WO2024087330A1 - 高压电缆绝缘材料连续挤出加工特性评价优化方法及装置 - Google Patents

高压电缆绝缘材料连续挤出加工特性评价优化方法及装置 Download PDF

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WO2024087330A1
WO2024087330A1 PCT/CN2022/136788 CN2022136788W WO2024087330A1 WO 2024087330 A1 WO2024087330 A1 WO 2024087330A1 CN 2022136788 W CN2022136788 W CN 2022136788W WO 2024087330 A1 WO2024087330 A1 WO 2024087330A1
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melt
capillary
diameter
extruded
extrusion
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English (en)
French (fr)
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侯帅
傅明利
贾磊
展云鹏
朱闻博
惠宝军
黎小林
樊灵孟
张逸凡
冯宾
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南方电网科学研究院有限责任公司
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00—Sampling; Preparing specimens for investigation
    • G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
    • G01N1/36—Embedding or analogous mounting of samples
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N11/00—Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties
    • G01N11/10—Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties by moving a body within the material
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/02—Details
    • G01N3/04—Chucks
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/24—Investigating strength properties of solid materials by application of mechanical stress by applying steady shearing forces

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  • the present application relates to the technical field of cross-linked cables, and in particular to a method and device for evaluating and optimizing continuous extrusion processing characteristics of high-voltage cable insulation materials.
  • Submarine cables are the core components of cross-sea power transmission systems. Unlike land cables, submarine cable joints are more difficult and costly to make. Therefore, in engineering, it is always hoped that the length of a single section of submarine cable products is as long as possible to reduce the total number of intermediate joints or factory joints in the submarine cable.
  • Cross-linked polyethylene is currently the most important insulating material for high-voltage submarine cables.
  • This material is mainly composed of polyethylene resin and a certain proportion of antioxidants and cross-linking agents.
  • the manufacturing process of the cable insulation layer is: under high temperature conditions that are lower than the rapid decomposition temperature of the cross-linking agent and higher than the melting temperature of polyethylene, the cross-linkable polyethylene insulation material is heated into a melt by a screw extruder, and the melt is continuously extruded onto the cable conductor through the die head, and then enters the cross-linking pipeline, and continuously cross-linked under high temperature conditions where the cross-linking agent can be rapidly decomposed.
  • the continuous and uninterrupted operation time of the extruder is an important limiting factor for the length of a single-segment cable product.
  • the key to manufacturing long-length submarine cables is to extend the continuous production time of cables as much as possible. This requires the selection of insulating materials with good long-term extrusion processing performance through experiments, and the optimization of the processing parameters of the extruder to explore the optimal long-term processing conditions.
  • the cable manufacturing industry lacks clear criteria for the selection of insulating materials; on the other hand, in the actual submarine cable production process, the extruder processing parameters and the length of continuous production time can only be determined by experience.
  • the continuous production time is set too long, the material may be pre-crosslinked during the production process, resulting in a decrease in the insulation performance of the cable. If the continuous production time is set too short, the material performance cannot be fully utilized, and the cable product cannot reach the maximum length it should have. Due to the high price of high-voltage cable insulation materials, repeated attempts in large-scale production equipment will inevitably cause a lot of material waste and cost consumption. Therefore, it also leads to high cost and long cycle for adjusting and optimizing the extruder processing parameters.
  • the present application aims to provide a method and device for evaluating and optimizing the continuous extrusion processing characteristics of high-voltage cable insulation materials.
  • the method and device can be used to evaluate and optimize cross-linkable polyethylene insulation materials suitable for long-term extrusion processing, and can also be used to optimize the process parameters during long-term extrusion processing to achieve the optimal extrusion processing process parameter setting for a given material.
  • a method and apparatus for evaluating and optimizing continuous extrusion processing characteristics of high-voltage cable insulation materials are provided.
  • the present application provides a method for evaluating and optimizing the continuous extrusion processing characteristics of high-voltage cable insulation materials, comprising:
  • Step A1 heating the material to be tested into a melt at a set temperature, and continuously extruding the melt through a capillary die, and continuously measuring and recording the inlet pressure P of the capillary, the mass growth rate w of the melt extrusion, and the diameter D' of the melt spline during the extrusion process to obtain the apparent shear viscosity ⁇ a of the melt flow;
  • Step A2 calculating the outlet expansion rate ⁇ of the melt using the spline diameter D';
  • Step A3 recording and displaying the curves ⁇ a (t) and ⁇ (t) showing the changes of the apparent shear viscosity and the outlet expansion rate of the melt with time, and taking the time corresponding to the increase of ⁇ a (t) or ⁇ (t) by a set percentage on the ⁇ a (t) or ⁇ (t) curve as the starting time of the crosslinking reaction, recorded as Tx ;
  • Step A4 selecting a reference sample, testing the reference sample according to steps A1-A3, and determining the crosslinking reaction start time T S of the reference sample according to the ⁇ a (t) and ⁇ (t) curves of the reference sample;
  • Step A5 define an index ⁇ according to TX and TS , where the index ⁇ is a digital characteristic quantity for characterizing and evaluating the continuous extrusion processing characteristics of the material under test.
  • step A1 it includes:
  • Step A1.1 using the mass growth rate w of the extruded melt, calculate the shear rate of melt flow according to the following formula (1):
  • Step A1.2 using the capillary inlet pressure data P, the shear stress ⁇ of the melt flow is obtained according to the following formula (2):
  • P 0 is the atmospheric pressure of the experimental environment, which is taken as 0.1 MPa;
  • Step A1.3 using the calculated ⁇ and The apparent shear viscosity ⁇ a of the melt flow is obtained according to the following formula (3):
  • ⁇ a is calculated with 60 seconds as a data period.
  • step A2 the outlet expansion rate ⁇ of the melt is calculated using the spline diameter D' according to the following formula (4).
  • step A3 the percentage is set to 10%.
  • a reference sample is made of low-density polyethylene resin, a cross-linking agent and an antioxidant, wherein the low-density polyethylene resin is LDPE, the cross-linking agent is diisopropylbenzene peroxide-DCP, and the antioxidant is antioxidant 1010, and the sample is prepared in a ratio of 2phrDCP and 0.3phr antioxidant 1010 to 100phrLDPE.
  • step A4 the speed of the screw extruder is adjusted during the test so that the initial shear rate of the extruded melt is within the range of 1000-1200 s -1 , and the experimental test is continuously performed at this speed to finally determine the starting time of the crosslinking reaction of the reference sample.
  • step A5 the ⁇ index is defined according to the following formula (5):
  • ⁇ >0 it means that the continuous extrusion processing characteristics of the tested material are higher than those of the reference sample, and the larger the value, the longer the continuous processing time of the material in the equipment;
  • ⁇ 0 it means that the continuous extrusion processing characteristics of the tested material are lower than those of the reference sample, and the larger the absolute value, the shorter the continuous processing time of the material in the equipment.
  • the present application provides a device for evaluating and optimizing the continuous extrusion processing characteristics of high-voltage cable insulation materials.
  • the test device includes: a single screw extruder of set specifications and a capillary extrusion die. Under set extrusion processing conditions, the melt of the material to be tested is continuously extruded from the single screw extruder through the capillary;
  • a multi-hole throttling device is arranged at the entrance of the capillary die, and the polymer melt enters the extrusion capillary through the multi-hole throttling device;
  • a melt pressure sensor is arranged at the inlet of the capillary tube to continuously measure the melt pressure at the inlet of the capillary tube;
  • an automatic weighing device For the melt after being extruded through the capillary, an automatic weighing device is used to continuously measure the mass of the extruded melt per unit time;
  • a non-contact optical diameter measuring instrument is arranged at the outlet of the extruded melt to continuously measure the diameter of the extruded melt specimen.
  • the specifications of the single-screw extruder are: screw diameter ⁇ 20mm, aspect ratio 20:1, compression ratio 1:1.18; weighing device range 100g, accuracy 1mg; diameter gauge range 5mm, accuracy 5 ⁇ m.
  • the throttling device includes two 100-mesh stainless steel filter screens and one 500-mesh stainless steel filter screen.
  • the three stainless steel filter screens form a sandwich combination structure.
  • the throttling device is installed at the entrance of the capillary mold.
  • the capillary mold with the throttling device is connected to the single-screw extruder as a whole.
  • the present application provides a method for optimizing a continuous extrusion process of a cross-linked polyethylene insulation material for a high-voltage cable, comprising:
  • Step B1 using a set cross-linkable polyethylene insulation material, and selecting a small single-screw extruder with a similar structure and the same number of heating sections according to the number of heating sections of a large extruder used in actual production;
  • Step B2 heating the cross-linkable polyethylene insulation material into a melt under set processing conditions, and continuously extruding the melt through a capillary die by a single screw extruder, and continuously measuring and recording the inlet pressure P of the capillary, the mass growth rate w of the melt extrusion and the diameter D' of the melt spline during the extrusion process to obtain the apparent shear viscosity ⁇ a of the melt flow;
  • Step B3 calculating the outlet expansion rate ⁇ of the melt using the spline diameter D';
  • Step B4 recording and displaying the curves ⁇ a (t) and ⁇ (t) showing the apparent shear viscosity and outlet expansion rate of the melt changing with time, and taking the time corresponding to the increase of ⁇ a (t) or ⁇ (t) by a set percentage on the ⁇ a (t) or ⁇ (t) curve as the starting time of the crosslinking reaction, recorded as Tx ;
  • Step B5 setting multiple groups of different process conditions, and continuously extruding the melt of the material to be tested through a capillary die under each group of process conditions, retesting the crosslinking reaction start time TX of the material, and obtaining each group of TX values related to the processing conditions;
  • Step B6 taking the shear viscosity ⁇ a corresponding to the maximum value of TX as the numerical characteristic of the melt being in the optimal flow state, and taking the process conditions corresponding to the shear viscosity as the optimal conditions for the extrusion processing of the long-length submarine cable;
  • Step B7 according to the process parameter rules obtained from the small and medium-sized extruder test in step B6, the production process parameters of the actual extruder are set, and the optimal process parameters are obtained through fine-tuning.
  • the processing conditions include: the screw speed of the screw extruder and the working temperature of each heating section.
  • step B2 it includes:
  • Step B2.1 using the mass growth rate w of the extruded melt, calculate the shear rate of the melt flow according to the following formula (1):
  • Step B2.2 using the capillary inlet pressure data P, the shear stress ⁇ of the melt flow is obtained according to the following formula (2):
  • P 0 is the atmospheric pressure of the experimental environment, which is taken as 0.1 MPa;
  • Step B2.3 using the calculated ⁇ and The apparent shear viscosity ⁇ a of the melt flow is obtained according to the following formula (3):
  • ⁇ a is calculated with 60 seconds as a data period.
  • step B3 the outlet expansion rate ⁇ of the melt is calculated using the spline diameter D' according to the following formula (4):
  • step B4 the percentage is set to 10%.
  • step B5 in each set of process conditions, the temperature of each heating section and extruder head and the screw speed are different.
  • the present application provides an optimization device for continuous extrusion processing of cross-linked polyethylene insulation materials for high-voltage cables,
  • the optimized device includes: a single screw extruder and a capillary extrusion die with set specifications,
  • the melt of the material to be tested is continuously extruded through a capillary by a single-screw extruder;
  • a multi-hole throttling device is arranged at the entrance of the capillary die, and the polymer melt enters the extrusion capillary through the multi-hole throttling device;
  • a melt pressure sensor is arranged at the inlet of the capillary tube to continuously measure the melt pressure at the inlet of the capillary tube;
  • an automatic weighing device For the melt after being extruded through the capillary, an automatic weighing device is used to continuously measure the mass of the extruded melt per unit time;
  • a non-contact optical diameter measuring instrument is arranged at the outlet of the extruded melt to continuously measure the diameter of the extruded melt specimen.
  • the single screw extruder is similar in structure to a large extruder used in actual production, and has the same number of heating sections.
  • the specifications of the single-screw extruder are: screw diameter ⁇ 20mm, aspect ratio 20:1, compression ratio 1:1.18; weighing device range 100g, accuracy 1mg; diameter gauge range 5mm, accuracy 5 ⁇ m.
  • the throttling device includes two 100-mesh stainless steel filter screens and one 500-mesh stainless steel filter screen.
  • the three stainless steel filter screens form a sandwich combination structure.
  • the throttling device is installed at the entrance of the capillary mold.
  • the capillary mold with the throttling device is connected to the single-screw extruder as a whole.
  • FIG1 is a flow chart of a method for evaluating continuous extrusion processing characteristics of insulating materials in some embodiments
  • FIG2 is a flow chart of a method for optimizing a process of continuous extrusion of insulating materials in some embodiments
  • FIG3 is a schematic diagram of a melt extrusion test device in some embodiments.
  • FIG4a is a schematic diagram of a throttling device in some embodiments.
  • FIG4b is a schematic diagram of the matching mode of the capillary mold, the throttling device, the caliper, and the pressure sensor in some embodiments;
  • FIG5 is a schematic diagram of a capillary core in some embodiments.
  • FIG. 6 is a schematic diagram of a curve showing changes of ⁇ a (t) and ⁇ (t) over time in some embodiments.
  • 1 is a 100-mesh stainless steel filter
  • 2 is a 500-mesh stainless steel filter
  • 3 is the inlet of the capillary mold
  • 4 is a pressure sensor
  • 5 is a heating jacket
  • 6 is the outlet of the capillary mold
  • 7 is a non-contact optical diameter gauge.
  • this application designs a device that continuously monitors the changes in shear viscosity and extrusion expansion rate of polyethylene cable insulation material melt during continuous extrusion, and quantitatively characterizes the continuous extrusion processing characteristics of the material through the continuous changes in shear viscosity and extrusion expansion rate with extrusion processing time.
  • two main purposes can be achieved: (i) to evaluate the continuous extrusion processing characteristics of cross-linked polyethylene insulation materials for high-voltage cables; (ii) to optimize and determine the optimal process conditions for continuous extrusion processing of long-length submarine cables.
  • Embodiment (I) is to evaluate the continuous extrusion processing characteristics of cross-linked polyethylene insulation material for high voltage cables.
  • Step A1 heat the material to be tested to a melt at a temperature of 115 ⁇ 2°C, and extrude it continuously through a capillary die by a single screw extruder at an appropriate screw speed (the appropriate screw speed should be set according to the conditions given when describing the test of the reference sample, and the shear rate of the test sample and the reference sample should be set to the same).
  • the extrusion process continuously measure and record the capillary inlet pressure P (MPa), the mass growth rate of the melt extrusion w (g/s) and the diameter D ' ( ⁇ m) of the melt sample. Perform the following calculations with 60 seconds as a data cycle:
  • Step A1.1 using the mass rate of the extruded melt, calculate the shear rate of the melt flow according to formula (1):
  • ⁇ (g/cm 3 ) is the melt density
  • C 1.02 ⁇ 10 4 /cm 3 is the equipment constant.
  • Step A1.2 using the capillary inlet pressure data, obtain the shear stress ⁇ (MPa) of the melt flow according to equation (2).
  • P0 is the atmospheric pressure of the experimental environment, which can usually be taken as 0.1MPa.
  • Step A1.3 using the calculated ⁇ and The apparent shear viscosity ⁇ a (Pa ⁇ s) of the melt flow is obtained according to formula (3).
  • Step A2 while completing step A1, using the spline diameter D ' according to formula (4) to calculate the outlet expansion rate ⁇ (%) of the melt.
  • Step A3 recording and displaying in real time the curves ⁇ a (t) and ⁇ (t) of the apparent shear viscosity and outlet expansion rate of the melt changing with time.
  • the shear viscosity and outlet expansion rate of the melt are stable values, that is, ⁇ a (t) and ⁇ (t) are almost horizontal curves. If the material undergoes a certain degree of pre-cross-linking, a gel point will be formed in the melt. At this time, the flux of the melt will decrease when passing through the throttling device, which will significantly increase the apparent shear viscosity obtained by the test, and the outlet expansion rate of the melt will also increase.
  • the increase of ⁇ a (t) or ⁇ (t) by more than a certain percentage (preferably 10%) is used as a criterion.
  • a certain percentage preferably 10%
  • ⁇ a (t) or ⁇ (t) reaches more than 1.1 times of the initial value, it indicates that the material has begun to pre-crosslink.
  • the experiment is stopped, and the time corresponding to the increase of ⁇ a (t) or ⁇ (t) by 10% is found on the ⁇ a (t) or ⁇ (t) curve as the starting time of the crosslinking reaction, recorded as Tx .
  • the curve is shown in Figure 6.
  • Step A4 select a reference sample, test the reference sample according to step A1-3, and determine the cross-linking reaction start time T S of the reference sample based on the ⁇ a (t) and ⁇ (t) curves of the reference sample.
  • test results are further processed using reference samples.
  • the reference sample is recommended to use low-density polyethylene resin (LDPE), crosslinking agent (diisopropylbenzene peroxide-DCP) and antioxidant (antioxidant 1010) used in the industry to manufacture high-voltage cable insulation materials, and is prepared in the proportion of 100phrLDPE adding 2phrDCP and 0.3phr antioxidant 1010.
  • LDPE low-density polyethylene resin
  • crosslinking agent diisopropylbenzene peroxide-DCP
  • antioxidant antioxidant
  • the ⁇ a (t) and ⁇ (t) curves of the reference sample are tested.
  • the speed of the screw extruder should be adjusted so that the initial shear rate of the extruded melt is within the range of 1000-1200 s -1 , and the experimental test is carried out continuously at this speed to finally determine the starting time of the cross-linking reaction of the reference sample, which is recorded as T S .
  • Step A5 define the ⁇ index according to TX and TS as a digital characteristic quantity characterizing the continuous extrusion processing characteristics of the material under test.
  • the ⁇ index is defined according to the following formula (5):
  • ⁇ >0 it means that the continuous extrusion processing characteristics of the tested material are higher than those of the reference sample, and the larger the value, the longer the material can be continuously processed in the equipment.
  • ⁇ 0 it means that the continuous extrusion processing characteristics of the tested material are lower than those of the reference sample, and the larger the absolute value, the shorter the time the material can be continuously processed in the equipment.
  • the principle block diagram of the test device is shown in FIG3 , through which the pressure P of the melt of the tested material flowing through the capillary inlet, the mass m of the extruded melt per unit time, and the diameter D ' of the extruded melt spline can be continuously obtained as basic data.
  • the test device specifically includes a single-screw extruder of specific specifications and a capillary extrusion die, which are used to continuously extrude the melt of the material to be tested through the capillary under specific extrusion processing conditions (the extruder temperature is set between 105 and 120°C); the recommended specifications of the single-screw extruder in the test device are: screw diameter ⁇ 20mm, aspect ratio 20:1, compression ratio 1:1.18; the weighing device has a range of 100g and an accuracy of 1mg; the diameter gauge has a range of 5mm and an accuracy of 5 ⁇ m.
  • a porous throttling device is set at the entrance of the capillary die, and the polymer melt enters the extrusion capillary through the device.
  • the throttling device is composed of two 100-mesh and one 500-mesh stainless steel filter screens to form a sandwich structure, as shown in Figure 4 (a).
  • the throttling device is installed at the entrance of the capillary die, as shown in Figure 4 (b).
  • the capillary die with the throttling device is connected to the single-screw extruder as a whole.
  • a melt pressure sensor is provided at the inlet of the capillary tube to continuously measure the melt pressure at the inlet of the capillary tube; the capillary tube core is shown in Figure 5.
  • an automatic weighing device For the melt after being extruded through the capillary, an automatic weighing device is used to continuously measure the mass of the extruded melt per unit time;
  • a non-contact optical diameter measuring instrument is arranged at the outlet of the extruded melt to continuously measure the diameter of the extruded melt specimen.
  • Embodiment (two), optimize and determine the optimal process conditions for continuous extrusion processing of long-length submarine cables.
  • Step B1 using a set cross-linkable polyethylene insulation material, and selecting a small single-screw extruder with a similar structure and the same number of heating sections according to the number of heating sections of a large extruder used in actual production;
  • Step B2 the material to be tested is heated into a melt under a set of process conditions (including the temperature of each heating section and the screw speed), and is continuously extruded through a capillary die by a single screw extruder.
  • the capillary inlet pressure P (MPa) the mass rate of melt extrusion w (g/s) and the diameter D ' ( ⁇ m) of the melt specimen are continuously measured and recorded. The following calculations are performed with 60 seconds as a data cycle:
  • Step B2.1 using the mass rate of the extruded melt to calculate the shear rate of the melt flow according to formula (1):
  • ⁇ (g/cm 3 ) is the melt density
  • C 1.02 ⁇ 10 4 /cm 3 is the equipment constant.
  • Step B2.2 using the capillary inlet pressure according to formula (2) to obtain the shear stress ⁇ (MPa) of the melt flow.
  • P0 is the atmospheric pressure of the experimental environment, which can usually be taken as 0.1MPa.
  • Step B2.3 using the calculated ⁇ and The apparent shear viscosity ⁇ a (Pa ⁇ s) of the melt flow is obtained according to formula (3).
  • Step B3 while completing step B2, using the spline diameter D ' according to formula (4) to calculate the outlet expansion rate ⁇ (%) of the melt.
  • Step B4 real-time recording and displaying curves ⁇ a (t) and ⁇ (t) of the apparent shear viscosity and outlet expansion rate of the melt changing with time. If the molecular chains of the material are not cross-linked during the extrusion process, the shear viscosity and outlet expansion rate of the melt are stable values, and ⁇ a (t) and ⁇ (t) are almost horizontal curves. If the material is cross-linked to a certain extent, a gel point will be formed in the melt. At this time, the flux of the melt will decrease when passing through the throttling device, so that the apparent shear viscosity obtained by the test will increase significantly, and the outlet expansion rate of the melt will also increase.
  • the increase of ⁇ a (t) or ⁇ (t) by more than a certain percentage (preferably 10%) is used as a criterion.
  • a certain percentage preferably 10%
  • ⁇ a (t) or ⁇ (t) reaches more than 1.1 times of the initial value, it indicates that the material has begun to pre-crosslink.
  • the experiment is stopped, and the time corresponding to the increase of ⁇ a (t) or ⁇ (t) by 10% is found on the ⁇ a (t) or ⁇ (t) curve as the starting time of the crosslinking reaction, recorded as Tx .
  • the curve is shown in Figure 6.
  • Step B5 taking the screw speed and working temperature of the screw extruder as processing conditions, adjusting these parameters, setting multiple groups of different process conditions (including the temperature and screw speed of each heating section and extruder head), and continuously extruding the melt of the material to be tested through the capillary die under each group of process conditions, retesting the crosslinking reaction start time TX of the material, and obtaining each group of TX values related to the processing conditions.
  • Step B6 taking the shear viscosity corresponding to the maximum value of TX as the numerical characteristic of the melt being in the optimal flow state, and taking the process conditions corresponding to the shear viscosity as the optimal conditions for the extrusion processing of long-length submarine cables.
  • Step B7 according to the process parameter rules obtained from the small extruder test, set the production process parameters of the actual extruder and make fine adjustments to obtain the optimal process parameters, thereby reducing the test time on the large extruder and reducing the waste of materials and extruder production capacity.
  • the principle block diagram of the optimization device is shown in FIG3 .
  • the device can be used to continuously obtain the curves of the three parameters, namely, the pressure P of the melt of the material under test flowing through the capillary inlet, the mass m of the extruded melt per unit time, and the diameter D ' of the extruded melt spline, which vary with time as basic data.
  • the optimized device specifically includes: a small single-screw extruder, which is similar in structure to the large extruder used in actual production, with the same number of heating section segments; a weighing device with a range of 100g and an accuracy of 1mg; a diameter gauge with a range of 5mm and an accuracy of 5 ⁇ m.
  • the number of heating section partitions can be set according to the number of heating section partitions of the extruder to be used in actual cable production. If necessary, the specifications of the extruder can be adjusted to adapt to the realization of the number of heating section partitions.
  • a porous throttling device is set at the entrance of the capillary die, and the polymer melt enters the extrusion capillary through the device.
  • the throttling device consists of two 100-mesh and one 500-mesh stainless steel filter screens in a sandwich structure, as shown in Figure 4 (a).
  • the throttling device is installed at the entrance of the capillary die, as shown in Figure 4 (b).
  • the capillary die with the throttling device is connected to the single-screw extruder as a whole.
  • a melt pressure sensor is provided at the inlet of the capillary tube to continuously measure the melt pressure at the inlet of the capillary tube; the capillary tube core is shown in Figure 5.
  • the melt after being extruded through the capillary is continuously measured by an automatic weighing device in terms of the mass of the extruded melt per unit time;
  • a non-contact optical diameter measuring instrument is arranged at the outlet of the extruded melt to continuously measure the diameter of the extruded melt specimen.
  • the inventors have found in their long-term research that the long-term extrusion processing characteristics of cross-linkable polyethylene insulation materials are jointly determined by the rheological properties of the materials and the chemical properties of the cross-linking reaction.
  • Traditional methods for characterizing the extrusion processing performance of cross-linkable polyethylene insulation materials mostly use various types of rheometers (such as torque rheometers, rotational rheometers, high-pressure capillary rheometers, etc.) to test the rheological properties of the materials. Due to the small total mass of the test material, the small cavity space where the melt is located, and the short continuous test time, under the material extrusion processing temperature conditions, the material rheological characteristic parameters are poorly sensitive to pre-crosslinking.
  • test parameters related to the pre-crosslinking characteristics of the material must be obtained at a higher temperature (higher than the decomposition temperature of the cross-linking agent DCP).
  • relevant tests can only make qualitative and inaccurate inferences about the long-term extrusion processing performance. Since the test temperature deviates from (is higher than) the long-term extrusion processing conditions of the actual production process of the insulation material, the test results are of poor reference value.
  • This application uses an extruder with a throttling device and a capillary die to perform uninterrupted melt extrusion, and the continuous test time is not limited. Under the premise of more realistic simulation of the cable insulation extrusion process, it can not only measure more realistic performance parameters, but also save a lot of experimental material consumption.
  • the extrusion processing and testing device of the present application can provide multiple parameters for quantitatively evaluating the long-term extrusion processing performance of cross-linkable polyethylene insulation materials, can optimize materials through quantitative parameters, and can also provide clear optimization target directions for the setting of extruder processing parameters.
  • the method of using a low-power extruder to simulate large-scale production equipment can save materials and achieve the exploration of optimal process parameters, which can not only save a lot of production equipment capacity, but also save a lot of experimental cycles and material consumption.
  • the present application provides a sandwich structure throttling device composed of multiple layers of filter screens.
  • the throttling device is composed of high-precision filter screens.
  • the filter screens have a certain obstruction effect on the flow of the melt, and together with the capillary die connected to it, they constitute a part of the area with poor melt fluidity (which can be figuratively called a flow dead corner).
  • This coordination method simulates the existence of processing dead corners in the extruder during the actual extrusion production process. The existence of dead corners will cause the retained melt material to be pre-cross-linked, thereby deteriorating the quality of the insulation layer, and the cable will therefore not be able to be continuously extruded for a long time.
  • the device provided by the present application can fully test the problems of pre-cross-linking and long-term extrusion performance deterioration caused by melt flow dead corners, and fully simulate the specific problems in the actual cable production process. Therefore, the results obtained according to the method of the present application have good practical application reference value.

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Abstract

本申请提供了一种高压电缆绝缘材料连续挤出加工特性评价优化方法及装置，方法包括：将被测材料以熔体连续挤出，测量和记录入口压力P，质量增长速率w和熔体样条的直径D'，得到表观剪切粘度η a(步骤A1)；得到口膨大率δ(步骤A2)；记录显示曲线η a(t)和δ(t)，在曲线上将增大设定百分比所对应的时间作为交联反应起始时间TX(步骤A3)；选择参考试样进行测试，根据参考试样的η a(t)和δ(t)曲线，确定出交联反应起始时间T S(步骤A4)；根据T X和T S定义出指数α(步骤A5)。

Description

高压电缆绝缘材料连续挤出加工特性评价优化方法及装置
相关申请
本申请要求2022年10月28日申请的，申请号为202211331206.3，名称为“高压电缆绝缘材料连续挤出加工特性评价优化方法及装置”的中国专利申请的优先权，在此将其全文引入作为参考。
技术领域
本申请涉及交联电缆技术领域，特别是涉及一种高压电缆绝缘材料连续挤出加工特性评价优化方法及装置。
背景技术
海底电缆(以下简称海缆)是跨海输电系统中的核心部件，与陆上电缆不同的是，海底电缆接头制作的难度较大，成本较高，因此，工程上总是希望单段海缆制品的长度越长越好，以减少海缆中间接头或者工厂接头的总数量。
交联聚乙烯是目前最重要的高压海底电缆用绝缘材料，该材料主要由聚乙烯树脂以及一定比例的抗氧剂和交联剂混配构成。电缆绝缘层的制造流程是：在低于交联剂迅速分解温度并高于聚乙烯熔融温度的高温条件下，利用螺杆挤出机将可交联聚乙烯绝缘材料加热成熔体，通过机头连续不断地将熔体挤包在电缆导体之上，然后进入交联管道，在交联剂能够迅速分解的高温条件下，进行连续交联。上述过程之中，挤出机的连续不间断运行时间是单段电缆制品的长度的重要限制因素。
基于交联电缆生产的技术原理，可交联聚乙烯电缆绝缘材料在长期挤出加工过程中，由于熔体流动性的不均匀以及挤出机内存在流动性较差的局部死角等问题，材料会不可避免地在挤出机中的局部位置滞留，在挤出温度下，虽然交联剂分解速度慢，但是长期滞留的材料中，也会因交联剂分解而产生预交联，部分预交联材料在电缆绝缘中会形成凝胶点缺陷，凝胶点缺陷容易造成挤出机滤网的堵塞，进而限制连续挤出时间，部分从滤网中渗透通过的凝胶点还会导致绝缘层电学性能显著下降，因此，在产生不可接受的预交联现象后必须停止挤出机设备运转，对设备内部进行整体清理，这也就限制了挤出机的连续加工时间。
大长度海缆制造的关键是尽量延长电缆连续生产的时间，这就需要通过试验选用长期挤出加工性能较好的绝缘材料，且需要对挤出机的加工参数进行优化设置，摸索得到最优的长期加工工艺条件。然而目前在电缆制造工业中，缺乏准确评价交联聚乙烯电缆绝缘材料的连续挤出加工特性的方法，也缺乏表征这一特性的定量化评价指标。这一方面使得电缆制造业对于绝缘材料的优选缺乏明确的评判标准；另一方面使得在实际的海缆生产过程中，只能凭经验决定挤出机加工参数及其连续生产的时间长度，如果连续生产时间设置过长，可能在生产过程中发生材料预交联，导致电缆绝缘性能下降。如果连续生产时间设置过短，则无法充分发挥材料性能，达不到电缆制品应有的极限长度，由于高压电缆绝缘材料价格较为高昂，在大型生产设备中的反复尝试必然会造成大量的材料浪费和成本消耗，因此，也导致了挤出机加工工艺参数的调整优化成本过高、周期过长。
如何合理地选择可长期挤出加工的绝缘材料，以及如何合理地限定连续挤出时间，进而避免材料在挤出加工中形成预交联是决定电缆绝缘层质量的关键因素，然而目前缺乏对材料长期挤出加工性能的有效评价方法，对于绝缘材料的优选，缺乏可靠数据支撑，大长度海缆制造的连续挤出时间设置也缺乏客观依据。本申请旨在提供高压电缆绝缘材料连续挤出加工特性评价优化方法及装置，该方法和设备可以用于评价和优选适用于长期挤出加工的可交联聚乙烯绝缘材料，也可以用于对长期挤出加工过程中的工艺参数做优化，以实现某种给定材料最优的挤出加工工艺参数设置。
发明内容
根据本申请的各种实施例，提供一种高压电缆绝缘材料连续挤出加工特性评价优化方法及装置。
第一方面，本申请提供了一种高压电缆绝缘材料连续挤出加工特性评价优化方法，包括：
步骤A1，将被测材料在设定温度下加热成熔体，将熔体通过毛细管模具连续挤出，在挤出过程中连续测量和记录毛细管的入口压力P，熔体挤出的质量增长速率w和熔体样条的直径D’，得到熔体流动的表观剪切粘度η a；
步骤A2，利用样条直径D’计算熔体的出口膨大率δ；
步骤A3，记录和显示熔体的表观剪切粘度和出口膨大率随时间变化的曲线η a(t)和δ(t)，在η a(t)或δ(t)曲线上将η a(t)或δ(t)增大设定百分比所对应的时间作为交联反应起始时间，记为T X；
步骤A4，选择参考试样，按照步骤A1-A3对参考试样进行测试，根据参考试样的η a(t)和δ(t)曲线，确定出参考试样的交联反应起始时间T S；
步骤A5，根据T X和T S定义出指数α，指数α即为表征评价被测材料连续挤出加工特性的数字特征量。
在其中一个实施例中，在步骤A1中，包括：
步骤A1.1，利用挤出熔体的质量增长速率w，根据下式(1)计算熔体流动的剪切速率
Figure PCTCN2022136788-appb-000001
Figure PCTCN2022136788-appb-000002
式中ρ为熔体密度，C＝1.02×10 4/cm 3为设备常数；
步骤A1.2，利用毛细管入口压力数据P，根据下式(2)得到熔体流动的剪切应力τ：
Figure PCTCN2022136788-appb-000003
式中P 0为实验环境的大气压，取作0.1MPa；
步骤A1.3，利用计算得到的τ和
Figure PCTCN2022136788-appb-000004
数值，根据下式(3)得到熔体流动的表观剪切粘度η a：
Figure PCTCN2022136788-appb-000005
式中τ为熔体流动的剪切应力，
Figure PCTCN2022136788-appb-000006
为熔体流动的剪切速率。
在其中一个实施例中，在步骤A1中，以60秒为一个数据周期对η a进行计算。
在其中一个实施例中，在步骤A2中，利用样条直径D’根据下式(4)计算熔体的出口膨大率δ。
Figure PCTCN2022136788-appb-000007
在其中一个实施例中，在步骤A3中，设定百分比为10％。
在其中一个实施例中，在步骤A4中，参考试样采用低密度聚乙烯树脂、交联剂以及抗氧剂制作，其中，低密度聚乙烯树脂为LDPE、交联剂为过氧化二异丙苯-DCP，抗氧剂为抗氧剂1010，按照100phrLDPE添加2phrDCP和0.3phr抗氧剂1010的比例配制。
在其中一个实施例中，在步骤A4中，测试时调整螺杆挤出机转速，使得挤出熔体的初始剪切速率在1000～1200s -1范围之内，并以该转速连续进行实验测试，最终确定出参考试样的交联反应起始时间。
在其中一个实施例中，在步骤A5中，α指数按照下式(5)定义：
Figure PCTCN2022136788-appb-000008
若α>0，表示被测材料的连续挤出加工特性高于参考试样，并且数值越大代表材料在设备中连续加工的时间越长；
若α<0，表示被测材料的连续挤出加工特性低于参考试样，并且绝对值越大代表材料在设备中连续加工的时间越短。
第二方面，本申请提供了一种高压电缆绝缘材料连续挤出加工特性评价优化装置，
测试装置包括：设定规格的单螺杆挤出机和毛细管挤出模具，在设定的挤出加工条件下，将被测材料熔体由单螺杆挤出机通过毛细管连续挤出；
在毛细管模具入口处设置一个多孔节流装置，聚合物熔体通过所述多孔节流装置进入挤出毛细管；
在毛细管入口处设置熔体压力传感器，用于连续测量毛细管入口的熔体压力；
对于通过毛细管挤出之后的熔体，利用自动称重装置，连续测量单位时间中挤出熔体的质量；
在挤出熔体的出口处设置非接触式光学测径仪，用于连续测量挤出熔体样条的直径。
在其中一个实施例中，测试装置中，单螺杆挤出机规格为：螺杆直径Φ20mm，长径比20:1，压缩比1:1.18；称重装置量程100g，精度1mg；测径仪量程5mm，精度5μm。
在其中一个实施例中，节流装置包括两片100目不锈钢滤网和一片500目不锈钢滤网，三片不锈钢滤网组成三明治组合结构，节流装置安装在毛细管模具的入口处，带有节流装置的毛细管模具整体与单螺杆挤出机连接。
在其中一个实施例中，毛细管模芯参数为，毛细管直径D＝1.0±0.013mm，长度L＝30.0±0.13mm，入口角A＝40°±0°30’。
第三方面，本申请提供了一种高压电缆交联聚乙烯绝缘材料连续挤出加工工艺的优化方法，包括：
步骤B1，采用设定的可交联聚乙烯绝缘材料，根据实际生产中所使用的大型挤出机的加热段分段数量，选择结构相仿、加热段数量相同的小型单螺杆挤出机；
步骤B2，将所述可交联聚乙烯绝缘材料在设定的加工工艺条件下加热成熔体，将熔体由单螺杆挤出机通过毛细管模具连续挤出，在挤出过程中连续测量和记录毛细管的入口压力P，熔体挤出的质量增长速率w和熔体样条的直径D’，得到熔体流动的表观剪切粘度η a；
步骤B3，利用样条直径D’计算熔体的出口膨大率δ；
步骤B4，记录和显示熔体的表观剪切粘度和出口膨大率随时间变化的曲线η a(t)和δ(t)，在η a(t)或δ(t)曲线上将η a(t)或δ(t)增大设定百分比所对应的时间作为交联反应起始时间，记为T X；
步骤B5，设置多组不同的工艺条件，分别在每组工艺条件下，将被测材料熔体通过毛细管模具连续挤出，重新测试材料的交联反应起始时间T X，获得每一组与加工工艺条件相关的T X值；
步骤B6，将T X达到最大值对应的剪切粘度η a作为熔体处于最佳流动状态的数值特征，将达到该剪切粘度所对应的工艺条件作为大长度海缆挤出加工的最优条件；
步骤B7，按照步骤B6中小型挤出机试验获得的工艺参数规律，设置实际挤出机的生产工艺参数，通过微调得到最优的工艺参数。
在其中一个实施例中，在步骤B2中，加工工艺条件包括：螺杆挤出机螺杆转速以及每段加热段的工作温度。
在其中一个实施例中，在步骤B2中，包括：
步骤B2.1，利用挤出熔体的质量增长速率w，根据下式(1)计算熔体流动的剪切速率
Figure PCTCN2022136788-appb-000009
Figure PCTCN2022136788-appb-000010
式中ρ为熔体密度，C＝1.02×10 4/cm 3为设备常数；
步骤B2.2，利用毛细管入口压力数据P，根据下式(2)得到熔体流动的剪切应力τ
Figure PCTCN2022136788-appb-000011
式中P 0为实验环境的大气压，取作0.1MPa；
步骤B2.3，利用计算得到的τ和
Figure PCTCN2022136788-appb-000012
数值，根据下式(3)得到熔体流动的表观剪切粘度η a
Figure PCTCN2022136788-appb-000013
式中τ为熔体流动的剪切应力，
Figure PCTCN2022136788-appb-000014
为熔体流动的剪切速率。
在其中一个实施例中，在步骤B2中，以60秒为一个数据周期对η a进行计算。
在其中一个实施例中，在步骤B3中，利用样条直径D’根据下式(4)计算熔体的出口膨大率δ
Figure PCTCN2022136788-appb-000015
实时记录和显示熔体的表观剪切粘度和出口膨大率随时间变化的曲线η a(t)和δ(t)。
在其中一个实施例中，在步骤B4中，设定百分比为10％。
在其中一个实施例中，在步骤B5中，在每组工艺条件中，每个加热段及挤出机头的温度以及螺杆 转速不同。
第四方面，本申请提供了一种用于高压电缆交联聚乙烯绝缘材料连续挤出加工工艺的优化装置，
优化装置包括：设定规格的单螺杆挤出机和毛细管挤出模具，
在设定的挤出加工条件下，将被测材料熔体由单螺杆挤出机通过毛细管连续挤出；
在毛细管模具入口处设置一个多孔节流装置，聚合物熔体通过所述多孔节流装置进入挤出毛细管；
在毛细管入口处设置熔体压力传感器，用于连续测量毛细管入口的熔体压力；
对于通过毛细管挤出之后的熔体，利用自动称重装置，连续测量单位时间中挤出熔体的质量；
在挤出熔体的出口处设置非接触式光学测径仪，用于连续测量挤出熔体样条的直径。
在其中一个实施例中，单螺杆挤出机与实际生产中所使用的大型挤出机结构相仿，加热段分段数量相同。
在其中一个实施例中，优化装置中，单螺杆挤出机规格为：螺杆直径Φ20mm，长径比20:1，压缩比1:1.18；称重装置量程100g，精度1mg；测径仪量程5mm，精度5μm。
在其中一个实施例中，节流装置包括两片100目不锈钢滤网和一片500目不锈钢滤网，三片不锈钢滤网组成三明治组合结构，节流装置安装在毛细管模具的入口处，带有节流装置的毛细管模具整体与单螺杆挤出机连接。
在其中一个实施例中，毛细管模芯参数为，毛细管直径D＝1.0±0.013mm，长度L＝30.0±0.13mm，入口角A＝40°±0°30’。
本申请的一个或多个实施例的细节在下面的附图和描述中提出。本申请的其它特征、目的和优点将从说明书、附图以及权利要求书变得明显。
附图说明
为了更清楚地说明本申请实施例或传统技术中的技术方案，下面将对实施例或传统技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据公开的附图获得其他的附图。
图1是一些实施例中绝缘材料连续挤出加工特性评价方法流程图；
图2是一些实施例中绝缘材料连续挤出加工过程工艺优化方法流程图；
图3是一些实施例中熔体挤出测试装置原理图；
图4a是一些实施例中节流装置示意图；
图4b是一些实施例中毛细管模具、节流装置、测径仪、压力传感器配合方式示意图；
图5是一些实施例中毛细管模芯示意图；
图6是一些实施例中η a(t)，δ(t)随时间变化曲线示意图。
图中，1为100目不锈钢滤网；2为500目不锈钢滤网；3为毛细管模具入口；4为压力传感器；5为加热套；6为毛细管模具出口；7为非接触式光学测径仪。
具体实施方式
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。
本申请根据聚乙烯材料发生预交联将引起剪切粘度以及熔体挤出膨大率变化的原理，设计了持续监测聚乙烯电缆绝缘材料熔体在连续挤出过程中剪切粘度和挤出膨大率变化的装置，通过剪切粘度和挤出彭大率随挤出加工时间的连续变化情况对材料的连续挤出加工特性进行定量化表征。基于本申请可以实现两个主要目的：(一)实现高压电缆交联聚乙烯绝缘材料连续挤出加工特性的评价；(二)优化确定大长度海缆连续挤出加工最优工艺条件。
实施例(一)，实现高压电缆交联聚乙烯绝缘材料连续挤出加工特性的评价。
为了表征和评价可交联聚乙烯电缆绝缘材料的连续挤出加工特性，客观地反映不同材料之间的差异。实际上就是需要找到在相同的挤出加工条件下，材料从开始加工，直到发生可察觉的预交联，所经历的 加工时间长度，以这个时间长度作为表征材料连续加工特性的定量化指标。
高压海缆绝缘材料连续挤出加工特性表征的技术原理与测试方法如下：
步骤A1，将被测材料在115±2℃的温度下加热成熔体，以一个适当的螺杆转速(适当的螺杆转速应按照描述测试参考试样测试时所给定的条件进行设置，并且被测试样与参考试样的剪切速率应设定为相同)，由单螺杆挤出机通过毛细管模具连续挤出，在挤出过程中连续测量和记录毛细管的入口压力P(MPa)，熔体挤出的质量增长速率w(g/s)和熔体样条的直径D ’(μm)。以60秒为一个数据周期进行以下计算：
步骤A1.1，利用挤出熔体的质量速率根据(1)式计算熔体流动的剪切速率
Figure PCTCN2022136788-appb-000016
Figure PCTCN2022136788-appb-000017
式中ρ(g/cm 3)为熔体密度，C＝1.02×10 4/cm 3为设备常数。
步骤A1.2，利用毛细管入口压力数据，根据(2)式得到熔体流动的剪切应力τ(MPa)。
Figure PCTCN2022136788-appb-000018
式中P 0为实验环境的大气压，通常可以取作0.1MPa。
步骤A1.3，利用计算得到的τ和
Figure PCTCN2022136788-appb-000019
数值根据(3)式得到熔体流动的表观剪切粘度η a(Pa·s)。
Figure PCTCN2022136788-appb-000020
步骤A2，在完成步骤A1的同时，利用样条直径D ’根据(4)式计算熔体的出口膨大率δ(％)。
Figure PCTCN2022136788-appb-000021
步骤A3，实时记录和显示熔体的表观剪切粘度和出口膨大率随时间变化的曲线η a(t)和δ(t)。
如果材料在挤出过程中分子链没有发生交联，其熔体的剪切粘度和出口膨大率是稳定数值，即η a(t)和δ(t)几乎是水平曲线。如果材料发生了一定程度的预交联，将在熔体中形成凝胶点，此时熔体通过节流装置时通量会降低，使得测试得到的表观剪切粘度显著增加，同时熔体的出口膨大率也会增大。
以η a(t)或δ(t)增大超过一定百分比(优选10％)为判据，当η a(t)或δ(t)任一参数达到初始值的1.1倍以上时，表示材料已经开始预交联。此时停止实验，在η a(t)或δ(t)曲线上找到η a(t)或δ(t)增大10％所对应的时间作为交联反应起始时间，记为T X。曲线如图6所示。
步骤A4，选择参考试样，按照步骤A1-3对参考试样进行测试，根据参考试样的η a(t)和δ(t)曲线，确定出参考试样的交联反应起始时间T S。
为了降低不同实验设备之间参数和结构差异对实验结果的影响，利用参考试样对测试结果进一步处理。参考试样推荐采用工业上用于制造高压电缆绝缘材料的低密度聚乙烯树脂(LDPE)、交联剂(过氧化二异丙苯-DCP)以及抗氧剂(抗氧剂1010)，按照100phrLDPE添加2phrDCP和0.3phr抗氧剂1010的比例配制。
按照上述原理测试参考试样的η a(t)和δ(t)曲线，开始测试时应调整螺杆挤出机转速，使得挤出熔体的初始剪切速率在1000～1200s -1范围之内，并以该转速连续进行实验测试，最终确定出参考试样的交联反应起始时间，记为T S。
步骤A5，根据T X和T S定义α指数，作为表征被测材料连续挤出加工特性的数字特征量。其中，α指数按照下式(5)定义：
Figure PCTCN2022136788-appb-000022
若α>0，表示被测材料的连续挤出加工特性高于参考试样，并且数值越大代表材料可以在设备中连续加工的时间越长。
若α<0，表示被测材料的连续挤出加工特性低于参考试样，并且绝对值越大代表材料可以在设备中连续加工的时间越短。
测试装置的原理框图如图3所示，通过该装置可以连续获取被测材料熔体流过毛细管入口的压力P、 单位时间内挤出熔体的质量m、以及挤出熔体样条的直径D ’三个参数随时间变化的曲线，作为基础数据。
测试装置具体包括，特定规格的单螺杆挤出机，以及毛细管挤出模具，用于在特定的挤出加工条件下(挤出机温度设置为105～120℃之间)，将被测材料熔体通过毛细管连续挤出；测试装置中单螺杆挤出机规格推荐为，螺杆直径Φ20mm，长径比20:1，压缩比1:1.18；称重装置量程100g，精度1mg；测径仪量程5mm，精度5μm。
在毛细管模具入口处设置一个多孔节流装置，聚合物熔体通过该装置进入挤出毛细管。节流装置由两片100目和一片500目不锈钢滤网组成三明治组合结构，如图4(a)所示，节流装置安装在毛细管模具的入口处，如图4(b)所示。带有节流装置的毛细管模具整体与单螺杆挤出机连接。
在毛细管入口处设置熔体压力传感器，用于连续测量毛细管入口的熔体压力；毛细管模芯如图5所示。推荐参数为，毛细管直径D＝1.0±0.013mm，长度L＝30.0±0.13mm，入口角A＝40°±0°30 ’。
对于通过毛细管挤出之后的熔体，利用自动称重装置，连续测量单位时间中挤出熔体的质量；
在挤出熔体的出口处设置非接触式光学测径仪，用于连续测量挤出熔体样条的直径。
实施例(二)，优化确定大长度海缆连续挤出加工最优工艺条件。
为了优化确定大长度海缆连续挤出加工最优工艺条件，需要在确定材料品类的前提下，评价不同挤出工艺条件下，该材料从开始加工直到发生可察觉的预交联，所经历的加工时间长度，以这个时间长度作为评价和调整加工工艺参数的定量化指标，通过实验可以优选得到使得这一时间长度达到最大的某组工艺参数，这组工艺参数可以为大长度还连续挤出工艺参数的确定和优化提供数据参考。
优化确定大长度海缆连续挤出加工最优工艺条件的技术原理与优化方法如下：
步骤B1，采用设定的可交联聚乙烯绝缘材料，根据实际生产中所使用的大型挤出机的加热段分段数量，选择结构相仿、加热段数量相同的小型单螺杆挤出机；
步骤B2，将被测材料在设定的某一组工艺条件(包括每段加热段的温度及螺杆转速)下加热成熔体，由单螺杆挤出机通过毛细管模具连续挤出，在挤出过程中连续测量和记录毛细管的入口压力P(MPa)，熔体挤出的质量速率w(g/s)和熔体样条的直径D ’(μm)。以60秒为一个数据周期进行以下计算：
步骤B2.1，利用挤出熔体的质量速率根据(1)式计算熔体流动的剪切速率
Figure PCTCN2022136788-appb-000023
Figure PCTCN2022136788-appb-000024
式中ρ(g/cm 3)为熔体密度，C＝1.02×10 4/cm 3为设备常数。
步骤B2.2，利用毛细管入口压力根据(2)式得到熔体流动的剪切应力τ(MPa)。
Figure PCTCN2022136788-appb-000025
式中P 0为实验环境的大气压，通常可以取作0.1MPa。
步骤B2.3，利用计算得到的τ和
Figure PCTCN2022136788-appb-000026
数值根据(3)式得到熔体流动的表观剪切粘度η a(Pa·s)。
Figure PCTCN2022136788-appb-000027
步骤B3，在完成步骤B2的同时，利用样条直径D ’根据(4)式计算熔体的出口膨大率δ(％)。
Figure PCTCN2022136788-appb-000028
步骤B4，实时记录和显示熔体的表观剪切粘度和出口膨大率随时间变化的曲线η a(t)和δ(t)。如果材料在挤出过程中分子链没有发生交联，其熔体的剪切粘度和出口膨大率是稳定数值，η a(t)和δ(t)几乎是水平曲线。如果材料发生了一定程度的交联，将在熔体中形成凝胶点，此时熔体通过节流装置时通量会降低，使得测试得到的表观剪切粘度显著增加，同时熔体的出口膨大率也会增大。
以η a(t)或δ(t)增大超过一定百分比(优选10％)为判据，当η a(t)或δ(t)任一参数达到初始值的1.1倍以上时，表示材料已经开始预交联。此时停止实验，在η a(t)或δ(t)曲线上找到η a(t)或δ(t)增大10％所对应的时间作为交联反应起始时间，记为T X。曲线如图6所示。
步骤B5，将螺杆挤出机螺杆转速以及工作温度作为加工工艺条件，调整这些参数，设置出多组不 同的工艺条件(包含每个加热段及挤出机头的温度和螺杆转速)，分别在每组工艺条件下，将被测材料熔体通过毛细管模具连续挤出，重新测试材料的交联反应起始时间T X，获得每一组与加工工艺条件相关的T X值。
步骤B6，将T X达到最大值对应的剪切粘度作为熔体处于最佳流动状态的数值特征，将达到该剪切粘度所对应的工艺条件作为大长度海缆挤出加工的最优条件。
步骤B7，按照小型挤出机试验获得的工艺参数规律，设置实际挤出机的生产工艺参数，并进行微调，即可获得最优的工艺参数，从而缩减了大挤出机上的试验时间，减少了材料和挤出机产能的浪费。
优化装置的原理框图如图3所示，通过该装置可以连续获取被测材料熔体流过毛细管入口的压力P、单位时间内挤出熔体的质量m、以及挤出熔体样条的直径D ’三个参数随时间变化的曲线，作为基础数据。
优化装置具体包括：小型单螺杆挤出机，该小型单螺杆挤出机与实际生产中所使用的大型挤出机结构相仿，加热段分段数量相同；称重装置量程100g，精度1mg；测径仪量程5mm，精度5μm。加热段分区数可以依据实际电缆生产拟采用的挤出机加热段分区数进行设置，必要时可对挤出机规格参数做调整，以适应加热段分区数量的实现。
在毛细管模具入口处设置一个多孔节流装置，聚合物熔体通过该装置进入挤出毛细管。节流装置由两片100目和一片500目不锈钢滤网组成三明治结构，如图4(a)所示，节流装置安装在毛细管模具的入口处，如图4(b)所示。带有节流装置的毛细管模具整体与单螺杆挤出机连接。
在毛细管入口处设置熔体压力传感器，用于连续测量毛细管入口的熔体压力；毛细管模芯如图5所示。推荐参数为，毛细管直径D＝1.00±0.01mm，长度L＝30.0±0.1mm，入口角A＝40°±0°30’。
通过毛细管挤出之后的熔体，利用自动称重装置，连续测量单位时间中挤出熔体的质量；
在挤出熔体的出口处设置非接触式光学测径仪，用于连续测量挤出熔体样条的直径。
本申请的有益效果在于，与传统技术相比：
(1)发明人在长期研究中发现，可交联聚乙烯绝缘材料的长期挤出加工特性是由材料的流变特性和交联反应化学特性共同决定的，传统的表征可交联聚乙烯绝缘材料挤出加工性能的方法，大多采用各种类型的流变仪(如转矩流变仪、旋转流变仪、高压毛细管流变仪等)对材料的流变特性做测试，由于测试材料的总质量小，熔体所处的腔体空间小，持续测试时间短，在材料挤出加工温度条件下，材料流变特性参数对于预交联的敏感性差，因此必须在较高的温度(高于交联剂DCP分解温度)下才能获得与材料预交联特性相关的测试参数，且相关测试仅能定性地对长期挤出加工性能做出不准确推测，由于测试温度偏离(高于)绝缘材料实际生产过程的长期挤出加工条件，因此，测试结果参考性较差。本申请采用挤出机配合节流装置和毛细管模具进行不间断的熔体挤出，连续测试时间不受限，在较真实地模拟电缆绝缘挤出加工过程前提下，不仅能够测得更符合实际性的性能参数，还大量地节约了实验材料消耗量。
(2)本申请的挤出加工和测试装置，可以提供多个定量评价可交联聚乙烯绝缘材料长期挤出加工性能的参数，能通过量化参数对材料进行优选，也可以对挤出机加工工艺参数的设置提供明确的优化目标方向。采用小功率挤出机模拟大型生产设备的方法，以节约的材料，实现最优工艺参数的摸索，不仅可以节约大量的生产设备产能，还能节省大量实验周期和材料耗费。
(3)相比传统的测试方法以定期的、人工测得膨大率及挤出熔体质量的方法，本申请中所述的多个定量化参数均由设备自动化测试获得并持续记录，能连续不间断地获取材料长期挤出加工过程中重要参数变化情况，能获得更多材料挤出加工过程中的变化信息，因此能准确发觉材料因预交联而产生性能变化的准确时间节点，对材料长期挤出加工性能的评价更为准确、可靠。
(4)本申请提供了由多层滤网组成的三明治结构节流装置，该节流装置由高精密的滤网构成，该滤网对熔体流动形成了一定的阻碍作用，并与和它相连的毛细管模具，共同构成了一部分熔体流动性较差的区域(可形象地称为流动死角)，这一配合方式模拟了实际挤出加工生产过程中挤出机中存在加工死角的情况，死角的存在会导致滞留的熔体材料发生预交联，进而使绝缘层质量变差，电缆因此也无法长期连续挤出，本申请提供的装置可以充分地测试出熔体流动死角导致的预交联和长期挤出性能变差的问题，充分模拟了实际电缆生产过程中的具体问题，因此依据本申请的方法得到的结果具有很好的实际 应用参考价值。
以上所述实施例的各技术特征可以进行任意的组合，为使描述简洁，未对上述实施例中的各个技术特征所有可能的组合都进行描述，然而，只要这些技术特征的组合不存在矛盾，都应当认为是本说明书记载的范围。
以上所述实施例仅表达了本申请的几种实施方式，其描述较为具体和详细，但并不能因此而理解为对申请专利范围的限制。应当指出的是，对于本领域的普通技术人员来说，在不脱离本申请构思的前提下，还可以做出若干变形和改进，这些都属于本申请的保护范围。因此，本申请专利的保护范围应以所附权利要求为准。

Claims (24)

  1. 一种高压电缆绝缘材料连续挤出加工特性评价优化方法，包括：
    步骤A1，将被测材料在设定温度下加热成熔体，将熔体通过毛细管模具连续挤出，在挤出过程中连续测量和记录毛细管的入口压力P，熔体挤出的质量增长速率w和熔体样条的直径D’，得到熔体流动的表观剪切粘度η a；
    步骤A2，利用样条直径D’计算熔体的出口膨大率δ；
    步骤A3，记录和显示熔体的表观剪切粘度和出口膨大率随时间变化的曲线η a(t)和δ(t)，在η a(t)或δ(t)曲线上将η a(t)或δ(t)增大设定百分比所对应的时间作为交联反应起始时间，记为T X；
    步骤A4，选择参考试样，按照步骤A1-A3对参考试样进行测试，根据参考试样的η a(t)和δ(t)曲线，确定出参考试样的交联反应起始时间T S；
    步骤A5，根据T X和T S定义出指数α，指数α即为表征评价被测材料连续挤出加工特性的数字特征量。
  2. 根据权利要求1所述的方法，其特征在于，
    在步骤A1中，包括：
    步骤A1.1，利用挤出熔体的质量增长速率w，根据下式(1)计算熔体流动的剪切速率
    Figure PCTCN2022136788-appb-100001
    Figure PCTCN2022136788-appb-100002
    式中ρ为熔体密度，C＝1.02×10 4/cm 3为设备常数；
    步骤A1.2，利用毛细管入口压力数据P，根据下式(2)得到熔体流动的剪切应力τ
    Figure PCTCN2022136788-appb-100003
    式中P 0为实验环境的大气压，取作0.1MPa；
    步骤A1.3，利用计算得到的τ和
    Figure PCTCN2022136788-appb-100004
    数值，根据下式(3)得到熔体流动的表观剪切粘度η a：
    Figure PCTCN2022136788-appb-100005
    式中τ为熔体流动的剪切应力，
    Figure PCTCN2022136788-appb-100006
    为熔体流动的剪切速率。
  3. 根据权利要求1所述的方法，其特征在于，
    在步骤A1中，以60秒为一个数据周期对η a进行计算。
  4. 根据权利要求1所述的方法，其特征在于，
    在步骤A2中，利用样条直径D’根据下式(4)计算熔体的出口膨大率δ。
    Figure PCTCN2022136788-appb-100007
  5. 根据权利要求1所述的方法，其特征在于，
    在步骤A3中，设定百分比为10％。
  6. 根据权利要求1所述的方法，其特征在于，
    在步骤A4中，参考试样采用低密度聚乙烯树脂、交联剂以及抗氧剂制作，其中，交联剂为过氧化二异丙苯-DCP，抗氧剂为抗氧剂1010，按照100phr低密度聚乙烯添加2phrDCP和0.3phr抗氧剂1010的比例配制。
  7. 根据权利要求1所述的方法，其特征在于，
    在步骤A4中，测试时调整螺杆挤出机转速，使得挤出熔体的初始剪切速率在1000～1200s -1范围之内，并以该转速连续进行实验测试，最终确定出参考试样的交联反应起始时间。
  8. 根据权利要求1所述的方法，其特征在于，
    在步骤A5中，α指数按照下式(5)定义：
    Figure PCTCN2022136788-appb-100008
    若α>0，表示被测材料的连续挤出加工特性高于参考试样，并且数值越大代表材料在设备中连续加工的时间越长；
    若α<0，表示被测材料的连续挤出加工特性低于参考试样，并且绝对值越大代表材料在设备中连续加工的时间越短。
  9. 一种高压电缆绝缘材料连续挤出加工特性评价优化装置，用于实现根据权利要求1-8所述的方法，
    测试装置包括：设定规格的单螺杆挤出机和毛细管挤出模具，在设定的挤出加工条件下，将被测材料熔体由单螺杆挤出机通过毛细管连续挤出；
    在毛细管模具入口处设置一个多孔节流装置，聚合物熔体通过所述多孔节流装置进入挤出毛细管；
    在毛细管入口处设置熔体压力传感器，用于连续测量毛细管入口的熔体压力；
    对于通过毛细管挤出之后的熔体，利用自动称重装置，连续测量单位时间中挤出熔体的质量；
    在挤出熔体的出口处设置非接触式光学测径仪，用于连续测量挤出熔体样条的直径。
  10. 根据权利要求9所述的装置，其特征在于，
    测试装置中，单螺杆挤出机规格为：螺杆直径Φ20mm，长径比20:1，压缩比1:1.18；称重装置量程100g，精度1mg；测径仪量程5mm，精度5μm。
  11. 根据权利要求9所述的装置，其特征在于，
    节流装置包括两片100目不锈钢滤网和一片500目不锈钢滤网，三片不锈钢滤网组成三明治组合结构，节流装置安装在毛细管模具的入口处，带有节流装置的毛细管模具整体与单螺杆挤出机连接。
  12. 根据权利要求9所述的装置，其特征在于，
    毛细管模芯参数为，毛细管直径D＝1.0±0.013mm，长度L＝30.0±0.13mm，入口角A＝40°±0°30’。
  13. 一种高压电缆交联聚乙烯绝缘材料连续挤出加工工艺的优化方法，其特征在于，包括：
    步骤B1，采用设定的可交联聚乙烯绝缘材料，根据实际生产中所使用的大型挤出机的加热段分段数量，选择结构相仿、加热段数量相同的小型单螺杆挤出机；
    步骤B2，将所述可交联聚乙烯绝缘材料在设定的加工工艺条件下加热成熔体，将熔体由单螺杆挤出机通过毛细管模具连续挤出，在挤出过程中连续测量和记录毛细管的入口压力P，熔体挤出的质量增长速率w和熔体样条的直径D’，得到熔体流动的表观剪切粘度η a；
    步骤B3，利用样条直径D’计算熔体的出口膨大率δ；
    步骤B4，记录和显示熔体的表观剪切粘度和出口膨大率随时间变化的曲线η a(t)和δ(t)，在η a(t)或δ(t)曲线上将η a(t)或δ(t)增大设定百分比所对应的时间作为交联反应起始时间，记为T X；
    步骤B5，设置多组不同的工艺条件，分别在每组工艺条件下，将被测材料熔体通过毛细管模具连续挤出，重新测试材料的交联反应起始时间T X，获得每一组与加工工艺条件相关的T X值；
    步骤B6，将T X达到最大值对应的剪切粘度η a作为熔体处于最佳流动状态的数值特征，将达到该剪切粘度所对应的工艺条件作为大长度海缆挤出加工的最优条件；
    步骤B7，按照步骤B6中小型挤出机试验获得的工艺参数规律，设置实际挤出机的生产工艺参数，通过微调得到最优的工艺参数。
  14. 根据权利要求13所述的高压电缆交联聚乙烯绝缘材料连续挤出加工特性的优化方法，其特征在于，
    在步骤B2中，加工工艺条件包括：螺杆挤出机螺杆转速以及每段加热段的工作温度。
  15. 根据权利要求13所述的方法，其特征在于，
    在步骤B2中，包括：
    步骤B2.1，利用挤出熔体的质量增长速率w，根据下式(1)计算熔体流动的剪切速率
    Figure PCTCN2022136788-appb-100009
    Figure PCTCN2022136788-appb-100010
    式中ρ为熔体密度，C＝1.02×10 4/cm 3为设备常数；
    步骤B2.2，利用毛细管入口压力数据P，根据下式(2)得到熔体流动的剪切应力τ：
    Figure PCTCN2022136788-appb-100011
    式中P 0为实验环境的大气压，取作0.1MPa；
    步骤B2.3，利用计算得到的τ和
    Figure PCTCN2022136788-appb-100012
    数值，根据下式(3)得到熔体流动的表观剪切粘度η a：
    Figure PCTCN2022136788-appb-100013
    式中τ为熔体流动的剪切应力，
    Figure PCTCN2022136788-appb-100014
    为熔体流动的剪切速率。
  16. 根据权利要求13所述的方法，其特征在于，
    在步骤B2中，以60秒为一个数据周期对η a进行计算。
  17. 根据权利要求13所述的方法，其特征在于，
    在步骤B3中，利用样条直径D’根据下式(4)计算熔体的出口膨大率δ：
    Figure PCTCN2022136788-appb-100015
    记录和显示熔体的表观剪切粘度和出口膨大率随时间变化的曲线η a(t)和δ(t)。
  18. 根据权利要求13所述的方法，其特征在于，
    在步骤B4中，设定百分比为10％。
  19. 根据权利要求13所述的方法，其特征在于，
    在步骤B5中，在每组工艺条件中，每个加热段及挤出机头的温度以及螺杆转速不完全相同。
  20. 一种用于高压电缆交联聚乙烯绝缘材料连续挤出加工工艺的优化装置，用于实现根据权利要求13-19所述的方法，
    所述优化装置包括：设定规格的单螺杆挤出机和毛细管挤出模具，
    在设定的挤出加工条件下，将被测材料熔体由单螺杆挤出机通过毛细管连续挤出；
    在毛细管模具入口处设置一个多孔节流装置，聚合物熔体通过所述多孔节流装置进入挤出毛细管；
    在毛细管入口处设置熔体压力传感器，用于连续测量毛细管入口的熔体压力；
    对于通过毛细管挤出之后的熔体，利用自动称重装置，连续测量单位时间中挤出熔体的质量；
    在挤出熔体的出口处设置非接触式光学测径仪，用于连续测量挤出熔体样条的直径。
  21. 根据权利要求20所述的装置，其特征在于，
    单螺杆挤出机与实际生产中所使用的大型挤出机结构相仿，加热段分段数量相同。
  22. 根据权利要求20所述的用于高压电缆交联聚乙烯绝缘材料连续挤出工艺的优化装置，其特征在于，
    优化装置中，称重装置量程100g，精度1mg；测径仪量程5mm，精度5μm。
  23. 根据权利要求20所述的装置，其特征在于，
    节流装置包括两片100目不锈钢滤网和一片500目不锈钢滤网，三片不锈钢滤网组成三明治组合结构，节流装置安装在毛细管模具的入口处，带有节流装置的毛细管模具整体与单螺杆挤出机连接。
  24. 根据权利要求20所述的装置，其特征在于，
    毛细管模芯参数为，毛细管直径D＝1.0±0.013mm，长度L＝30.0±0.13mm，入口角A＝40°±0°30’。
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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1664556A (zh) * 2005-03-04 2005-09-07 华南理工大学 聚合物毛细管正弦脉动挤出流变仪
CN1773245A (zh) * 2005-11-12 2006-05-17 大连理工大学 一种在线式聚合物双毛细管挤出流变仪
CN101430267A (zh) * 2008-12-12 2009-05-13 湖南工业大学 一种聚合物复合材料流变特性的测试方法及装置
CN104568663A (zh) * 2015-01-04 2015-04-29 华南理工大学 一种在线测量聚合物熔体流变参数的装置及方法
CN106124362A (zh) * 2016-06-07 2016-11-16 中南大学 一种超声塑化毛细管流变仪及粘度测试方法
CN114216926A (zh) * 2021-11-18 2022-03-22 深圳供电局有限公司 一种交联半导电屏蔽材料流变性能评价方法
US11378505B1 (en) * 2021-10-08 2022-07-05 Coretech System Co., Ltd. Method of measuring extensional viscosity of polymer melts and capillary injection system

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1664556A (zh) * 2005-03-04 2005-09-07 华南理工大学 聚合物毛细管正弦脉动挤出流变仪
CN1773245A (zh) * 2005-11-12 2006-05-17 大连理工大学 一种在线式聚合物双毛细管挤出流变仪
CN101430267A (zh) * 2008-12-12 2009-05-13 湖南工业大学 一种聚合物复合材料流变特性的测试方法及装置
CN104568663A (zh) * 2015-01-04 2015-04-29 华南理工大学 一种在线测量聚合物熔体流变参数的装置及方法
CN106124362A (zh) * 2016-06-07 2016-11-16 中南大学 一种超声塑化毛细管流变仪及粘度测试方法
US11378505B1 (en) * 2021-10-08 2022-07-05 Coretech System Co., Ltd. Method of measuring extensional viscosity of polymer melts and capillary injection system
CN114216926A (zh) * 2021-11-18 2022-03-22 深圳供电局有限公司 一种交联半导电屏蔽材料流变性能评价方法

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