A kind of preparation process of polypropylene staple fiber

Abstract

The present application relates to the technical field of functionalized polypropylene staple fibers, and more specifically, it relates to a preparation process for high-strength polypropylene staple fibers. A preparation process for high-strength polypropylene staple fibers comprises the following steps: S1, drying of polypropylene fiberized slices; S2, melt extrusion; S3, oiling of polypropylene preparatory yarns by a tension-free oil tanker; 4, preparation and molding; In the S3 operation, the polypropylene oil agent is a polyoxyethylene ether-phosphate composition, and the polyoxyethylene ether-phosphate composition comprises the following raw materials: polyoxyethylene ether, phosphorus pentoxide, a catalyst, a methyltriethylammonium hydroxide aqueous solution and polyacrylic acid. The high-strength polypropylene staple fibers prepared by the preparation process for high-strength polypropylene staple fibers of the present application have better strength.

Description

Technical Field

[0001] The present application relates to the technical field of functionalized polypropylene staple fibers, and more specifically, to a preparation process of polypropylene staple fibers. Background Art

[0002] Polypropylene, also known as polypropylene fiber or PP fiber, is a fiber melt-spun from isotactic polypropylene. It has the advantages of high strength, low specific gravity, wear resistance and corrosion resistance. Therefore, it is widely used in civil and industrial fields.

[0003] In actual production, the quality of polypropylene staple fibers is affected not only by the quality of raw materials, but also by the process flow. When spinning polypropylene at high speed, the friction, tension and static electricity generated by the movement between the fiber and the equipment will cause the fiber bundle to diverge, causing the polypropylene fiber to produce lint, entanglement and broken fibers, which in turn leads to insufficient strength of the prepared polypropylene staple fibers. Summary of the invention

[0004] In order to improve the defect of low strength of polypropylene staple fibers, the present application provides a preparation process of polypropylene staple fibers.

[0005] The present application provides a process for preparing polypropylene staple fibers, which adopts the following technical solution:

[0006] A preparation process of polypropylene staple fibers comprises the following steps:

[0007] S1. Drying of polypropylene fiber chips: preheating the polypropylene fiber chips and the additives at 110-130°C and stirring for 20-40 minutes, followed by cooling, and then drying at 120-140°C for 3-4 hours to obtain a mixed masterbatch;

[0008] S2, melt extrusion: the mixed masterbatch is transported to the screw extruder, and after compaction and plasticization, screw melting, and filter filtration, it enters the melt channel, and then extrusion spinning and cooling and solidification are carried out to obtain the polypropylene pre-filament;

[0009] S3. Use a tension-free oil tanker to oil the polypropylene prepared yarn;

[0010] S4, preparing and molding, drawing, crimping, heat-setting, cutting, and packaging the oiled polypropylene pre-filaments to obtain polypropylene staple fibers;

[0011] In the S3 operation, the polypropylene oil agent is a polyoxyethylene ether-phosphate composition, which includes the following raw materials: polyoxyethylene ether, phosphorus pentoxide, a catalyst, a methyl triethylammonium hydroxide aqueous solution and polyacrylic acid;

[0012] The molar ratio of the polyoxyethylene ether to phosphorus pentoxide is (0.4-1.8):1, the added amount of the catalyst is 1-2% of the total mass, the added amount of the polyacrylic acid is 4-8% of the total mass, and the methyltriethylammonium hydroxide aqueous solution makes the pH value of the polyoxyethylene ether-phosphate composition = 8.

[0013] When polyoxyethylene ether, phosphorus pentoxide and methyl triethylammonium hydroxide aqueous solution are mixed for use, the prepared polyoxyethylene ether-phosphate ester composition will have the polyoxyethylene ether antistatic system, the phosphate ester antistatic system and the quaternary ammonium salt antistatic system.

[0014] Among them, polyoxyethylene ether can form hydrogen bonds with water, thereby increasing the hygroscopicity of polypropylene fiber, and reducing the surface resistance of polypropylene fiber due to increased water content, so that static electricity is easy to leak. Phosphate ester is the main functional group of anionic antistatic agents, and quaternary ammonium salt group is the main functional group of cationic antistatic agents. Therefore, when the three systems are mixed, the polyoxyethylene ether-phosphate ester composition will obtain a better antistatic agent.

[0015] However, since polyoxyethylene ether has excellent hygroscopic properties, the addition of water will lead to a significant decrease in the adhesion of the oil agent. When a water-soluble polymer compound is added to the polyoxyethylene ether-phosphate ester composition, the polyoxyethylene ether-phosphate ester composition will greatly improve the bundling of the polypropylene fiber, thereby reducing the effect of moisture on the adhesion of the polyoxyethylene ether-phosphate ester composition, and indirectly improving the antistatic effect of the polyoxyethylene ether-phosphate ester composition on the polypropylene fiber.

[0016] Preferably, the polyoxyethylene ether is one or a mixture of castor oil polyoxyethylene ether, lauric acid polyoxyethylene ether and octadecylamine polyoxyethylene ether.

[0017] Preferably, the polyoxyethylene ether is lauric acid polyoxyethylene ether, and the molar ratio of the lauric acid polyoxyethylene ether to phosphorus pentoxide is 1:1.

[0018] Castor oil polyoxyethylene ether, lauric acid polyoxyethylene ether and octadecylamine polyoxyethylene ether all belong to the polyoxyethylene ether system, and all three have excellent solubility in polymers. Among them, the hygroscopic properties of castor oil polyoxyethylene ether, lauric acid polyoxyethylene ether and octadecylamine polyoxyethylene ether gradually increase, and because the specific resistance of lauric acid polyoxyethylene ether is relatively low, when lauric acid polyoxyethylene ether is selected as the polyoxyethylene ether, the prepared polyoxyethylene ether-phosphate composition will have a better antistatic effect. In particular, when the molar ratio of lauric acid polyoxyethylene ether to phosphorus pentoxide is 1:1, the antistatic effect of the prepared polyoxyethylene ether-phosphate composition is particularly prominent.

[0019] Preferably, in the S3 operation, the tension-free oil tanker includes a plurality of relatively rotating oil tanker rings, the oil tanker rings include a ring seat, oil absorbing cotton and a plurality of oiling balls, an oil storage tank is provided in the ring seat, the oil absorbing cotton is embedded in the oil storage tank, and an oil filling hole interconnected with the oil storage tank is provided on the ring seat;

[0020] A plurality of oil outlet holes are formed through the bottom of the oil storage tank, and the diameter of the oil outlet holes is smaller than the diameter of the upper oil ball. The upper oil ball is accommodated in the oil storage tank, and the upper oil ball rotates freely in the oil storage tank. Part of the upper oil ball extends out of the oil outlet hole, and the outer peripheral surface of the upper oil ball is always in contact with the hole wall of the oil outlet hole, and the outer peripheral surface of the upper oil ball is always in contact with the polypropylene prepared yarn.

[0021] When oiling polypropylene fibers, workers can choose between two oiling methods: oiling with a nozzle and oiling with a tanker. Oiling with a tanker has excellent oiling uniformity, but when oiling with a tanker, the tanker needs to form a wrap angle with the polypropylene fiber, which causes the tanker to cause tension on the polypropylene fiber, and the existence of tension is likely to cause lint, floating fibers, and even broken ends. Although the oiling method with a nozzle can significantly eliminate the effect of tension on spinning, in addition to the disadvantage of uneven oiling, the oiling method with a nozzle is also prone to waste of spinning oil.

[0022] When the tension-free oil tanker is used, the oiling ball can gradually transfer the oil on the oil-absorbing cotton to the polypropylene fiber, thereby effectively reducing the waste of oil. Since the oiling ball rotates freely in the oil storage tank and different oil tanker rings rotate relatively, multiple oiling balls can perform all-round oiling operations on the outer surface of the polypropylene fiber, thereby effectively improving the uniformity of oiling. Moreover, since there is no wrap angle during the oiling process, no tension is generated, thereby effectively reducing the possibility of lint, floating silk or even broken ends of the polypropylene fiber.

[0023] Preferably, the plurality of tanker rings are coaxially and staggeredly arranged, and the tension-free tanker further comprises a driving member, which drives the plurality of tanker rings to rotate synchronously.

[0024] Since multiple oil wheel rings are coaxially staggered, different positions of the polypropylene can be oiled at the same time in the initial state. And since the driving member drives the oil wheel rings to rotate synchronously, the oil on the surface of the polypropylene will be more uniform and stable when the polypropylene is oiled.

[0025] Preferably, the ring seat includes a seat body and a cover body, the oil storage tank is opened on the outer peripheral surface of the seat body, the cover body is fixedly connected to the seat body and seals the oil storage tank; the upper end of the cover body is rotatably connected to an upper connecting ring, and the upper connecting ring protrudes toward the upper end of the cover body, and the lower end of the cover body is rotatably connected to a lower connecting ring, and the lower connecting ring protrudes toward the lower end of the cover body.

[0026] Since the upper connecting ring protrudes toward the upper end of the cover body and the lower connecting ring protrudes toward the lower end of the cover body, when different tanker rings are stacked, the upper connecting ring will first abut against the lower connecting ring, thereby causing different ring seats to be spaced apart from each other, effectively improving the smoothness and stability of the rotation of different tanker rings.

[0027] Preferably, the upper end surface of the upper connecting ring is provided with a plurality of limiting grooves, and the lower end surface of the lower connecting ring is provided with a plurality of limiting blocks, and the limiting grooves are used for inserting the limiting blocks.

[0028] When different tanker rings are stacked relatively, the limit block is inserted into the limit groove, thereby effectively reducing the possibility of relative slippage between the upper connecting ring and the lower connecting ring, and further improving the smoothness and stability of the tanker ring during rotation.

[0029] Preferably, the tension-free tanker further comprises a plurality of brackets, the brackets comprising a bottom rod, a connecting rod and a top rod, the bottom rod is fixedly connected to the lower end of the connecting rod, and a positioning groove is provided on the upper end surface of the bottom rod, and the positioning groove is used for the limit block to be inserted;

[0030] The push rod is rotatably connected to the upper end surface of the connecting rod. A positioning piece is arranged on the connecting rod, and the limiting groove is used for the positioning piece to be movably inserted.

[0031] When multiple tanker rings are stacked, the staff can first insert the bottom limit block into the positioning groove, then rotate the top rod and insert the positioning piece into the top limit groove, thereby completing the limiting operation of all tanker rings, effectively reducing the possibility of separation of the tanker rings, and indirectly improving the smoothness and stability of the tanker rings during rotation.

[0032] Preferably, the positioning member comprises a positioning column, a compression spring, a control shaft and a limit nut, a sliding groove is provided on the lower end surface of the push rod, a through hole is provided through the bottom of the sliding groove, the positioning column is slidably connected in the sliding groove, one end of the compression spring abuts against the bottom of the sliding groove, and the other end of the compression spring abuts against the positioning column;

[0033] The control shaft is fixedly connected to a side of the positioning column close to the compression spring, the control shaft passes through the through hole, the limiting nut is fixedly connected to one end of the control shaft passing through the through hole, and the outer diameter of the limiting nut is larger than the aperture of the through hole.

[0034] When the tanker ring needs to be locked, the staff can first slide the positioning column into the sliding groove through the control shaft, then rotate the top rod and transfer the positioning column to the uppermost limit groove, and then release the control shaft. The positioning column can be inserted into the above-mentioned limit groove under the drive of the compression spring, thereby realizing the locking operation of multiple tanker rings.

[0035] Preferably, a driven gear is disposed on the outer peripheral surface of the cover body, and the driving member includes a driving motor and a driving gear shaft, the driving gear shaft is fixedly connected to the output end of the driving motor, and the driving gear shaft is meshed with the plurality of driven gears.

[0036] When it is necessary to control the rotation of multiple tanker rings, the staff can directly turn on the drive motor, which drives the driving gear shaft to rotate, and the driving gear shaft drives different driven gears to rotate synchronously, thereby realizing the synchronous rotation operation of different tanker rings.

[0037] In summary, this application has the following beneficial effects:

[0038] 1. The addition of water will lead to a significant decrease in the adhesion of the oil agent. However, when a water-soluble polymer compound is added to the polyoxyethylene ether-phosphate ester composition, the polyoxyethylene ether-phosphate ester composition will greatly improve the bundling of the polypropylene fiber, thereby reducing the effect of water on the adhesion of the polyoxyethylene ether-phosphate ester composition.

[0039] 2. Castor oil polyoxyethylene ether, lauric acid polyoxyethylene ether and octadecylamine polyoxyethylene ether all belong to the polyoxyethylene ether system, and all three have excellent solubility in polymers. Among them, lauric acid polyoxyethylene ether has a relatively low specific resistance, which leads to the prepared polyoxyethylene ether-phosphate composition having a better antistatic effect.

[0040] 3. When the tension-free oil tanker is used, the oiling ball can gradually transfer the oil on the oil-absorbing cotton to the polypropylene fiber, thereby effectively reducing the waste of oil. Since the oiling ball rotates freely in the oil storage tank and different oil tanker rings rotate relatively, multiple oiling balls can perform all-round oiling operations on the outer surface of the polypropylene fiber, thereby effectively improving the uniformity of oiling. Moreover, since there is no wrap angle during the oiling process, no tension is generated, thereby effectively reducing the possibility of lint, floating silk or even broken ends of the polypropylene fiber. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic diagram of the structure of a tension-free tanker;

[0042] Figure 2 This is a top view of multiple tanker rings stacked together;

[0043] Figure 3 It is a schematic diagram of the structure of the tanker ring;

[0044] Figure 4 It is a schematic diagram of the explosion of the tanker ring;

[0045] Figure 5It is a schematic diagram of the structure of the driving part;

[0046] Figure 6 is a schematic diagram of the structure of the bracket;

[0047] Figure 7 It is an exploded diagram of the positioning parts.

[0048] 1. Driving member; 2. Bracket; 3. Oil tanker ring; 11. Driving motor; 12. Driving gear shaft; 13. Driven gear; 21. Bottom rod; 22. Connecting rod; 23. Top rod; 24. Positioning groove; 25. Positioning member; 31. Ring seat; 32. Oil absorbing cotton; 33. Upper oil ball; 251. Positioning column; 252. Compression spring; 253. Control shaft; 254. Limiting nut; 255. Sliding groove; 256. Through hole; 311. Seat body; 312. Cover body; 313. Oil storage tank; 314. Oil filling hole; 315. Oil outlet hole; 316. Upper connecting ring; 317. Limiting groove; 318. Lower connecting ring; 319. Limiting block. DETAILED DESCRIPTION

[0049] The following is combined with Figure 1-7 , Examples 1-6 and Comparative Examples 1-3 further illustrate the present application in detail.

[0050] Polypropylene chips PP BH Langang Petrochemical; Castor oil polyoxyethylene ether CAS: 61791-12-6; Lauric acid polyoxyethylene ether CAS: 9004-81-3; Octadecylamine polyoxyethylene ether CAS: 26635-92-7; Sorbitan laurate monoester CAS: 1338-39-2; Sorbitan palmitate monoester CAS: 26266-57-9; Phosphorus pentoxide CAS: 1314-56-3; Methyltriethylammonium hydroxide CAS: 109334-81-8; Boron trifluoride CAS: 7637-07-2. Example Example

[0051] A preparation process of polypropylene staple fibers comprises the following steps:

[0052] S1. Drying of polypropylene fiber chips: preheat the polypropylene fiber chips and additives at 120°C and stir for 30 minutes, then cool. Then dry at 130°C for 3.5 hours (3-4 hours is appropriate) to obtain a mixed masterbatch;

[0053] The amount or type of polypropylene fiber slices and additives can be selected according to actual needs; in this embodiment, in order to reduce the impact of the addition of additives on subsequent experiments, only polypropylene fiber slices are added;

[0054] S2, melt extrusion: the mixed masterbatch is transported to the screw extruder, and after compaction and plasticization, screw melting, and filter filtration, it enters the melt pipeline, and then extrusion spinning and cooling and solidification are carried out to obtain polypropylene pre-filament;

[0055] Among them, the mesh number of the filter is 200 mesh (180-220 mesh is suitable), and the temperatures of the five zones of the screw are: Zone 1: 305℃; Zone 2: 300℃; Zone 3: 295℃; Zone 4: 280℃; Zone 5: 275℃. Flange zone: 275℃, elbow zone: 270℃, spinning box: 267℃, ring blowing speed: 0.45m / min, wind temperature: 16℃, spinning speed: 750m / min, pre-spinning oiling: 1.5%; original silk oiling wet rate: 15%.

[0056] S3. Use a tension-free oil tanker to oil the polypropylene prepared yarn;

[0057] Among them, in the S3 operation, the polypropylene oil agent is a polyoxyethylene ether-phosphate ester composition.

[0058] The polyoxyethylene ether-phosphate composition is obtained by reacting castor oil polyoxyethylene ether, phosphorus pentoxide, a catalyst-boron trifluoride, an aqueous solution of methyltriethylammonium hydroxide and polyacrylic acid, wherein the molar ratio of castor oil polyoxyethylene ether to phosphorus pentoxide is 1:1, the added amount of the catalyst-boron trifluoride is 2% of the total mass, the added amount of the polyacrylic acid is 6% of the total mass, and the aqueous solution of methyltriethylammonium hydroxide is used to adjust the polyoxyethylene ether-phosphate composition to pH=8.

[0059] The preparation method of the polyoxyethylene ether-phosphate composition is as follows:

[0060] Castor oil polyoxyethylene ether was placed in a three-necked flask equipped with a stirrer, a spherical condenser and a thermometer, and then the stirrer was turned on. Phosphorus pentoxide was slowly added for 1.5 hours, and then 100 g of water was added for hydrolysis for 2.5 hours. Finally, methyltriethylammonium hydroxide aqueous solution (1 mol / L) was added at 55°C for neutralization, and finally polyacrylic acid was added and mixed evenly to obtain a polyoxyethylene ether-phosphate composition with a total mass of 1 kg±50 g.

[0061] In addition, the specific structure of the tension-free tanker is as follows.

[0062] Reference Figure 1 and Figure 2 The tension-free tanker includes a driving member 1, a plurality of brackets 2 and a plurality of tanker rings 3 rotatably connected to the brackets 2, wherein the plurality of tanker rings 3 rotate relatively, the tanker rings 3 are used for performing tension-free oiling operation on the polypropylene prepared yarn, the brackets 2 are used for locking the plurality of tanker rings 3, and the driving member 1 is used for driving the plurality of tanker rings 3 to rotate synchronously.

[0063] It should be noted that, in the present embodiment, two brackets 2 are provided, and six tanker rings 3 are provided. The six tanker rings 3 are stacked in sequence and coaxially staggered. The two brackets 2 are symmetrically arranged with the axis of the tanker ring 3 as the center.

[0064] Reference Figure 3 and Figure 4 The oil tanker ring 3 includes a ring seat 31, oil absorbing cotton 32 and a plurality of oiling balls 33. The ring seat 31 includes a seat body 311 and a cover body 312. An oil storage groove 313 is provided on the outer peripheral surface of the seat body 311, and the oil absorbing cotton 32 is embedded in the oil storage groove 313. An oil injection hole 314 is provided on the upper end surface of the seat body 311, and the oil injection hole 314 and the oil storage groove 313 are communicated with each other.

[0065] The bottom of the oil storage tank 313 is provided with a plurality of oil outlet holes 315. For example, six oil outlet holes 315 and the upper oil ball 33 are provided with six and one-to-one correspondence. The diameter of the oil outlet hole 315 is smaller than the diameter of the upper oil ball 33. The upper oil ball 33 is accommodated in the oil storage tank 313 and rotates freely in the oil storage tank 313. A part of the upper oil ball 33 extends out of the oil outlet hole 315, and the outer peripheral surface of the upper oil ball 33 always contacts the hole wall of the oil outlet hole 315, and the outer peripheral surface of the upper oil ball 33 always contacts the polypropylene prepared yarn.

[0066] The cover body 312 is threadedly connected to the outer peripheral surface of the seat body 311 and blocks the oil storage tank 313. The upper end of the cover body 312 is rotatably connected to an upper connecting ring 316, which protrudes toward the upper end of the cover body 312. The upper end surface of the upper connecting ring 316 is provided with a plurality of limiting grooves 317. In this embodiment, two limiting grooves 317 are provided, and the two limiting grooves 317 are symmetrically arranged with the axis of the cover body 312 as the center.

[0067] The lower end of the cover body 312 is rotatably connected to a lower connecting ring 318, which protrudes toward the lower end of the cover body 312. The lower end surface of the lower connecting ring 318 is fixedly connected to a plurality of limit blocks 319. In the present embodiment, two limit blocks 319 are provided, and the two limit blocks 319 correspond to the two limit grooves 317, and the limit grooves 317 are provided for the limit blocks 319 to be plugged in.

[0068] Reference Figure 3 and Figure 5 The driving member 1 includes a driving motor 11 and a driving gear shaft 12, and the driving gear shaft 12 is fixedly connected to the output shaft of the driving motor 11. A driven gear 13 is fixedly connected to the middle of the outer peripheral surface of the cover body 312, and the driving gear shaft 12 and the six driven gears 13 are meshed with each other.

[0069] Reference Figure 4 and Figure 6The bracket 2 includes a bottom rod 21, a connecting rod 22 and a top rod 23. The bottom rod 21 is fixedly connected to the lower end of the connecting rod 22. A positioning groove 24 is provided on the upper end surface of the bottom rod 21. The positioning groove 24 is used for the stop block 319 to be inserted and fixed. The top rod 23 is rotatably connected to the upper end of the connecting rod 22. A positioning member 25 is provided on the lower end surface of the top rod 23. The positioning member 25 is movably inserted into the stop groove 317.

[0070] Reference Figure 3 and Figure 7 The positioning member 25 includes a positioning column 251, a compression spring 252, a control shaft 253 and a limit nut 254. A sliding groove 255 is provided on the lower end surface of the push rod 23. A through hole 256 is provided at the bottom of the sliding groove 255. The positioning column 251 is slidably connected in the sliding groove 255. One end of the compression spring 252 abuts against the bottom of the sliding groove 255, and the other end of the compression spring 252 abuts against the positioning column 251.

[0071] The control shaft 253 is fixedly connected to one side of the positioning column 251 close to the compression spring 252. The control shaft 253 passes through the compression spring 252 and the through hole 256 in sequence. The limiting nut 254 is fixedly connected to one end of the control shaft 253 passing through the through hole 256. The outer diameter of the limiting nut 254 is larger than the aperture of the through hole 256.

[0072] Before oiling the polypropylene preparatory yarn, the staff first inserts the limit block 319 of the bottom tanker ring 3 into the positioning groove 24, then stacks the six tanker rings 3, and inserts the limit block 319 of the upper tanker ring 3 into the limit groove 317 of the lower tanker ring 3. After that, the positioning column 251 is slid into the sliding groove 255 through the control shaft 253, and then the top rod 23 is rotated. When the positioning column 251 is transferred to the uppermost limit groove 317, the control shaft 253 is then released, and the positioning column 251 can be inserted into the above-mentioned limit groove 317 under the drive of the compression spring 252, thereby completing the locking operation of the tanker ring 3. After that, after adjusting the six tanker rings 3 to coaxial staggered, the driving gear shaft 12 and the six driven gears 13 are meshed with each other, and the installation of the tension-free tanker is completed.

[0073] When the polypropylene prepared yarn needs to be oiled, the staff can first pass the polypropylene prepared yarn through the six oil wheel rings 3 in sequence, and then turn on the drive motor 11, which can drive the six oil wheel rings 3 to rotate synchronously. The movement of the polypropylene prepared yarn will also cause the oiling ball 33 to deflect, thereby causing the oiling ball 33 to transfer the oil on the oil-absorbing cotton 32 to the polypropylene prepared yarn evenly, stably and without tension.

[0074] It should be noted that in this embodiment, the above-mentioned fixed connection can be selected from conventional fixed connection methods such as welding, integral molding, threaded connection, etc. The above-mentioned rotation connection can be selected from conventional rotation connection methods such as bearing connection, pin connection, etc. according to actual conditions.

[0075] S4, preparation and molding, drawing, curling, heat-setting, cutting and packaging the oiled polypropylene pre-filaments to obtain polypropylene staple fibers.

[0076] Among them, in the S4 operation, the total denier of the bundle is 660,000 denier, the total drafting multiple is 4; the stretching speed is 90m / min, the stretching temperature is 56°C in oil bath, the superheated steam is 110°C, the main pressure of the crimping machine is 1.8kg / cm2, the back pressure is 1.2kg / cm2, the temperature of the four heat setting zones is: zone 1: 100°C, zone 2: 115°C, zone 3: 125°C, zone 4: 95°C; the packaging is cut at 95°C, and the cutting length is 35mm. Example

[0077] The difference from Example 1 is that the added amount of polyacrylic acid is 4% of the total mass. Example

[0078] The difference from Example 1 is that the added amount of polyacrylic acid is 8% of the total mass. Example

[0079] The difference from Example 1 is that the castor oil polyoxyethylene ether is replaced by the same amount of lauric acid polyoxyethylene ether. Example

[0080] The difference from Example 1 is that castor oil polyoxyethylene ether is replaced by the same amount of octadecylamine polyoxyethylene ether. Example

[0081] The difference from Example 1 is that castor oil polyoxyethylene ether is replaced by a mixture of lauric acid polyoxyethylene ether and octadecylamine polyoxyethylene ether in the same amount, and the molar ratio of lauric acid polyoxyethylene ether to octadecylamine polyoxyethylene ether is 1:1.

[0082] Comparative Example 1

[0083] The difference from Example 1 is that no polyacrylic acid is added.

[0084] Comparative Example 2

[0085] The difference from Example 1 is that the castor oil polyoxyethylene ether is replaced by the same amount of sorbitan laurate monoester.

[0086] Comparative Example 3

[0087] The difference from Example 1 is that castor oil polyoxyethylene ether is replaced by sorbitan palmitic acid monoester in the same amount.

[0088] 1. Elongation at break test

[0089] Three polypropylene staple fiber samples were taken from Examples 1-6 and Comparative Examples 1-3, respectively, and then the breaking strength of the samples was tested according to GB / T14337-1993 "Test method for breaking strength and breaking elongation of synthetic staple fibers", and the average value was taken.

[0090] The test data of Examples 1-6 and Comparative Examples 1-3 are shown in Table 1.

[0091] Table 1 Test data table of Examples 1-6 and Comparative Examples 1-3

[0092] Referring to Examples 1-3 and Comparative Example 1 and in combination with Table 1, it can be seen that the breaking strength of Examples 1-3 is significantly improved compared with Comparative Example 1. The reason for this is that polyoxyethylene ether can form hydrogen bonds with water, thereby increasing the hygroscopicity of polypropylene fibers. The increased water content reduces the surface resistance of polypropylene fibers, making it easier for static electricity to leak.

[0093] However, the addition of water will lead to a significant decrease in the adhesion of the oil agent. When a water-soluble polymer compound is added to the polyoxyethylene ether-phosphate ester composition, the polyoxyethylene ether-phosphate ester composition will greatly improve the bundling of the polypropylene fiber, thereby reducing the effect of water on the adhesion of the polyoxyethylene ether-phosphate ester composition, and indirectly improving the antistatic effect of the polyoxyethylene ether-phosphate ester composition on the polypropylene fiber.

[0094] Among Examples 1-3, the breaking strength of Example 1 is relatively the highest, which shows that when the amount of polyacrylic acid added is the same as that of Example 1, the polyoxyethylene ether-phosphate composition has the most prominent effect on improving the antistatic properties of polypropylene fibers.

[0095] Referring to Example 1, Examples 4-6 and Comparative Examples 1-2 and in combination with Table 1, it can be seen that, relative to Comparative Examples 1-2, the breaking strength of Examples 1 and Examples 4-5 is relatively higher. The reason is that, relative to sorbitan laurate monoester and sorbitan palmitate monoester, castor oil polyoxyethylene ether, lauric acid polyoxyethylene ether and octadecylamine polyoxyethylene ether all belong to the polyoxyethylene ether system, and all three have excellent solubility in polymers, further improving the antistatic effect of the polyoxyethylene ether-phosphate ester composition on polypropylene fiber.

[0096] Among Examples 1 and 4-6, Example 4 has the highest breaking strength, which is due to the relatively low specific resistance of polyoxyethylene laurate ether, resulting in the prepared polyoxyethylene ether-phosphate composition having a better antistatic effect. Compared with Example 4, the breaking strength of Example 6 is slightly reduced, which shows that polyoxyethylene laurate ether is suitable for use alone.

[0097] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A process for preparing polypropylene staple fibers, characterized in that: The following steps are involved: S1. Drying of polypropylene fiber chips: preheating the polypropylene fiber chips and the additives at 110-130°C and stirring for 20-40 minutes, followed by cooling, and then drying at 120-140°C for 3-4 hours to obtain a mixed masterbatch; S2, melt extrusion: the mixed masterbatch is transported to the screw extruder, and after compaction and plasticization, screw melting, and filter filtration, it enters the melt channel, and then extrusion spinning and cooling and solidification are carried out to obtain the polypropylene pre-filament; S3. Use a tension-free oil tanker to oil the polypropylene prepared yarn; The tension-free oil tanker comprises a plurality of relatively rotatable oil tanker rings (3), the oil tanker rings (3) comprising a ring seat (31), oil absorbing cotton (32) and a plurality of oiling balls (33), an oil storage groove (313) is provided in the ring seat (31), the oil absorbing cotton (32) is embedded in the oil storage groove (313), and an oil injection hole (314) is provided on the ring seat (31) and is communicated with the oil storage groove (313); The bottom of the oil storage tank (313) is provided with a plurality of oil outlet holes (315), the diameter of the oil outlet holes (315) being smaller than the diameter of the upper oil ball (33), the upper oil ball (33) being accommodated in the oil storage tank (313), the upper oil ball (33) being freely rotatable in the oil storage tank (313), a part of the upper oil ball (33) extending out of the oil outlet hole (315), the outer peripheral surface of the upper oil ball (33) always being in contact with the hole wall of the oil outlet hole (315), and the outer peripheral surface of the upper oil ball (33) always being in contact with the polypropylene prepared yarn; S4, preparing and molding, drawing, crimping, heat-setting, cutting, and packaging the oiled polypropylene pre-filaments to obtain polypropylene staple fibers; In the S3 operation, the polypropylene oil agent is a polyoxyethylene ether-phosphate composition, which includes the following raw materials: polyoxyethylene ether, phosphorus pentoxide, a catalyst, a methyl triethylammonium hydroxide aqueous solution and polyacrylic acid; The molar ratio of the polyoxyethylene ether to phosphorus pentoxide is (0.4-1.8):1, the added amount of the catalyst is 1-2% of the total mass, the added amount of the polyacrylic acid is 4-8% of the total mass, and the methyltriethylammonium hydroxide aqueous solution makes the pH value of the polyoxyethylene ether-phosphate composition = 8.

2. The process for preparing polypropylene staple fibers according to claim 1, characterized in that: The polyoxyethylene ether is one or a mixture of castor oil polyoxyethylene ether, lauric acid polyoxyethylene ether and octadecylamine polyoxyethylene ether.

3. The process for preparing polypropylene staple fibers according to claim 2, characterized in that: The polyoxyethylene ether is lauric acid polyoxyethylene ether, and the molar ratio of the lauric acid polyoxyethylene ether to phosphorus pentoxide is 1:

1.

4. The process for preparing polypropylene staple fibers according to claim 1, characterized in that: The tension-free tanker further comprises a driving member (1), wherein the driving member (1) drives a plurality of the tanker rings (3) to rotate synchronously.

5. The process for preparing polypropylene staple fibers according to claim 4, characterized in that: The ring seat (31) comprises a seat body (311) and a cover body (312); the oil storage groove (313) is provided on the outer peripheral surface of the seat body (311); the cover body (312) is fixedly connected to the seat body (311) and blocks the oil storage groove (313); an upper connecting ring (316) is rotatably connected to the upper end of the cover body (312); the upper connecting ring (316) protrudes toward the upper end of the cover body (312); and a lower connecting ring (318) is rotatably connected to the lower end of the cover body (312); the lower connecting ring (318) protrudes toward the lower end of the cover body (312).

6. The process for preparing polypropylene staple fibers according to claim 5, characterized in that: The upper end surface of the upper connecting ring (316) is provided with a plurality of limiting grooves (317), and the lower end surface of the lower connecting ring (318) is provided with a plurality of limiting blocks (319), wherein the limiting grooves (317) are provided for the limiting blocks (319) to be inserted.

7. The process for preparing polypropylene staple fibers according to claim 6, characterized in that: The tension-free tanker further comprises a plurality of brackets (2), wherein the brackets (2) comprise a bottom rod (21), a connecting rod (22) and a top rod (23), wherein the bottom rod (21) is fixedly connected to the lower end of the connecting rod (22), and a positioning groove (24) is formed on the upper end surface of the bottom rod (21), wherein the positioning groove (24) is for the limit block (319) to be inserted into; The push rod (23) is rotatably connected to the upper end surface of the connecting rod (22); a positioning member (25) is provided on the connecting rod (22); and the limiting groove (317) is used for the positioning member (25) to be movably plugged in.

8. The process for preparing polypropylene staple fibers according to claim 7, characterized in that: The positioning member (25) comprises a positioning column (251), a compression spring (252), a control shaft (253) and a limiting nut (254); a sliding groove (255) is provided on the lower end surface of the push rod (23); a through hole (256) is provided through the bottom of the sliding groove (255); the positioning column (251) is slidably connected in the sliding groove (255); one end of the compression spring (252) abuts against the bottom of the sliding groove (255); and the other end of the compression spring (252) abuts against the positioning column (251); The control shaft (253) is fixedly connected to a side of the positioning column (251) close to the compression spring (252); the control shaft (253) passes through the through hole (256); the limiting nut (254) is fixedly connected to an end of the control shaft (253) passing through the through hole (256); and the outer diameter of the limiting nut (254) is larger than the aperture of the through hole (256).

9. The process for preparing polypropylene staple fibers according to claim 5, characterized in that: A driven gear (13) is provided on the outer peripheral surface of the cover body (312); the driving member (1) comprises a driving motor (11) and a driving gear shaft (12); the driving gear shaft (12) is fixedly connected to the output end of the driving motor (11); the driving gear shaft (12) and the plurality of driven gears (13) are meshed with each other.

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