A method for preparing functional nylon fiber

Abstract

The present invention relates to a preparation method of a functional nylon fiber. Nylon, a functional powder and a phenolic antioxidant are used as main raw materials. After screw mixing is performed to obtain a low-viscosity melt in which the functional powder is uniformly dispersed, the low-viscosity melt is vacuumed to obtain a high-viscosity melt, and the high-viscosity melt is spun to obtain a functional nylon fiber. The relative viscosity of the nylon is 2.4-2.6. During the screw mixing process, the nylon undergoes a hydrolysis reaction, and the relative viscosity becomes lower. In the low-viscosity melt, the content of the functional powder is 1-10wt%. The relative viscosity of the low-viscosity melt is 2-2.2, and the relative viscosity of the high-viscosity melt is ≥2.4. The aperture of the spinneret holes on the spinneret used for the spinning process is 0.25-0.45mm. The preparation method of the present invention is simple. Under a higher addition amount of the functional powder, the functional powder can still be uniformly dispersed in the fiber, and the spinneret will not be blocked during spinning, and continuous spinning can be achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of functional fibers and relates to a method for preparing functional nylon fibers. Background Art

[0002] During the nylon fiber spinning process, functional powders are often introduced to impart special functionality to the fibers. For example, antistatic agents are added to impart conductivity or antistatic properties to the fibers; colorants are added to impart a specific color to the fibers; and luminescent powders are added to produce luminescent fibers. During the preparation of functional nylon fibers, the amount of these functional powders added is affected by the dispersion properties. The worse the dispersion, the lower the upper limit of the addition amount. This is because the functional powders are incompatible with the matrix and easily agglomerate, which in turn causes the powders to aggregate locally on the spinneret, leading to problems such as blockage and spinning instability.

[0003] To address these issues, nylons with lower relative viscosities are typically chosen for spinning. At lower relative viscosities, functional powders are more likely to achieve good dispersion. However, the relative viscosity of nylon cannot be too low; it should be at least 2.4. Otherwise, the relative viscosity of the spun yarn will be too low, which can easily lead to yarn breakage or even fiber failure. Therefore, while choosing a nylon with a lower relative viscosity facilitates the initial dispersion of the functional powder, it compromises spinnability.

[0004] To balance the above-mentioned spinning viscosity and functional powder dispersion issues, the more mature existing method is the masterbatch addition method, which first prepares the functional powder into a functional masterbatch, and then adds the functional masterbatch to the nylon matrix for spinning. For example, CN103965618A discloses a method for preparing a fine-denier nylon raw material blended spinning masterbatch. The masterbatch addition method has the advantages of constant ratios of various additives, easy control of the amount of spinning masterbatch added, uniform dispersion, and no damage to production equipment, thereby effectively ensuring the stability of the quality of the spun product. Therefore, most high-performance and new fiber varieties are synthesized using the masterbatch addition method. For example, patent CN114806096A discloses an anti-ultraviolet masterbatch for polyester fiber, a preparation method, and anti-ultraviolet polyester fiber and fabric. This patent first prepares a functional masterbatch with a functional powder content of 30-50 parts by weight, and then adds the masterbatch to the matrix to finally produce a functional fiber, wherein the functional powder accounts for 1-2.5wt% of the fiber. However, this process requires two screw mixing processes, a long process flow, and low production efficiency. Summary of the Invention

[0005] The purpose of the present invention is to solve the problems existing in the prior art and provide a method for preparing functional nylon fibers. Specifically, a method for preparing functional nylon fibers by directly adding functional powder to spinning raw materials is provided to improve the dispersion uniformity of the functional powder in the fibers, so as to achieve good spinnability without blocking the spinneret at a relatively high powder addition amount.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing functional nylon fiber comprises: using nylon, functional powder, and a phenolic antioxidant as main raw materials, screw mixing to obtain a low-viscosity melt in which the functional powder is evenly dispersed; vacuuming the low-viscosity melt to obtain a high-viscosity melt; and spinning the high-viscosity melt to obtain the functional nylon fiber;

[0008] The relative viscosity of nylon is 2.4-2.6;

[0009] During the screw mixing process, nylon undergoes hydrolysis reaction;

[0010] In the low-viscosity melt, the content of the functional powder is 1-10wt%;

[0011] The relative viscosity of low-viscosity melt is 2-2.2, and the relative viscosity of high-viscosity melt is ≥2.4;

[0012] The diameter of the spinneret holes used in the spinning process is 0.25-0.45 mm.

[0013] The present invention controls the nylon to undergo a certain degree of hydrolysis during the screw mixing stage, and the relative viscosity is significantly reduced. As is known, the screw contains threaded elements with shearing and dispersing functions. Therefore, the dispersion and distribution of the functional powder in the matrix are completed in the screw. The hydrolysis of the nylon in the screw is beneficial to the dispersion of the functional powder.

[0014] However, after hydrolysis, viscosity increase is required for smooth spinning. If viscosity increase is desired, the water content of the system must be effectively controlled. However, it is difficult to control the water content of the system at a low value by simply vacuuming. This is because nylon has a special structure, and water molecules form strong hydrogen bonds with the amine and carbonyl groups of nylon. The present invention solves this problem by combining phenolic antioxidants with vacuuming. The addition of phenolic antioxidants can break the hydrogen bonds between water molecules and the amine and carbonyl groups of nylon. The phenolic groups occupy the carbonyl and amine groups in nylon, and the benzene rings they contain create a steric hindrance effect, blocking the entry of water into the nylon molecular chain. This helps to extract water from the system during the vacuuming stage after melt blending, effectively controlling the water content in the system and providing conditions for reaction reversal.

[0015] The present invention uses medium-viscosity nylon as a raw material, controlling its viscosity to decrease during the screw mixing stage and increase after the screw mixing stage, rather than directly using low-viscosity nylon as a raw material and controlling its viscosity to increase after the screw mixing stage. This is because: if low-viscosity nylon is used directly, water must be removed from the raw material stage, which will cause the problem of viscosity increase in the screw but not to a large extent, or subsequent viscosity increase but not to a large extent. If the water content is controlled to be higher, it will tend to hydrolyze in the screw, further reducing the viscosity, and the subsequent viscosity increase may not reach a viscosity suitable for spinning. In the present invention, the viscosity of medium-viscosity nylon is reduced first and then increased, which avoids these problems and also ensures a sufficient concentration of active end groups to promote viscosity increase.

[0016] The maximum addition amount of functional powder is 10wt%. If it is too high, it will easily cause spinning problems. The aperture of the spinneret is 0.25-0.45mm. If the aperture is too low, it will also cause the spinneret to be easily blocked. If it is too high, the shear stress of the polymer melt will be small, and the speed of the melt leaving the spinneret will be reduced, so that a puffing zone will be directly formed on the spinneret, causing sediment to accumulate around the spinneret outlet, resulting in floating and parallel yarns.

[0017] As the preferred technical solution:

[0018] In the method for preparing functional nylon fiber as described above, the moisture content of nylon is 0.18-0.30 wt %; the screw mixing temperature is 250-290° C., the speed is 10-60 r / min, the time is 60-600 s, and no vacuum is performed during the screw mixing.

[0019] The present invention controls the moisture content of nylon and the screw mixing conditions so that the nylon undergoes a hydrolysis reaction during the screw mixing process, and the melt viscosity is reduced to 2-2.2, that is, the relative viscosity of the melt after hydrolysis is 0.3-0.5 lower than the relative viscosity of nylon, as described below:

[0020] After nylon enters the screw and is heated and melted, a balance exists between the polycondensation reaction and the hydrolysis reaction between the molecular chain end groups. The moisture content of the nylon determines the direction of the reaction. When the moisture content of the nylon is high, under the high-temperature stirring of the screw, the reaction balance shifts toward the hydrolysis direction, the molecular weight decreases, and the relative viscosity of the melt decreases. When the moisture content of the nylon is low, the reaction balance shifts toward the positive direction, the molecular weight increases, and the relative viscosity of the melt increases. The present invention selects nylon raw materials with a higher moisture content. When the moisture content is controlled at 0.18-0.30wt% in the screw mixing section, the higher moisture content will promote a certain degree of hydrolysis of the nylon, and the relative viscosity of the nylon after hydrolysis will decrease to a certain extent. In addition, water, as a small molecule lubricant, also promotes the movement of the nylon molecular chains.

[0021] The temperature of the screw mixing is 250-290℃. If the temperature is too high, the degree of hydrolysis will be too high, and if the temperature is too low, the plasticization will be poor.

[0022] The speed of the screw mixing is 10-60r / min. If the speed is too fast, the dispersion will not be in place, and if the speed is too slow, the degree of hydrolysis will be too high.

[0023] The screw mixing time is 60-600s. If the time is too long, the degree of hydrolysis will be too high, and if the time is too short, the dispersion will not be in place.

[0024] The screw used for spinning is generally divided into three sections: the feeding section, the melting and compression section, and the homogenizing and metering section. The plasticization of the resin raw materials and the dispersion and distribution of the functional powder are completed during the screw process. The existing technology generally sets a vacuum port in the screw, and vacuum is drawn during the screw mixing process to extract moisture and some small molecular volatiles to reduce the hydrolysis of the material in the screw. The present invention does not draw a vacuum during the screw mixing process. Therefore, once a vacuum is drawn, the water content in the melt will be reduced, which is not conducive to the hydrolysis of the melt.

[0025] In the above-mentioned method for preparing a functional nylon fiber, the content of the phenolic antioxidant in the low-viscosity melt is 1-5wt%; when vacuuming, the vacuum degree of the environment where the low-viscosity melt is located is adjusted to ≥0.01MPa.

[0026] The present invention increases the relative viscosity of the high-viscosity melt to above 2.4 by controlling the content of the phenolic antioxidant and the vacuum degree during vacuuming, as described in detail below:

[0027] In the low-viscosity melt, the content of the phenolic antioxidant is at least 1 wt %; when evacuating, the vacuum degree is set to ≥ 0.01 MPa, so that the water content in the system decreases sharply, and the melt viscosity in this section continues to increase.

[0028] In the method for preparing a functional nylon fiber as described above, a spinning manifold is used for the spinning process; after the low-viscosity melt leaves the screw, it enters a metering pump through an elbow assembly and is then fed into the spinning manifold by the metering pump; vacuuming the low-viscosity melt refers to vacuuming the low-viscosity melt in the elbow assembly.

[0029] In the method for preparing a functional nylon fiber as described above, the metering pump speed is 5-25 r / min; the metering pump speed, i.e., the spinning speed, is used to control the nylon polycondensation time. The faster the metering pump speed, the more spinning output and the shorter the time the nylon stays in the spinning box. When the metering pump speed is controlled at 5-25 r / min, the nylon polycondensation reaction time can be controlled at 100-500 seconds.

[0030] In the method for preparing a functional nylon fiber as described above, the spinning manifold temperature (i.e., the nylon polycondensation temperature) is 260-295°C.

[0031] Beneficial effects:

[0032] The method of the present invention is simple and can improve the dispersion uniformity of the functional powder in the fiber, thereby achieving good fiber spinnability without clogging the spinneret during spinning at a relatively high powder addition amount. DETAILED DESCRIPTION

[0033] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0034] In the following embodiments:

[0035] The relative viscosity of the low-viscosity melt refers to the relative viscosity of the polymer melt collected at the screw outlet, which represents the degree of hydrolysis of the nylon in the screw;

[0036] The relative viscosity of the high-viscosity melt refers to the relative viscosity of the polymer melt collected at the spinneret, which represents the relative viscosity level of the nylon after polymerization and viscosity enhancement during spinning.

[0037] The following are the test methods for the relevant properties in the embodiments:

[0038] Relative viscosity: The relative viscosity of nylon is tested according to GB / T38138-2019 "Test methods for fiber-grade polycaprolactam (nylon)".

[0039] Moisture content: The moisture content of nylon is tested according to GB / T38138-2019 "Test methods for fiber-grade polycaprolactam (nylon) nylon".

[0040] Antistatic property: The antistatic property of the fiber is tested according to GB / T14342-1993 “Test method for specific electrical resistivity of synthetic staple fibers”.

[0041] Color saturation: GB / T17644 "Test method for whiteness and chromaticity of textile fibers" is used to characterize the fiber color and measure the color saturation of the sample.

[0042] Functional powders for spinning typically have a mesh size of 1000 or larger. These powders are suitable for fiber production without the need for additional grinding. The size of functional powders suitable for spinning is well known and will not be elaborated on here. In the examples below, the mesh size of the long-lasting antistatic agent 8206 is approximately 5000 mesh; the mesh size of the SAS93 antistatic agent is approximately 5000 mesh; the mesh size of the S501 toner is approximately 3000 mesh; and the mesh size of the PBK26 toner is approximately 3500 mesh.

[0043] Example 1

[0044] A method for preparing functional nylon fiber, comprising the following steps:

[0045] (1) Preparation of raw materials:

[0046] Nylon: Manufacturer: Jiangsu Huafeng Microfiber Material Co., Ltd., brand: HF1024, relative viscosity: 2.4, moisture content: 0.28 wt%;

[0047] Functional powder: The manufacturer is Dongguan Dazhan Jiyuan New Material Technology Co., Ltd., and the brand is long-lasting antistatic agent 8206;

[0048] Phenolic antioxidant: manufacturer is BASF (China) Co., Ltd., brand name is IRGANOX 1076;

[0049] (2) Screw-mixing nylon, functional powder, and phenolic antioxidant to obtain a low-viscosity melt, vacuuming the low-viscosity melt to obtain a high-viscosity melt, and spinning the high-viscosity melt to obtain functional nylon fiber; wherein the relative viscosity of the low-viscosity melt is 2, and the relative viscosity of the high-viscosity melt is 2.5;

[0050] In the low-viscosity melt, the content of the functional powder is 1 wt%, and the content of the phenolic antioxidant is 2.5 wt%;

[0051] The spinning process uses a spinning box;

[0052] After leaving the screw, the low-viscosity melt enters the metering pump through the elbow assembly and is then fed into the spinning box.

[0053] The screw mixing temperature was 280 °C, the speed was 50 r / min, and the mixing time was 480 s;

[0054] The metering pump speed is 20r / min, and the spinning box temperature is 280℃;

[0055] The vacuuming of the low-viscosity melt refers to the vacuuming of the low-viscosity melt in the elbow assembly. When vacuuming, the vacuum degree of the environment where the low-viscosity melt is located is adjusted to 0.02MPa;

[0056] The diameter of the spinneret holes used in the spinning process is 0.25 mm.

[0057] The functional nylon fiber finally obtained can be spun continuously for 24 hours without floating filaments, and its antistatic property is 2.5×10 11 Ω·cm.

[0058] Comparative Example 1

[0059] A method for preparing functional nylon fiber is basically the same as Example 1, except that the phenolic antioxidant is replaced by nylon of equal mass (same as Example 1); and the relative viscosity of the high-viscosity melt in step (2) is 2.1.

[0060] Functional nylon fibers cannot be formed due to low fiber viscosity.

[0061] By comparing Comparative Example 1 with Example 1, it can be seen that since Comparative Example 1 does not contain a phenolic antioxidant, the viscosity cannot meet the spinning requirements under the same process conditions, and the viscosity at the spinneret is too low. This is because the presence of hydrogen bonds makes it difficult for nylon to quickly reduce its moisture content, resulting in insufficient viscosity increase.

[0062] Comparative Example 2

[0063] A method for preparing functional nylon fiber is basically the same as Example 1, except that the moisture content of nylon is 0.1wt%; the relative viscosity of the low-viscosity melt in step (2) is 2.4, and the relative viscosity of the high-viscosity melt is 2.8.

[0064] Due to the serious blockage of the spinneret, fiber formation is impossible.

[0065] Comparing Comparative Example 2 with Example 1, it can be seen that since the moisture content of nylon in Comparative Example 2 is too low, hydrolysis in the screw is relatively mild, which does not achieve a good effect of improving powder dispersion, and thus still cannot achieve the ideal effect of improving spinneret blockage.

[0066] Comparative Example 3

[0067] A method for preparing functional nylon fiber is basically the same as Example 1, except that the moisture content of nylon is 0.32wt%; the relative viscosity of the low-viscosity melt in step (2) is 1.9, and the relative viscosity of the high-viscosity melt is 2.2.

[0068] Since the fiber viscosity is too low, the fibers cannot be formed.

[0069] Comparing Comparative Example 3 with Example 1, it can be seen that since the moisture content of nylon in Comparative Example 3 is too high, it will cause serious degradation in the screw mixing stage, and is not enough to increase the viscosity to 2.40 in the subsequent conveying stage, which affects the spinning.

[0070] Comparative Example 4

[0071] A method for preparing functional nylon fiber is basically the same as Example 1, except that: the relative viscosity of the nylon prepared in step (1) is 2.8, the moisture content is within 400 ppm (the manufacturer is Guangdong Xinhui Meida Nylon Co., Ltd., the brand is M32800), and no phenolic antioxidant is prepared; and the vacuum operation is omitted in step (2).

[0072] The functional nylon fiber finally obtained can be spun continuously for 24 hours without floating filaments, and its antistatic property is 6.0×10 9 Ω·cm.

[0073] By comparing Comparative Example 4 with Example 1, it can be seen that since high-viscosity, low-moisture content nylon is directly used for spinning in Comparative Example 4, the performance of the obtained fiber is poor. This is because the moisture content of the nylon is too low, which is not conducive to the dispersion of the functional powder. Moreover, since the viscosity of the nylon is too high, although normal spinning can be performed when only 1wt% of the functional powder is added, the antistatic performance of the obtained fiber will be deteriorated. It can be seen that the functional powder in the fiber prepared by the technical solution of Comparative Example 4 is poorly dispersed, and the antistatic effect depends on the good dispersion of the antistatic agent to better form a conductive path.

[0074] Comparative Example 5

[0075] A method for preparing functional nylon fiber is basically the same as that of Example 1, except that the aperture of the spinneret is 0.2 mm.

[0076] Spinning is unstable and the spinneret may become clogged.

[0077] Comparing Comparative Example 5 with Example 1, it can be seen that since the spinneret aperture used in Comparative Example 4 is too small, spinning instability will occur. This is because the functional powder easily aggregates, thereby clogging the spinneret aperture and making spinning unstable.

[0078] Comparative Example 6

[0079] A method for preparing functional nylon fiber is basically the same as that in Example 1, except that the spinneret aperture is 0.5 mm.

[0080] The spinning is unstable and the phenomena of floating yarn and parallel yarn are easy to occur.

[0081] By comparing Comparative Example 6 with Example 1, it can be seen that since the aperture of the spinneret used in Comparative Example 6 is too large, deposits accumulate around the spinneret outlet, resulting in floating threads and parallel threads. This is because the shear stress of the polymer melt becomes smaller, and the speed at which the melt leaves the spinneret decreases, resulting in the formation of a puffing zone directly on the spinneret, thereby causing deposits to accumulate around the spinneret outlet, resulting in floating threads and parallel threads.

[0082] Example 2

[0083] A method for preparing functional nylon fiber, comprising the following steps:

[0084] (1) Preparation of raw materials:

[0085] Nylon: Manufacturer: Jiangsu Huafeng Microfiber Material Co., Ltd., brand: HF1024, relative viscosity: 2.4, moisture content: 0.18 wt%;

[0086] Functional powder: The manufacturer is Clariant Chemicals (China) Co., Ltd., and the brand is SAS93 antistatic agent;

[0087] Phenolic antioxidant: manufacturer is BASF (China) Co., Ltd., brand name is IRGANOX 1076;

[0088] (2) Screw-mixing nylon, functional powder, and phenolic antioxidant to obtain a low-viscosity melt, vacuuming the low-viscosity melt to obtain a high-viscosity melt, and spinning the high-viscosity melt to obtain functional nylon fiber; wherein the relative viscosity of the low-viscosity melt is 2.1, and the relative viscosity of the high-viscosity melt is 2.4;

[0089] In the low-viscosity melt, the content of the functional powder is 5wt%, and the content of the phenolic antioxidant is 1wt%;

[0090] The spinning process uses a spinning box;

[0091] After leaving the screw, the low-viscosity melt enters the metering pump through the elbow assembly and is then fed into the spinning box.

[0092] The screw mixing temperature was 250 °C, the speed was 10 r / min, and the mixing time was 60 s;

[0093] The metering pump speed is 5 r / min, and the spinning box temperature is 260 °C;

[0094] The vacuuming of the low-viscosity melt refers to the vacuuming of the low-viscosity melt in the elbow assembly. When vacuuming, the vacuum degree of the environment where the low-viscosity melt is located is adjusted to 0.01MPa;

[0095] The diameter of the spinneret holes used in the spinning process is 0.25 mm.

[0096] The functional nylon fiber finally produced can be spun continuously for 24 hours without floating filaments, and its antistatic property is 6.2×10 12 Ω·cm.

[0097] Comparative Example 7

[0098] A method for preparing functional nylon fiber is basically the same as Example 2, except that: the relative viscosity of the nylon prepared in step (1) is 2.8, the moisture content is within 400 ppm (the manufacturer is Guangdong Xinhui Meida Nylon Co., Ltd., the brand is M32800), and no phenolic antioxidant is prepared; and the vacuum operation is omitted in step (2).

[0099] The spinning is unstable, the floating phenomenon is serious, and it is impossible to make fibers.

[0100] By comparing Comparative Example 7 with Example 2, it can be seen that since Comparative Example 7 directly uses high-viscosity, low-moisture content nylon for spinning, it will lead to unstable spinning and serious floating silk phenomenon. This is because the moisture content of nylon is too low, which is not conducive to the dispersion of functional powders, and since the viscosity of nylon is too high, it will also cause easy aggregation at the spinneret, which is not conducive to the stability of spinning and the floating silk phenomenon is serious.

[0101] Example 3

[0102] A method for preparing functional nylon fiber, comprising the following steps:

[0103] (1) Preparation of raw materials:

[0104] Nylon: manufacturer: Guangdong Xinhui Meida Nylon Co., Ltd., brand: M2400, relative viscosity: 2.45, moisture content: 0.2wt%;

[0105] Functional powder: The manufacturer is Clariant Chemicals (China) Co., Ltd., and the brand is SAS93 antistatic agent;

[0106] Phenolic antioxidant: manufacturer is SI Group Chemical (Shanghai) Co., Ltd., brand number 2246;

[0107] (2) Screw-mixing nylon, functional powder, and phenolic antioxidant to obtain a low-viscosity melt, vacuuming the low-viscosity melt to obtain a high-viscosity melt, and spinning the high-viscosity melt to obtain functional nylon fiber; wherein the relative viscosity of the low-viscosity melt is 2.1, and the relative viscosity of the high-viscosity melt is 2.5;

[0108] In the low-viscosity melt, the content of the functional powder is 10 wt%, and the content of the phenolic antioxidant is 2 wt%;

[0109] The spinning process uses a spinning box;

[0110] After leaving the screw, the low-viscosity melt enters the metering pump through the elbow assembly and is then fed into the spinning box.

[0111] The screw mixing temperature was 260 °C, the speed was 20 r / min, and the mixing time was 120 s;

[0112] The metering pump speed is 8 r / min, and the spinning box temperature is 270 °C;

[0113] The vacuuming of the low-viscosity melt refers to the vacuuming of the low-viscosity melt in the elbow assembly. When vacuuming, the vacuum degree of the environment where the low-viscosity melt is located is adjusted to 0.013MPa;

[0114] The diameter of the spinneret holes used in the spinning process is 0.35 mm.

[0115] The functional nylon fiber finally obtained can be spun continuously for 24 hours without floating filaments, and its antistatic property is 2.2×10 13 Ω·cm.

[0116] Comparative Example 8

[0117] A method for preparing functional nylon fiber is basically the same as Example 3, except that: the relative viscosity of the nylon prepared in step (1) is 2.8, the moisture content is within 400 ppm (the manufacturer is Guangdong Xinhui Meida Nylon Co., Ltd., the brand is M32800), and no phenolic antioxidant is prepared; and the vacuum operation is omitted in step (2).

[0118] During the spinning process, the spinneret was severely clogged and no fibers could be produced.

[0119] By comparing Comparative Example 8 with Example 3, it can be seen that since high-viscosity, low-moisture content nylon is directly used for spinning in Comparative Example 8, the performance of the obtained fiber is poor. This is because the moisture content of the nylon is too low, which is not conducive to the dispersion of the functional powder, and since the viscosity of the nylon is too high, the spinneret is severely blocked during the spinning process and no fiber can be produced.

[0120] Example 4

[0121] A method for preparing functional nylon fiber, comprising the following steps:

[0122] (1) Preparation of raw materials:

[0123] Nylon: manufacturer: Guangdong Xinhui Meida Nylon Co., Ltd., brand: M2400, relative viscosity: 2.45, moisture content: 0.24wt%;

[0124] Functional powder: The manufacturer is Shanghai Jingyan Chemical Co., Ltd., and the brand is S501 color powder;

[0125] Phenolic antioxidant: manufacturer is SI Group Chemical (Shanghai) Co., Ltd., brand number 2246;

[0126] (2) Screw-mixing nylon, functional powder, and phenolic antioxidant to obtain a low-viscosity melt, vacuuming the low-viscosity melt to obtain a high-viscosity melt, and spinning the high-viscosity melt to obtain functional nylon fiber; wherein the relative viscosity of the low-viscosity melt is 2.2, and the relative viscosity of the high-viscosity melt is 2.6;

[0127] In the low-viscosity melt, the content of the functional powder is 1 wt%, and the content of the phenolic antioxidant is 2.5 wt%;

[0128] The spinning process uses a spinning box;

[0129] After leaving the screw, the low-viscosity melt enters the metering pump through the elbow assembly and is then fed into the spinning box.

[0130] The screw mixing temperature was 260 °C, the speed was 30 r / min, and the mixing time was 240 s;

[0131] The metering pump speed is 12 r / min, and the spinning box temperature is 275 °C;

[0132] The vacuuming of the low-viscosity melt refers to the vacuuming of the low-viscosity melt in the elbow assembly. When vacuuming, the vacuum degree of the environment where the low-viscosity melt is located is adjusted to 0.018MPa;

[0133] The diameter of the spinneret holes used in the spinning process is 0.35 mm.

[0134] The functional nylon fiber finally produced can be spun continuously for 24 hours without floating filaments, and has a color saturation of 1.5%.

[0135] Comparative Example 9

[0136] A method for preparing functional nylon fiber is basically the same as Example 4, except that: the relative viscosity of the nylon prepared in step (1) is 2.8, the moisture content is within 400 ppm (the manufacturer is Guangdong Xinhui Meida Nylon Co., Ltd., the brand is M32800), and no phenolic antioxidant is prepared; and the vacuum operation is omitted in step (2).

[0137] The functional nylon fiber finally produced can be spun continuously for 24 hours without floating filaments, and the color saturation is 0.22%.

[0138] By comparing Comparative Example 9 with Example 4, it can be seen that since high-viscosity, low-moisture content nylon is directly used for spinning in Comparative Example 9, the performance of the obtained fiber is poor. This is because the moisture content of the nylon is too low, which is not conducive to the dispersion of the functional powder. Moreover, since the viscosity of the nylon is too high and only 1% of the functional powder is added, although normal spinning can be performed, the color saturation of the obtained fiber will be deteriorated. This is caused by the relatively serious accumulation and agglomeration of the color powder.

[0139] Example 5

[0140] A method for preparing functional nylon fiber, comprising the following steps:

[0141] (1) Preparation of raw materials:

[0142] Nylon: Manufacturer: Guangdong Xinhui Meida Nylon Co., Ltd., brand: M2400H, relative viscosity: 2.6, moisture content: 0.28 wt%;

[0143] Functional powder: The manufacturer is Hunan Kelai New Materials Co., Ltd., and the brand is PBK26 color powder;

[0144] Phenolic antioxidant: manufacturer is Jinan Yucai Chemical Co., Ltd., brand number 246;

[0145] (2) Screw-mixing nylon, functional powder, and phenolic antioxidant to obtain a low-viscosity melt, vacuuming the low-viscosity melt to obtain a high-viscosity melt, and spinning the high-viscosity melt to obtain functional nylon fiber; wherein the relative viscosity of the low-viscosity melt is 2.2, and the relative viscosity of the high-viscosity melt is 2.6;

[0146] In the low-viscosity melt, the content of the functional powder is 5wt%, and the content of the phenolic antioxidant is 4wt%;

[0147] The spinning process uses a spinning box;

[0148] After leaving the screw, the low-viscosity melt enters the metering pump through the elbow assembly and is then fed into the spinning box.

[0149] The screw mixing temperature was 270 °C, the speed was 40 r / min, and the mixing time was 360 s;

[0150] The metering pump speed is 16 r / min, and the spinning box temperature is 285 °C;

[0151] The vacuuming of the low-viscosity melt refers to the vacuuming of the low-viscosity melt in the elbow assembly. When vacuuming, the vacuum degree of the environment where the low-viscosity melt is located is adjusted to 0.025MPa;

[0152] The diameter of the spinneret holes used in the spinning process is 0.45 mm.

[0153] The functional nylon fiber finally produced can be spun continuously for 24 hours without floating filaments, and has a color saturation of 4.5%.

[0154] Comparative Example 10

[0155] A method for preparing functional nylon fiber is basically the same as Example 5, except that: the relative viscosity of the nylon prepared in step (1) is 2.8, the moisture content is within 400 ppm (the manufacturer is Guangdong Xinhui Meida Nylon Co., Ltd., the brand is M32800), and no phenolic antioxidant is prepared; and the vacuum operation is omitted in step (2).

[0156] The spinning is unstable, the floating phenomenon is serious, and it is impossible to make fibers.

[0157] By comparing Comparative Example 10 with Example 5, it can be seen that since Comparative Example 10 directly uses high-viscosity, low-moisture content nylon for spinning, the spinning will be unstable and the floating phenomenon will be serious. This is because the moisture content of the nylon is too low, which is not conducive to the dispersion of the functional powder, and since the viscosity of the nylon is too high, it will also cause easy aggregation at the spinneret, which is not conducive to the stability of spinning and the floating phenomenon is serious.

[0158] Example 6

[0159] A method for preparing functional nylon fiber, comprising the following steps:

[0160] (1) Preparation of raw materials:

[0161] Nylon: Manufacturer: Guangdong Xinhui Meida Nylon Co., Ltd., brand: M2400H, relative viscosity: 2.6, moisture content: 0.3wt%;

[0162] Functional powder: The manufacturer is Hunan Kelai New Materials Co., Ltd., and the brand is PBK26 color powder;

[0163] Phenolic antioxidant: manufacturer is Jinan Yucai Chemical Co., Ltd., brand number 246;

[0164] (2) Screw-mixing nylon, functional powder, and phenolic antioxidant to obtain a low-viscosity melt, vacuuming the low-viscosity melt to obtain a high-viscosity melt, and spinning the high-viscosity melt to obtain functional nylon fiber; wherein the relative viscosity of the low-viscosity melt is 2.2, and the relative viscosity of the high-viscosity melt is 2.7;

[0165] In the low-viscosity melt, the content of the functional powder is 10 wt %, and the content of the phenolic antioxidant is 5 wt %;

[0166] The spinning process uses a spinning box;

[0167] After leaving the screw, the low-viscosity melt enters the metering pump through the elbow assembly and is then fed into the spinning box.

[0168] The screw mixing temperature was 290 °C, the speed was 60 r / min, and the mixing time was 600 s;

[0169] The metering pump speed is 25 r / min, and the spinning box temperature is 295 °C;

[0170] The vacuuming of the low-viscosity melt refers to the vacuuming of the low-viscosity melt in the elbow assembly. When vacuuming, the vacuum degree of the environment where the low-viscosity melt is located is adjusted to 0.03MPa;

[0171] The diameter of the spinneret holes used in the spinning process is 0.45 mm.

[0172] The functional nylon fiber finally produced can be spun continuously for 24 hours without floating filaments, has an antistatic property of 0.5 / Ω·cm, and a color saturation of 9.2%.

[0173] Comparative Example 11

[0174] A method for preparing functional nylon fiber is basically the same as Example 6, except that: the relative viscosity of the nylon prepared in step (1) is 2.8, the moisture content is within 400 ppm (the manufacturer is Guangdong Xinhui Meida Nylon Co., Ltd., the brand is M32800), and no phenolic antioxidant is prepared; and the vacuum operation is omitted in step (2).

[0175] The spinneret was severely clogged and no fiber could be produced.

[0176] By comparing Comparative Example 11 with Example 6, it can be seen that since high-viscosity, low-moisture content nylon is directly used for spinning in Comparative Example 11, the performance of the obtained fiber is poor. This is because the moisture content of the nylon is too low, which is not conducive to the dispersion of the functional powder, and since the viscosity of the nylon is too high, the spinneret is severely blocked during the spinning process and no fiber can be produced.

Claims

1. A method for preparing functional nylon fiber, characterized in that: Nylon, functional powder and phenolic antioxidant are used as main raw materials, and after screw mixing is performed to obtain a low-viscosity melt, the low-viscosity melt is vacuumed to obtain a high-viscosity melt, and the high-viscosity melt is then spun to obtain functional nylon fiber; The moisture content of nylon is 0.18-0.30wt%; the relative viscosity of nylon is 2.4-2.6; During the screw mixing process, nylon undergoes hydrolysis reaction; In the low-viscosity melt, the content of the functional powder is 1-10wt%, and the content of the phenolic antioxidant is 1-5wt%; When vacuuming, adjust the vacuum degree of the environment where the low-viscosity melt is located to ≥0.01MPa; The relative viscosity of low-viscosity melt is 2-2.2, and the relative viscosity of high-viscosity melt is ≥2.4; The diameter of the spinneret holes used in the spinning process is 0.25-0.45 mm.

2. The method for preparing a functional nylon fiber according to claim 1, characterized in that: The temperature of the screw mixing is 250-290° C., the speed is 10-60 r / min, the time is 60-600 s, and no vacuum is performed during the screw mixing.

3. The method for preparing a functional nylon fiber according to claim 1, wherein: The spinning process uses a spinning manifold; after the low-viscosity melt leaves the screw, it enters the metering pump through the elbow assembly and is fed into the spinning manifold by the metering pump; vacuuming the low-viscosity melt refers to vacuuming the low-viscosity melt in the elbow assembly.

4. The method for preparing a functional nylon fiber according to claim 3, characterized in that: The metering pump speed is 5-25r / min.

5. The method for preparing a functional nylon fiber according to claim 3, characterized in that: The spinning box temperature is 260-295℃.