CN-122013334-A - Stretching device and method for ultra-high molecular weight polyethylene fibers

CN122013334ACN 122013334 ACN122013334 ACN 122013334ACN-122013334-A

Abstract

The invention relates to a drawing device and a drawing method for ultra-high molecular weight polyethylene fibers, wherein the drawing device comprises a multitube constant-temperature heat transfer component, a negative pressure yarn guiding mechanism and a drawing device, wherein the multitube constant-temperature heat transfer component comprises a sealed jacket shell and a plurality of metal channel pipes with two ends open, the metal channel pipes longitudinally penetrate through the jacket shell and are arranged in parallel along the transverse direction, a heating cavity for heating the metal channel pipes is formed in the jacket shell, independent drawing channels for allowing single fibers to pass through in a non-contact mode are formed in the metal channel pipes, and the inlet ends of the negative pressure yarn guiding mechanism can be clung to the outlet ends of the metal channel pipes and are used for carrying out initial yarn end generation and broken end recovery of the fibers. Compared with the prior art, the invention thoroughly eliminates the wind trembling phenomenon through an independent extremely high-temperature uniform temperature thermal field without forced air flow interference, realizes high-multiplying power and high-uniformity stretching of the fiber, solves the problem of continuous yarn guiding in a slender limited space by matching with an instantaneous negative pressure technology, and greatly improves the production stability and the mechanical property limit of the finished fiber.

Inventors

WANG XINWEI
ZHENG HAN
SUN YONGFEI
HUANG ZHOUYU

Assignees

上海化工研究院有限公司

Dates

Publication Date: 20260512
Application Date: 20260330

Claims (10)

1. A drawing apparatus for ultra-high molecular weight polyethylene fiber, comprising: the multi-tube constant temperature heat transfer assembly comprises a sealed jacket shell and a plurality of metal channel tubes with two ends open, wherein the metal channel tubes longitudinally penetrate through the jacket shell and are arranged in parallel along the transverse direction, a heating cavity for heating the metal channel tubes is formed in the jacket shell, and independent stretching channels for allowing single fibers to pass through in a non-contact manner are formed in the metal channel tubes; and the inlet end of the negative pressure yarn guiding mechanism can be clung to the outlet end of the metal channel pipe and is used for carrying out initial yarn end generation and broken end recovery of the fiber.
2. The drawing device of ultra-high molecular weight polyethylene fiber according to claim 1, wherein the side wall of the inlet end of the metal channel tube is further provided with an air inlet hole, and the side wall is connected with an inert gas distribution main pipe through a gas injection branch connected in parallel, so as to form a micro-positive pressure inert environment in the independent drawing channel.
3. The drawing device for ultra-high molecular weight polyethylene fiber according to claim 1, wherein the jacket shell is provided with metal end plates in a sealing manner along the longitudinal direction, and two ends of the metal channel pipe respectively penetrate through the two metal end plates and are fixed with the metal end plates in a sealing manner.
4. The drawing device for ultra-high molecular weight polyethylene fiber according to claim 1, wherein the inner diameter of the independent drawing channel is 3-15 mm, the length is 2-8 m, and the inner wall of the independent drawing channel is subjected to mirror polishing.
5. The drawing device of ultra-high molecular weight polyethylene fiber according to claim 1, wherein the heating chamber is internally provided with a heating element which is wrapped on the outer wall of the metal channel pipe or is internally provided with a heating cavity for forced circulation of a heat conducting working medium.
6. The drawing device for the ultra-high molecular weight polyethylene fiber according to claim 5, wherein the temperature of the heat conducting working medium is 120-150 ℃.
7. The device for stretching ultra-high molecular weight polyethylene fiber according to claim 1, wherein the negative pressure yarn guiding mechanism comprises a negative pressure yarn guiding shell and a venturi nozzle structure arranged in the negative pressure yarn guiding shell, one end of the negative pressure yarn guiding shell is provided with an annular opposite joint communicated with the inlet end of the venturi nozzle structure, and when the annular opposite joint of the negative pressure yarn guiding shell is tightly buckled on the outlet end of the metal channel tube, partial vacuum negative pressure can be generated at the outlet end of the jointed metal channel tube by utilizing high-speed jet generated by the venturi nozzle structure so as to guide the fiber to pass through the corresponding metal channel tube.
8. A method for stretching ultra-high molecular weight polyethylene fibers, comprising the steps of: S1, constructing the stretching device according to any one of claims 1-7, and controlling the temperature of a heating chamber circulating in the multi-tube constant temperature heat transfer assembly to be stable within a preset range; S2, introducing gas for providing inert atmosphere to the inlet end of the metal channel pipe, and constructing a micro-positive pressure inert environment in the independent stretching channel; s3, the negative pressure yarn guiding mechanism is tightly attached to the outlet end of the metal channel tube, compressed air is connected to construct a negative pressure environment in the corresponding metal channel tube, meanwhile, fibers to be stretched are sent into the inlet of the target metal channel tube, the fibers to be stretched are guided to penetrate out of the outlet end by utilizing negative pressure, and the process is repeated until the head-producing operation of the fibers in all the metal channel tubes is completed; S4, uniformly bundling the penetrated fibers and introducing the fibers into a subsequent drafting device, so that the fibers are stressed and tensioned and kept not to contact with the inner wall of the metal channel tube, and performing hot stretching.
9. The method for drawing ultra-high molecular weight polyethylene fiber according to claim 8, wherein in S2, the inert atmosphere providing gas is nitrogen.
10. The method for drawing ultra-high molecular weight polyethylene fiber according to claim 8, wherein in S2, the pressure in the micro-positive pressure inert environment is 10-1000 pa, and the gas flow is 0.1-10 l/min.

Description

Stretching device and method for ultra-high molecular weight polyethylene fibers Technical Field The invention belongs to the technical field of high-performance special fiber manufacturing, and relates to a drawing device and method for ultra-high molecular weight polyethylene fibers. Background Ultra High Molecular Weight Polyethylene (UHMWPE) fibers are one of the three world high performance fibers, the ultra high breaking strength and modulus of which are mainly derived from the high linearity of their macromolecular chains, the extremely high molecular weight and the highly oriented crystalline structure formed during the ultra-drawing process. In the gel spinning process, the primary fiber extruded by a spinneret plate and formed by condensation is in a gel state, and macromolecular chains in the primary fiber are in a highly entangled disordered state, so that the orientation degree is extremely low, and the primary fiber basically does not have the mechanical characteristics of high strength and high modulus. Therefore, it is necessary to induce the macromolecular chains to be sufficiently disentangled by external force in a specific temperature range near the melting point of the polymer through the subsequent multistage super heat stretching process, and to highly orient and recrystallize in the fiber axis direction. The process has almost strict requirements on the uniformity and stability of the thermal field environment, and any tiny temperature fluctuation or physical interference can directly lead to the generation of crystallization defects in the fiber, thereby limiting the comprehensive performance of the finished fiber. In the current large-scale industrial production, the technical scheme adopted generally is a multistage horizontal tiling type convection hot box stretching process. The process passes hundreds of tows in parallel, curtain-like arrangement, continuously through a sealed hot box, typically 3 to 6 meters in length. The heating unit in the hot box generates heat energy, and then the fan drives air to circulate in the box. After the hot air is distributed through the complicated diversion air duct and the pore plate, the hot air is blown to the surface of the fiber running at high speed, and the temperature rise and the constant temperature of the fiber are realized through the convective heat exchange between the gas-solid interface. However, the consistency of the temperature field is difficult to control accurately when the traditional hot box is stretched. The hot box has large volume, and the dead angle, edge effect and turbulent boundary layer of the flow field inevitably exist in the hot box, so that the temperature gradient in the hot box is directly caused, the temperature difference is often over +/-2 ℃, the mechanical property discrete coefficient of the final fiber is greatly increased, and the high uniformity of high-strength performance is difficult to realize. And the internal wind circulation is difficult to achieve complete static pressure, and a large amount of hot air is dissipated from the two ends of the hot box, so that serious heat dissipation is caused. The problems are that the drawing of the polyethylene fiber cannot further improve the precision, the production cost is higher, the uniformity and the performance of the product cannot be further improved, the production stability is poor, the phenomena of yarn breakage and yarn floating easily occur, and the inherent physical and thermodynamic bottlenecks are increasingly highlighted under the development trend of pursuing higher breaking strength, lower linear density and higher quality stability. Disclosure of Invention The invention aims to provide a drawing device and a drawing method for ultra-high molecular weight polyethylene fibers, which thoroughly eliminate the phenomenon of wind trembling by creating an independent ultra-high temperature uniform thermal field without forced air flow interference, realize high-rate and high-uniformity drawing of the fibers under the protection of ultra-low energy consumption and inert gas, solve the problem of continuous yarn guiding in a slender limited space by matching with an instantaneous negative pressure technology, and greatly improve the production stability and the mechanical property limit of finished fibers. The aim of the invention can be achieved by the following technical scheme: in a first aspect, the present invention provides a drawing apparatus for ultra-high molecular weight polyethylene fibers, comprising: The multi-tube constant temperature heat transfer assembly comprises a sealed jacket shell and a plurality of metal channel tubes with two ends open, wherein the metal channel tubes longitudinally penetrate through the jacket shell and are arranged in parallel along the transverse direction, a heating chamber for forced circulation flow of heat conduction working media is formed in the jacket shell, and independent stretching channels