtain the meta-aramid filament; wherein the drying process adopts vacuum drying, and the drying temperature is 120℃.

[0081] Performance detection:

[0082] The meta-aramid filament prepared in this embodiment 5 is subjected to performance detection, and the detection result is that the breaking strength of the meta-aramid filament is 4.410 cN·dtex -1 , and the mechanical property is good.

[0083] Embodiment 6

[0084] The embodiment 6 provides a preparation method of meta-aramid filament, comprising the following steps:

[0085] Step 1, meta-phenylenediamine (MPD) and isophthaloyl chloride (IPC) are sequentially dissolved in N, N-dimethylacetamide (DMAc) for low-temperature polymerization reaction to prepare a meta-aramid spinning solution; wherein the mass of MPD is 30 g, the mass of IPC is 90 g, and the mass of DMAc is 500 g; the temperature of the low-temperature polymerization reaction is -15 ℃.

[0086] Step 2, the meta-aramid spinning solution in step 1 is warmed to 30 ℃, and then is sent into a spinning device for spinning forming treatment to obtain a fiber filament; wherein the pore size of the spinning device is 0.35 mm.

[0087] Step 3, the meta-aramid filament is drawn by a drawing device and is sequentially introduced into two-stage coagulation baths for two-stage coagulation forming treatment to obtain a coagulation forming product; wherein the drawing speed is 3.0 m / min; the first-stage coagulation forming treatment is completed in a first-stage coagulation bath, the coagulation forming temperature is 38 ℃, and the coagulation forming time is 30 s; the first-stage coagulation bath is an aqueous solution of N, N-dimethylacetamide, and the mass concentration of the aqueous solution of N, N-dimethylacetamide is 45%; the second-stage coagulation forming treatment is completed in a second-stage coagulation bath, the coagulation forming temperature is 55 ℃, and the coagulation forming time is 10 s; the second-stage coagulation bath is an aqueous solution of N, N-dimethylacetamide, and the mass concentration of the aqueous solution of N, N-dimethylacetamide is 45%; after the second-stage coagulation forming treatment, an alkali liquor is added to adjust the pH value of the second-stage coagulation bath to 7.0 to neutralize hydrogen chloride generated in the polymerization process; wherein the alkali liquor is prepared by mixing potassium hydroxide (KOH) and water.

[0088] Step 4, the coagulation forming product is drawn by a drawing device and is sequentially introduced into two-stage washing liquids for washing to obtain a washing product; wherein the drawing speed is 3.0 m / min; wherein the first-stage washing treatment is completed by using a low-temperature DMAc aqueous solution, the mass concentration of the low-temperature DMAc aqueous solution is 15%, and the temperature is 40 ℃; the second-stage washing treatment is completed by using a high-temperature DMAc aqueous solution, the mass concentration of the high-temperature DMAc aqueous solution is 3%, and the temperature is 75 ℃.

[0089] Step 5, drying the washing product to obtain the meta-aramid filament; wherein the drying process adopts vacuum drying, and the drying temperature is 105°C.

[0090] Performance detection:

[0091] The meta-aramid filament prepared in this embodiment 6 is subjected to performance detection, and the detection result is that the breaking strength of the meta-aramid filament is 3.932 cN·dtex -1 , and the mechanical property is good.

[0092] Embodiment 7

[0093] The embodiment 7 provides a preparation method of a meta-aramid filament, comprising the following steps:

[0094] Step 1, dissolving meta-phenylenediamine (MPD) and isophthaloyl chloride (IPC) in N, N-dimethylacetamide (DMAc) in sequence to carry out a low-temperature polymerization reaction to prepare a meta-aramid spinning solution; wherein the mass of MPD is 45 g, the mass of IPC is 75 g, and the mass of DMAc is 450 g; the temperature of the low-temperature polymerization reaction is -20°C.

[0095] Step 2, the meta-aramid spinning solution in step 1 is heated to 40°C, and then is sent into a spinning device to carry out a spinning forming treatment to obtain a fiber filament; wherein the pore diameter of the spinning device is 0.4 mm.

[0096] Step 3, using a traction device to pull the meta-aramid filament, and sequentially introducing the meta-aramid filament into two-stage coagulation baths to carry out two-stage coagulation forming treatment to obtain a coagulation forming product; wherein the pulling speed is 4.5 m / min; in the first-stage coagulation forming treatment, the coagulation forming is completed in a first-stage coagulation bath, the coagulation forming temperature is 35°C, and the coagulation forming time is 40 s; the first-stage coagulation bath is an aqueous solution of N, N-dimethylacetamide, and the mass concentration of the aqueous solution of N, N-dimethylacetamide is 30%; in the second-stage coagulation forming treatment, the coagulation forming is completed in a second-stage coagulation bath, the coagulation forming temperature is 65°C, and the coagulation forming time is 10 s; the second-stage coagulation bath is an aqueous solution of N, N-dimethylacetamide, and the mass concentration of the aqueous solution of N, N-dimethylacetamide is 65%; after the second-stage coagulation forming treatment, an alkali liquor is added to adjust the pH value of the second-stage coagulation bath to 5.5 to neutralize hydrogen chloride generated in the polymerization reaction; wherein the alkali liquor is prepared by mixing calcium hydroxide (CaOH) and water.

[0097] Step 4, the coagulation molding product is pulled by using a traction device, and is sequentially introduced into two-stage washing liquid for washing to obtain a washing product; wherein, the pulling speed is 4.5 m / min; wherein, the first-stage washing treatment is completed by using a low-temperature DMAc aqueous solution, the mass concentration of the low-temperature DMAc aqueous solution is 14%, and the temperature is 35℃; the second-stage washing treatment is completed by using a high-temperature DMAc aqueous solution, the mass concentration of the high-temperature DMAc aqueous solution is 7%, and the temperature is 85℃.

[0098] Step 5, the washing product is subjected to drying treatment to obtain the meta-aramid filament; wherein, the drying process adopts vacuum drying, and the drying temperature is 100℃.

[0099] Performance detection:

[0100] The meta-aramid filament prepared in the embodiment 7 is subjected to performance detection, and the detection result is that the breaking strength of the meta-aramid filament is 4.172 cN·dtex -1 , and the mechanical property is good.

[0101] The meta-aramid filament, the preparation method and the application thereof, by adjusting the coagulation bath temperature and concentration in the coagulation molding process, the meta-aramid filament with uniform and dense structure is obtained; the meta-aramid filament has a flat surface morphology and uniform and dense structure; meanwhile, the meta-aramid filament shows excellent mechanical strength, which provides a theoretical basis for preparing high-strength meta-aramid filament, and has important significance for large-scale production of high-performance meta-aramid fiber and series products.

[0102] The above embodiment is only one of the implementation manners capable of realizing the technical scheme of the present application, and the scope of the present application is not limited to the above embodiment, but also includes any changes, substitutions and other implementation manners easily thought by those skilled in the art within the technical scope disclosed by the present application.

Claims

1. A method of making meta-aramid filaments, characterized by, The method comprises the following steps: Step 1, mixing m-phenylenediamine, isophthaloyl chloride and N, N-dimethylacetamide, and then performing a polymerization reaction to obtain meta-aramid spinning dope; the m-phenylenediamine, isophthaloyl chloride and N, N-dimethylacetamide are mixed in a mass ratio of (30-45):(70-90):(400-550); Step 2, performing a spinning forming treatment on the meta-aramid spinning dope to obtain a fiber filament; Step 3, sequentially performing two-stage coagulation forming treatments on the fiber filament to obtain a coagulation forming product; In the first-stage coagulation forming treatment, the treatment is completed in a first-stage coagulation bath, the coagulation forming temperature is 20-38 DEG C, and the coagulation forming time is 25-40 s; the first-stage coagulation bath is an aqueous solution of N, N-dimethylacetamide, and the mass concentration of the aqueous solution of N, N-dimethylacetamide is 25%-45%; In the second-stage coagulation forming treatment, the treatment is completed in a second-stage coagulation bath, the coagulation forming temperature is 45-65 DEG C, and the coagulation forming time is 5-20 s; the second-stage coagulation bath is an aqueous solution of N, N-dimethylacetamide, and the mass concentration of the aqueous solution of N, N-dimethylacetamide is 45%-65%; after the second-stage coagulation forming treatment, an alkali liquor is added to adjust the pH value of the second-stage coagulation bath to neutralize hydrogen chloride generated in the polymerization reaction; Step 4, performing a washing and drying treatment on the coagulation forming product to obtain the meta-aramid filament; vacuum drying is adopted in the drying, and the drying temperature is 90-120 DEG C.

2. The method for preparing meta-aramid filament according to claim 1, characterized in that, In step 1, the temperature of the polymerization reaction is-20 DEG C-0 DEG C.

3. The method for preparing meta-aramid filament according to claim 1, characterized in that, In step 2, the process of performing a spinning forming treatment on the meta-aramid spinning dope to obtain a fiber filament is as follows: performing a temperature raising treatment on the meta-aramid spinning dope to obtain a spinning dope after temperature raising; performing a spinning forming treatment on the spinning dope after temperature raising to obtain a fiber filament.

4. The method for preparing meta-aramid filament according to claim 1, characterized in that, In step 3, the fiber filament is drawn and sequentially introduced into two-stage coagulation baths to perform coagulation forming treatments; wherein the drawing speed is 2-5 m / min.

5. The method for preparing meta-aramid filament according to claim 1, characterized in that, After the alkali liquor is added, the pH value of the second-stage coagulation bath is adjusted to 5.5-7.

5.

6. The method for preparing meta-aramid filament according to claim 1, characterized in that, In step 4, the coagulation forming product is sequentially subjected to two-stage washing treatments; wherein in the first-stage washing treatment, a low-temperature DMAc aqueous solution is adopted, the mass concentration of the low-temperature DMAc aqueous solution is 10%-15%, and the temperature is 20-40 DEG C; in the second-stage washing treatment, a high-temperature DMAc aqueous solution is adopted, the mass concentration of the high-temperature DMAc aqueous solution is 2%-7%, and the temperature is 70-90 DEG C.

7. The method for preparing meta-aramid filament according to claim 6, characterized in that, The coagulation forming product is drawn and sequentially introduced into the low-temperature DMAc aqueous solution and the high-temperature DMAc aqueous solution to perform washing; wherein the drawing speed is 2-5 m / min.

8. A method of making meta-aramid filaments, characterized by, The method comprises the following steps: Step 1, sequentially dissolving m-phenylenediamine and isophthaloyl chloride in N, N-dimethylacetamide to perform a low-temperature polymerization reaction to prepare a meta-aramid spinning dope; wherein the mass of MPD is 40 g, the mass of IPC is 75 g, and the mass of DMAc is 500 g; the temperature of the low-temperature polymerization reaction is-15 DEG C; Step 2, the meta-aramid spinning dope in step 1 is heated to 30℃, and then sent to a spinning device for spinning forming treatment, to obtain a fiber filament; wherein the pore size of the spinning device is 0.2mm; Step 3, the fiber filament is drawn by a drawing device, and is sequentially introduced into two-stage coagulation baths for two-stage coagulation forming treatment, to obtain a coagulation forming product; wherein the drawing speed is 3.5m / min; the first-stage coagulation forming treatment is completed in a first-stage coagulation bath, the coagulation forming temperature is 25℃, and the coagulation forming time is 40s; the first-stage coagulation bath is an aqueous solution of N,N-dimethylacetamide, and the mass concentration of the aqueous solution of N,N-dimethylacetamide is 40%; the second-stage coagulation forming treatment is completed in a second-stage coagulation bath, the coagulation forming temperature is 50℃, and the coagulation forming time is 10s; the second-stage coagulation bath is an aqueous solution of N,N-dimethylacetamide, and the mass concentration of the aqueous solution of N,N-dimethylacetamide is 40%; after the second-stage coagulation forming treatment, an alkali liquor is added to adjust the pH value of the second-stage coagulation bath to 6.5, to neutralize hydrogen chloride generated in the polymerization process; wherein the alkali liquor is prepared by mixing sodium hydroxide and water; Step 4, the coagulation forming product is drawn by a drawing device, and is sequentially introduced into two-stage washing liquids for washing, to obtain a washing product; wherein the drawing speed is 3.5m / min; wherein the first-stage washing treatment is completed by using a low-temperature DMAc aqueous solution, the mass concentration of the low-temperature DMAc aqueous solution is 10%, and the temperature is 20℃; the second-stage washing treatment is completed by using a high-temperature DMAc aqueous solution, the mass concentration of the high-temperature DMAc aqueous solution is 2%, and the temperature is 80℃; Step 5, the washing product is dried, to obtain the meta-aramid filament; wherein the drying process adopts vacuum drying, and the drying temperature is 100℃.

9. A meta-aramid filament, characterized by, The meta-aramid filament is prepared by the preparation method of the meta-aramid filament according to any one of claims 1-8.

10. Use of meta-aramid filaments according to claim 9, characterized in that The meta-aramid filament is used for preparing a fiber filter material or a flexible fabric.

Images