A method for preparing ultra-high molecular weight polyethylene fiber and ultra-high molecular weight polyethylene fiber

Abstract

The invention discloses a method for preparing ultra-high molecular weight polyethylene fiber and the ultra-high molecular weight polyethylene fiber, comprising: dissolving the swollen ultra-high molecular weight polyethylene spinning solution through a twin screw, quantitatively extruding with a metering pump, and then passing through a spinneret, a spinneret in an air gap section, stretching, and a coagulation bath to obtain primary jelly yarn; extracting, drying, and hot roller stretching the prepared primary jelly yarn and then collecting the yarn to obtain the ultra-high molecular weight polyethylene fiber. The invention optimizes the spinneret flow channel, and as the diameter of the guide hole gradually decreases, the flow rate of the spinning melt gradually increases, and a multi-stage extrusion process similar to stretching is formed on the ultra-high molecular weight polyethylene melt, so that the primary jelly yarn with high orientation of the ultra-high molecular weight polyethylene molecular chain is obtained, and the formation of folded lamellae is induced at the same time, and the highly oriented jelly yarn is quickly and effectively obtained by high-multiple hot stretching to obtain highly oriented and crystallized ultra-high molecular weight polyethylene fiber.

Description

Technical Field

[0001] The invention belongs to the field of high-performance fiber preparation, and specifically relates to a preparation method of ultra-high molecular weight polyethylene fiber and the ultra-high molecular weight polyethylene fiber. Background Art

[0002] Ultra-high molecular weight polyethylene (UHMWPE) fiber is one of the three major high-performance fibers in the world. Compared with other fiber varieties (including carbon fiber and aramid), ultra-high molecular weight polyethylene fiber has the advantages of light weight, high strength, high modulus, impact resistance, wear resistance, corrosion resistance, and radiation resistance. It is widely used in bulletproof, explosion-proof, industrial protection, aerospace, marine engineering, deep-sea fisheries, life and health and other fields.

[0003] Ultra-high molecular weight polyethylene fiber is prepared by ultra-high molecular weight polyethylene gel spinning and super-stretching technology. The preparation process is that ultra-high molecular weight polyethylene powder is evenly mixed with a suitable solvent and spinning aid, dissolved by a screw, quantitatively extruded by a metering pump, and collected after passing through a spinneret, an air gap section and a coagulation bath to obtain primary gel yarn; the primary gel yarn is extracted, dried, and finally subjected to multi-stage super-stretching to obtain ultra-high molecular weight polyethylene fiber.

[0004] At present, when preparing ultra-high molecular weight polyethylene fibers in the prior art, the jelly filaments are extruded through the spinneret, and then enter the coagulation bath through the air gap section for quenching, so that the disentangled state of the ultra-high molecular weight polyethylene molecular chain is maintained. The orientation and crystallization of the jelly filaments prepared by this process are mainly concentrated in the spinneret stretching induction in the air gap section between the spinneret and the coagulation bath, but the spinneret stretching multiple is limited and completed in a very short time. The orientation degree and crystallinity of the obtained jelly fiber are low. In order to obtain high-strength fibers, it is necessary to stretch through a multi-stage hot box to obtain highly oriented and crystallized ultra-high molecular weight polyethylene fibers. In this process, the orientation and crystallization of the ultra-high molecular weight polyethylene fiber molecular chain are slow. In order to obtain high-strength ultra-high molecular weight polyethylene fibers, it is necessary to reduce the speed of super-stretching to fully orient and crystallize them, resulting in a low super-stretching speed in the existing process, affecting production efficiency. Improving the orientation degree and crystallinity of the primary jelly filaments can greatly increase the speed of super-stretching, improve production efficiency, and reduce production costs.

[0005] Chinese patent CN113622037B discloses a method for preparing ultra-high molecular weight polyethylene fibers and its application, which induces the orientation and crystallization of the frozen gelatin fibers by multi-stage coagulation and multi-stage stretching of the frozen gelatin fibers extruded from the spinneret. However, after the spinning solution passes through the spinneret stretching in the air gap section and the first stage coagulation bath, its stretchability is greatly reduced. In the subsequent stages of coagulation baths, excessively high stretching multiples can destroy the structure of the frozen gelatin fibers, affecting the subsequent super-stretching, thereby affecting the performance of the ultra-high molecular weight polyethylene fibers. Summary of the invention

[0006] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0007] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0008] Therefore, the object of the present invention is to overcome the deficiencies in the prior art and provide a method for preparing ultra-high molecular weight polyethylene fibers.

[0009] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for preparing ultra-high molecular weight polyethylene fiber, comprising:

[0010] preparing a swollen ultra-high molecular weight polyethylene spinning solution;

[0011] The swollen ultra-high molecular weight polyethylene spinning solution is added to the feeding port of the twin screw through a weight-loss feeding device, dissolved by the twin screw, quantitatively extruded by a metering pump, stretched by a spinneret in a spinneret air gap section, and solidified in a coagulation bath, and then the primary jelly filaments are obtained, wherein the spinneret guide holes have a structure of 3 to 5 levels of gradually decreasing sizes, the diameter of the first-level guide hole is 5 to 20 mm, the aspect ratio is 2 to 5, the diameter of the next-level guide hole is 0.3 to 0.6 times that of the previous-level guide hole, the aspect ratio is 2 to 5, the diameter of the multi-level guide holes decreases step by step, the capillary diameter of the spinneret is 0.4 to 1.0 mm, and the aspect ratio is 6 to 12;

[0012] The obtained primary jelly fibers are extracted and dried, stretched by hot rollers, and then collected to obtain ultra-high molecular weight polyethylene fibers.

[0013] As a preferred embodiment of the preparation method of the present invention, the preparation method of the swollen ultra-high molecular weight polyethylene spinning solution comprises:

[0014] The ultra-high molecular weight polyethylene powder is mixed evenly with the spinning solvent and the antioxidant by a high-speed emulsifier, and then added into the swelling kettle, and the swelling kettle is evacuated and nitrogen is passed through 1 to 3 times to replace the air in the swelling kettle and the solution;

[0015] The swelling kettle is heated at a heating rate of 1 to 5°C / min to 100 to 120°C and kept warm for 0.5 to 5 hours to obtain a fully swollen ultra-high molecular weight polyethylene spinning solution.

[0016] As a preferred embodiment of the preparation method of the present invention, the molecular weight of the ultra-high molecular weight polyethylene powder is 1500000-10000000 g / mol, and the bulk density of the ultra-high molecular weight polyethylene powder is 0.30-0.50 g / cm 3 .

[0017] As a preferred embodiment of the preparation method of the present invention, the average particle size of the ultra-high molecular weight polyethylene powder is D≤100um and the particle size distribution is D±5um; the ultra-high molecular weight polyethylene powder accounts for 3-15wt% of the total mass of the mixed solution.

[0018] As a preferred embodiment of the preparation method of the present invention, the spinning solvent is one or more hydrocarbons, including one or more of decalin, tetralin, kerosene, liquid paraffin, and white oil.

[0019] As a preferred embodiment of the preparation method of the present invention, the antioxidant is a mixture of one or more of a phenolic antioxidant and a phosphite antioxidant, including a mixture of one or more of tris[2,4-di-tert-butylphenyl]phosphite, tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 2,6-di-tert-butyl-4-methylphenol, and distearylpentaerythritol diphosphite; the antioxidant is added in an amount of 0.1 to 1.5 wt% of the mass of the UHMWPE resin.

[0020] As a preferred embodiment of the preparation method of the present invention, in the process of preparing the primary jelly silk,

[0021] The stretching ratio of the spinneret is 5 to 20 times, the air gap distance between the spinneret and the coagulation bath is 1 to 10 cm, and the primary gel yarn collection speed is 50 to 150 m / min;

[0022] Twin screw diameter 18-150mm, aspect ratio 36-75;

[0023] Twin screw speed: 50~200RPM;

[0024] The temperature of the twin-screw feeding section is 90-180°C, the temperature of the twin-screw compression section is 160-260°C, and the temperature of the twin-screw homogenization section is 180-260°C.

[0025] As a preferred embodiment of the preparation method of the present invention, the obtained primary jelly silk is extracted and dried, and then stretched by a hot roller to obtain ultra-high molecular weight polyethylene fiber, wherein the extractant is one or more combinations of xylene, dichloromethane, carbon tetrachloride, dichloroethane, n-hexane, gasoline, and hydrocarbon cleaning agent, and the extractant temperature is 20-40°C.

[0026] As a preferred embodiment of the preparation method described in the present invention, the fiber is collected after being stretched by hot rollers, wherein 6 groups of hot roller stretching devices are used for super-multiple hot stretching, each group of hot roller stretching devices is composed of two hot rollers, and by adjusting the angle between the two hot rollers, the fiber can be wound around the two hot rollers for 10 to 30 turns, thereby increasing the heating time of the fiber super-multiple stretching process, the hot roller temperature is 100 to 148°C, the total hot roller stretching multiple is 10 to 50 times, and the collection speed is 200 to 400 m / min.

[0027] Another object of the present invention is to overcome the deficiencies in the prior art and provide an ultra-high molecular weight polyethylene fiber prepared by a method for preparing an ultra-high molecular weight polyethylene fiber, characterized in that: the ultra-high molecular weight polyethylene fiber has a breaking strength greater than 45 cN / dtex and an initial modulus greater than 1900 cN / dtex.

[0028] Beneficial effects of the present invention:

[0029] (1) The present invention uses a loss-in-weight feeding device to feed the spinning solution, and controls the feeding amount of the loss-in-weight feeding device and the extrusion amount of the metering pump so that the screw is not filled with the spinning solution. Compared with the prior art method of directly feeding the solution using a feeding kettle, the problem of the spinning solution settling in the spinning pipeline is reduced. Compared with the prior art method in which the spinning solution fills the screw, the residence time of the spinning solution in the screw is shortened, so that the residence time of the ultra-high molecular weight polyethylene in the high temperature field and high shear field of the twin screw is shortened, thereby reducing the degradation of the ultra-high molecular weight polyethylene.

[0030] (2) The present invention optimizes the spinneret flow channel and adds a multi-stage guide hole structure with gradually decreasing diameters. As the diameter of the guide holes gradually decreases, the flow rate of the spinning melt gradually increases, and a multi-stage extrusion process similar to stretching is formed for the ultra-high molecular weight polyethylene melt. After being extruded through the spinneret holes, a primary jelly filament with highly oriented ultra-high molecular weight polyethylene molecular chains is obtained, and the formation of folded lamellae is induced at the same time. The highly oriented jelly filaments can be quickly and effectively obtained by super-multiple hot stretching to obtain highly oriented and crystallized ultra-high molecular weight polyethylene fibers. The fiber collection speed is greatly improved, which can reach 200-500 m / min, greatly improving production efficiency and reducing production costs.

[0031] (3) The present invention adds a multi-stage flow guide hole structure with gradually decreasing diameters in the flow channel of the spinneret, so that the residence time of the spinning melt in the spinneret is appropriately extended, the relaxation time of the ultra-high molecular weight polyethylene macromolecular chains in the spinning melt is prolonged, the internal stress of the ultra-high molecular weight polyethylene macromolecular chains is weakened, the flow stability of the melt is improved, and the diameter and performance fluctuation of the obtained jelly fiber are greatly reduced, so that the stretchable multiples of the ultra-high molecular weight polyethylene primary jelly fiber are increased, the stretching stability is improved, and the number of broken ends per 500,000 meters is reduced to less than 5 times.

[0032] (4) The present invention uses hot rollers for super-stretching, which improves production efficiency, shortens production line length, simplifies production equipment, and reduces production energy consumption compared with hot box stretching in conventional ultra-high molecular weight polyethylene gel spinning processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0034] Figure 1 The figure is a flow chart of the preparation process of ultra-high molecular weight polyethylene fiber in an embodiment of the present invention.

[0035] Figure 2 Schematic diagram of the spinneret structure in an embodiment of the present invention.

[0036] Figure 3 Schematic diagram of the multi-stage structure of the spinneret guide holes in an embodiment of the present invention. DETAILED DESCRIPTION

[0037] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0038] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0039] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0040] The present invention provides a process for preparing ultra-high molecular weight polyethylene fiber. Figure 1 The preparation process system of ultra-high molecular weight polyethylene fiber includes a weight-loss feeding device 100, a twin-screw extruder 200, a metering pump 300, a spinning assembly 400, a coagulation bath 500, a fiber barrel 600, an extraction device 700, a drying device 800, a hot roller stretching device 900 and a winding device 1000. Specifically, the swollen ultra-high molecular weight polyethylene spinning solution is quantitatively added to the feeding port of the twin-screw extruder 200 through the weight-loss feeding device 100, and the feeding amount of the weight-loss feeding device 100 is the same as the feeding amount of the metering pump 300;

[0041] The spinning solution is dissolved by a twin-screw extruder 200 and quantitatively extruded by a metering pump 300, and then passed through a spinning assembly 400 and a coagulation bath 500 to obtain primary gel filaments;

[0042] The raw jelly fibers are extracted from the fiber barrel 600 by the extraction device 700, dried by the drying device 800, collected by the hot roller stretching device 900, and wound by the winding device 1000 to obtain ultra-high molecular weight polyethylene fibers.

[0043] Further, see Figure 2 The spinning assembly 400 includes a spinneret 401, wherein a spinneret flow guide structure 402 composed of multi-stage flow guide holes and capillaries is disposed inside the spinneret 401, and the spinneret flow guide structure 402 is multiple;

[0044] See also Figure 3 The spinneret guide structure 402 is composed of a multi-stage guide hole 402a and a capillary hole 402b. The multi-stage guide hole 402a is provided with 1 to n stages of guide hole structures with gradually decreasing diameters from top to bottom, n is an integer greater than 1, and preferably, the number of the guide holes in the present invention is 3 to 5 stages; specifically, the diameter of the first-stage guide hole is 5 to 20 mm, and the aspect ratio is 2 to 5, the diameter of the next-stage guide hole is 0.3 to 0.6 times that of the previous-stage guide hole, and the aspect ratio is 2 to 5, the diameter of the multi-stage guide hole decreases step by step, and the diameter of the spinneret capillary hole 402b is 0.4 to 1.0 mm, and the aspect ratio is 6 to 12.

[0045] Example 1

[0046] 16 kg of ultra-high molecular weight polyethylene powder with a molecular weight of 6500000 g / mol, 184 kg of white oil and 160 g of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid n-octadecyl ester were mixed uniformly by a high-speed emulsifier, and added to a swelling kettle to obtain a spinning solution with an ultra-high molecular weight polyethylene concentration of 8%; the swelling kettle was evacuated and nitrogen was passed through for 3 times to replace the air in the swelling kettle and the solution, and the swelling kettle was heated at a heating rate of 2.5° C. / min to 113° C. and kept warm for 1 hour to fully swell the ultra-high molecular weight polyethylene powder, wherein the bulk density of the ultra-high molecular weight polyethylene powder is 0.43 g / cm 3 , the average particle size is 89um and the particle size distribution is D±5um.

[0047] The swollen ultra-high molecular weight polyethylene spinning solution is quantitatively added to the twin-screw feeding port through a loss-in-weight feeding device. The feeding amount of the loss-in-weight feeding device is the same as the feeding amount of the metering pump, and the feeding amount is set to 12kg / h. The twin screw diameter is 62mm, the aspect ratio is 50, the screw speed is set to 120RPM, the temperature of the twin screw feeding section is set to 110, 130, 170℃, the temperature of the compression section is set to 180, 200, 220, 240, 250℃, and the temperature of the homogenization section is set to 250, 250, 250℃.

[0048] The spinning solution is dissolved by a twin screw and quantitatively extruded by a metering pump, and then passed through a spinneret, a spinneret for stretching, and a coagulation bath to obtain primary jelly filaments. The spinneret stretching multiple is 9 times, the air gap distance between the spinneret and the coagulation bath is 3.5 cm, the flow guide holes in the flow channel of the spinneret are a three-level structure, the first-level flow guide hole has a diameter of 5 mm and a length of 25 mm, the second-level flow guide hole has a diameter of 3 mm and a length of 15 mm, the third-level flow guide hole has a diameter of 1.8 mm and a length of 9 mm, and the spinneret capillary hole has a diameter of 1 mm and a length of 9 mm.

[0049] After extraction and drying, the raw gel fibers were stretched by 6 sets of hot rollers and then collected to obtain ultra-high molecular weight polyethylene fibers. The temperatures of the 6 sets of hot rollers were 100, 120, 130, 140, 143, and 146°C, respectively. The total stretching multiple of the hot rollers was 31.5 times, the collection speed was 221 m / min, and the number of broken ends was 4 for every 50 km of collection.

[0050] Example 2

[0051] 18 kg of ultra-high molecular weight polyethylene powder with a molecular weight of 5800000 g / mol, 182 kg of decalin, 90 g of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, and 90 g of tris[2,4-di-tert-butylphenyl]phosphite are mixed uniformly by a high-speed emulsifier, and added into a swelling kettle to obtain a spinning solution with an ultra-high molecular weight polyethylene concentration of 9%; the swelling kettle is evacuated and nitrogen is passed through twice to replace the air in the swelling kettle and the solution, and the swelling kettle is heated at a heating rate of 2°C / min to 115°C, and the temperature is kept for 1.5 hours to fully swell the ultra-high molecular weight polyethylene powder, wherein the ultra-high molecular weight polyethylene powder has a bulk density of 0.48 g / cm3, an average particle size of 84 um, and a particle size distribution of D±5 um.

[0052] The swollen ultra-high molecular weight polyethylene spinning solution is quantitatively added to the twin-screw feeding port through a loss-in-weight feeding device. The feeding amount of the loss-in-weight feeding device is the same as the feeding amount of the metering pump, and the feeding amount is set to 12kg / h. The twin screw diameter is 52mm, the aspect ratio is 60, the screw speed is set to 105RPM, the twin screw feeding section temperature is set to 110, 130, 170℃, the compression section temperature is set to 190, 210, 240, 250, 250℃, and the homogenization section temperature is set to 250, 250, 260℃.

[0053] The spinning solution is dissolved by a twin screw and quantitatively extruded by a metering pump, and then passed through a spinneret, a spinneret stretching, and a coagulation bath to obtain primary jelly filaments. The spinneret stretching multiple is 12 times, the air gap distance between the spinneret and the coagulation bath is 4.5 cm, the guide holes in the spinneret are a four-level structure, the first-level guide hole has a diameter of 15 mm and a length of 30 mm, the second-level guide hole has a diameter of 7.5 mm and a length of 15 mm, the third-level guide hole has a diameter of 3.5 mm and a length of 7 mm, the fourth-level guide hole has a diameter of 2 mm and a length of 4 mm, and the spinneret capillary has a diameter of 0.9 mm and a length of 9.9 mm.

[0054] After extraction and drying, the nascent frozen gel fibers are stretched by 6 sets of hot rollers and then collected to obtain ultra-high molecular weight polyethylene fibers. The temperatures of the 6 sets of hot rollers are 110, 120, 130, 140, 144, and 146°C, respectively. The total hot roller stretching multiple is 37.8 times. The collection speed is 265m / min, and the number of broken ends is 2 for every 50km of collection.

[0055] Example 3

[0056] 12kg of ultra-high molecular weight polyethylene powder with a molecular weight of 8600000g / mol, 188kg of tetrahydronaphthalene, 60g of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and 120g of tris[2,4-di-tert-butylphenyl]phosphite are mixed uniformly by a high-speed emulsifier, and added into a swelling kettle to obtain a spinning solution with an ultra-high molecular weight polyethylene concentration of 6%; the swelling kettle is evacuated and nitrogen is passed through twice to replace the air in the swelling kettle and the solution, and the swelling kettle is heated at a heating rate of 3°C / min to 112°C, and the temperature is kept for 2 hours to fully swell the ultra-high molecular weight polyethylene powder, wherein the ultra-high molecular weight polyethylene powder has a bulk density of 0.42g / cm3, an average particle size of 92um and a particle size distribution of D±5um.

[0057] The swollen ultra-high molecular weight polyethylene spinning solution is quantitatively added to the twin-screw feeding port through a loss-in-weight feeding device. The feeding amount of the loss-in-weight feeding device is the same as the feeding amount of the metering pump, and the feeding amount is set to 18kg / h. The twin screw diameter is 80mm, the aspect ratio is 54, the screw speed is set to 130RPM, the temperature of the twin screw feeding section is set to 130, 150, 160℃, the temperature of the compression section is set to 180, 200, 210, 230, 230℃, and the temperature of the homogenization section is set to 230, 230, 230℃.

[0058] The spinning solution is dissolved by a twin screw and quantitatively extruded by a metering pump, and then passed through a spinneret, a spinneret for stretching, and a coagulation bath to obtain primary jelly filaments. The spinneret stretching multiple is 14 times, the air gap distance between the spinneret and the coagulation bath is 5.0 cm, the guide holes in the spinneret are a four-level structure, the first-level guide hole has a diameter of 12 mm and a length of 36 mm, the second-level guide hole has a diameter of 6 mm and a length of 18 mm, the third-level guide hole has a diameter of 3 mm and a length of 9 mm, the fourth-level guide hole has a diameter of 1.5 mm and a length of 4.5 mm, and the spinneret capillary hole has a diameter of 0.8 mm and a length of 8.0 mm.

[0059] After extraction and drying, the nascent frozen gel fibers are stretched by 6 sets of hot rollers and then collected to obtain ultra-high molecular weight polyethylene fibers. The temperatures of the 6 sets of hot rollers are 110, 120, 130, 135, 140, and 145°C, respectively. The total hot roller stretching multiple is 40.7 times. The collection speed is 312 m / min, and one broken end occurs every 50 km of collection.

[0060] Example 4

[0061] 14 kg of ultra-high molecular weight polyethylene powder with a molecular weight of 4300000 g / mol, 186 kg of liquid paraffin and 70 g of distearyl pentaerythritol diphosphite are mixed evenly by a high-speed emulsifier, and added into a swelling kettle to obtain a spinning solution with an ultra-high molecular weight polyethylene concentration of 7%; the swelling kettle is evacuated and nitrogen is passed through for 3 times to replace the air in the swelling kettle and the solution, and the swelling kettle is heated at a heating rate of 2°C / min to 111°C, and the temperature is kept for 2 hours to fully swell the ultra-high molecular weight polyethylene powder, wherein the ultra-high molecular weight polyethylene powder has a bulk density of 0.45 g / cm3, an average particle size of 94 um and a particle size distribution of D±5 um.

[0062] The swollen ultra-high molecular weight polyethylene spinning solution is quantitatively added to the twin-screw feeding port through a loss-in-weight feeding device. The feeding amount of the loss-in-weight feeding device is the same as the feeding amount of the metering pump, and the feeding amount is set to 10kg / h. The twin screw diameter is 36mm, the aspect ratio is 64, the screw speed is set to 110RPM, the temperature of the twin screw feeding section is set to 110, 130, and 160°C, the temperature of the compression section is set to 180, 200, 230, 250, and 250°C, and the temperature of the homogenization section is set to 250, 250, and 255°C.

[0063] The spinning liquid gap is dissolved by a twin screw and quantitatively extruded by a metering pump, and then passed through a spinneret, a spinneret stretching, and a coagulation bath to obtain primary jelly filaments. The spinneret stretching multiple is 12 times, the air section distance between the spinneret and the coagulation bath is 2.5 cm, and the guide holes in the spinneret are a three-level structure, with a first-level guide hole diameter of 14 mm and a guide hole length of 30 mm, a second-level guide hole diameter of 6 mm and a length of 15 mm, a third-level guide hole diameter of 2.5 mm and a length of 8 mm, and a spinneret capillary hole diameter of 0.8 mm and a length of 5.6 mm.

[0064] After extraction and drying, the raw gel silk is stretched by 6 sets of hot rollers and then collected to obtain ultra-high molecular weight polyethylene fiber. The temperatures of the 6 sets of hot rollers are 110, 120, 130, 135, 140, and 145°C respectively, the total stretching multiple of the hot rollers is 32.4 times, the collection speed is 227m / min, and the number of broken ends is 4 for every 50km of collection.

[0065] Example 5

[0066] 10 kg of ultra-high molecular weight polyethylene powder with a molecular weight of 8500000 g / mol, 190 kg of white oil, 50 g of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and 50 g of distearyl pentaerythritol diphosphite are mixed uniformly by a high-speed emulsifier, and added into a swelling kettle to obtain a spinning solution with a UHMWPE concentration of 5%; the swelling kettle is evacuated and nitrogen is passed through twice to replace the air in the swelling kettle and the solution, and the swelling kettle is heated at a heating rate of 1.5°C / min to 114°C, and the temperature is kept for 1 hour to fully swell the ultra-high molecular weight polyethylene powder, wherein the ultra-high molecular weight polyethylene powder has a bulk density of 0.44 g / cm3, an average particle size of 89 um and a particle size distribution of D±5 um.

[0067] The swollen ultra-high molecular weight polyethylene spinning solution is quantitatively added to the twin-screw feeding port through a loss-in-weight feeding device. The feeding amount of the loss-in-weight feeding device is the same as the feeding amount of the metering pump, and the feeding amount is set to 10kg / h. The diameter of the twin screw is 92mm, the aspect ratio is 48, the screw speed is set to 100RPM, the temperature of the twin screw feeding section is set to 110, 150, 160℃, the temperature of the compression section is set to 180, 220, 250, 255, 255℃, and the temperature of the homogenization section is set to 255, 255, 255℃.

[0068] The spinning solution is dissolved by a twin screw and quantitatively extruded by a metering pump, and then passed through a spinneret, a spinneret for stretching, and a coagulation bath to obtain primary jelly filaments. The spinneret stretching multiple is 13 times, the air gap distance between the spinneret and the coagulation bath is 4.0 cm, the guide holes in the spinneret are a five-level structure, the first-level guide hole has a diameter of 16 mm and a length of 32 mm, the second-level guide hole has a diameter of 8 mm and a length of 20 mm, the third-level guide hole has a diameter of 4 mm and a length of 12 mm, the fourth-level guide hole has a diameter of 2 mm and a length of 6 mm, the fifth-level guide hole has a diameter of 1.0 mm and a length of 3 mm, and the spinneret capillary hole has a diameter of 0.6 mm and a length of 3.6 mm.

[0069] After extraction and drying, the nascent frozen gel fibers are stretched by 6 sets of hot rollers and then collected to obtain ultra-high molecular weight polyethylene fibers. The temperatures of the 6 sets of hot rollers are 110, 120, 130, 140, 145, and 147°C, respectively. The total hot roller stretching multiple is 36.1 times. The collection speed is 247 m / min, and 3 broken ends occur every 50 km of collection.

[0070] Example 6

[0071] 14 kg of ultra-high molecular weight polyethylene powder with a molecular weight of 5400000 g / mol, 186 kg of decalin, 70 g of tris[2,4-di-tert-butylphenyl]phosphite and 70 g of distearyl pentaerythritol diphosphite are mixed evenly by a high-speed emulsifier, and added into a swelling kettle to obtain a spinning solution with an ultra-high molecular weight polyethylene concentration of 7%; the swelling kettle is evacuated and nitrogen is passed through twice to replace the air in the swelling kettle and the solution, and the swelling kettle is heated at a heating rate of 2.5°C / min to 116°C, and the temperature is kept for 1.5 hours to fully swell the ultra-high molecular weight polyethylene powder, wherein the ultra-high molecular weight polyethylene powder has a bulk density of 0.41 g / cm3, an average particle size of 82 um and a particle size distribution of D±5 um.

[0072] The swollen ultra-high molecular weight polyethylene spinning solution is quantitatively added to the twin-screw feeding port through a loss-in-weight feeding device. The feeding amount of the loss-in-weight feeding device is the same as the feeding amount of the metering pump, and the feeding amount is set to 16kg / h. The twin screw diameter is 72mm, the aspect ratio is 54, the screw speed is set to 150RPM, the twin screw feeding section temperature is set to 110, 130, 150℃, the compression section temperature is set to 170, 190, 210, 225, 225℃, and the homogenization section temperature is set to 225, 225, 220℃.

[0073] The spinning solution is dissolved by a twin screw and quantitatively extruded by a metering pump, and then passed through a spinneret, a spinneret stretching, and a coagulation bath to obtain primary jelly filaments. The spinneret stretching multiple is 12 times, the air gap distance between the spinneret and the coagulation bath is 4.0 cm, the guide holes in the spinneret are a five-level structure, the first-level guide hole has a diameter of 18 mm and a length of 36 mm, the second-level guide hole has a diameter of 9 mm and a length of 18 mm, the third-level guide hole has a diameter of 5 mm and a length of 10 mm, the fourth-level guide hole has a diameter of 3 mm and a length of 6 mm, the fifth-level guide hole has a diameter of 1.5 mm and a length of 3 mm, and the spinneret capillary has a diameter of 0.75 mm and a length of 7.5 mm.

[0074] After extraction and drying, the nascent frozen gel fibers are stretched by 6 sets of hot rollers and then collected to obtain ultra-high molecular weight polyethylene fibers. The temperatures of the 6 sets of hot rollers are 100, 110, 120, 130, 140, and 146°C, respectively. The total hot roller stretching multiple is 35.7 times. The collection speed is 235 m / min, and the number of broken ends is 3 for every 50 km of collection.

[0075] Comparative Example 1 (kettle feeding, the guide hole in the spinneret is a primary structure, hot box stretching)

[0076] 16 kg of ultra-high molecular weight polyethylene powder with a molecular weight of 6500000 g / mol, 184 kg of white oil and 160 g of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid n-octadecyl ester were mixed uniformly by a high-speed emulsifier, and added into a swelling kettle to obtain a homogeneous spinning solution with an ultra-high molecular weight polyethylene concentration of 8%; the swelling kettle was evacuated and nitrogen was passed through for 3 times to replace the air in the swelling kettle and the solution, and the swelling kettle was heated at a heating rate of 2.5° C. / min to 113° C. and kept warm for 1 hour to fully swell the ultra-high molecular weight polyethylene powder, wherein the bulk density of the ultra-high molecular weight polyethylene powder is 0.43 g / cm 3 , the average particle size is 89um and the particle size distribution is D±5um.

[0077] The swollen ultra-high molecular weight polyethylene spinning solution is transferred to the feeding kettle through a mechanical pump, and the spinning solution is added to the twin-screw feeding port through the feeding kettle. The twin screw diameter is 62 mm, the aspect ratio is 50, the screw speed is set to 120 RPM, the twin screw feeding section temperature is set to 110, 130, 170°C, the compression section temperature is set to 180, 200, 220, 240, 250°C, and the homogenization section temperature is set to 250, 250, 250°C.

[0078] The spinning solution is dissolved by a twin screw and quantitatively extruded by a metering pump, and then passed through a spinneret, a spinneret stretching, and a coagulation bath to obtain primary jelly filaments. The spinneret stretching multiple is 9 times, the air gap distance between the spinneret and the coagulation bath is 3.5 cm, the guide hole in the spinneret is a primary structure, the guide hole diameter is 3 mm, the guide hole length is 9 mm, and the spinneret capillary pore diameter is 1.0 mm and the length is 9 mm.

[0079] After extraction and drying, the raw gel silk is stretched through three-stage hot boxes and then collected to obtain ultra-high molecular weight polyethylene fibers. The temperatures of the three groups of hot boxes are 130, 140, and 146°C respectively, the total hot box stretching multiple is 16.5 times, the collection speed is 68m / min, and the number of broken ends is 16 for every 50km of collection.

[0080] Comparative Example 2 (kettle feeding, the guide hole in the spinneret is a primary structure, and hot roller stretching)

[0081] 16 kg of ultra-high molecular weight polyethylene powder with a molecular weight of 6500000 g / mol, 184 kg of white oil and 160 g of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid n-octadecyl ester were mixed uniformly by a high-speed emulsifier, and added into a swelling kettle to obtain a homogeneous spinning solution with an ultra-high molecular weight polyethylene concentration of 8%; the swelling kettle was evacuated and nitrogen was passed through for 3 times to replace the air in the swelling kettle and the solution, and the swelling kettle was heated at a heating rate of 2.5° C. / min to 113° C. and kept warm for 1 hour to fully swell the ultra-high molecular weight polyethylene powder, wherein the bulk density of the ultra-high molecular weight polyethylene powder is 0.43 g / cm 3 , the average particle size is 89um and the particle size distribution is D±5um.

[0082] The swollen ultra-high molecular weight polyethylene spinning solution is transferred to the feeding kettle through a mechanical pump, and the spinning solution is added to the twin-screw feeding port through the feeding kettle. The twin screw diameter is 62 mm, the aspect ratio is 50, the screw speed is set to 120 RPM, the twin screw feeding section temperature is set to 110, 130, 170°C, the compression section temperature is set to 180, 200, 220, 240, 250°C, and the homogenization section temperature is set to 250, 250, 250°C.

[0083] The spinning solution is dissolved by a twin screw and quantitatively extruded by a metering pump, and then passed through a spinneret, a spinneret stretching, and a coagulation bath to obtain primary jelly filaments. The spinneret stretching multiple is 9 times, the air gap distance between the spinneret and the coagulation bath is 3.5 cm, the guide hole in the spinneret is a primary structure, the guide hole diameter is 3 mm, the guide hole length is 9 mm, and the spinneret capillary pore diameter is 1.0 mm and the length is 9 mm.

[0084] After extraction and drying, the nascent frozen gel fibers are stretched by 6 sets of hot rollers and then collected to obtain ultra-high molecular weight polyethylene fibers. The temperatures of the 6 sets of hot rollers are 110, 120, 130, 140, 145, and 147°C, respectively. The total hot roller stretching multiple is 18.9 times. The collection speed is 82 m / min, and 13 broken ends occur every 50 km of collection.

[0085] Comparative Example 3 (feeding with a loss-in-weight feeding device, the guide holes in the spinneret are of a primary structure, and the hot roller is stretched)

[0086] 12kg of ultra-high molecular weight polyethylene powder with a molecular weight of 8600000g / mol, 188kg of tetrahydronaphthalene, 60g of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and 120g of tris[2,4-di-tert-butylphenyl]phosphite are mixed uniformly by a high-speed emulsifier, and added into a swelling kettle to obtain a spinning solution with an ultra-high molecular weight polyethylene concentration of 6%; the swelling kettle is evacuated and nitrogen is passed through twice to replace the air in the swelling kettle and the solution, and the swelling kettle is heated at a heating rate of 3°C / min to 112°C, and the temperature is kept for 2 hours to fully swell the ultra-high molecular weight polyethylene powder, wherein the ultra-high molecular weight polyethylene powder has a bulk density of 0.42g / cm3, an average particle size of 92um and a particle size distribution of D±5um.

[0087] The swollen ultra-high molecular weight polyethylene spinning solution is quantitatively added to the twin-screw feeding port through a loss-in-weight feeding device. The feeding amount of the loss-in-weight feeding device is the same as the feeding amount of the metering pump, and the feeding amount is set to 18kg / h. The twin screw diameter is 80mm, the aspect ratio is 54, the screw speed is set to 130RPM, the temperature of the twin screw feeding section is set to 130, 150, 160℃, the temperature of the compression section is set to 180, 200, 210, 230, 230℃, and the temperature of the homogenization section is set to 230, 230, 230℃.

[0088] The spinning solution is dissolved by a twin screw and quantitatively extruded by a metering pump, and then passed through a spinneret, a spinneret stretching, and a coagulation bath to obtain primary gel filaments. The spinneret stretching multiple is 14 times, the air gap distance between the spinneret and the coagulation bath is 5.0 cm, the guide hole in the spinneret is a primary structure, the guide hole in the spinneret is a primary structure, the guide hole diameter is 4 mm, the guide hole length is 12 mm, the spinneret capillary diameter is 0.8 mm, and the length is 8.0 mm.

[0089] After extraction and drying, the raw gel silk is stretched by 6 sets of hot rollers and then collected to obtain ultra-high molecular weight polyethylene fiber. The temperatures of the 6 sets of hot rollers are 110, 120, 130, 135, 140 and 145°C respectively, the total stretching multiple of the hot rollers is 21.5 times, the collection speed is 93m / min, and the number of broken ends is 12 for every 50km of collection.

[0090] Comparative Example 4 (kettle feeding, three-level structure of flow guide holes in the spinneret, hot roller stretching)

[0091] 12kg of ultra-high molecular weight polyethylene powder with a molecular weight of 8600000g / mol, 188kg of tetrahydronaphthalene, 60g of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and 120g of tris[2,4-di-tert-butylphenyl]phosphite are mixed uniformly by a high-speed emulsifier, and added into a swelling kettle to obtain a spinning solution with an ultra-high molecular weight polyethylene concentration of 6%; the swelling kettle is evacuated and nitrogen is passed through twice to replace the air in the swelling kettle and the solution, and the swelling kettle is heated at a heating rate of 3°C / min to 112°C, and the temperature is kept for 2 hours to fully swell the ultra-high molecular weight polyethylene powder, wherein the ultra-high molecular weight polyethylene powder has a bulk density of 0.42g / cm3, an average particle size of 92um and a particle size distribution of D±5um.

[0092] The swollen ultra-high molecular weight polyethylene spinning solution is transferred to the feeding kettle through a mechanical pump, and the spinning solution is added to the twin-screw feeding port through the feeding kettle. The twin-screw diameter is 80 mm, the aspect ratio is 54, the screw speed is set to 130 RPM, the twin-screw feeding section temperature is set to 130, 150, 160°C, the compression section temperature is set to 180, 200, 210, 230, 230°C, and the homogenization section temperature is set to 230, 230, 230°C.

[0093] The spinning solution is dissolved by a twin screw and quantitatively extruded by a metering pump, and then passed through a spinneret, a spinneret stretching, and a coagulation bath to obtain primary jelly filaments. The spinneret stretching multiple is 14 times, the air gap distance between the spinneret and the coagulation bath is 5.0 cm, the guide holes in the spinneret are a three-level structure, the first-level guide hole has a diameter of 12 mm and a length of 30 mm, the second-level guide hole has a diameter of 5 mm and a length of 15 mm, the third-level guide hole has a diameter of 2 mm and a length of 6 mm, and the spinneret capillary hole has a diameter of 0.8 mm and a length of 8 mm.

[0094] After extraction and drying, the nascent frozen gel fibers are stretched by 6 sets of hot rollers and then collected to obtain ultra-high molecular weight polyethylene fibers. The temperatures of the 6 sets of hot rollers are 110, 120, 130, 135, 140, and 145°C, respectively. The total hot roller stretching multiple is 27.8 times. The collection speed is 176 m / min, and the number of broken ends is 6 for every 50 km of collection.

[0095] Comparative Example 5 (feeding by weightlessness feeding device, the guide holes in the spinneret are of secondary structure, and hot roller stretching)

[0096] 12kg of ultra-high molecular weight polyethylene powder with a molecular weight of 8600000g / mol, 188kg of tetrahydronaphthalene, 60g of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and 120g of tris[2,4-di-tert-butylphenyl]phosphite are mixed uniformly by a high-speed emulsifier, and added into a swelling kettle to obtain a spinning solution with an ultra-high molecular weight polyethylene concentration of 6%; the swelling kettle is evacuated and nitrogen is passed through twice to replace the air in the swelling kettle and the solution, and the swelling kettle is heated at a heating rate of 3°C / min to 112°C, and the temperature is kept for 2 hours to fully swell the ultra-high molecular weight polyethylene powder, wherein the ultra-high molecular weight polyethylene powder has a bulk density of 0.42g / cm3, an average particle size of 92um and a particle size distribution of D±5um.

[0097] The swollen ultra-high molecular weight polyethylene spinning solution is transferred to the feeding kettle through a mechanical pump, and the spinning solution is added to the twin-screw feeding port through the feeding kettle. The twin-screw diameter is 80 mm, the aspect ratio is 54, the screw speed is set to 130 RPM, the twin-screw feeding section temperature is set to 130, 150, 160°C, the compression section temperature is set to 180, 200, 210, 230, 230°C, and the homogenization section temperature is set to 230, 230, 230°C.

[0098] The spinning solution is dissolved by a twin screw and quantitatively extruded by a metering pump, and then passed through a spinneret, a spinneret stretching, and a coagulation bath to obtain primary jelly filaments. The spinneret stretching multiple is 14 times, the air gap distance between the spinneret and the coagulation bath is 4.5 cm, and the guide holes in the spinneret are a secondary structure, with a primary guide hole diameter of 3 mm and a guide hole length of 12 mm, a secondary guide hole diameter of 1.5 mm and a length of 6 mm, and a spinneret hole diameter of 0.8 mm and a length of 8 mm.

[0099] After extraction and drying, the raw gel silk is stretched by 6 sets of hot rollers and then collected to obtain ultra-high molecular weight polyethylene fiber. The temperatures of the 6 sets of hot rollers are 110, 120, 130, 135, 140, and 145°C respectively, the total stretching multiple of the hot rollers is 24.5 times, the collection speed is 137m / min, and the number of broken ends is 8 for every 50km of collection.

[0100] Comparative Example 6 (feeding with a weightlessness feeding device, six-level structure of flow guide holes in the spinneret, and hot roller stretching)

[0101] 18 kg of ultra-high molecular weight polyethylene powder with a molecular weight of 5800000 g / mol, 182 kg of decalin, 90 g of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, and 90 g of tris[2,4-di-tert-butylphenyl]phosphite are mixed uniformly by a high-speed emulsifier, and added into a swelling kettle to obtain a spinning solution with an ultra-high molecular weight polyethylene concentration of 9%; the swelling kettle is evacuated and nitrogen is passed through twice to replace the air in the swelling kettle and the solution, and the swelling kettle is heated at a heating rate of 2°C / min to 115°C, and the temperature is kept for 1.5 hours to fully swell the ultra-high molecular weight polyethylene powder, wherein the ultra-high molecular weight polyethylene powder has a bulk density of 0.48 g / cm3, an average particle size of 84 um, and a particle size distribution of D±5 um.

[0102] The swollen ultra-high molecular weight polyethylene spinning solution is quantitatively added to the twin-screw feeding port through a loss-in-weight feeding device. The feeding amount of the loss-in-weight feeding device is the same as the feeding amount of the metering pump, and the feeding amount is set to 12kg / h. The twin screw diameter is 52mm, the aspect ratio is 60, the screw speed is set to 105RPM, the twin screw feeding section temperature is set to 110, 130, 170℃, the compression section temperature is set to 190, 210, 240, 250, 250℃, and the homogenization section temperature is set to 250, 250, 260℃.

[0103] The spinning solution is dissolved by a twin screw and quantitatively extruded by a metering pump, and then stretched by a spinneret and a coagulation bath to obtain primary jelly filaments. The spinneret stretching multiple is 12 times, the air gap distance between the spinneret and the coagulation bath is 4.5 cm, the guide holes in the spinneret are a six-level structure, the first-level guide hole has a diameter of 30 mm and a length of 60 mm, the second-level guide hole has a diameter of 18 mm and a length of 36 mm, the third-level guide hole has a diameter of 9 mm and a length of 18 mm, the fourth-level guide hole has a diameter of 5 mm and a length of 10 mm, the fifth-level guide hole has a diameter of 3 mm and a length of 6 mm, the sixth-level guide hole has a diameter of 1.5 mm and a length of 3 mm, and the spinneret capillary has a diameter of 0.9 mm and a length of 9.9 mm.

[0104] After extraction and drying, the nascent frozen gel fibers are stretched by 6 sets of hot rollers and then collected to obtain ultra-high molecular weight polyethylene fibers. The temperatures of the 6 sets of hot rollers are 110, 120, 130, 140, 144, and 146°C, respectively. The total hot roller stretching multiple is 30.8 times. The collection speed is 209 m / min, and the number of broken ends is 5 for every 50 km of collection.

[0105] Comparative Example 7 (feeding with a weightlessness feeding device, the guide holes in the spinneret are of a four-level structure, the ratio of the diameter of the next-level guide holes to the diameter of the upper-level guide holes is greater than 0.6 times, and hot roller stretching)

[0106] 18 kg of ultra-high molecular weight polyethylene powder with a molecular weight of 5800000 g / mol, 182 kg of decalin, 90 g of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, and 90 g of tris[2,4-di-tert-butylphenyl]phosphite are mixed uniformly by a high-speed emulsifier, and added into a swelling kettle to obtain a spinning solution with an ultra-high molecular weight polyethylene concentration of 9%; the swelling kettle is evacuated and nitrogen is passed through twice to replace the air in the swelling kettle and the solution, and the swelling kettle is heated at a heating rate of 2°C / min to 115°C, and the temperature is kept for 1.5 hours to fully swell the ultra-high molecular weight polyethylene powder, wherein the ultra-high molecular weight polyethylene powder has a bulk density of 0.48 g / cm3, an average particle size of 84 um, and a particle size distribution of D±5 um.

[0107] The swollen ultra-high molecular weight polyethylene spinning solution is quantitatively added to the twin-screw feeding port through a loss-in-weight feeding device. The feeding amount of the loss-in-weight feeding device is the same as the feeding amount of the metering pump, and the feeding amount is set to 12kg / h. The twin screw diameter is 52mm, the aspect ratio is 60, the screw speed is set to 105RPM, the twin screw feeding section temperature is set to 110, 130, 170℃, the compression section temperature is set to 190, 210, 240, 250, 250℃, and the homogenization section temperature is set to 250, 250, 260℃.

[0108] The spinning solution is dissolved by a twin screw and quantitatively extruded by a metering pump, and then passed through a spinneret, a spinneret stretching, and a coagulation bath to obtain primary jelly filaments. The spinneret stretching multiple is 12 times, the air gap distance between the spinneret and the coagulation bath is 4.5 cm, the guide holes in the spinneret are a four-level structure, the first-level guide hole has a diameter of 3.5 mm and a length of 10.5 mm, the second-level guide hole has a diameter of 2.4 mm and a length of 7.2 mm, the third-level guide hole has a diameter of 1.6 mm and a length of 4.8 mm, the fourth-level guide hole has a diameter of 1 mm and a length of 3 mm, and the spinneret capillary has a diameter of 0.9 mm and a length of 9.9 mm.

[0109] After extraction and drying, the nascent frozen gel fibers are stretched by 6 sets of hot rollers and then collected to obtain ultra-high molecular weight polyethylene fibers. The temperatures of the 6 sets of hot rollers are 110, 120, 130, 140, 144, and 146°C, respectively. The total stretching multiple of the hot rollers is 25.4 times. The collection speed is 159 m / min, and the number of broken ends per 50 km of collection is 7.

[0110] Comparative Example 8 (feeding with a loss-in-weight feeding device, the guide holes in the spinneret are a three-level structure, the ratio of the diameter of the next-level guide hole to the diameter of the upper-level guide hole is less than 0.3, and hot roller stretching)

[0111] 18 kg of ultra-high molecular weight polyethylene powder with a molecular weight of 5800000 g / mol, 182 kg of decalin, 90 g of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, and 90 g of tris[2,4-di-tert-butylphenyl]phosphite are mixed uniformly by a high-speed emulsifier, and added into a swelling kettle to obtain a spinning solution with an ultra-high molecular weight polyethylene concentration of 9%; the swelling kettle is evacuated and nitrogen is passed through twice to replace the air in the swelling kettle and the solution, and the swelling kettle is heated at a heating rate of 2°C / min to 115°C, and the temperature is kept for 1.5 hours to fully swell the ultra-high molecular weight polyethylene powder, wherein the ultra-high molecular weight polyethylene powder has a bulk density of 0.48 g / cm3, an average particle size of 84 um, and a particle size distribution of D±5 um.

[0112] The swollen ultra-high molecular weight polyethylene spinning solution is quantitatively added to the twin-screw feeding port through a loss-in-weight feeding device. The feeding amount of the loss-in-weight feeding device is the same as the feeding amount of the metering pump, and the feeding amount is set to 12kg / h. The twin screw diameter is 52mm, the aspect ratio is 60, the screw speed is set to 105RPM, the twin screw feeding section temperature is set to 110, 130, 170℃, the compression section temperature is set to 190, 210, 240, 250, 250℃, and the homogenization section temperature is set to 250, 250, 260℃.

[0113] The spinning solution is dissolved by a twin screw and quantitatively extruded by a metering pump, and then passed through a spinneret, a spinneret stretching, and a coagulation bath to obtain primary jelly filaments. The spinneret stretching multiple is 12 times, the air gap distance between the spinneret and the coagulation bath is 4.5 cm, and the flow guide holes in the flow channel of the spinneret are a three-level structure, with a first-level flow guide hole diameter of 30 mm and a flow guide hole length of 60 mm, a second-level flow guide hole diameter of 7.5 mm and a length of 15 mm, a third-level flow guide hole diameter of 2 mm and a length of 6 mm, and a spinneret capillary hole diameter of 0.7 mm and a length of 5.6 mm.

[0114] After extraction and drying, the raw gel silk is stretched by 6 sets of hot rollers and then collected to obtain ultra-high molecular weight polyethylene fiber. The temperatures of the 6 sets of hot rollers are 110, 120, 130, 140, 144 and 146°C respectively, the total stretching multiple of the hot rollers is 23.7 times, the collection speed is 146m / min, and the number of broken ends is 6 for every 50km of collection.

[0115] The crystallinity and orientation degree of the nascent jelly yarn and ultra-high molecular weight polyethylene fiber obtained in Examples 1 to 6 and Comparative Examples 1 to 8 were tested respectively. At the same time, the mechanical properties of the ultra-high molecular weight polyethylene fiber were tested, and the super-drawing multiples in the fiber preparation process and the number of broken ends per 50 km of yarn were counted. The specific results are shown in Table 1 below.

[0116] The method for determining the orientation degree of primary jelly fibers in the present invention comprises extracting and drying the primary jelly fibers and preparing samples for testing, and using a two-dimensional wide-angle X-ray diffractometer to determine the orientation degree of the fibers.

[0117] The method for determining the crystallinity of primary jelly silk in the present invention is as follows: the primary jelly silk is extracted and dried, and then sample preparation and testing are performed. The testing method refers to JYT 0587-2020 General Rules for Polycrystalline X-ray Diffraction Methods.

[0118] The method for determining the degree of orientation of ultra-high molecular weight polyethylene fibers in the present invention is to use a two-dimensional wide-angle X-ray diffractometer to determine the degree of orientation of the fibers.

[0119] The method for determining the crystallinity of the ultra-high molecular weight polyethylene fiber in the present invention is as follows: refer to JYT 0587-2020 General Rules for Polycrystalline X-ray Diffraction Methods.

[0120] The test standards for the breaking strength and initial modulus of the ultra-high molecular weight polyethylene fiber in the present invention are as follows: refer to GB / T19975-2005 high-strength fiber filament tensile property test method.

[0121] Table 1

[0122]

[0123]

[0124] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. 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 solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the present invention.

Claims

1. A method for preparing ultra-high molecular weight polyethylene fiber, characterized in that: include, Preparation of swollen ultra-high molecular weight polyethylene spinning solution: ultra-high molecular weight polyethylene powder, spinning solvent and antioxidant are uniformly mixed by a high-speed emulsifier, and then added into a swelling kettle, and the swelling kettle is evacuated and nitrogen is passed through for 1 to 3 times to replace the air in the swelling kettle and the solution; the swelling kettle is heated at a heating rate of 1 to 5°C / min to 100 to 120°C, and the temperature is kept for 0.5 to 5 hours to obtain a fully swollen ultra-high molecular weight polyethylene spinning solution, The molecular weight of the ultra-high molecular weight polyethylene powder is 1500000-10000000 g / mol, and the bulk density of the ultra-high molecular weight polyethylene powder is 0.30-0.50 g / cm 3 ; The swollen ultra-high molecular weight polyethylene spinning solution is added to the feeding port of the twin screw through a weightlessness feeding device, dissolved by the twin screw, quantitatively extruded by a metering pump, stretched by a spinneret and an air gap section, and collected after a coagulation bath to obtain primary jelly filaments, wherein the spinneret guide hole is provided with a multi-stage guide hole structure and spinneret capillaries with 3 to 5 levels of gradually decreasing diameters from top to bottom, the diameter of the first-stage guide hole is 5 to 20 mm, and the aspect ratio is 2 to 5, the diameter of the next-stage guide hole is 0.3 to 0.6 times that of the previous-stage guide hole, and the aspect ratio is 2 to 5, the diameter of the multi-stage guide hole decreases step by step, the diameter of the spinneret capillaries is 0.4 to 1.0 mm, and the aspect ratio is 6 to 12; The obtained primary jelly fibers are extracted, dried, stretched by hot rollers, and then collected to obtain ultra-high molecular weight polyethylene fibers; Wherein, the ultra-high molecular weight polyethylene fiber has a breaking strength greater than 45 cN / dtex and an initial modulus greater than 1900 cN / dtex.

2. The preparation method according to claim 1, characterized in that: The average particle size of the ultra-high molecular weight polyethylene powder is D≤100um and the particle size distribution is D±5um; the ultra-high molecular weight polyethylene powder accounts for 3-15wt% of the total mass of the mixed solution.

3. The preparation method according to claim 2, characterized in that: The spinning solvent is one or more hydrocarbons, including one or more of decalin, tetralin, kerosene, liquid paraffin, and white oil.

4. The preparation method according to claim 3, characterized in that: The antioxidant is one or a mixture of phenolic antioxidants and phosphite antioxidants, including one or a mixture of tris[2,4-di-tert-butylphenyl]phosphite, tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 2,6-di-tert-butyl-4-methylphenol, distearyl pentaerythritol diphosphite; the amount of the antioxidant added is 0.1-1.5wt% of the mass of the ultra-high molecular weight polyethylene powder.

5. The preparation method according to claim 1, characterized in that: In the process of preparing primary jelly silk, The stretching ratio of the spinneret is 5 to 20 times, the air gap distance between the spinneret and the coagulation bath is 1 to 10 cm, and the primary gel yarn collection speed is 50 to 150 m / min; The twin screw diameter is 18-150 mm, the aspect ratio is 36-75, the twin screw speed is 50-200 RPM, the twin screw feeding section temperature is 90-180° C., the twin screw compression section temperature is 160-260° C., and the twin screw homogenization section temperature is 180-260° C.

6. The preparation method according to claim 1, characterized in that: The obtained primary jelly silk is extracted and dried, and then stretched by a hot roller and then collected to obtain ultra-high molecular weight polyethylene fiber, wherein the extractant is one or more combinations of xylene, dichloromethane, carbon tetrachloride, dichloroethane, n-hexane, gasoline, and hydrocarbon cleaning agent, and the extractant temperature is 20-40°C.

7. The preparation method according to claim 6, characterized in that: The fiber is drawn after being stretched by hot rollers, wherein 6 groups of hot roller stretching devices are used for stretching, each group of hot roller stretching devices is composed of two hot rollers, and by adjusting the angle between the two hot rollers, the fiber can be wound around the two hot rollers for 10 to 30 turns, thereby increasing the heating time of the fiber super-stretching process, the hot roller temperature is 100 to 148°C, the total hot roller stretching multiple is 10 to 50 times, and the wire drawing speed is 200 to 400 m / min.

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