An acrylic fiber, its preparation method and application

Abstract

This application relates to the field of fiber technology, and specifically discloses an acrylic fiber, a preparation method thereof and an application. The preparation method of the acrylic fiber provided in this application includes the following steps: spinning and forming, water washing and drawing, oiling, drying, crimping and setting; Oiling: adding an acrylic spinning oil agent to the tow after water washing and drawing, and the addition amount of the acrylic spinning oil agent is 0.22 - 0.54% of the total weight of the tow; The acrylic spinning oil agent comprises the following components in parts by weight: 20 - 30 parts of polyoxyethylene stearate, 12 - 20 parts of emulsifier SOPE-10, 10 - 20 parts of isomeric tridecyl polyoxyethylene ether sodium sulfate, 20 - 30 parts of castor oil / IPDI copolymer, 6 - 15 parts of polyoxyethylene sorbitan monooleate, 0 - 10 parts of alkyl phenyl thiophosphate; This application also provides the acrylic fiber obtained by the above preparation method. The preparation method of the acrylic fiber provided in this application can improve the surface roughness and softness of the acrylic fiber, and obtain an acrylic fiber with good smoothness and excellent softness.

Description

Technical Field

[0001] This application relates to the technical field of fibers, and particularly to an acrylic fiber, a preparation method thereof, and an application thereof. Background Art

[0002] As an important synthetic fiber, acrylic fiber is widely used in the production of products such as strong ropes, bulletproof vests, fishing lines, etc. due to its good acid and alkali resistance, strong weather resistance, high strength and elasticity, and excellent heat resistance. However, acrylic fiber has a relatively high hardness and is prone to fuzzing during the spinning process. Therefore, spinning oil agents are often used to improve its lubrication performance.

[0003] Traditional spinning oil agents mostly use a single surfactant. Although they can improve certain properties of the fiber to a certain extent, the comprehensive effect is not good. In recent years, composite oil agents prepared with mineral oil or synthetic oil as the base oil and added with a certain amount of antistatic agents, lubricants and other auxiliary components have been widely used as acrylic fiber spinning oil agents in the market. However, the above oil agents are prone to volatilization during high-temperature spinning, resulting in unstable fiber properties, and the effects of the above oil agents in improving the softness and processing hairiness rate of acrylic fibers still need to be improved. Summary of the Invention

[0004] In order to improve the smoothness and softness of acrylic fibers, this application provides an acrylic fiber, a preparation method thereof, and an application thereof.

[0005] In a first aspect, this application provides a preparation method of an acrylic fiber, adopting the following technical solution:

[0006] A preparation method of an acrylic fiber, comprising the following steps: spinning and forming, water washing and drawing, oiling, drying, crimping and shaping;

[0007] Oiling: Applying an acrylic fiber spinning oil agent to the tow after water washing and drawing, and the addition amount of the acrylic fiber spinning oil agent is 0.22 - 0.54% of the total weight of the tow;

[0008] The acrylic fiber spinning oil agent comprises the following components in parts by weight: 20 - 30 parts of polyoxyethylene stearate, 12 - 20 parts of emulsifier SOPE - 10, 10 - 20 parts of isomeric tridecyl polyoxyethylene ether sodium sulfate, 20 - 30 parts of castor oil / IPDI copolymer, 6 - 15 parts of polyoxyethylene sorbitan monooleate, and 0 - 10 parts of alkyl phenyl thiophosphate.

[0009] The present application provides a method for preparing acrylic fibers. In the above preparation method, an acrylic spinning finish is used to oil the tow after water washing and drawing. On the one hand, it endows the acrylic fibers with good softness, comparable to that of natural cotton; on the other hand, it can also reduce the friction coefficient on the fiber surface, improve the smoothness of the acrylic fibers, and reduce the hairiness rate of the acrylic fibers during subsequent processing. Therefore, the acrylic fibers prepared by using the preparation method provided by the present application have the advantages of good smoothness, good softness, and low processing hairiness rate, and can be widely used in the production of products such as strong ropes, bulletproof vests, fishing lines, etc., and have good application prospects.

[0010] In the acrylic spinning finish used in the present application, polyoxyethylene stearate and polyoxyethylene sorbitan monooleate belong to non-ionic surfactants, both of which have good lubricating properties, can reduce the friction between fibers, and make the fibers slide more easily during subsequent processing, thereby reducing the hairiness rate of fiber processing; in addition, polyoxyethylene stearate and polyoxyethylene sorbitan monooleate also have good antistatic effects, can reduce the accumulation of static charges on the fiber surface, and prevent the fibers from adhering or causing other adverse effects due to static electricity. Isotridecyl polyoxyethylene ether sulfate is an anionic surfactant, which can reduce the surface roughness of the fibers, improve the smoothness and comfort of the fibers, and thus endow the fibers with a soft and smooth hand feeling. The castor oil / IPDI copolymer can increase the softness and wear resistance of the fibers, and further improve the fiber processing performance. Alkyl phenyl thiophosphate has good lubricity and wear resistance. On the one hand, it can reduce the friction between fibers, improve the softness of the fibers, and on the other hand, it can relieve the damage caused by friction, reduce the hairiness rate of fiber processing, and improve the processing performance of the fibers.

[0011] Optionally, the acrylic spinning finish includes the following components in parts by weight: 20-30 parts of polyoxyethylene stearate, 12-20 parts of emulsifier SOPE-10, 12-17 parts of isotridecyl polyoxyethylene ether sulfate, 23-28 parts of castor oil / IPDI copolymer, 6-15 parts of polyoxyethylene sorbitan monooleate, and 3-8 parts of alkyl phenyl thiophosphate.

[0012] In the acrylic spinning finish used in the present application, the dosage of each component will affect the softness and smoothness of the acrylic fibers. Through experimental exploration, the present application finds that further controlling the parts by weight of isotridecyl polyoxyethylene ether sulfate, castor oil / IPDI copolymer, and alkyl phenyl thiophosphate within the above ranges, the obtained acrylic fibers have better smoothness, better softness, and lower hairiness rate during subsequent processing.

[0013] In some embodiments, the weight parts of the isomeric tridecyl alcohol polyoxyethylene ether sulfate can be 10 - 12 parts, 10 - 15 parts, 10 - 17 parts, 10 - 30 parts, 12 - 15 parts, 12 - 17 parts, 12 - 20 parts, 15 - 17 parts, 15 - 20 parts or 17 - 20 parts.

[0014] In a specific embodiment, the weight parts of the isomeric tridecyl alcohol polyoxyethylene ether sulfate can also be 10 parts, 12 parts, 15 parts, 17 parts or 20 parts.

[0015] In some embodiments, the weight parts of the castor oil / IPDI copolymer can be 20 - 23 parts, 20 - 25 parts, 20 - 28 parts, 20 - 30 parts, 23 - 25 parts, 23 - 28 parts, 23 - 30 parts, 25 - 28 parts, 25 - 30 parts or 28 - 30 parts.

[0016] In a specific embodiment, the weight parts of the castor oil / IPDI copolymer can also be 20 parts, 23 parts, 25 parts, 28 parts or 30 parts.

[0017] In some embodiments, the weight parts of the castor oil / IPDI copolymer can be 20 - 23 parts, 20 - 25 parts, 20 - 28 parts, 20 - 30 parts, 23 - 25 parts, 23 - 28 parts, 23 - 30 parts, 25 - 28 parts, 25 - 30 parts or 28 - 30 parts.

[0018] In a specific embodiment, the weight parts of the castor oil / IPDI copolymer can also be 20 parts, 23 parts, 25 parts, 28 parts or 30 parts.

[0019] In some embodiments, the weight parts of the alkyl phenyl thiophosphate can be 0 - 3 parts, 0 - 5 parts, 0 - 8 parts, 0 - 10 parts, 3 - 5 parts, 3 - 8 parts, 3 - 10 parts, 5 - 8 parts, 5 - 10 parts or 8 - 10 parts.

[0020] In a specific embodiment, the weight parts of the alkyl phenyl thiophosphate can also be 0 parts, 3 parts, 5 parts, 8 parts or 10 parts.

[0021] Optionally, the addition amount of the acrylic fiber spinning finish is 0.31 - 0.43% of the total mass of the tow.

[0022] In this application, the addition amount of the acrylic fiber spinning finish will affect the softness and smoothness of the fiber. As the addition amount of the acrylic fiber spinning finish increases, the softness of the obtained tow shows a trend of first increasing and then decreasing, and the dynamic friction coefficient shows a trend of first decreasing and then increasing. Therefore, considering comprehensively, in this application, the addition amount of the acrylic fiber spinning finish is further controlled within the above range, and acrylic fibers with excellent softness and smoothness can be obtained.

[0023] In some embodiments, the addition amount of the acrylic fiber spinning finish can be 0.22 - 0.31%, 0.22 - 0.38%, 0.22 - 0.43%, 0.22 - 0.54%, 0.31 - 0.38%, 0.31 - 43%, 0.31 - 0.54%, 0.38 - 0.43%, 0.38 - 0.54% or 0.43 - 0.54% of the total mass of the tow.

[0024] In a specific embodiment, the addition amount of the acrylic fiber spinning finish can also be 0.22%, 0.31%, 0.38%, 0.43% or 0.54% of the total mass of the tow.

[0025] Optionally, before use, the acrylic fiber spinning finish is heated and melted at 70 - 80°C, and then formulated into an aqueous solution with a mass concentration of 2 - 7% and injected into the upper oil tank of the spinning line; during the oiling process, the temperature in the oil tank is maintained at 70 - 75°C.

[0026] Optionally, the drying temperature is 150 - 160°C.

[0027] In a second aspect, the present application provides acrylic fibers obtained by a method for preparing acrylic fibers.

[0028] In a third aspect, the present application provides the use of the acrylic fibers in strong ropes, bulletproof vests, and fishing lines.

[0029] In summary, the present application has the following beneficial effects:

[0030] 1. The present application provides a method for preparing acrylic fibers. This preparation method uses an acrylic fiber spinning finish composed of components such as isomeric tridecyl alcohol polyoxyethylene ether sulfate, castor oil / IPDI copolymer, and polyoxyethylene sorbitan monooleate to oil the tow, significantly improving the surface roughness and softness of the obtained acrylic fibers, obtaining acrylic fibers with high smoothness and good flexibility. These acrylic fibers can be widely used in the production of products such as strong ropes, bulletproof vests, and fishing lines, and have good application prospects.

[0031] 2. The present application further adds alkyl phenyl thiophosphate to the acrylic fiber spinning finish and controls the addition amount of alkyl phenyl thiophosphate within the range of 3 - 8 parts. The obtained acrylic fibers have a smoother surface and better softness, with a pressure increase thickness change rate A1 > 70%, a remaining thickness change rate A2 < 15% after pressure relief, and a dynamic friction coefficient < 0.32.

[0032] 3. Through experimental exploration, the present application finds that when the addition amount of the acrylic fiber spinning finish is controlled within the range of 0.31 - 0.43% of the total weight of the tow, the obtained acrylic fibers have a lower friction coefficient and better softness. Description of the Drawings

[0033] Figure 1 It is a flow chart of the preparation method of acrylic fibers provided by this application. Specific embodiments

[0034] (1) Spinning and forming: Using polyacrylonitrile dry powder as raw material and dimethylacetamide as solvent, a polymer emulsion with a mass concentration of 20 - 30% is made. The polymer emulsion is heated to 90 - 100 °C and extruded from the shaped spinneret holes on the spinneret plate to form monofilaments, and primary fibers are formed through double diffusion in the coagulation bath; among them, in the polyacrylonitrile dry powder, the weight ratio of acrylonitrile to vinyl acetate is (92 - 94):(6 - 8).

[0035] (2) Washing and drawing: The above-mentioned primary fibers are washed and then drawn by a drawing machine. When washing, the temperature of the water tank is 70 - 90 °C, the drawing speed of the drawing machine is 30 - 60 m / min, and the drawing ratio is 3 - 5 times.

[0036] (3) Oiling:

[0037] (3 - 1) Prepare an acrylic fiber spinning oil agent according to the following ratio, heat and melt it at 70 - 80 °C, and then prepare an aqueous solution with a mass concentration of 2 - 7% and inject it into the upper - line oil agent tank of the spinning;

[0038] Among them, the acrylic fiber spinning oil agent includes the following components in parts by weight: 20 - 30 parts of polyoxyethylene stearate, 12 - 20 parts of emulsifier SOPE - 10, 10 - 20 parts of isomeric tridecyl polyoxyethylene ether sodium sulfate, 20 - 30 parts of castor oil / IPDI copolymer, 6 - 15 parts of polyoxyethylene sorbitan monooleate, 0 - 10 parts of alkyl phenyl thiophosphate, and 5 - 15 parts of water. Further, the acrylic fiber spinning oil agent includes the following components in parts by weight: 20 - 30 parts of polyoxyethylene stearate, 12 - 20 parts of emulsifier SOPE - 10, 12 - 17 parts of isomeric tridecyl polyoxyethylene ether sodium sulfate, 23 - 28 parts of castor oil / IPDI copolymer, 6 - 15 parts of polyoxyethylene sorbitan monooleate, 3 - 8 parts of alkyl phenyl thiophosphate, and 5 - 15 parts of water.

[0039] (3 - 2) Apply the acrylic fiber spinning oil agent to the tow after washing and drawing. During the oiling process, keep the temperature in the oil agent tank at 70 - 75 °C, and the addition amount of the acrylic fiber spinning oil agent is 0.22 - 0.54% of the total weight of the tow; further, the addition amount of the flat acrylic fiber spinning oil agent is 0.31 - 0.43% of the total mass of the tow.

[0040] (4) Drying: Dry the oiled tow by passing it through a drying hot roll at 150 - 160 °C.

[0041] (5) Crimping and setting: The dried tow is cooled and crimped, and then fed into a setting pot for heat setting at 130 - 140 °C and 20 - 60 KPa to obtain acrylic fibers.

[0042] In this application, the polyoxyethylene ester of stearic acid is of the SG-6 type; the emulsifier SOPE-10 is purchased from Haian Sensheng Chemical Co., Ltd.; the sodium isodecyl polyoxyethylene ether sulfate is of the emulsifier E-1310SA type; the castor oil / IPDI copolymer is purchased from Guangzhou Naibo Biotechnology Co., Ltd.; the polyoxyethylene sorbitan monooleate is polysorbate-80; the alkyl phenyl thiophosphate is of the E1412 type and is purchased from Hangzhou Shi'an Chemical Co., Ltd.; the remaining raw materials, reagents, solvents, etc. of this application can all be obtained through commercial purchase.

[0043] The following further elaborates on this application in detail in conjunction with preparation examples, examples, performance detection tests, and attached drawings.

[0044] Preparation Examples 1 - 9

[0045] Preparation Examples 1 - 9 respectively provide an acrylic spinning oil agent.

[0046] The differences between the above preparation examples are as follows: In the acrylic spinning oil agent, the addition amounts of sodium isodecyl polyoxyethylene ether sulfate and castor oil / IPDI copolymer are specifically shown in Table 1 below.

[0047] The preparation methods of the acrylic spinning oil agents provided by Preparation Examples 1 - 9 include the following steps: Weigh 25 g of polyoxyethylene ester of stearic acid, 15 g of emulsifier SOPE-10, sodium isodecyl polyoxyethylene ether sulfate, castor oil / IPDI copolymer, 10 g of polyoxyethylene sorbitan monooleate, and 10 g of water respectively, mix them evenly, stir and heat to 60 °C to make them fully compounded, and obtain a flat acrylic spinning oil agent after cooling.

[0048] Table 1 Addition amounts of some components in the acrylic spinning oil agents provided by Preparation Examples 1 - 9

[0049]

[0050] Preparation Examples 10 - 13

[0051] Preparation Examples 10 - 13 respectively provide an acrylic spinning oil agent.

[0052] The differences between the above preparation examples and Preparation Example 3 are as follows: The acrylic spinning oil agent also contains alkyl phenyl thiophosphate, and the addition amount of alkyl phenyl thiophosphate is shown in Table 2.

[0053] Table 2 Addition amount of alkyl phenyl thiophosphate in the acrylic spinning oil agents of Preparation Examples 10 - 13

[0054]

[0055] Comparative Preparation Example 1

[0056] Comparative Preparation Example 1 provides an acrylic fiber spinning finish.

[0057] The difference between the above Comparative Preparation Example and Preparation Example 3 is that the addition amount of isomeric tridecyl alcohol polyoxyethylene ether sodium sulfate in the acrylic fiber spinning finish is 0.

[0058] Comparative Preparation Example 2

[0059] Comparative Preparation Example 2 provides an acrylic fiber spinning finish.

[0060] The difference between the above Comparative Preparation Example and Preparation Example 3 is that the addition amount of castor oil / IPDI copolymer in the acrylic fiber spinning finish is 0.

[0061] Comparative Preparation Example 3

[0062] Comparative Preparation Example 3 provides an acrylic fiber spinning finish.

[0063] The difference between the above Comparative Preparation Example and Preparation Example 3 is that the castor oil / IPDI copolymer is replaced by polyoxyethylene castor oil acid ester.

[0064] Comparative Preparation Example 4

[0065] Comparative Preparation Example 4 provides an acrylic fiber spinning finish.

[0066] The difference between the above Comparative Preparation Example and Preparation Example 3 is that the isomeric tridecyl alcohol polyoxyethylene ether sodium sulfate is replaced by fatty alcohol polyoxyethylene ether sodium sulfate.

[0067] Examples 1 - 13

[0068] Examples 1 - 13 respectively provide a method for preparing acrylic fibers.

[0069] The difference between the above Examples is that the acrylic fiber spinning finishes used in the oiling step are respectively from Preparation Examples 1 - 13.

[0070] The method for preparing acrylic fibers provided by Examples 1 - 13, as Figure 1 shown, includes the following steps:

[0071] (1) Spinning and forming: Using polyacrylonitrile dry powder as the raw material and dimethylacetamide as the solvent, a polymer emulsion with a mass concentration of 20 - 30% is made. The polymer emulsion is heated to 95°C and extruded from the shaped spinneret holes on the spinneret plate to form monofilaments, and primary fibers are formed through double diffusion in the coagulation bath; among them, in the polyacrylonitrile dry powder, the weight ratio of acrylonitrile to vinyl acetate is 94:6.

[0072] (2) Water washing and drawing: The above-mentioned nascent fibers are washed with water and then drawn by a drawing machine. During water washing, the temperature of the water tank is 80°C, the drawing speed of the drawing machine is 50 m / min, and the drawing ratio is 4 times.

[0073] (3) Oiling:

[0074] (3-1) Melt the acrylic spinning oil agent at 75°C, then prepare an aqueous solution with a mass concentration of 5% and inject it into the upper spinning oil agent tank;

[0075] (3-2) Apply the acrylic spinning oil agent to the tow after water washing and drawing. During the oiling process, keep the temperature in the oil agent tank at 75°C, and the addition amount of the acrylic spinning oil agent is 0.38% of the total weight of the tow.

[0076] (4) Drying: Dry the oiled tow through a drying hot roll at 155°C.

[0077] (5) Crimping and setting; Cool and crimp the dried tow, then send it into a setting pot and perform heat setting treatment at 135°C and 40 KPa to obtain acrylic fibers.

[0078] Example 14-17

[0079] Examples 14-17 respectively provide a method for preparing acrylic fibers.

[0080] The difference between the above examples and Example 3 lies in: the addition amount of the acrylic spinning oil agent, as shown in Table 3 below.

[0081] Table 3 Addition amount of acrylic spinning oil agent in the preparation methods of Example 3, Examples 14-17

[0082]

[0083] Comparative Example 1-4

[0084] Comparative Examples 1-4 respectively provide a method for preparing acrylic fibers.

[0085] The difference between the above comparative examples and Example 3 lies in: the acrylic spinning oil agents used in the oiling step are respectively from Comparative Preparation Examples 1-4. Comparative Example 5

[0086] Comparative Example 5 provides a method for preparing acrylic fibers.

[0087] The difference between the above comparative example and Example 3 lies in: the addition amount of the acrylic spinning oil agent is 0.60% of the total weight of the tow.

[0088] Performance detection test

[0089] The acrylic fibers obtained in Examples 1-17 and Comparative Examples 1-5 were subjected to performance tests, and the results are shown in Table 4 below.

[0090] (1) Softness: The acrylic fibers were mechanically carded into a fiber web test specimen with a diameter D of 50 mm and a thickness T0 of 1 cm; then the test specimen was placed in a YG141D digital fabric thickness gauge for pressing, with a pressing weight of 25 cN and a pressing time of 30 s; the thickness T1 of the test specimen at 30 s of pressing was recorded; then after depressurization and resting for 5 min, the thickness T2 of the specimen was retested. The pressing thickness change rate A1 and the remaining thickness change rate A2 after depressurization were calculated respectively, and the calculation formulas are as follows:

[0091] Pressing thickness change rate A1 = (T0 - T1) / T0 × 100%

[0092] Remaining thickness change rate A2 after depressurization = (T0 - T2) / T0 × 100%

[0093] (2) Friction coefficient: The dynamic friction coefficient μ of the acrylic fibers was detected using a Y151 fiber friction coefficient tester. 10 acrylic fibers of each type were detected in parallel and the average value was taken. Note: The smaller the friction coefficient of the acrylic fibers, the lower the surface roughness of the acrylic fibers, the smoother the surface, and the lower the hairiness rate in the subsequent processing.

[0094] Table 4 Performance test results of the flat acrylic fibers obtained in Examples 1-17 and Comparative Examples 1-5

[0095]

[0096] According to the test results in Table 4, in Examples 1-17 of the present application, the acrylic spinning finish prepared with isomeric tridecyl alcohol polyoxyethylene ether sulfate, castor oil / IPDI copolymer, etc. was used to oil the tow, and the addition amount of the acrylic spinning finish was controlled within the range of 0.22 - 0.54% of the total weight of the tow. The pressing thickness change rate A1 of the obtained acrylic fibers was 60.42 - 74.34%, the remaining thickness change rate A2 after depressurization was 10.34 - 22.46%, and the dynamic friction coefficient μ was 0.243 - 0.410. Therefore, it shows that the method for preparing acrylic fibers provided by the present application can prepare acrylic fibers with good smoothness and softness.

[0097] When isomeric tridecyl alcohol polyoxyethylene ether sulfate was not added to the acrylic spinning finish used in Comparative Example 1, the pressing thickness change rate A1 of the obtained acrylic fibers was only 52.31%, the remaining thickness change rate A2 after depressurization was only 32.25%, and the dynamic friction coefficient μ was 0.478, indicating that the acrylic fibers obtained in Comparative Example 1 had a rough surface and poor softness.

[0098] When castor oil / IPDI copolymer was not added to the acrylic fiber spinning finish used in Comparative Example 2, the pressure-induced thickness change rate A1 of the obtained acrylic fiber was only 53.35%, and the remaining thickness change rate A2 after pressure relief was only 30.17%. The dynamic friction coefficient μ was 0.453, indicating that the surface of the acrylic fiber obtained in Comparative Example 2 was rough and had poor softness.

[0099] In Comparative Example 3, the acrylic fiber spinning finish containing polyoxyethylene castor oil acid was used to oil the tow. The pressure-induced thickness change rate A1 of the obtained acrylic fiber was 58.45%, and the remaining thickness change rate A2 after pressure relief was only 27.26%. The dynamic friction coefficient μ was 0.434, indicating that the surface of the acrylic fiber obtained in Comparative Example 3 was relatively rough and had slightly poor softness.

[0100] In Comparative Example 4, the acrylic fiber spinning finish containing sodium lauryl polyoxyethylene ether sulfate was used to oil the tow. The pressure-induced thickness change rate A1 of the obtained acrylic fiber was 57.23%, and the remaining thickness change rate A2 after pressure relief was only 28.34%. The dynamic friction coefficient μ was 0.441, indicating that the surface of the acrylic fiber obtained in Comparative Example 4 was relatively rough and had slightly poor softness.

[0101] From the test results of Examples 1-5, it can be seen that as the addition amount of isomeric tridecanol polyoxyethylene ether sulfate in the acrylic fiber spinning finish increased, the pressure-induced thickness change rate A1 of the prepared acrylic fiber showed a trend of first increasing and then remaining basically unchanged, and the remaining thickness change rate A2 and the dynamic friction coefficient after pressure relief showed a trend of first decreasing and then remaining basically unchanged. Therefore, considering comprehensively, in this application, the addition amount of isomeric tridecanol polyoxyethylene ether sulfate in the acrylic fiber spinning finish was further controlled between 12-17 parts, and the obtained acrylic fiber had a smoother surface and better softness.

[0102] From the test results of Example 3 and Examples 4-9, it can be seen that as the addition amount of castor oil / IPDI copolymer in the acrylic fiber spinning finish increased, the pressure-induced thickness change rate A1 of the prepared acrylic fiber showed a trend of first increasing and then remaining basically unchanged, and the remaining thickness change rate A2 and the dynamic friction coefficient after pressure relief showed a trend of first decreasing and then remaining basically unchanged. Therefore, considering comprehensively, in this application, the addition amount of castor oil / IPDI copolymer in the acrylic fiber spinning finish was further controlled between 23-28 parts, and the obtained acrylic fiber had a smoother surface and better softness.

[0103] From the test results of Example 3 and Examples 10 - 13, it can be seen that when alkyl phenyl thiophosphate is further added to the acrylic fiber spinning finish used in Examples 10 - 13, the pressure - induced thickness change rate A1 of the obtained acrylic fibers increases significantly, while the remaining thickness change rate A2 and the dynamic friction coefficient after pressure relief decrease significantly; and as the addition amount of alkyl phenyl thiophosphate increases, the pressure - induced thickness change rate A1 of the obtained acrylic fibers first increases and then decreases, and the remaining thickness change rate A2 and the dynamic friction coefficient after pressure relief first decrease and then basically remain unchanged; among them, the pressure - induced thickness change rate A1 of the acrylic fibers obtained in Examples 10 - 12 reaches 70.25 - 74.34% (>70%), the remaining thickness change rate A2 after pressure relief is as low as 10.37 - 12.46% (<15%), and the dynamic friction coefficient is only 0.243 - 0.318 (<0.32). Therefore, it shows that in the present application, alkyl phenyl thiophosphate is further added to the acrylic fiber spinning finish, and the addition amount of alkyl phenyl thiophosphate is controlled within the range of 3 - 8 parts, and the obtained acrylic fibers have a smoother surface and better softness.

[0104] From the test results of Example 3 and Examples 14 - 17, it can be seen that as the addition amount of the acrylic fiber spinning finish increases, the pressure - induced thickness change rate A1 of the obtained acrylic fibers first increases and then decreases, and the remaining thickness change rate A2 and the dynamic friction coefficient after pressure relief first decrease and then increase. Therefore, in the present application, the addition amount of the acrylic fiber spinning finish is further controlled within the range of 0.31 - 0.43% of the total weight of the tow, and the obtained acrylic fibers have a lower surface friction coefficient and better softness.

[0105] Although the present invention has been described in detail with general descriptions and specific embodiments above, based on the present invention, some modifications or improvements can be made, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection required by the present invention.

Claims

1. A method for preparing acrylic fiber, characterized in that: The following steps are involved: Spinning, washing, drawing, oiling, drying, curling and shaping; Oiling: applying acrylic spinning oil to the washed and drawn tow, wherein the amount of acrylic spinning oil added is 0.22-0.54% of the total mass of the tow; The acrylic spinning oil comprises the following components in parts by weight: 20-30 parts of polyoxyethylene stearate, 12-20 parts of emulsifier SOPE-10, 10-20 parts of isomeric tridecyl alcohol polyoxyethylene ether sodium sulfate, 20-30 parts of castor oil / IPDI copolymer, 6-15 parts of polyoxyethylene sorbitan monooleate, and 0-10 parts of alkylphenyl thiophosphate.

2. The method for preparing acrylic fiber according to claim 1, characterized in that: The acrylic spinning oil comprises the following components in parts by weight: 20-30 parts of polyoxyethylene stearate, 12-20 parts of emulsifier SOPE-10, 12-17 parts of isomeric tridecyl alcohol polyoxyethylene ether sodium sulfate, 23-28 parts of castor oil / IPDI copolymer, 6-15 parts of polyoxyethylene sorbitan monooleate, and 3-8 parts of alkylphenyl thiophosphate.

3. The method for preparing acrylic fiber according to claim 1, characterized in that: The acrylic spinning oil comprises the following components in parts by weight: 25 parts of polyoxyethylene stearate, 15 parts of emulsifier SOPE-10, 15 parts of isomeric tridecyl alcohol polyoxyethylene ether sodium sulfate, 25 parts of castor oil / IPDI copolymer, 10 parts of polyoxyethylene sorbitan monooleate, and 5 parts of alkylphenyl thiophosphate.

4. The method for preparing acrylic fiber according to claim 1, characterized in that: The amount of the acrylic spinning oil added is 0.31-0.43% of the total mass of the filament bundle.

5. The method for preparing acrylic fiber according to claim 1, characterized in that: The acrylic spinning oil is heated and melted at 70-80°C before use, and then prepared into an aqueous solution with a mass concentration of 2-7% and injected into the spinning oil tank; during the oiling process, the temperature in the oil tank is maintained at 70-75°C.

6. The method for preparing acrylic fiber according to any one of claims 1 to 5, characterized in that: The drying temperature is 150-160°C.

7. An acrylic fiber obtained by the method for preparing acrylic fiber according to any one of claims 1 to 6.

8. Use of the acrylic fiber as claimed in claim 7 in strong ropes, bulletproof vests and fishing lines.

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