Ultrahigh-fluidity fiber material as well as preparation method and application thereof

Abstract

The invention relates to an ultrahigh-fluidity fiber material as well as a preparation method and application thereof, and belongs to the technical field of high polymer materials. The preparation method comprises the following steps: continuously feeding polypropylene powder, peroxide and a stabilizer into a double-screw extruder respectively for melt extrusion to obtain a fiber melt; conveying the obtained fiber material melt into a water tank filled with process water for heat exchange, and crystallizing and curing the fiber material melt in the water of the water tank to obtain a fiber material strip; one end of the obtained fiber material strip is introduced into a granulator to be granulated, and the high-fluidity fiber material is obtained. Process water in the water tank is pumped out through a water pump, conveyed to the first heat exchanger for heat exchange and then introduced into the second heat exchanger for heat exchange, the temperature of the process water can be effectively reduced through two times of heat exchange, the melt can be crystallized and solidified in time in the water tank, on one hand, the probability of strip winding is reduced, stable and long-period operation of the process is ensured, and the production efficiency is improved. On the other hand, the pelletizing quality can be improved, the cutter is protected, and the service life of the extrusion pelletizer is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to an ultra-high fluidity fiber material and a preparation method and application thereof. Background Art

[0002] Industrial production of high-flow fiber materials began in the late 1960s and early 1970s. At that time, only existing polymers could be used as raw materials, and the melt flow rate MFR was mostly 12.3-35g / 10min. The melt flow rate of the raw materials currently used has reached 1200-1500g / 10min. Existing high-flow fiber material preparation companies usually use polypropylene powder as the basic raw material, add peroxide (98% di-tert-butyl peroxide), etc., melt and mix the raw materials through a twin-screw extruder, and the molten melt passes through a filter screen, and the melt flows out of the die hole. After heat exchange in a water tank filled with process water, it is pelletized to obtain granular high-flow fiber materials.

[0003] However, the existing process often causes knife entanglement and broken strands when preparing high-fluidity fiber materials, resulting in the inability to carry out the process continuously. For example, the temperature of the process water in the water tank has a great influence on the melt cooling and solidification process. Too high a temperature will lead to slow cooling, melt entanglement, and low melt strength; too low a temperature will lead to too fast cooling and uneven pelletizing. Therefore, the temperature of the cooling water must be strictly controlled during the production process. On the one hand, it can reduce the probability of entanglement and produce large pieces of material to ensure stable production and long-term operation. On the other hand, it can improve the pelletizing quality, protect the cutter, and increase the life of the extrusion granulator. At present, most people choose to introduce the process water in the water tank into the heat exchanger with the circulating water at a temperature of 28 to 35°C. The circulating water comes from the No. 6 circulating water of the Guangzhou Branch Polypropylene-2 ​​Unit for heat exchange, and then the process water after heat exchange is returned to the water tank. This method cannot quickly lower the temperature of the water tank, causing the water temperature in the water tank to be high, which can easily cause the melt to be unable to cool and crystallize in time in the water tank, and to entangle on the water surface. The melt that has not been completely cooled and crystallized has low strength, resulting in insufficient traction. The material strips will sag during the transportation process, making it impossible for the material strips to be smoothly pulled and pelletized, and accumulate at the discharge port, eventually leading to problems such as large pieces of material.

[0004] Therefore, it is very necessary to improve the preparation process of ultra-high fluidity fiber materials. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide an ultra-high fluidity fiber material and a preparation method and application thereof.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] In a first aspect, the present invention provides a method for preparing an ultra-high fluidity fiber material, comprising the following steps:

[0008] S1, continuously putting polypropylene powder, peroxide and stabilizer into a twin-screw extruder for melt extrusion to obtain a molten fiber material melt;

[0009] S2, conveying the fiber material melt obtained in step S1 to a water tank filled with process water for heat exchange, wherein the fiber material melt is crystallized and solidified in the process water in the water tank to obtain fiber material strips;

[0010] S3, introducing one end of the fiber material strip obtained in step S2 into a pelletizer for pelletizing to obtain a granular high-fluidity fiber material;

[0011] When performing step S2, the process water in the water tank is pumped out by a water pump and transported to the first heat exchanger for heat exchange, then passed into the second heat exchanger for heat exchange, and then returned to the water tank.

[0012] The present invention introduces process water in a water tank into a first heat exchanger and a second heat exchanger in sequence. In the first heat exchanger, the process water exchanges heat with cooling water, and in the second heat exchanger, the process water exchanges heat with frozen brine. Through the two heat exchanges, the temperature of the process water can be effectively reduced, so that the melt can be crystallized and solidified in the water tank in time. On the one hand, the probability of strip winding is reduced, ensuring stable process and long-cycle operation. On the other hand, it can improve the pelletizing quality, protect the cutter, and increase the life of the extrusion granulator.

[0013] As a preferred embodiment of the present invention, when performing step S2, the process water in the water tank is pumped out by a water pump and transported to the first heat exchanger for heat exchange with cooling water, so that the process water is cooled to 43-55°C, and then passed into the second heat exchanger for heat exchange with chilled brine, so that the process water is cooled to 3-20°C and then transported to the water tank, so that the temperature of the process water in the water tank is maintained at 35-40°C.

[0014] Furthermore, the temperature of the cooling water is 28 to 35°C, and the temperature of the frozen brine is -2 to 2°C.

[0015] Furthermore, the water inlet flow rate and the water outlet flow rate of the water tank are the same, and the water inlet flow rate of the water tank is 1500-3500 L / h.

[0016] Compared with the prior art, the melt temperature flowing out of the twin-screw extruder of the present invention is high, and the melt flows into the water tank to exchange heat with the process water. During the heat exchange process, the temperature of the process water will continue to rise. The inventors have found that the temperature of the process water is controlled at 3 to 20°C; then the process water at 3 to 20°C is returned to the water tank, thereby ensuring that the water inlet temperature of the water tank is low, and controlling the inlet and outlet water flow of the water tank can effectively ensure that the temperature of the process water is maintained at 35 to 40°C.

[0017] As a preferred embodiment of the present invention, in step S1, the feeding rate of the polypropylene powder is 320-520 Kg / h, the feeding rate of the peroxide is 25.5-36.4 mL / min, and the feeding rate of the stabilizer is 5-21 g / min.

[0018] As a preferred embodiment of the present invention, in step S1, the conditions for melt extrusion of the twin-screw extruder are: T1 zone temperature 40 ~ 70 ° C, T2 zone temperature 65 ~ 90 ° C, T3 zone temperature 230 ~ 260 ° C, T4 zone temperature 230 ~ 260 ° C, T5 zone temperature 225 ~ 260 ° C, T6 zone temperature 225 ~ 240 ° C, T7 zone temperature 210 ~ 240 ° C, T8 zone temperature 190 ~ 230 ° C, T9 zone temperature The temperature is 190-250°C, the temperature of zone T10 is 90-170°C, the temperature of zone T11 is 90-170°C, the temperature of zone T12 is 90-170°C, the temperature of zone T13 is 90-170°C, the temperature of zone T14 is 90-170°C, the temperature of zone T15 is 150-180°C, and the temperature of zone T16 is 150-180°C; the aspect ratio of the twin-screw extruder is (40-60):1, and the main engine speed is 45-70r / min.

[0019] In the present invention, polypropylene powder is added from the feed port corresponding to zone T1 of the twin-screw extruder, peroxide and stabilizer are added from zone T2 of the twin-screw extruder, a screen changer is provided in zone T15, and a die head is provided in zone T16.

[0020] The inventors have found that the temperature of the T1 zone and the T2 zone in the twin-screw extruder should be much lower than that of other zones. If the temperature of the T1 zone and the T2 zone is too high, the peroxide will be easily affected by the high temperature and produce a large amount of gas, which will easily cause the gas to accumulate in the twin-screw extruder, making the extruded melt unstable and the material strips easy to break, ultimately affecting the quality of the fiber material product.

[0021] The temperature of the T3 zone to the T9 zone in the twin-screw extruder should be higher than the temperature of other zones. If the temperature of the T3 zone to the T9 zone is too low, the melting of the polypropylene powder and the reaction between it and the additive cannot be fully carried out, so that the melt after extrusion is unstable and prone to fluctuations. The material strips are prone to entanglement with the blade and breakage during the traction process of the pelletizer.

[0022] Furthermore, step S1 first performs melt extrusion under the following conditions:

[0023] The temperature of zone T1 is 40-70°C, the temperature of zone T2 is 80-90°C, the temperature of zone T3 is 230-260°C, the temperature of zone T4 is 230-260°C, the temperature of zone T5 is 230-260°C, the temperature of zone T6 is 225-240°C, the temperature of zone T7 is 225-240°C, the temperature of zone T8 is 220-230°C, the temperature of zone T9 is 210-250°C, the temperature of zone T10 is 140-170°C, the temperature of zone T11 is 120-170°C, the temperature of zone T12 is 120-170°C, the temperature of zone T13 is 120-170°C, the temperature of zone T14 is 120-170°C, the temperature of zone T15 is 150-180°C, and the temperature of zone T16 is 150-180°C. The aspect ratio of the twin-screw extruder is (40-60):1, and the main engine speed is 45-70r / min.

[0024] After observing that the twin-screw extruder can stably extrude a fiber melt of uniform thickness, melt extrusion is then performed under the following conditions:

[0025] The temperature of zone T1 is 40-70℃, the temperature of zone T2 is 65-85℃, the temperature of zone T3 is 230-240℃, the temperature of zone T4 is 230-240℃, the temperature of zone T5 is 225-230℃, the temperature of zone T6 is 225-230℃, the temperature of zone T7 is 210-225℃, the temperature of zone T8 is 190-220℃, the temperature of zone T9 is 190-210℃, the temperature of zone T10 is 90-120℃, the temperature of zone T11 is 90-110℃, the temperature of zone T12 is 90-110℃, the temperature of zone T13 is 90-110℃, the temperature of zone T14 is 90-110℃, the temperature of zone T15 is 160-170℃, the temperature of zone T16 is 155-170℃, and the speed of the main engine is 45-70r / min.

[0026] The inventors have found that temperature control is the key to preparing ultra-high fluidity fiber materials. In the early stage of the operation of the twin-screw extruder, if the temperature of the T10 zone to the T16 zone is not within the above-defined range, the temperature is too high, which makes the formed material strips easily stick and break during pelletizing, while the temperature is too low, which makes the formed material strips unstable and leads to unsuccessful strip drawing; and keeping the temperature of the T10 zone to the T16 zone within the above-defined range is conducive to ensuring that the extruded material presents a stable melt state.

[0027] After the material strips are stable, the temperature of the T10 zone to the T16 zone is appropriately lowered, which can not only reduce energy consumption but also stabilize the size of the melt outflow.

[0028] As a preferred embodiment of the present invention, the rotation speed of the pelletizer is 28-50 r / min.

[0029] In a second aspect, the present invention provides an ultra-high fluidity fiber material prepared by the preparation method described in the first aspect.

[0030] As a preferred embodiment of the present invention, the melt mass flow rate of the ultra-high fluidity fiber material at 190° C. and 2.16 kg is not less than 1510 g / 10 min, for example, 1510 to 1540 g / 10 min.

[0031] In a third aspect, the present invention provides a use of the ultra-high fluidity fiber material as described in the first aspect in preparing non-woven fabrics.

[0032] The nonwoven fabric provided by the present invention has the characteristics of ultra-high fluidity, narrow molecular weight distribution, etc., and is suitable for preparing nonwoven fabric products by high-speed spinning through a spunbond method. Such nonwoven fabric products are widely used in packaging, construction, industry, medical and health care and other fields.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] (1) The present invention sends the fiber material melt into a water tank filled with process water for heat exchange, and the fiber material melt crystallizes and solidifies in the water in the water tank to obtain fiber material strips; in this process, the process water in the water tank is sequentially introduced into the first heat exchanger and the second heat exchanger, in the first heat exchanger, the process water exchanges heat with cooling water, and in the second heat exchanger, the process water exchanges heat with frozen brine. Through the two heat exchanges, the temperature of the process water can be effectively reduced, so that the melt can be crystallized and solidified in the water tank in time, which can reduce the probability of strip winding and ensure the smooth and long-term operation of the process, and improve the pelletizing quality, protect the cutter, and increase the life of the extrusion granulator;

[0035] (2) The present invention optimizes the process parameters of melt extrusion, regulates the temperature of each zone of the twin-screw extruder, balances the feeding rate, the speed of the pelletizer and the speed of the twin-screw extruder, stabilizes the extruded melt, avoids the material strips from being easily entangled with the blades and broken during the traction process of the pelletizer, and ensures the continuous progress of the fiber material production process;

[0036] (3) The nonwoven fabric provided by the present invention has the characteristics of ultra-high fluidity and narrow molecular weight distribution, and is suitable for preparing nonwoven fabric products by high-speed spinning through the spunbond method. Such nonwoven fabric products are widely used in packaging, construction, industry, medical and health care and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A schematic diagram of the structure of the cooling system for producing ultra-high fluidity fiber material provided by the present invention;

[0038] Figure 2 A schematic diagram of temperature control of a twin-screw extruder provided by the present invention;

[0039] Figure 3 A photograph of the material strips in the water tank during the preparation process of Example 2 provided by the present invention;

[0040] Figure 4 A photograph of the material strips in the water tank during the preparation process of Comparative Example 1 provided by the present invention;

[0041] Figure 5 A photograph showing the knife-tangling phenomenon during the pelletizing process of Comparative Example 1 provided by the present invention;

[0042] Figure 6 This is a photo of the material strips in the water tank during the preparation process of Comparative Example 2 provided by the present invention. DETAILED DESCRIPTION

[0043] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0044] Unless otherwise specified, the materials and reagents used in the examples can be obtained from commercial sources.

[0045] The following frozen brine refers to industrial ethylene glycol that complies with standard GB4649-84.

[0046] Example 1

[0047] This embodiment provides a production cooling system for ultra-high fluidity fiber material, and the results are as follows: Figure 1 shown.

[0048] The production cooling system comprises a twin-screw machine 1, a water tank 2, a water tank 3, a water pump 4, a first heat exchanger 5, a second heat exchanger 6 and a pelletizer.

[0049] The discharge port of the twin-screw extruder 2 is connected to the material inlet of the water trough 2, the water outlet of the water trough 2 is connected to the water inlet of the water tank 3 through a pipeline, and the water outlet of the water tank 3 is connected to the water inlet end of the water pump 4 through a pipeline.

[0050] The first heat exchanger 5 has a first passage and a second passage, the water outlet of the water pump 4 is connected to the inlet of the first passage through a pipeline, the inlet of the second passage is connected to a cooling water supply pipe, and the outlet of the second passage is connected to a cooling water output pipe;

[0051] The second heat exchanger 6 has a third passage and a fourth passage, the outlet of the first passage is connected to the inlet of the third passage through a pipe, the outlet of the third passage is connected to the water inlet of the water tank 2 through a pipe, the inlet of the fourth passage is connected to a chilled brine supply pipe, and the outlet of the fourth passage is connected to a chilled brine output pipe.

[0052] In this embodiment, the twin-screw extruder has 16 temperature control zones (such as Figure 2As shown, T1 area to T16 area), screen changer and die head, the screen changer is arranged in T15 area, and the die head is arranged in T16 area.

[0053] In this embodiment, valves are provided on each pipeline.

[0054] The working principle of the production cooling system of the ultra-high fluidity fiber material is as follows:

[0055] The polypropylene powder is fed into the twin screw extruder 1 through the feed port of the T1 zone, and each additive is fed into the twin screw extruder 1 through the feed port of the T2 zone. In the twin screw extruder 1, the polypropylene powder and the additive are mixed and melted to form a melt, which is discharged from the die hole of the die head after passing through the screen changer; the discharged melt enters the water tank 2 filled with process water, cools, crystallizes, and solidifies to form a material strip; the material strip is pelletized by the pelletizer to obtain a granular fiber material. In the above process, after the process water in the water tank 2 exchanges heat with the melt, the temperature of the process water increases. In order to control the temperature of the process water in the water tank 2 within an appropriate range, under the action of the water pump 4, the process water discharged from the water tank 2 enters the first heat exchanger 5 to exchange heat with the cooling water, and then enters the second heat exchanger 6 to exchange heat with the frozen brine. Through two heat exchange treatments, the process water can be quickly reduced to the required temperature, and the cooled water returns to the water tank 2, thereby reducing the overall temperature of the process water in the water tank 2.

[0056] Example 2

[0057] The preparation method of the ultra-high fluidity fiber material of the present invention is implemented by the production cooling system provided in Example 1, and the preparation method comprises the following steps:

[0058] S1. Prepare the following raw materials: polypropylene powder, di-tert-butyl peroxide and stabilizer;

[0059] Among them, polypropylene powder: the melt mass flow rate under 190℃ and 2.16KG load is 20-30g / 10min, the model is PPH-MM20-S, and it comes from the polypropylene powder produced by Mitsui Oil Chemical Process of Sinopec Guangzhou Branch Polypropylene-2 ​​Unit;

[0060] Stabilizer 1: Model is composite additive NAP60 168 1010, from Chenghe Technology Co., Ltd.;

[0061] Stabilizer 2: 325 mesh ultra-high purity calcium stearate, from Shanghai Xinxin Chemical Co., Ltd.;

[0062] Degradation agent: di-tert-butyl peroxide, from Lanzhou Additive Factory;

[0063] The polypropylene powder, di-tert-butyl peroxide, stabilizer 1, stabilizer 2 and degradation agent are respectively continuously fed into a twin-screw extruder 1 for melt extrusion to obtain a molten fiber material melt; the feeding rate of the polypropylene powder is 400 kg / h, the feeding rate of the di-tert-butyl peroxide is 29.8-30.5 mL / min, and the feeding rates of the stabilizer 1, stabilizer 2 and degradation agent are all 10 g / min;

[0064] In step S1, melt extrusion is first performed under the following conditions:

[0065] The temperature of zone T1 (polypropylene powder feeding section) is 40-70°C, the temperature of zone T2 (peroxide, stabilizer 1 stabilizer 2 and degradation agent feeding section) is 80-90°C, the temperature of zone T3 is 230-260°C, the temperature of zone T4 is 230-260°C, the temperature of zone T5 is 230-260°C, the temperature of zone T6 is 225-240°C, the temperature of zone T7 is 225-240°C, the temperature of zone T8 is 220-230°C, the temperature of zone T9 is 210 ~250℃, T10 zone temperature 140~170℃, T11 zone temperature 120~170℃, T12 zone temperature 120~170℃, T13 zone temperature 120~170℃, T14 zone temperature 120~170℃, T15 zone (screen changer) temperature 150-180℃, T16 zone (die head) temperature 150~180℃, the aspect ratio of twin-screw extruder 1 is 50:1, and the main engine speed is 60r / min;

[0066] After observing that the twin-screw extruder can stably extrude a fiber melt of uniform thickness, melt extrusion is then performed under the following conditions:

[0067] The temperature of zone T1 (polypropylene powder feeding section) is 40-70°C, the temperature of zone T2 (peroxide and stabilizer feeding section) is 65-85°C, the temperature of zone T3 is 230-240°C, the temperature of zone T4 is 230-240°C, the temperature of zone T5 is 225-230°C, the temperature of zone T6 is 225-230°C, the temperature of zone T7 is 210-225°C, the temperature of zone T8 is 190-220°C, the temperature of zone T9 is 190-2 10℃, T10 zone temperature 90~120℃, T11 zone temperature 90~110℃, T12 zone temperature 90~110℃, T13 zone temperature 90~110℃, T14 zone temperature 90~110℃, T15 zone (screen changer) temperature 160-170℃, T16 zone (die head) temperature 155-170℃, twin screw extruder 1 aspect ratio 50:1, main engine speed 60r / min;

[0068] S2, conveying the fiber material melt obtained in step S1 to a water tank 2 filled with process water for heat exchange, wherein the fiber material melt is crystallized and solidified in the process water in the water tank 2 to obtain fiber material strips;

[0069] S3, introducing the fiber material strips obtained in step S2 into a pelletizer from one end of the water tank 2 away from the twin-screw extruder 1 for pelletizing, wherein the rotation speed of the pelletizer is 45 r / min, to obtain a granular fiber material with high fluidity.

[0070] When performing step S2, the process water in the water tank 2 is pumped out by the water pump 4 and transported to the first heat exchanger 5 for heat exchange with cooling water. The water temperature of the cooling water is 28-35°C, so that the process water is cooled to 43-55°C. The process water is passed into the second heat exchanger 6 for heat exchange with the chilled brine (temperature is -2-2°C), so that the process water is cooled to 3-20°C. The cooled process water is returned to the water tank 2. The volume of the water tank 2 is 20-40m 3 , adjust the opening of the valves on each pipeline to make the water inlet flow and outlet flow of water tank 2 the same, controlled at 1000-1500L / h, and maintain the water temperature in water tank 2 at 35-40℃.

[0071] Embodiments 3 to 9

[0072] The embodiments of the ultra-high fluidity fiber material of the present invention, embodiments 3 to 9 are different from embodiment 2 in that:

[0073] In Example 3, the feeding rate of the polypropylene powder is 320 Kg / h, the feeding rate of the di-tert-butyl peroxide is 25.5-27.3 mL / min, the feeding rate of the stabilizer is 5 g / min, the main machine speed is 45 r / min, and the pelletizer speed is 28 r / min;

[0074] In Example 4, the feeding rate of the polypropylene powder is 350 Kg / h, the feeding rate of the di-tert-butyl peroxide is 27.2-28.4 mL / min, the feeding rate of the stabilizer is 6 g / min, the main machine speed is 50 r / min, and the pelletizer speed is 30 r / min;

[0075] In Example 5, the feeding rate of the polypropylene powder is 390 Kg / h, the feeding rate of the di-tert-butyl peroxide is 28.6-29.5 mL / min, the feeding rate of the stabilizer is 7 g / min, the main machine speed is 55 r / min, and the pelletizer speed is 33 r / min;

[0076] In Example 6, the feeding rate of the polypropylene powder is 410 Kg / h, the feeding rate of the di-tert-butyl peroxide is 30.2-31.5 mL / min, the feeding rate of the stabilizer is 11 g / min, the main machine speed is 45 r / min, and the pelletizer speed is 45 r / min;

[0077] In Example 7, the feeding rate of the polypropylene powder is 450 Kg / h, the feeding rate of the di-tert-butyl peroxide is 32.5-34.81.5 mL / min, the feeding rate of the stabilizer is 13 g / min, the main machine speed is 65 r / min, and the pelletizer speed is 48 r / min;

[0078] In Example 8, the feeding rate of the polypropylene powder is 500 Kg / h, the feeding rate of the di-tert-butyl peroxide is 35.1-36.4 mL / min, the feeding rate of the stabilizer is 15 g / min, the main engine speed is 70 r / min, and the pelletizer speed is 50 r / min;

[0079] In Example 9, the feeding rate of the polypropylene powder is 520 Kg / h, the feeding rate of the di-tert-butyl peroxide is 36.1-39.4 mL / min, the feeding rate of the stabilizer is 21 g / min, the main engine speed is 75 r / min, and the pelletizer speed is 55 r / min.

[0080] Comparative Example 1

[0081] The comparative example of the ultra-high fluidity fiber material of the present invention is different from Example 2 in that, after the twin-screw extruder can stably extrude the fiber material melt with uniform thickness, the temperature of the die head in the T16 zone is controlled at 140-150°C.

[0082] Comparative Example 2

[0083] The comparative example of the ultra-high fluidity fiber material of the present invention is different from Example 2 in that, in this comparative example, after the twin-screw extruder can stably extrude the fiber material melt with uniform thickness, the temperature of the die head in the T16 zone is controlled at 175-190°C.

[0084] Comparative Example 3

[0085] The comparative example of the ultra-high fluidity fiber material of the present invention is different from Example 2 in that, in this comparative example, after the twin-screw extruder can stably extrude the fiber material melt with uniform thickness, the temperature of the T1 zone is controlled at 105-125°C.

[0086] Comparative Example 4

[0087] The comparative example of the ultra-high fluidity fiber material of the present invention is different from Example 2 in that the system adopted in the comparative example does not have a second heat exchanger, and the outlet of the first passage of the first heat exchanger 5 is directly connected to the water inlet of the water tank 2; when performing step S2 in the comparative example, the water in the water tank 2 is pumped out by a water pump and transported to the first heat exchanger 5 for heat exchange with cooling water. The water temperature of the cooling water is 28-35°C. After cooling to 43-55°C, the cooled process water is directly transported back to the water tank 2.

[0088] In this comparative example, the water temperature in the water tank 2 was monitored and it was found that the water temperature in the water tank 2 was 70-90°C.

[0089] Effect Example 1

[0090] During the preparation of the fiber materials in the above embodiments and comparative examples, the production stability and pelletizing effect were observed, wherein normal pelletizing means that the size of the fiber materials is within the range of 3 to 6 mm, oversized particles means that the size of the fiber materials is greater than 10 mm, and undersized particles means that the size of the fiber materials is less than 2 mm;

[0091] The fiber material prepared by stably extruding the fiber material melt with uniform thickness by the twin-screw extruder of the above embodiment and comparative example was used as a sample to conduct the following performance tests:

[0092] (1) Melt mass flow rate: The melt mass flow rate of the sample was tested using a melt flow rate meter in accordance with standard GB / T 3682.1-2018. The test temperature was 190°C and the load was 2.16 kg.

[0093] (2) Tensile strength: The specimens were injection molded into standard specimens, and the tensile strength of the specimens was tested according to standard GB / T 1040-2018 at a tensile rate of 10 mm / min;

[0094] (3) Volatile content: The percentage of the amount of volatile matter in the sample to the mass of the sample before drying is called the volatile content; the sample is dried at 105°C to constant weight, the mass reduction of the sample is measured, and the volatile content of the sample is calculated;

[0095] The test results are shown in Table 1 and Figures 3 to 6 shown.

[0096] Table 1

[0097]

[0098] The fiber material prepared in the embodiment of the present invention has moderate particles in the range of 3 to 6 mm, low volatile content, good fluidity, a melt mass flow rate of more than 1510 g / 10 min at 190°C and a load of 2.16 kg, and good tensile properties, with a tensile strength between 52 and 56.3 MPa, and is suitable for preparing non-woven fabric products by high-speed spinning through a spunbond method.

[0099] Compared with the embodiment, the temperature of the die head in the T16 zone of the comparative example 1 is too low. During the production process, the material strips are entangled with the blade and the pelletizing is poor, and continuous production cannot be achieved. In addition, the particle size of the obtained fiber material is greater than 10 mm, and the prepared fiber material has poor fluidity. The temperature of the die head in the T16 zone of the comparative example 2 is too high. Although the prepared fiber material has good fluidity, during the production process, the material strips are entangled with the blade and broken, and continuous production cannot be achieved. The particle size of the obtained fiber material is less than 2 mm. The temperature in zone 1 is too high, so that the heating temperature of the polypropylene powder in zone T1 is too high. When the polypropylene material with too high a temperature enters zone T2, it is easy to cause a large amount of gas to appear at the feeding port of zone T2 (for example, the injection port of the degradation agent), resulting in explosion and broken strips. The water temperature in the water tank of comparative example 4 is controlled at 70-90°C, which is too high and the fiber material melt cannot be fully cooled in the water tank. The material strips are very likely to be entangled with the knife and broken during the pelletizing process, and continuous production cannot be achieved. In addition, the particles of the obtained fiber material are small.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing ultra-high fluidity fiber material, characterized in that: The steps include: S1, continuously putting polypropylene powder, peroxide and stabilizer into a twin-screw extruder for melt extrusion to obtain a molten fiber material melt; S2, conveying the fiber material melt obtained in step S1 to a water tank filled with process water for heat exchange, wherein the fiber material melt is crystallized and solidified in the process water in the water tank to obtain fiber material strips; S3, introducing one end of the fiber material strip obtained in step S2 into a pelletizer for pelletizing to obtain a granular high-fluidity fiber material; When performing step S2, the process water in the water tank is pumped out by a water pump and transported to the first heat exchanger for heat exchange, then passed into the second heat exchanger for heat exchange, and then returned to the water tank.

2. The method for preparing the ultra-high fluidity fiber material according to claim 1, characterized in that: When performing step S2, the process water in the water tank is pumped out by a water pump and transported to the first heat exchanger for heat exchange with cooling water, so that the process water is cooled to 43-55°C, and then passed into the second heat exchanger for heat exchange with chilled brine, so that the process water is cooled to 3-20°C and then transported to the water tank, so that the temperature of the process water in the water tank is maintained at 35-40°C.

3. The method for preparing the ultra-high fluidity fiber material according to claim 2, characterized in that: The water temperature of the cooling water is 28-35°C, and the temperature of the frozen brine is -2-2°C.

4. The method for preparing the ultra-high fluidity fiber material according to claim 2, characterized in that: The water inlet flow rate and the water outlet flow rate of the water tank are the same, and the water inlet flow rate of the water tank is 1500-3500L / h.

5. The method for preparing the ultra-high fluidity fiber material according to claim 1, characterized in that: In step S1, the feeding rate of the polypropylene powder is 320-520 Kg / h, the feeding rate of the peroxide is 25.5-36.4 mL / min, and the feeding rate of the stabilizer is 5-21 g / min.

6. The method for preparing the ultra-high fluidity fiber material according to claim 1, characterized in that: In step S1, the conditions for melt extrusion of the twin-screw extruder are: temperature of zone T1 is 40-70°C, temperature of zone T2 is 65-90°C, temperature of zone T3 is 230-260°C, temperature of zone T4 is 230-260°C, temperature of zone T5 is 225-260°C, temperature of zone T6 is 225-240°C, temperature of zone T7 is 210-240°C, temperature of zone T8 is 190-230°C, temperature of zone T9 is 190-250°C, temperature of zone T10 is 90-170°C, temperature of zone T11 is 90-170°C, temperature of zone T12 is 90-170°C, temperature of zone T13 is 90-170°C, temperature of zone T14 is 90-170°C, temperature of zone T15 is 150-180°C, and temperature of zone T16 is 150-180°C.

7. The method for preparing ultra-high fluidity fiber material according to claim 1, characterized in that: In step S1, the aspect ratio of the twin-screw extruder is (40-60):1, and the main engine speed is 45-70 r / min.

8. The method for preparing ultra-high fluidity fiber material according to claim 1, characterized in that: The rotation speed of the pelletizer is 28-50 r / min.

9. An ultra-high fluidity fiber material, characterized in that: The fiber is prepared by the method for preparing the ultra-high fluidity fiber material according to any one of claims 1 to 8.

10. Use of the ultra-high fluidity fiber material as claimed in claim 9 in preparing non-woven fabrics.

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