High-concentration polyethylene fiber spinning solution, its preparation method and application

Abstract

This invention discloses a high-concentration polyethylene fiber spinning dope, its preparation method, and its application, belonging to the field of polyethylene fiber technology. The technical solution involves mixing ultra-high molecular weight polyethylene (UHMWPE) solution with extra-high molecular weight polyethylene (EHMWPE) powder, and then maintaining the mixture at 70-100°C to induce swelling, thereby obtaining the high-concentration polyethylene fiber spinning dope. The polyethylene fiber spinning dope prepared by this invention has a high solids content. Using this dope requires no modification to existing spinning processes and has lower requirements for the spinning process. The spinning process is stable, with fewer broken or fuzzy fibers. The prepared UHMWPE fibers exhibit stable properties, moderate strength, and low production costs, making them suitable for civilian applications.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polyethylene fibers, in particular to a high-concentration polyethylene fiber spinning dope, a preparation method and application thereof. BACKGROUND

[0002] Ultra-high molecular weight polyethylene fiber (UHMWPE) is also known as high-strength and high-modulus polyethylene fiber. It is one of the three high-performance fibers together with aramid fiber and carbon fiber. It is the highest-strength and highest-modulus fiber in the world at present. It has the advantages of light weight, high strength, high wear resistance, chemical corrosion resistance, good thermal conductivity, and difficulty in fouling. In the early stage, due to the low production technology and equipment level, the fiber price was high, and it was mainly used in military protection and other fields. In recent years, with the improvement of technology and equipment level, the cost of fiber is reduced, and it begins to gradually penetrate into the civilian market. Compared with the military market, the fiber for the civilian market does not require high strength and modulus, and reducing the spinning cost is the key to the development of the civilian market.

[0003] In the prior art, the preparation of ultra-high molecular weight polyethylene fiber usually uses gel spinning technology. That is, a suspension solution obtained by mixing and swelling a suitable solvent with ultra-high molecular weight polyethylene with a relative molecular weight of 1.5 million or more is used as a spinning dope. The spinning dope is sheared, uniformly mixed, and disentangled by a double screw extruder, and then extruded into a shape by a spinning pack assembly and cooled by cooling water to obtain a nascent gel fiber. The nascent gel fiber is prepared into an ultra-high molecular weight polyethylene fiber through subsequent extraction, drying, and super-drawing.

[0004] In the existing production process of ultra-high molecular weight polyethylene fiber, one of the main costs is the energy consumption in the recovery process of the spinning solvent and the extracting agent. The higher the concentration of the spinning dope, the less the amount of solvent used, the lower the energy consumption of extraction recovery, the higher the fiber yield, and the lower the fiber production cost. Therefore, increasing the concentration of the spinning dope, reducing the energy consumption of spinning, will greatly reduce the production cost of UHMWPE fiber, and further expand the application field of ultra-high molecular weight polyethylene fiber in the civilian market.

[0005] In order to improve the concentration of the spinning dope, Chinese invention patent CN1256471C uses a specially designed dissolution kettle with a complete set of heating and stirring device to stir and heat the ultra-high molecular weight polyethylene powder with a molecular weight of (1.5-7) x 10 6 × 10

[0006] Chinese invention patent CN106948022A uses a mixed solvent to dissolve ultra-high molecular weight polyethylene with a molecular weight of (1-8) x 106 The low boiling point solvent with high cost is recovered by flash evaporation, the high boiling point solvent has low cost, and the solvent cost is greatly reduced; in the flash evaporation process, the porous swelling state of the particles is retained, the ultra-high molecular weight polyethylene swelling body is more easily dissolved, and a solution with a higher concentration (15-50%) is prepared.

[0007] Chinese invention patent CN102605440A discloses a preparation method of a high-concentration ultra-high molecular weight polyethylene spinning solution, specifically, ultra-high molecular weight polyethylene powder with a molecular weight of (5-8) x 10 6 The ultra-high molecular weight polyethylene powder with a molecular weight of (5-8) x 10

[0008] Chinese invention patent CN103541024A discloses a preparation method of a high-concentration ultra-high molecular weight polyethylene gel spinning solution, wherein ultra-high molecular weight polyethylene powder with a molecular weight of (1.5-8) x 10 6 The ultra-high molecular weight polyethylene powder with a molecular weight of (1.5-8) x 10

[0009] Chinese invention patent CN101525778A adopts (2-5) x 10 6 The ultra-high molecular weight polyethylene is swelled and dissolved by a double-screw extruder in one step, the solid content reaches 10-15%, and the solvent content of the fiber yarn in the pre-stretching process is greatly reduced, the drawing speed and product quality are improved, and the ultra-high molecular weight polyethylene fiber with high strength (above 35 g / d) is obtained.

[0010] The above methods have achieved certain effects in solving the uniformity problem of the spinning solution, but have high requirements for the process and equipment, the operation process is complex, and the ultra-high molecular weight polyethylene has a high molecular weight, which easily causes uneven dissolution of the spinning solution, and problems such as broken yarn and loose yarn occur in the spinning process. Meanwhile, simply increasing the concentration of the spinning solution under the condition of unchanged molecular weight, the working pressure of the double-screw extruder is large, which is not conducive to the continuous and stable operation of the equipment.

[0011] Chinese invention patent CN102505158A discloses a high-concentration preparation method of an ultra-high molecular weight polyethylene fiber, which adopts ultra-high molecular weight polyethylene with a molecular weight of more than 8 x 10 5The high-molecular-weight polyethylene resin powder, the antioxidant and the solvent are mixed uniformly to obtain a swelling solution; the swelling solution is cooled and extruded by a double-screw extruder to obtain a high-concentration gelatinous-like ultra-high-molecular-weight polyethylene spinning solution (20-40%). SUMMARY

[0012] The technical problem solved by the present application is to overcome the shortcomings of the prior art, provide a high-concentration polyethylene fiber spinning solution and a preparation method and application thereof, the prepared polyethylene fiber spinning solution has high solid content, the spinning solution does not need to modify the existing spinning process, has low requirements on the spinning process, the spinning process is stable, the number of broken filaments and loose filaments is small, the prepared ultra-high-molecular-weight polyethylene fiber has stable performance and moderate strength, has low production cost and is suitable for civilian fields.

[0013] The technical scheme of the present application is as follows:

[0014] In a first aspect, the present application provides a preparation method of a high-concentration polyethylene fiber spinning solution, wherein an ultra-high-molecular-weight polyethylene solution and a super-high-molecular-weight polyethylene powder are mixed, and the mixture is swelled at 70-100℃ to obtain the high-concentration polyethylene fiber spinning solution.

[0015] Preferably, the preparation method of the ultra-high-molecular-weight polyethylene solution is as follows: the ultra-high-molecular-weight polyethylene powder and an antioxidant are added to a solvent, and the mixture is heated to 130-190℃ and stirred to obtain the ultra-high-molecular-weight polyethylene solution.

[0016] Preferably, the mass ratio of the solvent, the ultra-high-molecular-weight polyethylene powder and the antioxidant is 95-99:1-5:0.1-0.5; the solvent is a paraffin hydrocarbon solvent, the number of carbon atoms of the paraffin hydrocarbon is 25-50; and the antioxidant is one or both of antioxidant 1010 and antioxidant 168.

[0017] Preferably, after the ultra-high-molecular-weight polyethylene solution is prepared, the solution is cooled to below 60℃, the super-high-molecular-weight polyethylene powder and a surfactant are added, and the mixture is heated to 70-100℃ and swelled.

[0018] Preferably, the mass ratio of the ultra-high-molecular-weight polyethylene solution, the super-high-molecular-weight polyethylene powder and the surfactant is 100:14-50:0.03-0.08; and the surfactant is basic aluminum stearate, stearic acid or Span.

[0019] Preferably, the viscosity-average molecular weight of the ultra-high-molecular-weight polyethylene powder is more than twice the viscosity-average molecular weight of the super-high-molecular-weight polyethylene powder.

[0020] Preferably, the viscosity average molecular weight of the ultra-high molecular weight polyethylene powder is 15-80 million, and the viscosity average molecular weight of the very-high molecular weight polyethylene powder is 30-140 million.

[0021] Preferably, the viscosity average molecular weight of the ultra-high molecular weight polyethylene powder is 15-80 million, and the viscosity average molecular weight of the very-high molecular weight polyethylene powder is 30-140 million.

[0022] Preferably, the concentration of the high-concentration polyethylene fiber spinning dope is 15-35 wt.%.

[0023] After cooling, the ultra-high molecular weight polyethylene solution will crystallize and precipitate, and the addition of the very-high molecular weight polyethylene powder can re-swelling, and after dissolution in the screw, the problems of filter blockage and unstable spinning caused by incomplete dissolution of high-concentration ultra-high molecular weight polyethylene can be avoided, ensuring good fluidity and continuity of the spinning dope, and avoiding the occurrence of hair and broken filaments in the subsequent spinning process. At the same time, the addition of the ultra-high molecular weight polyethylene solution can better induce the orientation of the spinning dope to form extended chain crystals, reduce the disorientation of the gel yarn and the formation of excessive entanglement, so that the tension can be smoothly transmitted during the subsequent drawing process to achieve super-drawing, prevent broken filaments, ensure the stability of the properties of the ultra-high molecular weight polyethylene fiber, increase the super-drawing characteristics and the strength of the fiber, and make the strength of the fiber much greater than that of pure very-high molecular weight polyethylene spinning.

[0024] In a second aspect, the present application provides a high-concentration polyethylene fiber spinning dope prepared by the above preparation method.

[0025] In a third aspect, the present application provides the use of the high-concentration polyethylene fiber spinning dope prepared by the above preparation method, and the high-concentration polyethylene fiber spinning dope is used for preparing a polyethylene fiber.

[0026] Preferably, the high-concentration polyethylene fiber spinning dope is used for preparing a polyethylene fiber, which comprises the following steps:

[0027] S1 double-screw extruder extrusion: the high-concentration polyethylene fiber spinning dope is sent into a double-screw extruder to obtain a transparent gel solution;

[0028] S2 gel yarn preparation: the gel solution is extruded through a spinning nozzle into a coagulation water tank, and the yarn is shaped to obtain a gel yarn;

[0029] S3 extraction, drying and high-multiple heat stretching: the gel yarn is extracted, dried and then heat stretched to obtain a polyethylene fiber.

[0030] In a fourth aspect, the present application provides a polyethylene dissolving and swelling device, which is composed of three stirred tanks, wherein the first stirred tank is an inner heat-conducting oil electric heating jacket stirred tank, and the device further comprises a second stirred tank and a third stirred tank in parallel.

[0031] The first stirred tank is a dissolving tank, and after the ultra-high molecular weight polyethylene powder is heated and stirred to dissolve in the first stirred tank, an ultra-high molecular weight polyethylene solution is formed; then the solution flows into the second stirred tank or the third stirred tank, and the first stirred tank can maintain a high-temperature state throughout the process, and the process is in a circulating state of adding solvent, solid material, stirring, dissolving, heat preservation, discharging, and then adding solvent, solid material, stirring, dissolving, heat preservation, and discharging; the second stirred tank and the third stirred tank are two parallel swelling tanks, one tank is used for heat preservation and swelling of the feed, and the other tank is used for batching and pre-swelling, and the two tanks ensure stable feeding, and the swelling tank can adopt cold and hot water circulation.

[0032] Compared with the prior art, the present application has the following beneficial effects:

[0033] The polyethylene fiber spinning dope prepared by the present application has high solid content, and the use of the spinning dope does not require modification of the existing spinning process and has lower requirements for the spinning process. The spinning process is stable, the number of broken filaments and loose filaments is small, the prepared ultra-high molecular weight polyethylene fiber has stable performance and moderate strength, the production cost is low, and the spinning dope is suitable for civilian use. The spinning dope prepared by the present application not only avoids the problem of too low spinning strength of the ultra-high molecular weight polyethylene, but also avoids the problem of difficulty in increasing the spinning concentration of the ultra-high molecular weight polyethylene, and can manufacture moderate-strength polyethylene fiber at high concentration and low cost. DETAILED DESCRIPTION

[0034] The preparation method of the high-concentration polyethylene fiber spinning dope of the present application comprises the following steps:

[0035] (1) adding ultra-high molecular weight polyethylene powder and an antioxidant into a solvent, heating to 130-190℃ and stirring to obtain an ultra-high molecular weight polyethylene solution; wherein the mass ratio of the solvent, the ultra-high molecular weight polyethylene powder and the antioxidant is 95-99:1-5:0.1-0.5; the solvent is a paraffin solvent; and the antioxidant is one or both of antioxidant 1010 and antioxidant 168.

[0036] (2) cooling the ultra-high molecular weight polyethylene solution to below 60℃, adding the ultra-high molecular weight polyethylene powder and the surfactant, and heating to 70-100℃ to swell, to obtain a polyethylene swelling liquid, which is the high-concentration polyethylene fiber spinning solution; the mass ratio of the ultra-high molecular weight polyethylene solution, the ultra-high molecular weight polyethylene powder and the surfactant is 100:14-50:0.03-0.08; the surfactant is basic aluminum stearate, stearic acid or Span, and the concentration of the obtained polyethylene fiber spinning solution is 15-35 wt.%; preferably, the concentration of the polyethylene fiber spinning solution is 25-35 wt.%.

[0037] The ultra-high molecular weight polyethylene solution refers to a uniform solution obtained by mixing the ultra-high molecular weight polyethylene with a solvent, and then allowing the solvent small molecules to penetrate and diffuse into the ultra-high molecular weight polyethylene, so that the ultra-high molecular weight polyethylene macromolecules are dissolved; the polyethylene swelling liquid refers to a polyethylene suspension obtained by mixing the polyethylene with a solvent, and then allowing the solvent small molecules to penetrate between the polyethylene particles and partially penetrate into the particles, while the polyethylene particles still maintain the particle state.

[0038] When the ultra-high molecular weight polyethylene solution and the ultra-high molecular weight polyethylene powder are mixed and stirred to prepare the spinning solution, the stirring time is 20-120 min, preferably 40-90 min, and more preferably 50-70 min; the temperature for heat preservation and swelling is 70-100℃, preferably 80-98℃, and more preferably 90-95℃.

[0039] When the ultra-high molecular weight polyethylene solution and the ultra-high molecular weight polyethylene powder are mixed and stirred to prepare the spinning solution, the following steps are preferably adopted:

[0040] The ultra-high molecular weight polyethylene powder and the solvent are stirred in a mixing kettle at normal temperature and pressure, and then the mixed liquid is heated to a temperature higher than the dissolution temperature of the polyethylene, preferably 130-190℃. The dissolution temperature of the polyethylene is well known to those skilled in the art and varies with the molecular weight, and is about 120-135℃. After the mixed liquid is heated to 130-190℃, the ultra-high molecular weight polyethylene solution is obtained by stirring and mixing.

[0041] In the process of preparing the ultra-high molecular weight polyethylene solution, the mixed liquid is heated to a temperature higher than the dissolution temperature of the ultra-high molecular weight polyethylene, to obtain a uniform mixed liquid. The concentration of the ultra-high molecular weight polyethylene is relatively low, and the overall viscosity of the ultra-high molecular weight polyethylene solution is low. After cooling, the solution becomes a low-viscosity suspension state, rather than the common block-like polyethylene-solvent phase separation state formed after the ultra-high molecular weight polyethylene spinning solution is cooled.

[0042] After the solution of the ultra-high molecular weight polyethylene is cooled to below 60℃ and the solution of the ultra-high molecular weight polyethylene becomes a suspension, the ultra-high molecular weight polyethylene powder is added for swelling. In the above operation, the ultra-high molecular weight polyethylene is dissolved first, and then the ultra-high molecular weight polyethylene powder is added for swelling. The purpose of this is that the ultra-high molecular weight polyethylene can form a good stretching orientation structure in the spinning process, ensure that the spinning dope has good spinning stability, induce the spinning dope to form a sheared straight crystal, reduce the entanglement in the spinning dope, and ensure that the tension in the yarn can be smoothly transmitted in the subsequent drawing process, so as to achieve the purpose of super-drawing. If the two kinds of polyethylene are directly mixed and dissolved, part of the ultra-high molecular weight polyethylene may not be completely dissolved, resulting in the occurrence of broken ends and loose ends in the spinning process.

[0043] According to the present application, when preparing the spinning dope, the following steps are preferably used:

[0044] The solvent, the ultra-high molecular weight polyethylene powder and the antioxidant are added to the first stirring kettle for stirring; the mass ratio of the solvent, the ultra-high molecular weight polyethylene powder and the antioxidant is 95-99:1-5:0.1-0.5; the solvent is a paraffin hydrocarbon solvent; and the antioxidant is one or both of antioxidant 1010 and antioxidant 168.

[0045] The mixture obtained by stirring is heated to 130-190℃ by an electric heating jacket heat conducting oil for 40-120min to obtain an ultra-high molecular weight polyethylene solution. The ultra-high molecular weight polyethylene solution is discharged from the first stirring kettle into a second stirring kettle (or a third stirring kettle in parallel with the second stirring kettle) with jacket circulating normal temperature water. The ultra-high molecular weight polyethylene solution is cooled to below 60℃ in the second stirring kettle, and the solution becomes a white suspension. The ultra-high molecular weight polyethylene powder and the surfactant are added to the second stirring kettle; the mass ratio of the ultra-high molecular weight polyethylene solution, the ultra-high molecular weight polyethylene powder and the surfactant is 100:14-50:0.03-0.08; and the surfactant is basic aluminum stearate, stearic acid or Span. The circulating normal temperature water of the second stirring kettle is replaced with circulating hot water, and the temperature of the circulating hot water is preferably 70-100℃, preferably 80-98℃, more preferably 90-95℃. The stirring time is preferably 20-120min, more preferably 40-90min, and most preferably 50-70min. After the stirring is completed, the product is fed into a double screw extrusion spinning machine through a feeder.

[0046] After the solution in the first stirring kettle is discharged, the valve is closed, and the solvent, the ultra-high molecular weight polyethylene powder and the antioxidant are added for the next dissolution process. The ultra-high molecular weight polyethylene solution after dissolution is discharged into another empty stirring kettle (the third stirring kettle or the second stirring kettle) for a new swelling process. The swelling liquids in the two swelling kettles are fed into the double screw extruder in turn.

[0047] According to the present application, the stirring speed of the first stirred tank is 150-500 rpm, preferably 250-300 rpm; the stirring time is 20-100 min, more preferably 30-80 min, and most preferably 40-60 min.

[0048] According to the present application, when the first stirred tank is kept warm for dissolution, the warm-keeping time is adjusted according to the dissolution condition, which is mainly related to the molecular weight and particle size of the ultra-high molecular weight polyethylene. The solution is finally transparent, and the stirring can be stopped every 10 min for observation through the window. When no white material is observed through the window, it can be discharged to the second or third stirred tank.

[0049] According to the present application, when preparing the ultra-high molecular weight polyethylene solution, the following steps are preferably used:

[0050] The first stirred tank is added with a certain amount of solvent, and then weighed ultra-high molecular weight polyethylene powder and antioxidant are added. The temperature and stirring speed of the stirred tank are set. The temperature is preferably 130-190℃, more preferably 150-170℃, the stirring speed is preferably 150-500 rpm, preferably 250-300 rpm, and the stirring time is preferably 20-100 min, more preferably 30-80 min, and most preferably 40-60 min. After the temperature reaches the set temperature, the timer starts, and the solution is observed every 10 min. After the polymer solution is transparent, the stirring is stopped, and the ultra-high molecular weight polyethylene solution in the first stirred tank is discharged to the second reaction tank. The first stirred tank can be added with solvent, ultra-high molecular weight polyethylene powder and antioxidant for a new batch of dissolution.

[0051] The second stirred tank is cooled by room temperature water. When the temperature drops to below 60℃, the cooling water circulation is stopped, and the polymer solution is observed. When the polymer solution is not transparent and white substances are precipitated, weighed high molecular weight polyethylene powder and surfactant are added, and stirring and hot water circulation are started at the same time. The temperature of the circulating hot water is preferably 70-100℃, preferably 80-98℃, and more preferably 90-95℃; the stirring speed is preferably 450-1500 rpm, preferably 900-1100 rpm; the stirring time is preferably 20-120 min, more preferably 40-90 min, and most preferably 50-70 min; and after stirring, it is fed into the double screw extrusion spinning through the feeder.

[0052] After the solution in the first stirred tank is added into the third stirred tank, the mixed solution in the second stirred tank is configured and swelled according to the process of the second stirred tank, while the first stirred tank is used to prepare and dissolve a new batch of the solution of the ultra-high molecular weight polyethylene; the spinning dope swelled in the second stirred tank is added into the screw extruder under the condition of heat preservation, after the spinning dope in the second stirred tank is used up, the mixed solution in the third stirred tank is also swelled, and the third stirred tank is switched to feed the double screw extruder. The hot water circulation of the jacket of the second stirred tank is changed to cold water circulation, at this time, the third batch of the solution of the ultra-high molecular weight polyethylene in the first stirred tank is also dissolved and discharged into the second stirred tank, and the new cooling and precipitation, the addition of the ultra-high molecular weight polyethylene powder and the surfactant and the heating and swelling are carried out again. In this way, the first stirred tank is used to dissolve the ultra-high molecular weight polyethylene all the time, while the second and third stirred tanks are used to carry out the processes of cooling and precipitation, the addition of the ultra-high molecular weight polyethylene powder, heating and swelling, the feeding of the mixed solution into the double screw extruder and the addition of the solution of the ultra-high molecular weight polyethylene in turn and alternately.

[0053] According to the application, in the process of preparing the mixed and swelled solution of the ultra-high molecular weight polyethylene and the ultra-high molecular weight polyethylene, the viscosity average molecular weight of the ultra-high molecular weight polyethylene powder is 3-6 million, preferably 4-5 million; the viscosity average molecular weight of the ultra-high molecular weight polyethylene powder is 30-140 million, preferably 60-120 million; the mass ratio of the solution of the ultra-high molecular weight polyethylene, the ultra-high molecular weight polyethylene powder and the surfactant is 100:14-50:0.03-0.08. The concentration of the prepared polyethylene fiber spinning dope is 15-35 wt.%.

[0054] The viscosity average molecular weight of the ultra-high molecular weight polyethylene powder used in the application is 150-800 million, preferably 200-360 million; the viscosity average molecular weight of the ultra-high molecular weight polyethylene powder is 30-140 million, preferably 60-120 million; the viscosity average molecular weight of the ultra-high molecular weight polyethylene powder is 2-6 times, more preferably 3-4 times, of the viscosity average molecular weight of the ultra-high molecular weight polyethylene powder. The ultra-high molecular weight polyethylene and the ultra-high molecular weight polyethylene powder with Gaussian distribution of particle size are preferably used in the application, and the particle size of the powder is preferably 60-200 mesh.

[0055] The polyethylene fiber spinning dope prepared according to the application can be used to prepare the ultra-high molecular weight polyethylene fiber according to the gel spinning technology known to those skilled in the art, and specifically can be:

[0056] S1 twin-screw extruder extrusion: the polyethylene fiber spinning dope is fed into a twin-screw extruder, the inlet temperature of the twin-screw extruder is preferably 85-120℃, the middle extrusion temperature is preferably 240-280℃, and the outlet temperature is preferably 270-310℃; the residence time of the polyethylene fiber spinning dope in the twin-screw extruder is not more than 15 min, preferably 3-7 min, and more preferably 4-6 min; the rotation speed of the twin-screw extruder is preferably 70-260 rpm, and more preferably 180-220 rpm.

[0057] S2 gel strand preparation: the spinneret aperture is preferably 0.4-3 mm, the spinneret length-diameter ratio is preferably 5-20:1, the spinning dope extrusion rate is preferably 0.5-20 m / min, and the spinning dope is cooled and shaped by 0-25℃ cooling water to obtain a gel strand;

[0058] S3 extraction, drying and high-multiple heat stretching: the gel strand is extracted by an extracting agent, the extracting agent is preferably dichloromethane, solvent oil or kerosene, and more preferably dichloromethane; the gel strand is dried after extraction, and the drying temperature is preferably 30-60℃; the dried gel strand is subjected to 30-130 times, preferably 40-60 times, of super-multiple heat stretching at a temperature range of 70-160℃ to obtain a polyethylene fiber.

[0059] In the present application, the mechanical properties of the ultra-high molecular weight polyethylene fiber are tested by the following method: the strength and modulus of the fiber are determined by a DXLL-20000 electronic tensile testing machine, and the test conditions are a clamp distance of 250 mm and a tensile speed of 50 mm / min; X1, X2, …, Xn are taken from each sample, and the average value of the n samples is calculated. n The performance value of the n samples is calculated, and the arithmetic average value is calculated as shown in the following formula (1):

[0060]

[0061] In the formula, X is the average performance value, Xi is the performance value of each sample, and n is the number of samples.

[0062] The standard deviation S of the performance value is calculated by the following formula (2):

[0063]

[0064] In the formula, S is the standard deviation of the performance value, X is the average performance value, Xi is the performance value of each sample, and n is the number of samples.

[0065] The dispersion coefficient CV of the performance value is calculated by the following formula (3):

[0066]

[0067] In the formula, CV is the dispersion coefficient, S is the standard deviation of the performance value, and X is the average performance value.

[0068] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention.

[0069] Example 1

[0070] The preparation method of the high-concentration polyethylene fiber spinning solution in this embodiment includes the following steps:

[0071] (1) Add about 70% of the volume of white oil to the first stirring vessel, with a density of 0.85 g / cm³. 3 The weight of white oil is recorded as 95 parts, and then 5 parts of ultra-high molecular weight polyethylene powder (viscosity average molecular weight 1.6 × 10⁻⁶) are added. 6 The mixture contains g / mol of powder with a particle size of 80-120μm and 0.2 parts of antioxidant 1010. The temperature of the first stirred tank is 170℃, and the stirring speed is 250rpm. The timer is started after the temperature inside the tank reaches 165℃. Stirring is stopped and the condition inside the tank is observed every 10 minutes. After 30 minutes, the inside of the tank becomes basically transparent, and the stirred liquid is discharged into the second stirred tank.

[0072] (2) The second mixing vessel is stirred at a low speed of 400 rpm, with cold water circulating through the jacket. Stirring is stopped when the temperature inside the vessel drops to 60℃. The condition inside the vessel is observed. Once solids precipitate out, 30 parts of ultra-high molecular weight polyethylene powder (UVPE with a viscosity-average molecular weight of 4.5 × 10⁻⁶) are added. 5 g / mol of basic aluminum stearate (powder particle size of 70-110 μm) and 0.035 parts of basic aluminum stearate were added; hot water at 90℃ was introduced, and the stirring speed was set to 1000 rpm. After stirring for 50 min, polyethylene fiber spinning solution was obtained, and the polyethylene content in the spinning solution was about 26 wt.%.

[0073] Example 2

[0074] The preparation method of the high-concentration polyethylene fiber spinning solution in this embodiment includes the following steps:

[0075] (1) Add about 70% of the volume of white oil to the first stirring vessel, with a density of 0.85 g / cm³. 3 The weight of white oil is recorded as 95 parts, and then 5 parts of ultra-high molecular weight polyethylene powder (viscosity average molecular weight 1.5 × 10⁻⁶) are added. 6 The mixture contains g / mol of powder with a particle size of 80-120μm and 0.2 parts of antioxidant 1010. The temperature of the first stirred tank is 165℃, and the stirring speed is 250rpm. The timer is started after the temperature inside the tank reaches 160℃. Stirring is stopped and the condition inside the tank is observed every 10 minutes. After 30 minutes, the inside of the tank becomes basically transparent, and the stirred liquid is discharged into the second stirred tank.

[0076] (2) The second stirring kettle is stirred at a low speed of 400 rpm, and cold water is circulated through the jacket. When the temperature in the kettle drops to 60°C, stop stirring, observe the situation in the kettle, and when solids precipitate, add 47 parts of a special high molecular weight polyethylene powder (the viscosity average molecular weight of the special high molecular polyethylene is 3.5 x 10 5 g / mol, and the powder particle size is 70-110 μm) and 0.035 parts of basic aluminum stearate. Then, hot water at 90°C is circulated, the stirring speed is set to 1000 rpm, and after 50 minutes of stirring, a polyethylene fiber spinning solution is obtained, and the polyethylene content in the spinning solution is about 35 wt.%.

[0077] Example 3

[0078] The preparation method of the high-concentration polyethylene fiber spinning solution in this example includes the following steps:

[0079] (1) Add white oil to the first stirring kettle to about 70% of the volume of the kettle body, and the density of the white oil is 0.85 g / cm 3 , and the weight of the white oil is recorded as 97 parts. Then, add 3 parts of an ultra-high molecular weight polyethylene powder (the viscosity average molecular weight is 2.0 x 10 6 g / mol, and the powder particle size is 80-120 μm) and 0.2 parts of antioxidant 1010. The temperature of the first stirring kettle is 175°C, and the stirring speed is 250 rpm. After the temperature in the kettle reaches 170°C, start timing, stop stirring every 10 minutes, and observe the situation in the kettle. After 30 minutes, the stirring solution is basically transparent, and is discharged to the second stirring kettle.

[0080] (2) The second stirring kettle is stirred at a low speed of 400 rpm, and cold water is circulated through the jacket. When the temperature in the kettle drops to 50°C, stop stirring, observe the situation in the kettle, and when solids precipitate, add 25 parts of a special high molecular weight polyethylene powder (the viscosity average molecular weight of the special high molecular polyethylene is 6.5 x 10 5 g / mol, and the powder particle size is 70-110 μm) and 0.035 parts of basic aluminum stearate. Then, hot water at 92°C is circulated, the stirring speed is set to 1000 rpm, and after 60 minutes of stirring, a polyethylene fiber spinning solution is obtained, and the polyethylene content in the spinning solution is about 22 wt.%.

[0081] Example 4

[0082] The preparation method of the high-concentration polyethylene fiber spinning solution in this example includes the following steps:

[0083] (1) Add white oil to the first stirring kettle to about 70% of the volume of the kettle body, and the density of the white oil is 0.85 g / cm 3 , and the weight of the white oil is recorded as 98 parts. Then, add 2 parts of an ultra-high molecular weight polyethylene powder (the viscosity average molecular weight is 2.5 x 10 6The mixture contains g / mol of powder with a particle size of 80-120μm and 0.2 parts of antioxidant 1010. The temperature of the first stirred tank is 175℃, and the stirring speed is 250rpm. The timer is started after the temperature inside the tank reaches 170℃. Stirring is stopped and the condition inside the tank is observed every 10 minutes. After 40 minutes, the inside of the tank becomes basically transparent, and the stirred liquid is discharged into the second stirred tank.

[0084] (2) The second mixing vessel is stirred at a low speed of 400 rpm, with cold water circulating through the jacket. Stirring is stopped when the temperature inside the vessel drops to 60℃. The condition inside the vessel is observed. Once solids precipitate out, 20 parts of ultra-high molecular weight polyethylene powder (UVPE with a viscosity-average molecular weight of 1.0 × 10⁻⁶) are added. 6 g / mol of basic aluminum stearate (powder particle size of 70-110μm) and 0.035 parts of basic aluminum stearate were added; hot water at 95℃ was introduced, and the stirring speed was set to 1000rpm. After stirring for 60min, polyethylene fiber spinning solution was obtained, and the polyethylene content in the spinning solution was about 18wt.%.

[0085] Example 5

[0086] The preparation method of the high-concentration polyethylene fiber spinning solution in this embodiment includes the following steps:

[0087] (1) Add about 70% of the volume of white oil to the first stirring vessel, with a density of 0.85 g / cm³. 3 The weight of white oil was recorded as 98 parts, and then 2 parts of ultra-high molecular weight polyethylene powder (viscosity average molecular weight 3.5 × 10⁻⁶) were added. 6 The mixture contained g / mol of powder with a particle size of 80-120μm and 0.2 parts of antioxidant 1010. The temperature of the first stirred tank was 177℃, and the stirring speed was 250rpm. The timer was started after the temperature inside the tank reached 172℃. The stirring was stopped and the condition inside the tank was observed every 10 minutes. After 40 minutes, the inside of the tank became basically transparent, and the stirred liquid was discharged into the second stirred tank.

[0088] (2) The second mixing vessel is stirred at a low speed of 400 rpm with cold water circulating in the jacket. Stirring is stopped when the temperature inside the vessel drops to 60℃. The condition inside the vessel is observed. Once solids precipitate out, 16 parts of ultra-high molecular weight polyethylene powder (the viscosity-average molecular weight of ultra-high molecular weight polyethylene is 1.2 × 10⁻⁶) are added. 6 g / mol of basic aluminum stearate (powder particle size of 70-110 μm) and 0.035 parts of basic aluminum stearate were added; hot water at 95℃ was introduced, and the stirring speed was set to 1000 rpm. After stirring for 60 min, polyethylene fiber spinning solution was obtained, with a polyethylene content of about 16 wt.%.

[0089] Example 6

[0090] The preparation method of the high-concentration polyethylene fiber spinning solution in this embodiment includes the following steps:

[0091] (1) Add about 70% of the volume of white oil to the first stirring vessel, with a density of 0.85 g / cm³. 3 The weight of white oil is recorded as 99 parts, and then 1 part of ultra-high molecular weight polyethylene powder (viscosity average molecular weight 5.5 × 10⁻⁶) is added. 6 The mixture contains g / mol of powder with a particle size of 80-120μm and 0.2 parts of antioxidant 1010. The temperature of the first stirred tank is 180℃, and the stirring speed is 250rpm. The timer is started after the temperature inside the tank reaches 175℃. Stirring is stopped and the condition inside the tank is observed every 10 minutes. After 50 minutes, the inside of the tank becomes basically transparent, and the stirred liquid is discharged into the second stirred tank.

[0092] (2) The second mixing vessel is stirred at a low speed of 400 rpm with cold water circulating through the jacket. Stirring is stopped when the temperature inside the vessel drops to 60℃. The condition inside the vessel is observed. Once solids precipitate out, 16 parts of ultra-high molecular weight polyethylene powder (the viscosity-average molecular weight of ultra-high molecular weight polyethylene is 1.4 × 10⁻⁶) are added. 6 g / mol of basic aluminum stearate (powder particle size of 70-110μm) and 0.035 parts of basic aluminum stearate were added; hot water at 95℃ was introduced, and the stirring speed was set to 1000rpm. After stirring for 70min, polyethylene fiber spinning solution was obtained, and the polyethylene content in the spinning solution was about 15wt.%.

[0093] Comparative Example 1

[0094] The preparation method of the polyethylene fiber spinning solution in Comparative Example 1 includes the following steps:

[0095] (1) Add about 70% of the volume of white oil to the first stirring vessel, with a density of 0.85 g / cm³. 3 The weight of white oil is recorded as 95 parts, and then 5 parts of ultra-high molecular weight polyethylene powder (ultra-high molecular weight polyethylene has a viscosity-average molecular weight of 3.5 × 10⁻⁶) are added. 5 The mixture contains g / mol of powder with a particle size of 70-110μm and 0.2 parts of antioxidant 1010. The temperature of the first stirred tank is 165℃, and the stirring speed is 250rpm. The timer is started after the temperature inside the tank reaches 160℃. Stirring is stopped and the condition inside the tank is observed every 10 minutes. After 30 minutes, the inside of the tank becomes basically transparent, and the stirred liquid is discharged into the second stirred tank.

[0096] (2) The second mixing vessel is stirred at a low speed of 400 rpm, with cold water circulating through the jacket. Stirring is stopped when the temperature inside the vessel drops to 60℃. The condition inside the vessel is observed. Once solids precipitate out, 47 parts of ultra-high molecular weight polyethylene powder (the viscosity-average molecular weight of ultra-high molecular weight polyethylene is 3.5 × 10⁻⁶) are added. 5g / mol, powder particle size 70-110 μm) and 0.035 parts of basic aluminum stearate; change to 90°C hot water, set the stirring speed to 1000 rpm, after stirring for 50 min, polyethylene fiber spinning dope is obtained, the polyethylene content in the spinning dope is about 35 wt.%.

[0097] Comparative Example 2

[0098] The preparation method of the polyethylene fiber spinning dope of Comparative Example 2 comprises the following steps:

[0099] (1) Add white oil to the first stirring kettle at about 70% of the kettle volume, the density of the white oil is 0.85 g / cm 3 , and the weight of the white oil is recorded as 99 parts, then add 1 part of ultrahigh molecular weight polyethylene powder (the viscosity average molecular weight of the ultrahigh molecular polyethylene is 1.4 x 10 6 g / mol, and the powder particle size is 70-110 μm) and 0.2 parts of antioxidant 1010, the temperature of the first stirring kettle is 180°C, the stirring speed is 250 rpm, and after the temperature in the kettle reaches 175°C, start timing, stop stirring every 10 min and observe the situation in the kettle, after 50 min, the kettle is basically transparent, and the stirring liquid is discharged to the second stirring kettle.

[0100] (2) The second stirring kettle is stirred at a low speed of 400 rpm, and the jacket is circulated with cold water, the stirring is stopped when the temperature in the kettle drops to 60°C, the situation in the kettle is observed, and after solid is precipitated, add 16 parts of ultrahigh molecular weight polyethylene powder (the viscosity average molecular weight of the ultrahigh molecular polyethylene is 1.4 x 10 6 g / mol, and the powder particle size is 70-110 μm) and 0.035 parts of basic aluminum stearate; change to 95°C hot water, set the stirring speed to 1000 rpm, after stirring for 70 min, polyethylene fiber spinning dope is obtained, the polyethylene content in the spinning dope is about 15 wt.%.

[0101] Comparative Example 3

[0102] Add white oil to the second stirring kettle at about 70% of the kettle volume, the density of the white oil is 0.85 g / cm 3 , the weight of the white oil is recorded as 99 parts, add 5 parts of ultrahigh molecular weight polyethylene powder (the viscosity average molecular weight is 1.5 x 10 6 g / mol, and the powder particle size is 80-120 μm), 47 parts of ultrahigh molecular weight polyethylene powder (the viscosity average molecular weight is 3.5 x 10 5 , and the powder particle size is 70-110 μm), 0.2 parts of antioxidant 1010, and 0.035 parts of basic aluminum stearate; change to 90°C hot water, set the stirring speed to 1000 rpm, after stirring for 100 min, polyethylene fiber spinning dope is obtained, the polyethylene content in the spinning dope is about 35 wt.%.

[0103] Comparative Example 4

[0104] Add approximately 70% of the volume of white oil (with a density of 0.85 g / cm³) to the second mixing vessel. 3 The white oil weighs 99 parts, and 1 part by weight of ultra-high molecular weight polyethylene powder (viscosity average molecular weight 5.5 × 10⁻⁶) is added. 6 g / mol, powder particle size 80-120μm), 16 parts of ultra-high molecular weight polyethylene powder (viscosity average molecular weight 1.4×10 g / mol, powder particle size 80-120μm), 5 The following ingredients were added: powder with a particle size of 70-110 μm, 0.2 parts of 1010 antioxidant, and 0.035 parts of basic aluminum stearate; hot water at 95℃ was passed through, and the stirring speed was set to 1000 rpm. After stirring for 100 minutes, polyethylene fiber spinning solution was obtained, with a polyethylene content of about 15 wt.%.

[0105] Comparative Example 5

[0106] The preparation method of the polyethylene fiber spinning solution of Comparative Example 5 includes the following steps:

[0107] (1) Add about 70% of the volume of white oil to the first stirring vessel, with a density of 0.85 g / cm³. 3 The weight of white oil was recorded as 98 parts, and then 2 parts of ultra-high molecular weight polyethylene powder (ultra-high molecular weight polyethylene has a viscosity-average molecular weight of 3.5 × 10⁻⁶) were added. 6 The mixture contains g / mol of powder with a particle size of 80-120μm and 0.2 parts of antioxidant 1010. The temperature of the first stirred tank is 180℃, and the stirring speed is 250rpm. The timer is started after the temperature inside the tank reaches 175℃. Stirring is stopped and the condition inside the tank is observed every 10 minutes. After 30 minutes, the inside of the tank becomes basically transparent, and the stirred liquid is discharged into the second stirred tank.

[0108] (2) The second mixing vessel was stirred at a low speed of 400 rpm with cold water circulating through the jacket. Stirring was stopped when the temperature inside the vessel dropped to 60℃. The condition inside the vessel was observed. Once solid precipitates, 47 parts of ultra-high molecular weight polyethylene powder (ultra-high molecular weight polyethylene with a viscosity-average molecular weight of 3.5 × 10⁻⁶) were added. 6 g / mol of basic aluminum stearate (powder particle size of 80-120μm) and 0.035 parts of basic aluminum stearate were added; hot water at 90℃ was introduced, and the stirring speed was set to 1000rpm. After stirring for 50min, polyethylene fiber spinning solution was obtained, and the polyethylene content in the spinning solution was about 35wt.%.

[0109] Comparative Example 6

[0110] The preparation method of the polyethylene fiber spinning solution of Comparative Example 6 includes the following steps:

[0111] (1) Add about 70% of the volume of white oil to the first stirring vessel, with a density of 0.85 g / cm³. 3 The weight of white oil was recorded as 98 parts, and then 2 parts of ultra-high molecular weight polyethylene powder (ultra-high molecular weight polyethylene has a viscosity-average molecular weight of 3.5 × 10⁻⁶) were added. 6 The mixture contains g / mol of powder with a particle size of 80-120μm and 0.2 parts of antioxidant 1010. The temperature of the first stirred tank is 180℃, and the stirring speed is 250rpm. The timer is started after the temperature inside the tank reaches 175℃. Stirring is stopped and the condition inside the tank is observed every 10 minutes. After 30 minutes, the inside of the tank becomes basically transparent, and the stirred liquid is discharged into the second stirred tank.

[0112] (2) The second mixing vessel is stirred at a low speed of 400 rpm, with cold water circulating through the jacket. Stirring is stopped when the temperature inside the vessel drops to 60℃. The condition inside the vessel is observed. Once solids precipitate out, 16 parts of ultra-high molecular weight polyethylene powder (ultra-high molecular weight polyethylene with a viscosity-average molecular weight of 3.5 × 10⁻⁶) are added. 6 g / mol of basic aluminum stearate (powder particle size of 80-120μm) and 0.035 parts of basic aluminum stearate were added; hot water at 90℃ was introduced, and the stirring speed was set to 1000rpm. After stirring for 50min, polyethylene fiber spinning solution was obtained, and the polyethylene content in the spinning solution was about 15wt.%.

[0113] Comparative Example 7

[0114] The preparation method of the polyethylene fiber spinning solution of Comparative Example 7 includes the following steps:

[0115] (1) Add approximately 35% of the volume of white oil to the first stirring vessel, with a density of 0.85 g / cm³. 3 The weight of white oil was recorded as 98 parts, and then 2 parts of ultra-high molecular weight polyethylene powder (ultra-high molecular weight polyethylene has a viscosity-average molecular weight of 3.5 × 10⁻⁶) were added. 6 The mixture contained g / mol of an antioxidant 1010 (powder particle size of 80-120μm) and 0.2 parts of the first stirred tank at a temperature of 180℃ and a stirring speed of 250rpm. The timer was started after the temperature inside the tank reached 175℃. Stirring was stopped and the condition inside the tank was observed every 10 minutes. After 30 minutes, the inside of the tank became basically transparent, and heating was stopped. The mixture was then poured into the third stirred tank, which was water-cooled. The cooling water was stopped when the temperature reached 100℃. Finally, the temperature inside the tank stabilized at around 90℃.

[0116] (2) Add 30 parts of ultra-high molecular weight polyethylene powder (UVHMWPE with a viscosity-average molecular weight of 1.2 × 10⁻⁶) to the second mixing vessel. 6The mixture contained g / mol of powder with a particle size of 70-110 μm, 70 parts of white oil, and 0.08 parts of basic aluminum stearate. Hot water at 90℃ was introduced, and the stirring speed was set to 1000 rpm. After stirring for 50 minutes, the slurry from the second stirring vessel (approximately 35% of the vessel volume) was also introduced into the third stirring vessel. The mixture was stirred and mixed to obtain a polyethylene fiber spinning solution (approximately 70% of the total vessel volume), with a polyethylene content of approximately 16 wt.% in the spinning solution.

[0117] Comparative Example 8

[0118] (1) Add approximately 35% of the volume of white oil to the first stirring vessel, with a density of 0.85 g / cm³. 3 The weight of white oil is recorded as 95 parts, and then 5 parts of ultra-high molecular weight polyethylene powder (ultra-high molecular weight polyethylene has a viscosity-average molecular weight of 1.5 × 10⁻⁶) are added. 6 The mixture contained g / mol of an antioxidant 1010 (powder particle size of 80-120μm) and 0.2 parts of the powder. The temperature of the first stirred tank was 180℃, and the stirring speed was 250rpm. The timer was started after the temperature inside the tank reached 175℃. The stirring was stopped and the condition inside the tank was observed every 10 minutes. After 30 minutes, the inside of the tank became basically transparent, and the heating was stopped. The stirred liquid was drained into the third stirred tank, which was water-cooled. When the temperature reached 100℃, the cooling water was stopped. Finally, the temperature inside the tank stabilized at about 90℃.

[0119] (2) Add 47 parts of ultra-high molecular weight polyethylene powder (UVHMWPE with a viscosity-average molecular weight of 1.0 × 10⁻⁶) to the second mixing vessel. 6 g / mol, powder particle size of 70-110μm), 100 parts white oil and 0.08 parts basic aluminum stearate; pass 90℃ hot water, set the stirring speed to 1000rpm, stir for 50min, then transfer the slurry from the second stirring vessel into the third stirring vessel, stir and mix to obtain polyethylene fiber spinning solution, the polyethylene content in the spinning solution is about 20wt.%.

[0120] Spinning experiment

[0121] The spinning solutions prepared in Examples 1-6 and Comparative Examples 1-8 were spun using the same process to prepare ultra-high molecular weight polyethylene fibers. The specific spinning process is as follows:

[0122] S1 twin-screw extruder extrusion

[0123] The spinning solution is fed into a twin-screw extruder to detangle the macromolecules. The twin-screw extruder has an inlet temperature of 95℃, an intermediate temperature of 260℃, and an outlet temperature of 290℃. The spinning solution stays in the extruder for 5 minutes, and the twin-screw extruder rotates at 200 rpm. After the spinning solution is detangled and extruded by the twin-screw extruder, a transparent gel is produced.

[0124] Preparation of S2 gel filaments

[0125] The gel solution is passed through a metering pump, a filter, and a spinneret (392 spinneret holes, 0.5 mm diameter, and L / D ratio of 15:1) and extruded into a 20°C coagulation water tank at a spinning speed of 2 m / min. The gel solution is then solidified to obtain gel filaments.

[0126] S3 extraction, drying and high-ratio heat stretching

[0127] The gel filaments were extracted with dichloromethane and dried in two stages at 25°C and 45°C. The dried gel filaments underwent three stages of hot stretching, specifically: the first stage stretching temperature was 110°C with a draw ratio of 2.4 times; the second stage stretching temperature was 130°C with a draw ratio of 3.9 times; and the third stage stretching temperature was 134°C with a draw ratio of 4.5 times. The gel filaments were then stretched in three stages to obtain polyethylene fibers.

[0128] Mechanical properties were tested on samples of polyethylene fibers obtained in Examples 1-6 and Comparative Examples 1-8. Ten samples were taken each time, and the results were taken as the arithmetic mean. The results are shown in Table 1.

[0129] Table 1. Test results of the mechanical properties of polyethylene fibers obtained in Examples 1-6 and Comparative Examples 1-8

[0130] Test item Strength (cN / dtex) Strength CV value (%) Modulus (cN / dtex) Example 1 17.2 2.7 750 Example 2 15.8 2.9 708 Example 3 18.6 2.7 780 Example 4 21.7 3.8 882 Example 5 24.3 2.9 1008 Example 6 26.8 3.0 1182 Comparative Example 1 10.4 2.8 684 Comparative Example 2 22.6 4.9 977 Comparative Example 3 13.2 4.7 692 Comparative Example 4 12.8 3.6 689 Comparative Example 5 Spinning failure Spinning failure Spinning failure Comparative Example 6 19.5 28.9 915 Comparative Example 7 22.1 2.9 935 Comparative Example 8 18.9 3.0 935

[0131] As shown in Table 1, the spinning solution prepared by the two-step method of the present invention, which involves first dissolving and then swelling ultra-high molecular weight polyethylene powder, produces polyethylene fibers with lower CV values ​​and better fiber stability under the same spinning concentration and spinning conditions. The fiber strength is much higher than that of fibers prepared by spinning solutions of ultra-high molecular weight polyethylene powder with the same concentration and molecular weight (Comparative Examples 1-2), and also higher than that of fibers prepared by spinning solutions of ultra-high molecular weight polyethylene powder directly mixed with ultra-high molecular weight polyethylene powder without pre-dissolving (Comparative Example 4).

[0132] Meanwhile, although Comparative Example 5 used a two-step method, it did not add ultra-high molecular weight polyethylene. The resulting 35 wt.% spinning solution, even with the screw temperature raised to 310°C, could not be extruded to produce gel filaments due to excessive pressure and screw current. In Comparative Example 6, the two-step method also did not add ultra-high molecular weight polyethylene. The resulting 15 wt.% spinning solution required the screw temperature to be raised to 310°C before gel fibers could be obtained with minimal stability.

[0133] In Comparative Example 7, after preparing ultra-high molecular weight polyethylene (UHMWPE) solution and extra-high molecular weight polyethylene (UHMWPE) swelling solution separately, and then mixing them for spinning, the utilization rate of the stirred tank was significantly reduced, and continuous operation was difficult. An additional mixing tank was needed (the UHMWPE solution was cooled before mixing with the UHMWPE swelling solution; if the UHMWPE solution was not cooled and directly mixed with the UHMWPE swelling solution, the UHMWPE swelling solution would partially dissolve in the mixture, causing the solution in the tank to clump and preventing material feeding). Switching between two mixing tanks was necessary to achieve uninterrupted operation. In Comparative Example 8, the utilization rate of the stirred tank was significantly reduced, and continuous operation was difficult. The volume of the three stirred tanks needed to be increased by more than 70%, or an additional mixing tank needed to be added, to achieve uninterrupted operation. Furthermore, when extruding the gel, the screw temperature needed to be increased to 300℃ to obtain a stable gel for subsequent spinning experiments.

Claims

1. A method for preparing a high-concentration polyethylene fiber dope solution, characterized by, The high-concentration polyethylene fiber spinning solution is prepared by mixing an ultra-high molecular weight polyethylene solution and ultra-high molecular weight polyethylene powder, and then swelling at 70-100 DEG C.

2. The method for preparing the high-concentration polyethylene fiber spinning solution as described in claim 1, characterized in that, The mass ratio of the solvent, the ultra-high molecular weight polyethylene powder and the antioxidant is 95-99:1-5:0.1-0.5; the solvent is a paraffin solvent; and the antioxidant is one or both of antioxidant 1010 and antioxidant 168.

3. The method for preparing the high-concentration polyethylene fiber spinning solution as described in claim 1, characterized in that, The mass ratio of the ultra-high molecular weight polyethylene solution, the ultra-high molecular weight polyethylene powder and the surfactant is 100:14-50:0.03-0.08; and the surfactant is basic aluminum stearate, stearic acid or Span.

4. The method for preparing the high-concentration polyethylene fiber spinning solution as described in claim 1, characterized in that, The viscosity-average molecular weight of the ultra-high molecular weight polyethylene powder is more than twice that of the ultra-high molecular weight polyethylene powder.

5. The method for preparing the high-concentration polyethylene fiber spinning solution as described in claim 4, characterized in that, The viscosity-average molecular weight of the ultra-high molecular weight polyethylene powder is 150-800 million, and the viscosity-average molecular weight of the ultra-high molecular weight polyethylene powder is 30-140 million.

6. The method for preparing the high-concentration polyethylene fiber spinning solution as described in claim 5, characterized in that, The viscosity-average molecular weight of the ultra-high molecular weight polyethylene powder is 200-360 million, and the viscosity-average molecular weight of the ultra-high molecular weight polyethylene powder is 60-120 million.

7. The high-concentration polyethylene fiber spinning solution prepared by the preparation method of any one of claims 1-6.

8. Use of the high-concentration polyethylene fiber spinning dope prepared according to the preparation method of any one of claims 1 to 6, characterized in that, The high-concentration polyethylene fiber spinning solution is used for preparing polyethylene fibers.

9. The use of a high-concentration polyethylene fiber spinning dope according to claim 8, characterized in that, The method comprises the following steps: S1 double-screw extruder extrusion: feeding the high-concentration polyethylene fiber spinning solution into a double-screw extruder to obtain a transparent gel solution; S2 gel yarn preparation: extruding the gel solution through a spinning nozzle into a coagulation water tank, and then shaping the yarn to obtain a gel yarn; S3 extraction, drying and high-multiple heat stretching: after the gel yarn is extracted and dried, the gel yarn is subjected to heat stretching to obtain a polyethylene fiber.

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