160results about "Spinning solution de-aerating" patented technology

The application pertains to an artificial turf monofilament comprising a sheath comprising a virgin polyolefin polymer, a core comprising recycled polyolefin polymer obtained from recycled artificial turf. Furthermore, the application pertains to an artificial turf comprising said monofilament as well as a process for manufacturing said monofilament.

The invention discloses a synthetic leather nascent fiber melt extrusion device and a use method, and belongs to the technical field of spinning machines.The synthetic leather nascent fiber melt extrusion device comprises a shell, an injection pipe is installed at the position, close to the upper end, of the left side of the shell, a conveying pipeline is installed at the position, close to the lower end, of the right side of the shell, and a spinneret plate is installed at the right end of the conveying pipeline; and a filter cartridge is mounted in the shell. The motor can drive the filter cartridge to rotate and dynamically change the filtering area, so that the possibility of blockage of the filtering holes is effectively reduced, the uniformity of the filtering process is ensured, excessive blockage of the local filtering area is avoided, and when the filter cartridge rotates, the touch block is utilized to touch the touch switch, so that the filtering efficiency is improved. The electromagnet is instantly controlled to drive the cleaning needle to automatically clean impurities and small bubbles in the filter holes, then the small bubbles are discharged in time by using vibration force during cleaning, and the problem that the bubbles penetrate through the filter holes due to pressure deformation, and spinning is interrupted is solved.

The invention relates to the technical field of high polymer material processing, and discloses an efficient polyester fiber continuous production method based on multi-screw cooperation, which comprises the following steps: S1, raw material pretreatment and conveying: carrying out multi-stage filtration on a polyester raw material, and simultaneously directly conveying supercritical fluid to a feed port of a multi-screw extruder through a closed pipeline; s2, adding a catalyst: adding an organic metal complex catalyst before the polyester raw material enters a reaction extrusion stage; s3, carrying out multi-screw synergistic reaction; s4, data acquisition and analysis; s5, performing dynamic adjustment and feedback; s6, separating and recycling; and S7, spinning and post-processing. Through cooperation of multiple screws and the supercritical fluid and the catalyst, impurities in the raw materials can be dissolved, the activation energy of the reaction can be reduced, the purity of the raw materials can be improved, the viscosity of the materials can be reduced, the flowability is improved, uniform mixing of the raw materials and the catalyst is promoted, the reaction activity is remarkably enhanced, and a foundation is laid for subsequent efficient polymerization reaction; the quality and the production efficiency of the polyester fibers are improved.

The invention discloses a method for preparing polyester industrial filaments by recycling polyester chips from waste spinning products and the polyester industrial filaments, and belongs to the technical field of chemical fibers. The method comprises the following steps: by taking waste spinning product recycled materials as raw materials, carrying out solid-phase tackifying on the polyester chips recycled by a DMT method to obtain high-viscosity chips; extruding and melting the high-viscosity slices to obtain a spinning melt; extruding the spinning melt to obtain a melt trickle; carrying out slow cooling treatment on the melt trickles, and cooling through circular blowing or lateral blowing to obtain a strand body; the filament body is stretched and shaped, then low polymer blowing and winding are carried out, and the industrial polyester filament is obtained. According to the method, the waste spinning products are used for recycling raw materials, the production process is optimized, resources are saved, incineration is reduced, carbon emission is avoided, landfill is reduced, environmental protection is facilitated, land occupation is reduced, and human health is protected; and good performance and qualified rate of the product are ensured, so that the physical performance, broken filament performance and spinnability of the final product can meet the requirements.

The invention relates to the technical field of control systems, in particular to a high-strength polyethylene fiber melt flow control system and method. Comprising a melt conveying unit, a pressure adjusting unit, a temperature control unit, a flow monitoring unit and a central control unit, the melt conveying unit is used for conveying high-strength polyethylene fiber melt; the pressure adjusting unit is arranged in a pipeline of the melt conveying unit and used for adjusting melt conveying pressure. The temperature control unit is used for controlling the temperature in the melt conveying process; the flow monitoring unit is arranged at the tail end of the melt conveying unit and used for monitoring the melt flow in real time; the central control unit is electrically connected with the pressure adjusting unit, the temperature control unit and the flow monitoring unit, receives monitoring data of the flow monitoring unit and conducts coordinated regulation and control on the pressure and temperature of the melt through the pressure adjusting unit and the temperature control unit according to preset flow parameters. The flow of the high-strength polyethylene fiber melt is accurately controlled.

The invention discloses an extrusion device for a composite hollow three-dimensional fiber spinning machine, the extrusion device comprises a rack, the rack is provided with a feeding assembly, a transmission assembly, a filtering assembly, an extrusion assembly and a spinneret plate which are connected in sequence, the spinneret plate is densely provided with spinneret units, and each spinneret unit comprises a first through hole and a second through hole which are adjacent to each other. According to the extrusion device for the composite hollow three-dimensional fiber spinning machine, two different materials can be conveyed at the same time through the conveying assembly, and after impurities are filtered out through the filtering assembly, the two different materials are extruded out of the first through hole and the second through hole in the spinneret plate through the extrusion assembly; the two materials generate different shrinkage amounts under the air cooling effect at the same time, the bulkiness of finally formed fibers is improved, then the heat retention property is improved, and the device is compact in structure.

The invention belongs to the technical field of polyester fiber spinning, and discloses a polyester fiber spinning device and a processing method thereof.The polyester fiber spinning device comprises a shell, a metering pump fixed to the top of the shell and an air cooling heat dissipation part located at the bottom of the shell, a conveying assembly is fixedly connected to the interior of the shell in a sleeved mode, and the bottom of the conveying assembly fixedly communicates with a distribution assembly. Staggering is completed by means of left-right deflection of the upper-layer spinning assembly and the lower-layer spinning assembly, after moving and staggering are conducted through a first adaptation groove and a second adaptation groove in the spinning assemblies, the first adaptation groove is aligned and communicated with the lower hole, the second adaptation groove is aligned and communicated with the upper hole, and flushing water guided into the first adaptation groove and the second adaptation groove is utilized for flushing the upper hole and the lower hole. According to the spinneret assembly, flushing and cleaning from inside to outside are carried out towards the spray holes in the upper side and the lower side in an isolated mode along the interior of the spinneret assembly, on one hand, blocking objects in the spray holes are cut off when the deflected lower half spinneret plate rotates, on the other hand, a flushing mode from inside to outside exists, and the final flushing effect is improved.

The invention belongs to the field of high-performance materials, and discloses a high-thermal-conductivity PBO fiber and a preparation method thereof, and the preparation method comprises the following steps: (1) preparing a PBO polymer solution with a conventional molecular weight; (2) preparing an ultra-high molecular weight PBO polymer solution; (3) mixing the two PBO polymer solutions in a double-screw extruder according to a certain proportion to obtain a PBO spinning solution; (4) preparing as-spun PBO fibers by adopting a dry-wet liquid crystal spinning process and a condensed state structure regulation and control means; and (5) washing, drying, oiling and winding the as-spun PBO fiber to obtain the high-thermal-conductivity PBO fiber. According to the method, a small amount of the ultra-high molecular weight PBO polymer is added into the conventional spinning solution, the heat conduction performance of the PBO fiber is remarkably improved through the induced orientation crystallization effect of an ultra-high molecular weight PBO long chain, and the method has good application prospects in the field of high-power radio frequency microwave circuits with high requirements for heat dissipation capacity.

The present application relates to a cord comprising para-aramid fibers, a method of manufacturing the same, a reinforcing material comprising the cord, and a tire. Specifically, since the cord comprises para-aramid fibers having a large crystal size and a high degree of crystallinity and thereby exhibiting excellent mechanical properties, which has high resistance to external force deformation, can be effectively used as a tire reinforcing material.

A method for preparing an aramid nanofiber dispersion includes dissolving an aromatic polyamide-based polymer in a solution including a basic material and an aprotic polar solvent, while performing stirring so that a nanofiber is produced, wherein the aromatic polyamide-based polymer is a polymer in a form of a solid which is not spun into a fiber form, the stirring is performed at a temperature of 50° C. or lower and at a speed of 10-1000 rpm so that a time taken for the aromatic polyamide-based polymer to be dissolved and formed into an aramid nano-fiber dispersion is 80 hours or less, an aramid nanofiber in the aramid nanofiber dispersion has an average diameter of 1 to 100 nm and an average length of 0.1 to 100 μm, and the basic material includes potassium hydroxide or sodium hydroxide.

The invention discloses a preparation method of ultra-high molecular weight polyethylene fiber, fiber and spinning equipment, and the preparation method comprises the following steps: (1) mixing ultra-high molecular weight polyethylene powder with a solvent, uniformly swelling, and feeding into a twin-screw extruder for fully dissolving to obtain a spinning solution; spraying the spinning solution through a spinneret plate, drafting in an air gap, and cooling in a cooling bath to obtain gel silk; (2) carrying out shrinkage balance on the gel silk; then carrying out pre-extraction and pre-drying to obtain gel filaments with low solvent concentration, and storing the gel filaments in a filament containing barrel for later use; and (3) sequentially carrying out multi-stage extraction, drying, multi-stage drafting and winding on the jelly silk with low solvent concentration to obtain the ultra-high molecular weight polyethylene fiber. Through the steps of shrinkage balance, pre-extraction and drying treatment on the gel silk, adverse effects caused by solvent precipitation and gel silk shrinkage in the standing process of the gel silk can be reduced, the fiber fineness can be controlled to be stable and uniform, the production process is short, the occupied area of equipment is small, and the investment is low.

A melt-spun single-reactor high-viscosity PET / low-viscosity PET two-component elastic fiber and preparation method therefor. The preparation method includes steps of obtaining an ethylene terephthalate prepolymer, a step of introducing the ethylene terephthalate prepolymer into a final polymerization reactor for polymerization, wherein the final polymerization reactor has a low-viscosity melt outlet from which a low-viscosity PET melt is discharged and a high-viscosity melt outlet from which a high-viscosity PET melt are is discharged, and a step of spinning the low-viscosity PET melt and the high-viscosity PET melt through a same parallel composite spinning assembly to obtain the PET two-component elastic fiber. The method can realize simultaneous polymerization of high-viscosity and low-viscosity components in the same final polymerization reactor, and the obtained fiber has good performance.

The invention discloses a preparation method of a silver ion antibacterial non-woven fabric. The preparation method comprises the following steps: S1, blending a PP-zirconium phosphate silver-loaded antibacterial agent; s2, airflow conveying; s3, extruding and melting by a screw rod; s4, filtering; s5, melt blowing; and S6, carrying out air drafting to form a net. The proportion is customized according to the types of bacteria, the characteristics of different bacteria are deeply observed, and the proportion of the raw materials is specifically adjusted. The product can accurately act on target bacteria, and the antibacterial ability to common germs such as escherichia coli and staphylococcus aureus is greatly improved. In the preparation process, the unique mixing technology ensures that the antibacterial agent is uniformly dispersed, and the antibacterial effect is fully exerted. From the perspective of product performance, the dissolution rate of silver ions can be effectively reduced while the powerful antibacterial effect is ensured, and the potential influence on the environment is reduced. According to the precise customization mode, an efficient and safe antibacterial product solution is provided for the fields of medical treatment, sanitation and the like with extremely high bacteria prevention and control requirements.

The present application relates to polybutylene terephthalate (PBT) material toothbrush filament technical field, specifically relates to a kind of multifilament version anti-lodging PBT monofilament and preparation method thereof;The preparation method is realized with the basic concept of multifilament to realize the basic form of monofilament, in the drawing process, every three monofilaments are gathered into a multifilament, in the subsequent water cooling, oiling etc. Process path, with the mode of multifilament, drafting, winding forming are completed.In the condition that monofilament specification remains unchanged, corresponding design is carried out to production process, and the quality indexes such as breaking strength, breaking strength variation coefficient, breaking elongation, breaking elongation variation coefficient of monofilament are controlled.In the realization equipment efficiency is improved three times target, product quality is upgraded, and the anti-lodging performance of PBT monofilament is improved.

The invention discloses a chinlon 6 filament based on high carboxyl modification and a preparation method thereof, and belongs to the technical field of chinlon production. The polyamide 6 filament based on high carboxyl modification is prepared by adopting PA6 slices with low-end amino groups and high-end carboxyl groups as raw materials, the ordered combining capacity of fibers and anionic dye is enhanced by reducing the content of the end amino groups and increasing the proportion of the end carboxyl groups, the dye is prevented from being accumulated on the surface, the dyeing uniformity and the dyeing permeability of the polyamide 6 filament are improved, and the dyeing quality of the polyamide 6 filament is improved. Meanwhile, the production parameter combination is precisely regulated and controlled, so that more microporous structures are reserved to adsorb the dye while the high viscosity of the high-carboxyl section is solved in the production process, and dye molecules are more easily diffused into the fiber; the prepared chinlon 6 filament based on high carboxyl modification realizes high-saturation and high-uniformity dyeing under low dye concentration, has ideal dye-uptake and fixation rate, and also has excellent dyeing effect on light-color sensitive colors, not only reduces the washing times after the chinlon filament is dyed, but also does not fade after being washed for multiple times.

A melt blowing nozzle apparatus for producing a plurality of fiber strands from a polymer melt has at least one melt inlet and at least one process air inlet. The apparatus further has a nozzle plate having a plurality of small tubes, each having a capillary bore for extruding the fiber strands, and an extrusion plate arranged underneath the nozzle plate, which extrusion plate has a plurality of extrusion openings for blowing out the fiber strands, corresponding to the small tubes. Each extrusion opening encloses one of the small tubes with an air gap. To ensure mountability in case of a large number of small tubes, a channel system of a common distribution device is provided for connection and distribution of the melt inlet to the capillaries of the small tubes and for connection and distribution of the process air inlet to the extrusion openings of the extrusion plate.

The invention discloses a polylactic acid fiber non-woven fabric preparation method, which comprises: putting PLA particles into a vacuum dryer, drying at 60-80 DEG C for 4-6 h, and feeding the dried PLA particles into a storage hopper of a screw extruder through a screw conveyor; pLA particles are melted and plasticized through an extruder, melt is filtered through a metal sintering filter screen, a gear pump is used for conveying and metering, and the melt is conveyed to a spinning assembly; manufacturing the melt into a polylactic acid fiber net by using a spinning assembly; winding the polylactic acid fiber net by using a winding machine; the temperature of the screw extruder is controlled in a partitioned manner, the screw extruder comprises a feeding section, a compression section and a homogenization section, the temperature of the feeding section is 150-160 DEG C, the temperature of the compression section is 170-180 DEG C, and the temperature of the homogenization section is 180-190 DEG C; in the spinneret plate assembly, spinneret orifices are special-shaped orifices. The method can guarantee the mechanical property of the fiber, improve the interception efficiency of the non-woven fabric and improve the longitudinal tensile strength of the non-woven fabric. The method is more suitable for manufacturing masks, wet tissues, packaging bags, sanitary napkins and paper diapers.

The invention discloses a flame-retardant fiber prepared from a modified inorganic nano material and a production device of the flame-retardant fiber, belongs to the technical field of flame-retardant fiber production, and solves the problems that a filter element is difficult to disassemble and assemble, the filter element is inconvenient to clean and the melt filtering stability is poor in the prior art. A filter assembly is arranged in each of the two filter cavities, a switching valve is arranged on the outer wall of the melt filter, the filter states of the two filter assemblies are switched through the switching valve, each filter assembly comprises a base, and a plurality of mounting holes are formed in each base. The filter element can be mounted and dismounted by directly inserting and pulling out the inserting rod after the connecting rope is opened, so that the dismounting difficulty of the filter element is greatly reduced.

The invention relates to the technical field of manufacturing of lyocell filaments, in particular to a manufacturing method of colored lyocell filaments, and aims to solve the problem of low color fastness caused by the fact that an existing jeans wear fabric is manufactured by adopting a process of weaving and then dyeing. According to the present invention, the dyeing agent is added in the lyocell filament spinning solution preparation stage so as to prepare the stable colored spinning solution, the color fixation is completed during the spinning process, and then the colored filament is used to spin the cloth, such that the color fastness is high, the cloth with the target color can be prepared by using the less dye through the method, and the good development prospect is provided.

The invention discloses an anti-dripping flame-retardant polyester fiber with seeds and a production device thereof, belongs to the technical field of polyester fibers, and solves the problems that a spinning plate is easy to block, high in replacement frequency and high in production cost in the prior art, the anti-dripping flame-retardant polyester fiber comprises a spinning assembly, the spinning assembly comprises a shell, a sealing plate is arranged on the upper portion of the inner side of the shell, and the spinning plate is arranged on the lower portion of the inner side of the shell; a filter unit is arranged between the spinning plate and the sealing plate, the shell comprises an upper half shell and a lower half shell, a limiting ring is arranged on the lower portion of the inner side of the lower half shell, a first step groove is formed in the outer wall of the spinning plate, and the first step groove is erected on the limiting ring in a matched mode. By designing the spinning assembly which can be rapidly and conveniently detached, the detaching and cleaning efficiency of the spinning plate is improved, so that the spinning requirement of polyester fibers can still be met under the condition that the inventory of the spinning plate is reduced, and it is ensured that when a melt contains more compounds such as a melt drop resisting agent, the melt drop resisting agent can still be removed. The spinning assembly can complete spinning operation with a high standard.

The present invention relates to a polyacrylonitrile-based carbon fiber, a polyacrylonitrile solution and a preparation process thereof, which mainly solves the problem that the presence of gel particles in the polyacrylonitrile solution in the prior art causes poor mechanical properties of the carbon fiber. The present invention provides a polyacrylonitrile-based carbon fiber, wherein the micropore radial size LP is less than or equal to 2.0 nm and the micropore aspect ratio L / LP is greater than or equal to 50 and less than or equal to 100, and optionally the diameter Cv value is less than or equal to 3%. The present invention also provides a polyacrylonitrile spinning dope, wherein the total number of gel particles with a particle size greater than 0.15 µm is less than or equal to 1×105 particles / mL, and the proportion of gel particles with a particle size greater than 5 µm to the total gel particles is less than or equal to 0.3%; wherein the equilibrium swelling degree of the gel particles is 250~5000%. The present invention also provides a preparation process of a polyacrylonitrile solution and a preparation process of a polyacrylonitrile-based carbon fiber.

The invention relates to the technical field of chemical fiber production equipment, and discloses a production device of flame-retardant anti-molten-drop chinlon 6 filaments, which comprises a production platform and a console arranged on the production platform, and further comprises a feeding assembly, the feeding assembly comprises a chinlon 6 slice feeding cylinder, a first-stage mixing assembly is arranged below the chinlon 6 slice feeding cylinder, and a second-stage mixing assembly is arranged below the first-stage mixing assembly. The tail end of the first-stage mixing assembly is connected with the second-stage mixing assembly, and the melting assembly is nested on the outer side of the first-stage mixing assembly. According to the device, a two-stage mixing structure of double-screw staggered shearing and planetary gear meshing shearing is adopted, accurate quantity control feeding is achieved through the metering screw, a global uniform shearing field is constructed, a mixing path is prolonged, the technical problems of flame retardant agglomeration and uneven mixing in traditional single-stage mixing are solved, and the flame retardant mixing efficiency is improved. According to the invention, the dispersion precision of the flame retardant in the melt is ensured to reach the required dispersion precision of filament molding, the spinneret orifice blockage and the linear density deviation are avoided through filter plate filtration and multi-stage parameter regulation and control, and the flame-retardant consistency and the molding qualification rate of the chinlon 6 filament are obviously improved.

The invention discloses an efficient continuous spinning machine for polyester stretch yarn production, which comprises a spinning mechanism, the spinning mechanism comprises a conveying shell, and first electric heaters are arranged in the middles of the two sides of the conveying shell; one end of a first stirring rod arranged in the middle of the interior of the conveying shell is connected with a first bevel gear set connected with the output end of the lower end of the bidirectional motor through a first driving assembly, and the lower end of a discharging pipe arranged on the side, away from the first driving assembly, of the lower end of the conveying shell is detachably connected with a spinning nozzle. Two ends of the coupling are respectively connected with the other end of the first stirring rod and the cooling assembly. According to the efficient continuous spinning machine for polyester stretch yarn production, the liquid storage tank, the liquid conveying pipe and the liquid conveying pump are arranged and used in cooperation, a dissolving solution in the liquid storage tank is conveniently conveyed into the discharging pipe, then residual materials in the spinning nozzle are dissolved through the dissolving solution, and therefore the spinning nozzle is conveniently cleaned and dredged, blocking of the spinning nozzle is avoided, time and labor are saved in the mode, and the production efficiency is improved. The processing and production progress is improved.

The application discloses a kind of preparation device and process of recycled colored hollow polyester staple fiber for automotive interior, belong to polyester fiber preparation technical field, solve the problem that material is easy to jam, material disturbance is small, extrusion is not smooth in prior art, including storage tank, screw rod extruder, melt filter and spinning machine, the lower portion of storage tank and the hopper of screw rod extruder are funnel-shaped that gradually converges from top to bottom, and the outside of storage tank is provided with a clearing mechanism.The application can drive the plug rod by the extension and contraction of hydraulic cylinder and the expansion and contraction of air cushion when in use, effectively prevent the material from being jammed in the lower part of the storage tank or the upper part of the hopper, and the air cushion can supply air to the inside of the plug rod, thereby forming an air current at the opening of the plug rod, further improving the disturbance effect on the material.

A textile recycling method receives textile-waste-to-be-recycled, sorts the waste to isolate cellulose-containing articles from non-cellulose-containing articles, and re-sizes at least some of the cellulose-containing articles to create feedstock. The feedstock is processed in a cellulose solvent reactor, which has at least one ionic liquid. The ionic liquid dissolves intermolecular cellulose bonds of the feedstock to create a spinning dope. Cellulose fibers dissolved in the cellulose-bearing spinning dope solution are extruded in a cellulose coagulation bath reservoir to reconstitute at least some of the cellulose fibers, and the reconstituted fibers are wet-spun to form a continuous cellulose thread that is commercially indistinguishable from virgin fiber thread. Synthetic fiber material is vacuum-extracted or mechanically extracted from the cellulose-bearing solution and recycled into a continuous synthetic thread. Original color of textile-waste-to-be-recycled can be retained or removed, and new color can be added.

The invention relates to the technical field of regenerated polyester fiber production, in particular to regenerated high-elastic super-soft polyester staple fiber as well as a preparation method and application thereof. According to the method, regenerated polyester foam materials with the same viscosity are adopted as double-component raw materials, 0.1-2.0 wt% of a nucleating agent is added into a component A melt to improve the crystallinity, and 0.5-10.0 wt% of an aliphatic polyester oligomer is added into a component B melt to enhance the thermal shrinkage difference; the short fiber with the high-density spiral curly structure is prepared through parallel composite spinning, double-steam drafting and relaxation heat setting processes. The obtained fiber has excellent bulkiness, rebound resilience and soft hand feeling, is suitable for replacing traditional sponge and latex cotton, and is widely applied to the field of household filling.

The invention discloses a high-thermal-conductivity filler dispersion spinning assembly for producing ice-cold cotton-like filaments and a cooling process. The spinning assembly comprises a dispersion spinning assembly body and a three-partition side-blowing cooling assembly. The dispersion spinning assembly body is provided with a magnetic coupling non-penetrating-shaft dynamic shearing dispersion cavity, an annular ultrasonic vibration dispersion section and a gradient filtering unit. The side blowing cooling assembly comprises a low-temperature dry air area, an atomization wet air area and a rectification steady-state air area, and the air temperature, the humidity, the air speed and the atomization amount are adjusted in a linkage mode based on the spinning speed, the winding tension and the tow surface temperature. According to the scheme, the dispersion uniformity of the high-thermal-conductivity filler in the melt can be improved, the filtering pressure difference and spinneret orifice blockage are reduced, broken ends are reduced, the continuous spinning stability is improved, and meanwhile the contact instant cool feeling, the cotton-like style consistency and the washability are enhanced.

The present application relates to a cord including para-aramid fiber, a method for manufacturing the same, a reinforcing material and a tire comprising the cord. Specifically, as the cord includes a para-aramid fiber having large crystal size and high crystallinity and thus exhibiting excellent mechanical properties, it has high resistance to deformation due to external force, and thus can be usefully used as a tire reinforcing material.

The invention discloses a carbon fiber precursor dry-jet wet spinning solidification device and process, and relates to the technical field of carbon fiber precursor spinning. The device comprises a spinning solution storage tank, a temperature control system is arranged on one side of the spinning solution storage tank, and the temperature control system comprises a first temperature control system and a second temperature control system; a conveying pump is fixedly installed at the bottom of the spinning solution storage tank, and high-strength and high-modulus carbon fiber production can be achieved by accurately controlling the components and temperature of the spinning solution. Physical characteristics of fibers are more consistent under stable process conditions, defects are reduced, an automatic metering and temperature control system is adopted, production efficiency can be remarkably improved, manual intervention is reduced, higher production efficiency means that more fibers can be produced within unit time, market requirements are met, production cost of unit products is reduced, and production efficiency is improved. The production cost can be effectively reduced by optimizing process conditions, such as reducing the use amount of a solvent and treating wastes.

The application discloses a preparation method of low-grain-size polyacrylonitrile precursor. The method comprises the following steps: drying and densifying the fiber after hot water drawing and oiling through 10-25 hot rollers, wherein the hot roller pressure is 0.45-0.55 MPa, the temperature interval is 146-167 DEG C, the temperature gradient between the hot rollers is 3-5 DEG C, and then the fiber after the drying and densifying treatment is subjected to steam drawing under the steam pressure of 0.30-0.60 MPa, and the drawing ratio is 4.0-4.5 times, so as to obtain the low-grain-size polyacrylonitrile precursor. The application uses steam as the heating medium, and realizes the effective regulation of the grain size of the precursor by the low-temperature long-time drying and densifying technology and the high-multiple steam drawing technology, the regulation of the drying temperature and time of the precursor bundle, the gradual removal of the water molecules in the bundle by the outward diffusion, and the crystal rupture of the grains under the high stress by the high-multiple steam drawing.