A system and method for forming a high-strength and high-modulus polyethylene fiber spinneret

Abstract

The present invention relates to the technical field of high-performance polymer material processing, and specifically to a system and method for forming a high-strength, high-modulus polyethylene fiber spinneret. The system comprises a melt state monitoring module, a dynamic rheological coordination module, a micro-flow field reconstruction module, a molecular chain orientation module, and an extrusion stabilization module. The system comprises: a melt state monitoring module for obtaining the real-time orientation value and pressure fluctuation value of the melt at the spinneret inlet; a dynamic rheological coordination module for generating shear rate adjustment instructions and pressure compensation instructions; a micro-flow field reconstruction module for responding to instructions and outputting a melt that meets preset shear distribution conditions; and a molecular chain orientation module for generating an axial stretching flow field in a converging flow channel. The present invention achieves a coordinated guarantee of orientation improvement and extrusion stability during the high-strength, high-modulus polyethylene fiber spinning process through a melt state-driven multi-stage flow field regulation and segment orientation control mechanism.

Description

Technical Field

[0001] The present invention relates to the technical field of high-performance polymer material processing, and in particular to a system and method for forming a high-strength and high-modulus polyethylene fiber spinneret. Background Art

[0002] Polyethylene fiber is widely used in bulletproof materials, high-performance fabrics and industrial reinforcement materials due to its low density, high breaking strength and excellent chemical corrosion resistance. Among them, the performance of high-strength and high-modulus polyethylene fiber directly depends on the orientation and crystallinity of its molecular chains, and the spinneret forming process is the key link that determines the evolution of the molecular chain structure. In actual production, the melt is often affected by various unstable factors such as shear disturbance, pressure fluctuation and turbulent interference during the process of flowing through the spinneret channel, resulting in a disordered flow field structure, thereby affecting the orderly arrangement of the molecular chains, and then causing quality problems such as uneven fiber strength and large modulus fluctuations.

[0003] Existing spinneret forming technologies mostly rely on fixed flow channel structures and static process parameters. This makes it difficult to dynamically adjust shear and pressure control strategies based on real-time changes in the melt state. Furthermore, they are unable to effectively control turbulence development and molecular chain orientation instability during the extrusion process, limiting the ability to stably output highly oriented polyethylene melts. Therefore, a spinneret forming system and method for high-strength, high-modulus polyethylene fibers is urgently needed to address the challenges of orientation control and flow stability during the forming process. Summary of the Invention

[0004] Based on the above objectives, the present invention provides a system and method for forming a high-strength and high-modulus polyethylene fiber spinneret.

[0005] A high-strength and high-modulus polyethylene fiber spinneret forming system includes a melt state monitoring module, a dynamic rheological coordination module, a micro-flow field reconstruction module, a molecular chain orientation module, and an extrusion stabilization module; wherein:

[0006] Melt state monitoring module: used to obtain the real-time orientation value and pressure fluctuation value of the melt at the spinneret inlet;

[0007] Dynamic rheological coordination module: generates shear rate adjustment instructions based on the difference between the real-time orientation value and the preset target orientation value, and generates pressure compensation instructions based on the pressure fluctuation value;

[0008] Micro-flow field reconstruction module: used to respond to shear rate adjustment instructions and pressure compensation instructions, and output the melt that meets the preset shear distribution conditions through the adjustable geometric flow channel;

[0009] Molecular chain orientation module: used to receive the melt that meets the preset shear distribution conditions, generate an axial stretching flow field in the convergent flow channel, and output the melt that meets the preset orientation conditions;

[0010] Extrusion stabilization module: used to receive the melt that meets the preset orientation conditions, and output the extrusion flow that meets the preset velocity distribution conditions to the spinneret through the turbulence suppression structure.

[0011] Optionally, the melt state monitoring module includes an orientation detection unit and a pressure fluctuation collection unit, wherein:

[0012] Orientation detection unit: This unit is located in the melt channel before the spinneret inlet. It uses the birefringence detection principle to obtain the optical anisotropy index of the melt, and calculates the real-time value of the orientation based on this. The value is then output to the dynamic rheological coordination module at fixed time intervals.

[0013] Pressure fluctuation acquisition unit: A piezoelectric sensor is installed at the inlet of the spinneret, which is used to sample the inlet pressure data and calculate the pressure change range within the sliding time window to form a pressure fluctuation value.

[0014] Optionally, the orientation detection unit includes:

[0015] Light source emission subunit: used to emit a linearly polarized laser beam. The laser beam penetrates the melt channel perpendicular to the main flow direction of the melt, causing the orientation state of the chain segments in the melt to cause a change in polarization state.

[0016] Polarization signal receiving subunit: It is set on the laser beam output side and is used to measure the intensity change of the laser after passing through polarizers in different directions and calculate the difference in birefringence intensity. ;

[0017] Orientation calculation subunit: based on birefringence intensity difference , calculate the real-time value of the orientation degree of the melt , the formula is: ,in, is the laser wavelength, is the optical path thickness, is the circumference constant of pi.

[0018] Optionally, the dynamic rheological coordination module includes an orientation difference analysis unit and a shear rate control unit; wherein:

[0019] Orientation difference analysis unit: used to receive the real-time orientation value provided by the melt state monitoring module and with the preset target orientation Perform difference calculation to generate orientation deviation value and transmit it to the shear rate control unit;

[0020] Shear rate control unit: based on orientation deviation value , calculate the target shear rate adjustment , and generates the shear rate adjustment instruction through proportional control, the expression of which is: ,in, is the shear sensitivity coefficient.

[0021] Optionally, the dynamic rheological coordination module further includes a pressure fluctuation analysis unit and a pressure compensation calculation unit; wherein:

[0022] Pressure fluctuation analysis unit: receives the pressure fluctuation value, recorded as and with the set pressure fluctuation threshold Perform comparison to determine whether to trigger pressure compensation;

[0023] Pressure compensation calculation unit: When Calculate the target pressure compensation amount when , and then generate the pressure compensation instruction, the formula is: ,in; is the pressure adjustment factor.

[0024] Optionally, the microfluidic field reconstruction module includes a shear adjustment unit, a pressure compensation unit and an adjustable geometric flow channel structure unit, wherein:

[0025] Shear adjustment unit: Based on the shear rate adjustment instruction, it controls the dynamic deformation mechanism of the middle area of ​​the inner wall of the adjustable geometric flow channel structure unit, and adjusts the local flow channel width in real time to form a velocity gradient field corresponding to the adjustment instruction;

[0026] Pressure compensation unit: Based on the pressure compensation instruction, it adjusts the opening angle of the pressure-controlled throttling part at the front end of the adjustable geometric flow channel structure unit, dynamically adjusts the local flow resistance to maintain the pressure drop balance along the process;

[0027] Adjustable geometric flow channel structure unit: composed of flexible deformable flow channel walls and partition drive components, supporting two-way control of the middle width of the flow channel and the front throttling angle.

[0028] Optionally, the molecular chain orientation module includes a convergent flow channel structure unit, a stretching rate control unit and an orientation stability evaluation unit; wherein:

[0029] Convergent flow channel structural unit: used to receive the melt that meets the preset shear distribution conditions. Its channel cross-section gradually shrinks along the axial direction to form a geometric channel with accelerated flow rate, thereby naturally inducing axial tensile deformation of the melt without external force intervention and establishing an initial tensile flow field;

[0030] Stretching rate control unit: controls the axial stretching rate of the melt in the convergent section by adjusting the taper angle and channel length of the convergent flow channel ;

[0031] Orientation stability assessment unit: used to monitor the axial stretching rate and molecular chain stress distribution characteristics at the outlet of the convergent flow channel, and compare them with the preset orientation parameters to confirm whether the output melt meets the target orientation requirements.

[0032] Optionally, the orientation stability evaluation unit includes:

[0033] Flow rate monitoring subunit: used to measure the axial stretching rate at the outlet of the convergent flow channel online and output the corresponding monitoring value in real time;

[0034] Stress tensor analysis subunit: measures the principal stress difference at each point on the flow channel outlet cross section, and calculates the local stress tensor amplitude based on the material stress-birefringence response relationship;

[0035] Orientation determination subunit: The stretching rate monitoring value and stress tensor amplitude at the outlet are compared with the preset orientation parameter range at the same time. If both meet the threshold conditions, it is determined that the current output melt meets the target orientation requirement.

[0036] Optionally, the extrusion stabilization module includes a velocity rectification unit, a turbulence suppression unit and a trickle distribution unit, wherein:

[0037] Velocity rectifier unit: It is located at the downstream inlet of the molecular chain orientation module and is used to receive the melt that meets the preset orientation conditions. It uses a built-in stepped transition channel to gradually release the axial flow velocity, thereby reducing the velocity difference at different radial positions and forming a uniform axial velocity distribution.

[0038] Turbulence suppression unit: located after the rectifying structure, it has an array of microchannel grid structures inside, which is used to weaken the disturbance vortex in the melt by increasing the local Reynolds number critical value while keeping the overall flux unchanged;

[0039] Fine flow distribution unit: The stable axial melt flow after rectification and suppression is introduced into the equalizing pressure chamber connected to the spinneret hole, and the flow of each spinneret hole is equally distributed through the cavity volume ratio and the spinneret hole arrangement structure, and finally the multi-channel extrusion fine flow that meets the preset speed distribution conditions is output.

[0040] A method for forming a high-strength and high-modulus polyethylene fiber spinneret is implemented by the above-mentioned high-strength and high-modulus polyethylene fiber spinneret forming system, comprising the following steps:

[0041] S1: Obtain the real-time orientation value and pressure fluctuation value of the polyethylene melt at the spinneret inlet;

[0042] S2: Generate a shear rate adjustment instruction based on the difference between the real-time orientation value obtained in S1 and the target orientation value, and generate a pressure compensation instruction based on the pressure fluctuation value;

[0043] S3: responding to the shear rate adjustment instruction and pressure compensation instruction generated in S2, adjusting the variable flow channel structure, and outputting the melt that meets the preset shear distribution conditions;

[0044] S4: The melt output from S3 is introduced into the convergent flow channel to form an axial stretching flow field. The stretching rate is controlled by structural parameters to achieve orientation of the molecular chains along the flow direction.

[0045] S5: monitoring the axial stretching rate and stress tensor distribution characteristics at the melt outlet after S4 treatment, and comparing them with the preset orientation parameters to determine whether the molding conditions are met;

[0046] S6: The melt that meets the orientation requirements determined by S5 is introduced into the turbulence suppression structure, and is processed by velocity rectification and fine flow distribution, and finally transported to the spinneret in the form of a fine flow with uniform velocity distribution for molding.

[0047] Beneficial effects of the present invention:

[0048] The present invention realizes real-time monitoring of the orientation and pressure fluctuations of the polyethylene melt during the flow process by constructing a spinneret forming system that includes multiple organic linkage modules such as melt state monitoring, dynamic rheological coordination, microflow field reconstruction, molecular chain orientation and extrusion stabilization, and dynamically adjusts the shear rate and pressure compensation strategy accordingly to ensure that the melt has stable flow field conditions and a preset structural evolution basis before entering the forming section.

[0049] The present invention achieves full-process regulation of the spatial orientation of the molecular chain and flow stability by precisely controlling the stretching rate in the convergent flow channel and conducting orientation assessment in combination with the stress tensor monitoring results, and stabilizing the output flow with the turbulence suppression and velocity rectification structures, thereby effectively improving the molding consistency and mechanical property control accuracy of the high-strength and high-modulus polyethylene fiber. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only for the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0051] Figure 1 Schematic diagram of a fiber spinneret forming system according to an embodiment of the present invention;

[0052] Figure 2 Schematic diagram of a fiber spinneret forming method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0053] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. It is also noted that, to provide a more detailed description, the following embodiments are best and preferred embodiments, and those skilled in the art may employ alternative methods for implementing certain known technologies. Furthermore, the accompanying drawings are intended only to provide a more detailed description of the embodiments and are not intended to limit the present invention.

[0054] It should be noted that references in the specification to "one embodiment," "an embodiment," "exemplary embodiments," "some embodiments," etc. indicate that the described embodiments may include specific features, structures, or characteristics, but not necessarily every embodiment will include such specific features, structures, or characteristics. Furthermore, when specific features, structures, or characteristics are described in conjunction with an embodiment, it is within the knowledge of persons skilled in the relevant art to implement such features, structures, or characteristics in conjunction with other embodiments (whether or not explicitly described).

[0055] In general, terms can be understood, at least in part, from their use in context. For example, depending at least in part on the context, the term "one or more" as used herein can be used to describe any feature, structure, or characteristic in the singular sense, or can be used to describe a combination of features, structures, or characteristics in the plural sense. Additionally, the term "based on" can be understood as not necessarily intended to convey an exclusive set of factors, but can instead, depending at least in part on the context, allow for the presence of other factors that are not necessarily explicitly described.

[0056] like Figure 1 As shown, a high-strength and high-modulus polyethylene fiber spinneret forming system includes a melt state monitoring module, a dynamic rheological coordination module, a micro-flow field reconstruction module, a molecular chain orientation module, and an extrusion stabilization module; wherein:

[0057] Melt state monitoring module: used to obtain the real-time orientation value and pressure fluctuation value of the melt at the spinneret inlet;

[0058] The melt state monitoring module includes an orientation detection unit and a pressure fluctuation acquisition unit, wherein:

[0059] Orientation detection unit: This unit is located in the melt channel before the spinneret inlet. It uses the birefringence detection principle to obtain the optical anisotropy index of the melt, and calculates the real-time value of the orientation based on this. The value is then output to the dynamic rheological coordination module at fixed time intervals.

[0060] Pressure fluctuation acquisition unit: A piezoelectric sensor is installed at the inlet of the spinneret, which is used to sample the inlet pressure data and calculate the pressure variation range within the sliding time window to form the pressure fluctuation value;

[0061] The specific calculation formula is as follows: , ;in, Indicates the pressure fluctuation value within the sliding time window; Indicates at a point in time The instantaneous pressure obtained by sampling at is the current sliding time window; and They represent the maximum pressure and minimum pressure within the time window respectively; this formula embodies the concept of the maximum pressure change amplitude in a short period of time. The system will roll the window at a certain time interval and repeat the above calculation to form pressure fluctuation data in the form of time series.

[0062] The orientation detection unit includes:

[0063] Light source emission subunit: used to emit a linearly polarized laser beam. The laser beam penetrates the melt channel perpendicular to the main flow direction of the melt, causing the orientation state of the chain segments in the melt to cause a change in polarization state.

[0064] Polarization signal receiving subunit: It is set on the laser beam output side and is used to measure the intensity change of the laser after passing through polarizers in different directions and calculate the difference in birefringence intensity. , the calculation formula is:

[0065] ,in, is the outgoing light intensity parallel to the initial polarization direction, is the vertical outgoing light intensity, is the system calibration coefficient;

[0066] Orientation calculation subunit: based on birefringence intensity difference , calculate the real-time value of the orientation degree of the melt , the formula is: ,in, is the laser wavelength, is the optical path thickness, is the pi constant, which takes a value of approximately 3.1416; the above-mentioned subunit responds to the dual-path interference of polarized laser. This structure can not only accurately quantify the optical anisotropy characteristics inside the polymer melt, but also convert it into segment orientation data in real time, ensuring that the system has a quantitative and closed-loop control measurement basis before the melt enters shear regulation, thereby improving the stability and controllability of the melt forming process.

[0067] The calculation of the above orientation degree is based on the physical coupling relationship between the optical anisotropy of the polymer melt and the orientation of the molecular chain. When linearly polarized light passes vertically through the polyethylene melt with an oriented structure, due to the uneven arrangement of the molecular chains in a specific direction, the refractive intensity of the light in different polarization directions is different, which manifests as a birefringence phenomenon. By measuring the optical anisotropy of the light along the main orientation direction of the molecule, the optical anisotropy of the molecule is measured. Vertical direction The difference in birefringence intensity can be calculated from the difference in transmission intensity. , as an optical indicator of melt anisotropy; and according to the relationship between optical phase difference and refractive intensity, the optical path difference caused by birefringence can be It is deduced that is the laser wavelength, is the transmission path length, is the pi constant; this expression reflects the direct influence of the microscopic orientation state inside the material on the light propagation characteristics. Therefore, this calculation formula can stably and accurately convert the birefringence response into a real-time orientation value, realizing continuous monitoring and quantitative control of the orientation state of the melt molecular chain.

[0068] Dynamic rheological coordination module: generates shear rate adjustment instructions based on the difference between the real-time orientation value and the preset target orientation value, and generates pressure compensation instructions based on the pressure fluctuation value;

[0069] The dynamic rheological coordination module includes an orientation difference analysis unit and a shear rate control unit; wherein:

[0070] Orientation difference analysis unit: used to receive the real-time orientation value provided by the melt state monitoring module and with the preset target orientation Perform difference calculation to generate orientation deviation value and transmit it to the shear rate control unit;

[0071] Shear rate control unit: based on orientation deviation value , calculate the target shear rate adjustment , and generates the shear rate adjustment instruction through proportional control, the expression of which is: ,in, is the shear sensitivity coefficient, which indicates the linear response of the orientation change to the shear rate control; It indicates the degree of response of the orientation change to the required amplitude of shear rate adjustment, and the unit is usually , which reflects the shear rate adjustment corresponding to each unit orientation deviation. Within the small perturbation linear range, the stable orientation values ​​corresponding to different shear rates can be measured experimentally and linearly fitted. The expression is as follows:

[0072] ,in, is the shear rate under two different shear conditions; is the corresponding steady-state melt orientation value.

[0073] The dynamic rheological coordination module also includes a pressure fluctuation analysis unit and a pressure compensation calculation unit; wherein:

[0074] Pressure fluctuation analysis unit: receives the pressure fluctuation value, recorded as and with the set pressure fluctuation threshold Perform comparison to determine whether to trigger pressure compensation;

[0075] Pressure compensation calculation unit: When Calculate the target pressure compensation amount when , and then generate the pressure compensation instruction, the formula is: ,in; is the pressure adjustment coefficient, which controls the response intensity of the pressure fluctuation amplitude to the compensation amount; It represents the pressure compensation required when the unit pressure fluctuation exceeds the limit, and the unit is usually Pa. Assuming that the system needs to provide additional compensation to stabilize the flow state when the pressure fluctuation exceeds the limit, it can be fitted by the following expression: ,in, is the actual pressure compensation amount applied; is the monitored pressure fluctuation value; is the set pressure fluctuation threshold.

[0076] Micro-flow field reconstruction module: used to respond to shear rate adjustment instructions and pressure compensation instructions, and output the melt that meets the preset shear distribution conditions through the adjustable geometric flow channel;

[0077] The microfluidic field reconstruction module includes a shear adjustment unit, a pressure compensation unit, and an adjustable geometric flow channel structure unit, wherein:

[0078] Shear adjustment unit: Based on the shear rate adjustment instruction, it controls the dynamic deformation mechanism in the middle area of ​​the inner wall of the adjustable geometric flow channel structure unit, adjusts the local flow channel width in real time to form a velocity gradient field corresponding to the adjustment instruction, thereby realizing the shear rate reconstruction of the melt in the radial direction;

[0079] Pressure compensation unit: Based on the pressure compensation instruction, the opening angle of the pressure-controlled throttling part at the front end of the adjustable geometric flow channel structure unit is adjusted to dynamically adjust the local flow resistance to maintain the pressure drop balance along the process and achieve stable axial flow of the melt;

[0080] Adjustable geometric flow channel structure unit: composed of flexible deformable flow channel wall and partition drive components, it supports two-way control of the flow channel middle width and front end throttling angle, so that the final output melt meets the target shear rate distribution function on the cross section , and maintain steady-state velocity distribution in the axial direction; the target shear rate distribution function expression is: ,in, At the radius Target shear rate at is the maximum shear rate near the central axis; is the current radius position, the value range is ; is the flow channel radius; is the shear reduction control index, which determines the rate of shear rate decrease from the center to the boundary, and its value range is , adjusted according to the rheological properties; the function form is derived from the modified form of the power law model of non-Newtonian fluid in the laminar flow state in a circular tube, which is characterized by the shear rate increasing from the center of the tube to the boundary and reaching the maximum near the boundary; by setting a reasonable The value can achieve adjustable control from linear decline to high shear concentration at the boundary, which is suitable for the directional stress control requirements of polyethylene melt molecular segments under specific flow fields.

[0081] Molecular chain orientation module: used to receive the melt that meets the preset shear distribution conditions, generate an axial stretching flow field in the convergent flow channel, and output the melt that meets the preset orientation conditions;

[0082] The molecular chain orientation module includes a convergent channel structure unit, a stretching rate control unit, and an orientation stability evaluation unit; wherein:

[0083] Convergent flow channel structural unit: used to receive the melt that meets the preset shear distribution conditions. Its channel cross-section gradually shrinks along the axial direction to form a geometric channel with accelerated flow rate, thereby naturally inducing axial tensile deformation of the melt without external force intervention and establishing an initial tensile flow field;

[0084] Stretching rate control unit: controls the axial stretching rate of the melt in the convergent section by adjusting the taper angle and channel length of the convergent flow channel , whose expression is: ,in, Indicates axial position The cross-sectional area of ​​the flow channel at Indicates axial position The local volume flow rate at Indicates the volume flow rate along the axial direction The rate of change of , that is, the flow velocity increment per unit length, reflects the acceleration trend of the fluid;

[0085] Orientation stability assessment unit: used to monitor the axial stretching rate and molecular chain stress distribution characteristics at the outlet of the convergent flow channel, and compare them with the preset orientation parameters to confirm whether the output melt meets the target orientation requirements; the above unit calculates the axial change rate of the volume flow in the convergent flow channel. This module can accurately assess and control the local stretching rate, so that the melt molecular chains obtain directional arrangement during the flow. At the same time, combined with the outlet state assessment, it ensures that the output melt structure is highly ordered, providing a flow basis with sufficient orientation and stable tension for the formation of high-strength and high-modulus fibers.

[0086] The Orientation Stability Assessment Unit includes:

[0087] Flow rate monitoring subunit: used to measure the axial stretching rate at the outlet of the convergent flow channel online and output the corresponding monitoring value in real time;

[0088] Stress tensor analysis subunit: measures the principal stress difference at each point on the flow channel outlet cross section, and calculates the local stress tensor amplitude based on the material stress-birefringence response relationship , the expression is: ,in, is the birefringence intensity difference, is the optical path thickness, is the material stress optical coefficient;

[0089] Orientation determination subunit: The tensile rate monitoring value at the outlet is compared with the stress tensor amplitude. At the same time, it is compared with the preset orientation parameter range. If both meet the threshold conditions, it is determined that the current output melt meets the target orientation requirements; the above-mentioned subunit synchronously detects the axial stretching rate and the stress tensor amplitude based on the photoelastic response, and jointly compares it with the orientation target range. This unit can efficiently determine whether the melt molecular chain is fully oriented, effectively ensuring the orientation consistency and tensile stability during the high modulus polyethylene fiber molding process.

[0090] Extrusion stabilization module: used to receive the melt that meets the preset orientation conditions, and output the extrusion flow that meets the preset velocity distribution conditions to the spinneret through the turbulence suppression structure;

[0091] The extrusion stabilization module includes a velocity rectification unit, a turbulence suppression unit, and a trickle distribution unit, among which:

[0092] Velocity rectifier unit: It is located at the downstream inlet of the molecular chain orientation module and is used to receive the melt that meets the preset orientation conditions. It uses a built-in stepped transition channel to gradually release the axial flow velocity, thereby reducing the velocity difference at different radial positions and forming a uniform axial velocity distribution.

[0093] Turbulence suppression unit: Located after the rectifying structure, it has an array of microchannel grid structures inside. It is used to weaken the disturbance vortex appearing in the melt by increasing the local Reynolds number critical value while keeping the overall flux unchanged, delaying the critical position where the flow turns into turbulence, thereby suppressing non-axial disturbances;

[0094] Fine stream distribution unit: The stable axial melt flow after rectification and suppression is introduced into the equalizing pressure chamber connected to the spinneret, and the flow of each spinneret is equally distributed through the volume ratio of the cavity and the arrangement structure of the spinneret, and finally the multi-path extrusion fine stream that meets the preset speed distribution conditions is output; this module uses multi-stage structure collaborative control to make the highly oriented melt achieve flow velocity uniformity, minimize disturbance and balance distribution before entering the spinneret link, thereby effectively reducing the risk of flow field fluctuations during the spinning process, ensuring the melt supply stability of each spinneret, and significantly improving the consistency and mechanical properties of fiber forming.

[0095] like Figure 2 As shown, a method for forming a high-strength and high-modulus polyethylene fiber spinneret is implemented by the above-mentioned high-strength and high-modulus polyethylene fiber spinneret forming system, comprising the following steps:

[0096] S1: Obtain the real-time orientation value and pressure fluctuation value of the polyethylene melt at the spinneret inlet;

[0097] S2: Generate a shear rate adjustment instruction based on the difference between the real-time orientation value obtained in S1 and the target orientation value, and generate a pressure compensation instruction based on the pressure fluctuation value;

[0098] S3: responding to the shear rate adjustment instruction and pressure compensation instruction generated in S2, adjusting the variable flow channel structure, and outputting the melt that meets the preset shear distribution conditions;

[0099] S4: The melt output from S3 is introduced into the convergent flow channel to form an axial stretching flow field. The stretching rate is controlled by structural parameters to achieve orientation of the molecular chains along the flow direction.

[0100] S5: monitoring the axial stretching rate and stress tensor distribution characteristics at the melt outlet after S4 treatment, and comparing them with the preset orientation parameters to determine whether the molding conditions are met;

[0101] S6: The melt that meets the orientation requirements determined by S5 is introduced into the turbulence suppression structure, and is processed by velocity rectification and fine flow distribution, and finally transported to the spinneret in the form of a fine flow with uniform velocity distribution for molding.

[0102] The present invention encompasses any alternatives, modifications, equivalents, and solutions that fall within the spirit and scope of the present invention. To provide a thorough understanding of the present invention, specific details are described in detail below in connection with the preferred embodiments of the present invention, but those skilled in the art will be able to fully understand the present invention without these detailed descriptions. Furthermore, to avoid unnecessary confusion regarding the essence of the present invention, well-known methods, processes, procedures, components, and circuits have not been described in detail.

[0103] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A high-strength and high-modulus polyethylene fiber spinneret forming system, characterized in that: It includes melt state monitoring module, dynamic rheological coordination module, micro-flow field reconstruction module, molecular chain orientation module and extrusion stabilization module; among which: Melt state monitoring module: used to obtain the real-time orientation value and pressure fluctuation value of the melt at the spinneret inlet; The melt state monitoring module includes an orientation detection unit and a pressure fluctuation collection unit, wherein: Orientation detection unit: This unit is located in the melt channel before the spinneret inlet. It uses the birefringence detection principle to obtain the optical anisotropy index of the melt, and calculates the real-time value of the orientation based on this. The value is then output to the dynamic rheological coordination module at fixed time intervals. Pressure fluctuation acquisition unit: A piezoelectric sensor is installed at the inlet of the spinneret, which is used to sample the inlet pressure data and calculate the pressure variation range within the sliding time window to form the pressure fluctuation value; Dynamic rheological coordination module: generates shear rate adjustment instructions based on the difference between the real-time orientation value and the preset target orientation value, and generates pressure compensation instructions based on the pressure fluctuation value; Micro-flow field reconstruction module: used to respond to shear rate adjustment instructions and pressure compensation instructions, and output the melt that meets the preset shear distribution conditions through the adjustable geometric flow channel; Molecular chain orientation module: used to receive the melt that meets the preset shear distribution conditions, generate an axial stretching flow field in the convergent flow channel, and output the melt that meets the preset orientation conditions; Extrusion stabilization module: used to receive the melt that meets the preset orientation conditions, and output the extrusion flow that meets the preset velocity distribution conditions to the spinneret through the turbulence suppression structure; The extrusion stabilization module includes a velocity rectification unit, a turbulence suppression unit and a trickle distribution unit, wherein: Velocity rectifier unit: It is located at the downstream inlet of the molecular chain orientation module and is used to receive the melt that meets the preset orientation conditions. It uses a built-in stepped transition channel to gradually release the axial flow velocity, thereby reducing the velocity difference at different radial positions and forming a uniform axial velocity distribution. Turbulence suppression unit: located after the rectifying structure, it has an array of microchannel grid structures inside, which is used to weaken the disturbance vortex in the melt by increasing the local Reynolds number critical value while keeping the overall flux unchanged; Fine flow distribution unit: The stable axial melt flow after rectification and suppression is introduced into the equalizing pressure chamber connected to the spinneret hole, and the flow of each spinneret hole is equally distributed through the cavity volume ratio and the spinneret hole arrangement structure, and finally the multi-channel extrusion fine flow that meets the preset speed distribution conditions is output.

2. A high-strength and high-modulus polyethylene fiber spinneret forming system according to claim 1, characterized in that: The orientation detection unit includes: Light source emission subunit: used to emit a linearly polarized laser beam. The laser beam penetrates the melt channel perpendicular to the main flow direction of the melt, causing the orientation state of the chain segments in the melt to cause a change in polarization state. Polarization signal receiving subunit: It is set on the laser beam output side and is used to measure the intensity change of the laser after passing through polarizers in different directions and calculate the difference in birefringence intensity. ; Orientation calculation subunit: based on birefringence intensity difference , calculate the real-time value of the orientation degree of the melt , the formula is: ,in, is the laser wavelength, is the optical path thickness, is the circumference constant of pi.

3. The high-strength and high-modulus polyethylene fiber spinneret forming system according to claim 2, characterized in that: The dynamic rheological coordination module includes an orientation difference analysis unit and a shear rate control unit; wherein: Orientation difference analysis unit: used to receive the real-time orientation value provided by the melt state monitoring module and with the preset target orientation Perform difference calculation to generate orientation deviation value and transmit it to the shear rate control unit; Shear rate control unit: based on orientation deviation value , calculate the target shear rate adjustment , and generates the shear rate adjustment instruction through proportional control, the expression of which is: ,in, is the shear sensitivity coefficient.

4. The high-strength and high-modulus polyethylene fiber spinneret forming system according to claim 1, characterized in that: The dynamic rheological coordination module also includes a pressure fluctuation analysis unit and a pressure compensation calculation unit; wherein: Pressure fluctuation analysis unit: receives the pressure fluctuation value, recorded as and with the set pressure fluctuation threshold Perform comparison to determine whether to trigger pressure compensation; Pressure compensation calculation unit: When Calculate the target pressure compensation amount when , and then generate the pressure compensation instruction, the formula is: ,in; is the pressure adjustment factor.

5. The high-strength and high-modulus polyethylene fiber spinneret forming system according to claim 4, characterized in that: The microfluidic field reconstruction module includes a shear adjustment unit, a pressure compensation unit and an adjustable geometric flow channel structure unit, wherein: Shear adjustment unit: Based on the shear rate adjustment instruction, it controls the dynamic deformation mechanism of the middle area of ​​the inner wall of the adjustable geometric flow channel structure unit, and adjusts the local flow channel width in real time to form a velocity gradient field corresponding to the adjustment instruction; Pressure compensation unit: Based on the pressure compensation instruction, it adjusts the opening angle of the pressure-controlled throttling part at the front end of the adjustable geometric flow channel structure unit, dynamically adjusts the local flow resistance to maintain the pressure drop balance along the process; Adjustable geometric flow channel structure unit: composed of flexible deformable flow channel walls and partition drive components, supporting two-way control of the middle width of the flow channel and the front throttling angle.

6. The high-strength and high-modulus polyethylene fiber spinneret forming system according to claim 1, characterized in that: The molecular chain orientation module includes a convergent flow channel structure unit, a stretching rate control unit and an orientation stability evaluation unit; wherein: Convergent flow channel structural unit: used to receive the melt that meets the preset shear distribution conditions. Its channel cross-section gradually shrinks along the axial direction to form a geometric channel with accelerated flow rate, thereby naturally inducing axial tensile deformation of the melt without external force intervention and establishing an initial tensile flow field; Stretching rate control unit: controls the axial stretching rate of the melt in the convergent section by adjusting the taper angle and channel length of the convergent flow channel ; Orientation stability assessment unit: used to monitor the axial stretching rate and molecular chain stress distribution characteristics at the outlet of the convergent flow channel, and compare them with the preset orientation parameters to confirm whether the output melt meets the target orientation requirements.

7. The high-strength and high-modulus polyethylene fiber spinneret forming system according to claim 6, characterized in that: The orientation stability evaluation unit comprises: Flow rate monitoring subunit: used to measure the axial stretching rate at the outlet of the convergent flow channel online and output the corresponding monitoring value in real time; Stress tensor analysis subunit: measures the principal stress difference at each point on the flow channel outlet cross section, and calculates the local stress tensor amplitude based on the material stress-birefringence response relationship; Orientation determination subunit: The stretching rate monitoring value and stress tensor amplitude at the outlet are compared with the preset orientation parameter range at the same time. If both meet the threshold conditions, it is determined that the current output melt meets the target orientation requirement.

8. A method for forming a high-strength and high-modulus polyethylene fiber spinneret, which is implemented by the high-strength and high-modulus polyethylene fiber spinneret forming system according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: Obtain the real-time orientation value and pressure fluctuation value of the polyethylene melt at the spinneret inlet; S2: Generate a shear rate adjustment instruction based on the difference between the real-time orientation value obtained in S1 and the target orientation value, and generate a pressure compensation instruction based on the pressure fluctuation value; S3: responding to the shear rate adjustment instruction and pressure compensation instruction generated in S2, adjusting the variable flow channel structure, and outputting the melt that meets the preset shear distribution conditions; S4: The melt output from S3 is introduced into the convergent flow channel to form an axial stretching flow field. The stretching rate is controlled by structural parameters to achieve orientation of the molecular chains along the flow direction. S5: monitoring the axial stretching rate and stress tensor distribution characteristics at the melt outlet after S4 treatment, and comparing them with the preset orientation parameters to determine whether the molding conditions are met; S6: The melt that meets the orientation requirements determined by S5 is introduced into the turbulence suppression structure, and is processed by velocity rectification and fine flow distribution, and finally transported to the spinneret in the form of a fine flow with uniform velocity distribution for molding.

Images