Evaluation method for gel aggregation condition in extruded material

Abstract

The invention relates to the field of cable insulation material testing, in particular to a method for evaluating the aggregation condition of gel in an extruded material. The method for evaluating the gel aggregation condition in the extruded material comprises the following steps: in the production process of the cable insulation material, melting, blending and extruding raw materials for preparing the cable insulation material to prepare the extruded material; or melting and plasticizing the cable insulation material, and homogenizing the melt to prepare an extruded material; filtering the extrudate through a filter screen, and respectively collecting a first extrudate on the feeding side of the filter screen and a second extrudate on the discharging side of the filter screen; obtaining the crystallinity of the first extruded material on the feeding side of the filter screen and the crystallinity of the second extruded material on the discharging side of the filter screen; according to the difference value between the crystallinity of the second extruded material on the discharging side of the filter screen and the crystallinity of the first extruded material on the feeding side of the filter screen, the gel aggregation condition in the extruded materials is obtained. According to the method, complicated gel separation and counting operation is not needed, and the gel aggregation degree can be quickly, intuitively and accurately reflected through the crystallinity.

Description

Technical Field

[0001] This application relates to the field of cable insulation material testing, and in particular to a method for evaluating gel aggregation in extruded materials. Background Technology

[0002] Cables are critical equipment for transmitting high-voltage electricity. Their shielding layer needs to optimize the electric field distribution, protect the insulation layer, and improve the safety of cable operation. Their insulation layer needs to have excellent electrical insulation performance, mechanical strength, and aging resistance to ensure the safe and stable transmission of power. Polyethylene and other matrix resins are the core materials of the main insulation layer of high-voltage cables. During the extrusion process, they may experience excessive cross-linking of molecular chains due to local overheating, abnormal reactions caused by catalyst residue, or oxidative degradation and impurity contamination, resulting in the formation of gel aggregates.

[0003] Detecting or evaluating gel aggregation can promptly identify inherent quality defects in the extruded material, preventing problems such as reduced insulation breakdown strength and surface unevenness caused by gel particles. This ensures the stability of the extrusion process and the insulation performance of the finished cable. At the same time, it provides data support for optimizing the production process and improving material purity, thereby ensuring the safety and reliability of the cable during long-term operation. Summary of the Invention

[0004] Therefore, it is necessary to provide a reliable, efficient and accurate method for evaluating gel aggregation in extruded materials.

[0005] A first aspect of this application provides a method for evaluating gel aggregation in extruded materials, comprising the following steps:

[0006] The raw materials for cable insulation are melt-blended and extruded to prepare extruded materials; or the cable insulation material is melt-plasticized and homogenized to prepare extruded materials.

[0007] The extruded material is filtered through a filter screen, and the first extruded material from the feed side of the filter screen and the second extruded material from the discharge side of the filter screen are collected respectively.

[0008] The crystallinity of the first extruded material on the feed side of the filter screen and the second extruded material on the discharge side of the filter screen is obtained;

[0009] The gel aggregation status in the extruded material is obtained based on the difference between the crystallinity of the second extruded material on the filter screen discharge side and the crystallinity of the first extruded material on the filter screen feed side.

[0010] In one embodiment, the step of obtaining the gel aggregation in the extrudate includes:

[0011] The lower the difference in crystallinity between the second extruded material on the filter screen discharge side and the first extruded material on the filter screen feed side, the less gel aggregation occurs in the extruded material.

[0012] The mesh size of the filter screen is 300 to 500 mesh.

[0013] In one embodiment, the step of obtaining the gel aggregation in the extrudate further includes:

[0014] Based on the difference between the crystallinity of the second extruded material on the filter screen discharge side and the crystallinity of the first extruded material on the filter screen feed side, the gel aggregation in the extruded material is determined to be level 0 and level 1.

[0015] If the difference between the crystallinity of the second extruded material on the filter screen discharge side and the crystallinity of the first extruded material on the filter screen feed side is ≤10%, then the gel aggregation of the extruded material is confirmed as level 0.

[0016] When the difference between the crystallinity of the second extruded material on the filter screen discharge side and the crystallinity of the first extruded material on the filter screen feed side is greater than 10%, the gel aggregation of the extruded material is confirmed as level 1.

[0017] Among them, the gel aggregation of the extrudate confirmed as grade 0 is lower than that of the extrudate confirmed as grade 1.

[0018] In one embodiment, the step of obtaining the crystallinity of the first extruded material on the feed side of the filter screen and the second extruded material on the discharge side of the filter screen includes:

[0019] The first extruded material is stripped off from the feed side of the filter screen, and the second extruded material is stripped off from the discharge side of the filter screen;

[0020] X-ray diffraction was used to test the first extruded material and the second extruded material to obtain the crystallinity of the first extruded material on the feed side of the filter screen and the second extruded material on the discharge side of the filter screen.

[0021] In one embodiment, the detection parameters of the X-ray diffraction method have one or more of the following characteristics:

[0022] (1) The angle 2θ between the incident direction and the diffraction direction of the X-rays is 5°~90°;

[0023] (2) The step size is 0.01°~0.03°;

[0024] (3) The target material used to generate X-rays is a copper target;

[0025] (4) The wavelength of X-rays is 0.15 nm to 0.16 nm;

[0026] (5) The tube voltage is 35kV~45kV;

[0027] (6) The current is 35mA~45mA.

[0028] In one embodiment, the first extrusion crystallinity on the filter feed side and / or the second extrusion crystallinity on the filter discharge side are calculated using the following formula: X c =A c / (A c +A a )×100%.

[0029] Among them, X c Indicates the crystallinity of the first extrudate and / or the second extrudate; A c A represents the diffraction intensity of the first extruded material and / or the second extruded material at the characteristic peak of the crystalline region; a This represents the diffraction intensity of the first extruded material and / or the second extruded material at the characteristic peak in the amorphous region.

[0030] In one embodiment, in the step of testing the first extrudate and the second extrudate using X-ray diffraction, the area of ​​the sample to be tested made from the first extrudate and / or the second extrudate is 1 cm². 2 ~4cm 2 The thickness of the test sample made from the first extrusion and / or the second extrusion is 1 μm to 100 μm.

[0031] In one embodiment, the raw materials for preparing the cable insulation material include polyethylene matrix resin and functional additives.

[0032] In one embodiment, the cable insulation material is cross-linked polyethylene insulation material.

[0033] In one embodiment, the weight-average molecular weight of the polyethylene matrix resin is 60,000 to 110,000.

[0034] In one embodiment, the number-average molecular weight of the polyethylene matrix resin is 12,000 to 20,000.

[0035] In one embodiment, the ratio of the weight-average molecular weight to the number-average molecular weight of the polyethylene matrix resin is 3 to 7.5.

[0036] A second aspect of this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements at least one step of the method for evaluating gel aggregation in extruded material according to any one of the first aspects of this application.

[0037] The method for evaluating gel aggregation in extruded materials provided in this application has at least the following beneficial effects:

[0038] The method for evaluating gel aggregation in extruded materials provided in this application obtains the gel aggregation status of the extruded materials by acquiring the crystallinity difference between the first extruded material on the feed side of the filter screen and the second extruded material on the discharge side of the filter screen. This method does not require complex gel separation and counting operations, and can quickly, intuitively and accurately reflect the degree of gel aggregation through crystallinity.

[0039] Specifically, this application finds that low molecular weight resins used in cable insulation materials have relatively high crystallinity due to their lower degree of chain entanglement and easier orderly molecular chain stacking; while high molecular weight resins have lower crystallinity due to kinetic hindrance. Therefore, the crystallinity decreases on the filter feed side due to gel aggregation, while the crystallinity on the filter discharge side remains relatively stable. The difference between the two can accurately correlate the amount and distribution of gel accumulation. This not only simplifies the testing process and shortens the evaluation cycle, but also allows for dynamic tracking of real-time gel aggregation during extrusion. This provides technical guidance for rapidly analyzing the impact of extrusion process conditions on insulation materials or the compatibility of insulation materials with extrusion processes, as well as for the structural control of insulation materials, the development of insulation material formulations, and the optimization of cable extrusion process parameters. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of this application and to more completely understand this application and its beneficial effects, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of this application. Those skilled in the art can obtain other drawings based on these drawings without creative effort. It should also be noted that the drawings are all drawn in a simplified form and are only used to conveniently and clearly assist in illustrating this application. The various dimensions of each component shown in the drawings are arbitrarily shown; they may be precise or not drawn to scale. For example, to make the illustration clearer, the dimensions of some components are appropriately exaggerated in the drawings. Unless otherwise specified, the components in the drawings are not drawn to scale. This application does not limit each dimension of each component.

[0041] In the following description, the same reference numerals indicate the same parts.

[0042] Figure 1The images show the XRD patterns of the first extruded material on the feed side and the second extruded material on the discharge side of the filter screen in Examples 1-1 and 1-2; (a) is the XRD pattern of the first extruded material on the feed side and the second extruded material on the discharge side of the filter screen obtained in Example 1-1; (b) is the XRD pattern of the first extruded material on the feed side and the second extruded material on the discharge side of the filter screen obtained in Example 1-2; (c) is the XRD pattern of the first extruded material on the feed side and the second extruded material on the discharge side of the filter screen obtained in Example 1-3; (d) is the XRD pattern of the first extruded material on the feed side and the second extruded material on the discharge side of the filter screen obtained in Example 1-4; and (e) is the XRD pattern of the first extruded material on the feed side and the second extruded material on the discharge side of the filter screen obtained in Example 1-5.

[0043] Figure 2 The diagrams show the Young's modulus of the first extruded material on the feed side and the second extruded material on the discharge side of the filter screen in Examples 1-1 and 1-2. (a) is the Young's modulus of the first extruded material on the feed side of the filter screen obtained in Example 1-1; (b) is the Young's modulus of the second extruded material on the discharge side of the filter screen obtained in Example 1-1; (c) is the Young's modulus of the first extruded material on the feed side of the filter screen obtained in Example 1-2; and (d) is the Young's modulus of the second extruded material on the discharge side of the filter screen obtained in Example 1-2. Detailed Implementation

[0044] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0046] the term

[0047] Unless otherwise stated or in case of contradiction, the terms or phrases used herein shall have the following meanings:

[0048] In this application, the terms "multiple", "various", "multiple times", etc., unless otherwise specified, refer to a quantity greater than or equal to 2. For example, "one or more" means one or more than or equal to two.

[0049] In this application, terms such as "preferred," "better," "more suitable," and "ideal" are merely descriptions of more effective implementation methods or embodiments, and should be understood not to limit the scope of protection of this application. If multiple "preferred" terms appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "preferred" term shall be independent.

[0050] In this application, terms such as "further," "even more," and "particularly" are used for descriptive purposes and to indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0051] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0052] In this application, when numerical intervals (i.e., numerical ranges) are mentioned, unless otherwise specified, the distribution of selectable numerical values ​​within the numerical interval is considered continuous, and includes the two endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every numerical value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that numerical interval, including the two endpoint integers of the numerical range, as well as every integer between the two endpoints, is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed herein should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include numerical interval types such as percentage intervals, ratio intervals, and proportion intervals.

[0053] In this application, unless otherwise specified, the temperature parameters are allowed to be either constant temperature treatment or variations within a certain temperature range. It should be understood that the constant temperature treatment allows temperature fluctuations within the precision range controlled by the instrument. Fluctuations are permitted within ranges such as ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C.

[0054] High-voltage cables are the main arteries of power transmission. The structure of a high-voltage cable is typically a multi-layered composite structure, with its basic components including: a conductor, a conductor shielding layer, an insulation layer, an insulation shielding layer, and an outer sheath. The conductor shielding layer and the insulation shielding layer are collectively referred to as the shielding layer, and the conductor, conductor shielding layer, insulation layer, and insulation shielding layer are collectively referred to as the cable insulating core.

[0055] Because high-voltage cables operate under constant high voltage and high current, resulting in electric field stress and thermal effects, the presence of impurities, gel aggregates, or other contaminants in the insulation layer can create localized electric field concentration points. This can easily lead to partial discharge, insulation breakdown, and even cable failure, seriously threatening the safe and stable operation of the power system. Therefore, the cleanliness control requirements for the insulation layer of high-voltage cables are extremely high. Optimizing the melt extrusion process or the composition of the insulation material during processing to reduce physical impurities and large molecular weight gels such as ultra-high molecular weight gels is a key technology for the large-scale production of ultra-clean insulation materials.

[0056] In the extrusion process of cable insulation cores, optimizing the three-layer (conductor shielding layer, insulation layer, insulation shielding layer) co-extrusion process and production line speed, improving the rheological properties of the insulation material, and avoiding gel aggregation phenomena such as pre-crosslinking are also crucial for the stable extrusion of long lengths of XLPE insulation cores.

[0057] Currently, melt filtration systems are typically used in the production of insulation materials or insulated wire cores. These systems employ high-precision filters to reduce physical and chemical impurities, ensuring material cleanliness. However, chemical gels induced by polyethylene macromolecules or pre-crosslinking, along with other physical impurities, gradually accumulate on the surface of the precision filter during processing. Therefore, the current method primarily relies on visual observation of impurities on the extruded material to assess gel aggregation, which is then fed back to production. However, this visual observation method has significant limitations: the results are highly subjective and heavily influenced by operator experience, making it difficult to quantify the degree of gel aggregation, leading to potentially conflicting conclusions from different personnel. Furthermore, it struggles to accurately correlate production process parameters with gel formation, failing to provide scientific and objective data for process optimization and potentially causing raw material waste or quality issues in the finished product. Therefore, a method for evaluating gel aggregation in insulation materials is urgently needed to provide data support for optimizing production processes, preparing raw material components, and improving material purity, thereby ensuring the safety and reliability of cables during long-term operation.

[0058] Based on this, the first aspect of this application provides a method for evaluating gel aggregation in extruded materials, comprising the following steps:

[0059] S10: The raw materials for preparing cable insulation are melt-blended and extruded to prepare extruded material; or the cable insulation material is melt-plasticized and homogenized to prepare extruded material; the extruded material is filtered through a filter screen, and the first extruded material on the feed side of the filter screen and the second extruded material on the discharge side of the filter screen are collected respectively.

[0060] S20 obtains the crystallinity of the first extruded material on the feed side of the filter screen and the second extruded material on the discharge side of the filter screen.

[0061] S30: Based on the difference between the crystallinity of the second extruded material on the filter screen discharge side and the crystallinity of the first extruded material on the filter screen feed side, the gel aggregation status in the extruded material is obtained.

[0062] This application discovers that physical impurities accumulated on the filter screen surface can be observed using a high-magnification optical microscope. However, gel aggregates such as macromolecules or pre-crosslinked materials on the filter screen feed side have relatively low content, making sampling and analysis difficult and inconvenient to perform molecular weight testing and analysis of gel aggregates using conventional methods such as gel permeation chromatography. Therefore, the method for evaluating gel aggregation in extruded materials provided in this application obtains the gel aggregation status of the extruded materials by acquiring the crystallinity difference between the first extruded material on the filter screen feed side and the second extruded material on the filter screen discharge side. This method does not require complex gel separation and counting operations and can quickly, intuitively, and accurately reflect the degree of gel aggregation through crystallinity.

[0063] Specifically, this application finds that low molecular weight resin matrices in cable insulation materials have relatively high crystallinity due to their lower degree of chain entanglement and easier orderly molecular chain stacking; while high molecular weight resin matrices experience a decrease in crystallinity due to kinetic hindrance. Therefore, the crystallinity decreases on the filter feed side due to gel aggregation, while the crystallinity on the filter discharge side remains relatively stable. The difference between the two can accurately correlate the amount and distribution of gel accumulation. This not only simplifies the testing process and shortens the evaluation cycle but also allows for dynamic tracking of real-time gel aggregation during extrusion. This provides technical guidance for rapidly analyzing the impact of extrusion process conditions on insulation materials or the compatibility of insulation materials with extrusion processes, as well as for the structural control of insulation materials, the development of insulation material formulations, and the optimization of cable extrusion process parameters.

[0064] In some examples, S30: the step of obtaining the gel aggregation in the extrudate includes:

[0065] The lower the difference in crystallinity between the second extruded material on the filter screen discharge side and the first extruded material on the filter screen feed side, the less gel aggregation occurs in the extruded material.

[0066] Understandably, the first extruded material and the second extruded material in this application correspond to the same type of cable insulation material before and after extrusion, respectively, and their preparation components are the same.

[0067] Optionally, the mesh size of the filter screen is 300 to 500 mesh. Since melt filtration systems are typically used in the production process of insulating materials or insulated wire cores, the extruded material currently needs to be filtered through a filter screen during the production process. The mesh size of the filter screen defined in the evaluation method of this application is compatible with the production process of the insulating material / insulated wire core. For example, the mesh size of the filter screen includes, but is not limited to, 300 mesh, 350 mesh, 400 mesh, 450 mesh, or 500 mesh, or any two of the above values ​​as endpoints.

[0068] This application uses a method that judges gel aggregation by the difference in crystallinity. This method can objectively reflect the degree of gel aggregation with a quantitative data point of crystallinity difference, avoiding the subjectivity and reliance on experience from visual observation. If the difference in crystallinity is low, it indicates that the change in the material's crystallinity properties due to the retention of gel aggregates before and after filtration is small. In other words, the number of gel aggregates retained by the filter is small and the degree of accumulation is low, indicating that the extruded material itself has a high degree of cleanliness and few gel impurities.

[0069] Furthermore, the highest difference in crystallinity between extruded materials can be tested during production as a key threshold for determining whether the material meets production standards. When the actual measured crystallinity difference is below this threshold, it indicates that the degree of gel aggregation in the extruded material is within an acceptable range, ensuring the stability of subsequent processing and the quality of the finished product. If it exceeds this threshold, it suggests that the production process needs to be adjusted in a timely manner (such as optimizing the raw material ratio and controlling the extrusion process parameters), thereby achieving dynamic monitoring and precise control of gel aggregation, improving production efficiency and the reliability of cable insulation performance.

[0070] For example, S30: The step of obtaining the gel aggregation in the extrudate includes:

[0071] Based on the difference between the crystallinity of the second extruded material on the filter screen discharge side and the crystallinity of the first extruded material on the filter screen feed side, the gel aggregation in the extruded material is determined to be level 0 and level 1.

[0072] If the difference between the crystallinity of the second extruded material on the filter screen discharge side and the crystallinity of the first extruded material on the filter screen feed side is ≤10%, then the gel aggregation of the extruded material is confirmed as level 0.

[0073] When the difference between the crystallinity of the second extruded material on the filter screen discharge side and the crystallinity of the first extruded material on the filter screen feed side is greater than 10%, the gel aggregation of the extruded material is confirmed as level 1.

[0074] Optionally, the extrudate classified as grade 0 has lower gel aggregation than the extrudate classified as grade 1.

[0075] The above indicates that a difference of 10% is the production threshold for extruded materials after extrusion of raw materials for cable insulation. When the crystallinity difference is ≤10%, the extruded material is classified as Grade 0, indicating a low degree of gel aggregation, which is beneficial for further production. When the crystallinity difference is >10%, the extruded material is classified as Grade 1, indicating a high degree of gel aggregation. At this point, the impurity content is high, and further optimization of the raw material ratio or extrusion process parameters is required to reduce gel aggregation caused by pre-crosslinking.

[0076] In some examples, step S20: obtaining the crystallinity of the extruded material on the feed side of the filter screen and the extruded material on the discharge side of the filter screen includes:

[0077] The first extruded material is stripped off from the feed side of the filter screen, and the second extruded material is stripped off from the discharge side of the filter screen;

[0078] X-ray diffraction was used to test the first extruded material and the second extruded material to obtain the crystallinity of the first extruded material on the feed side of the filter screen and the second extruded material on the discharge side of the filter screen.

[0079] This application reveals that when using differential scanning calorimetry (DSC) and nuclear magnetic resonance spectroscopy (NMR) to test crystallinity, a hot stage or oven is required to heat and melt the gel aggregates on the filter surface before collecting the melt. Since the content of polymeric gel aggregates on the filter surface is very low, multiple filters need to be processed to accumulate a sufficient weight of melt sample, making both methods rather cumbersome.

[0080] The X-ray diffraction method provided in this example can perform in-situ, non-destructive testing of polymeric gel aggregates within a depth range of 0-100 μm on the surface of a filter. Crystallinity can be detected through θ-2θ reflection modes. The single test is quick, meeting the needs of industrial production lines for rapid testing of material properties.

[0081] Furthermore, in this example, the steps of peeling off the first extrusion material on the feed side of the filter screen and peeling off the second extrusion material on the discharge side of the filter screen include: heating the filter screen containing the extrusion material to the melting temperature of the raw material for preparing cable insulation material, peeling off the first extrusion material on the feed side of the filter screen, and peeling off the second extrusion material on the discharge side of the filter screen.

[0082] Understandably, if the melt filtration system used in the production of insulating materials or insulating wire cores consists of multiple overlapping filter screens of different mesh sizes, and the 300-500 mesh filter screen specified in this application is one of them, the overlapping composite filter screen can also be heated to the melting temperature to achieve the layer-by-layer peeling of the composite filter screen.

[0083] In some examples, the detection parameters for X-ray diffraction include an angle 2θ between the incident and diffraction directions of the X-rays, ranging from 5° to 90°. For example, the angle 2θ between the incident and diffraction directions includes, but is not limited to, 5°, 10°, 12°, 14°, 16°, 18°, 20°, 22°, 24°, 26°, 28°, 30°, 40°, 50°, 60°, 70°, 80°, or 90°, or any two of these values ​​as endpoints within a range. It is understood that the angle 2θ between the incident and diffraction directions can encompass both the diffraction intensity at the characteristic peaks in amorphous regions and the diffraction intensity at the characteristic peaks in crystalline regions.

[0084] In some examples, the detection parameters for X-ray diffraction include a step size of 0.01° to 0.03°. For example, the step size includes, but is not limited to, 0.01°, 0.02°, or 0.03°, or any two of the above point values ​​as endpoints.

[0085] In some of these examples, the detection parameters for X-ray diffraction include: the target material used to generate X-rays is a copper target.

[0086] In some examples, the detection parameters for X-ray diffraction include: the wavelength of the X-rays being 0.15 nm to 0.16 nm. For example, the wavelength of the X-rays includes, but is not limited to, 0.15 nm, 0.152 nm, 0.153 nm, 0.154 nm, 0.155 nm, 0.156 nm, or 0.16 nm.

[0087] In some examples, the detection parameters for X-ray diffraction include a tube voltage of 35kV to 45kV. The tube voltage includes, but is not limited to, 35kV, 38kV, 40kV, 42kV, 43kV, or 45kV, or any two of the above values ​​as endpoints.

[0088] In some examples, the detection parameters for X-ray diffraction include a current of 35 mA to 45 mA. The current includes, but is not limited to, 35 mA, 38 mA, 40 mA, 42 mA, or 45 mA.

[0089] In some examples, the first extruded material crystallinity on the filter feed side and / or the second extruded material crystallinity on the filter discharge side are calculated using the following formula: X c =A c / (A c +A a )×100%.

[0090] Among them, X c Indicates the crystallinity of the first extruded material and / or the second extruded material; A c Indicates the diffraction intensity of the first extruded material and / or the second extruded material at the characteristic peak of the crystalline region; A a This represents the diffraction intensity of the first extruded material and / or the second extruded material at the characteristic peak in the amorphous region.

[0091] In some examples, during the step of testing the first extruder and / or the second extruder using X-ray diffraction, the area of ​​the sample to be tested made from the first extruder and / or the second extruder is 1 cm². 2 ~4cm 2The thickness of the test sample made from the first extrusion and / or the second extrusion is 1 μm to 100 μm. As a further example, in the step of testing the first extrusion and / or the second extrusion using X-ray diffraction, the area of ​​the test sample made from the first extrusion and / or the second extrusion is 1 cm × 1 cm. Understandably, to ensure the accuracy of the test results, extrusions from different filter positions can be randomly selected as test samples for parallel testing.

[0092] In some examples, the process parameters for melt blending and extrusion include: rotation speed 300 rpm to 500 rpm, screw temperature 80°C to 120°C, barrel temperature 140°C to 170°C, and feed temperature 165°C to 180°C. Understandably, the evaluation method of this application involves using different matrix resins for cable insulation under the same melt blending and extrusion process conditions during the cable insulation material preparation process to evaluate the influence of the raw materials on gel aggregation in the extruded material. Alternatively, during the cable insulation material preparation process, the same matrix resin can be used under different melt blending and extrusion conditions to evaluate the influence of extrusion process parameters on gel aggregation in the extruded material. Or, in the three-layer co-extrusion process of cable insulation core, the same cross-linked polyethylene insulation material can be used under the same melt plasticizing and melt homogenization process conditions, and the crystallinity of the feed side and extruded side of the extruded material at different extrusion times can be detected to evaluate the influence of extrusion time on gel aggregation in the extruded material.

[0093] In some of these examples, the raw materials for preparing the cable insulation material include polyethylene matrix resin and functional additives.

[0094] In some of these examples, the cable insulation is cross-linked polyethylene insulation.

[0095] Since gel aggregation mainly originates from the pre-crosslinking of polyethylene matrix resin, the evaluation method provided in this application can effectively detect insulating materials with polyethylene matrix resin as the base material.

[0096] In some examples, the weight-average molecular weight of the polyethylene matrix resin is 60,000 to 110,000. For example, the weight-average molecular weight of the polyethylene matrix resin includes, but is not limited to, 60,000, 70,000, 80,000, 100,000, or 110,000.

[0097] In some examples, the number-average molecular weight of the polyethylene matrix resin is 12,000 to 20,000. For example, the number-average molecular weight of the polyethylene matrix resin includes, but is not limited to, 12,000, 13,000, 16,000, 18,000, or 20,000.

[0098] In some examples, the weight-average molecular weight to number-average molecular weight ratio of the polyethylene matrix resin is 3 to 7.5. The weight-average molecular weight to number-average molecular weight ratio of the polyethylene matrix resin includes, but is not limited to, 3, 4, 5, 6, 7, or 7.5.

[0099] Understandably, the above examples illustrate the properties of raw materials for preparing polyethylene matrix resins.

[0100] In some examples, the evaluation method for gel aggregation in the extrudate further includes verifying the gel aggregation in the extrudate using a verification method. Examples of verification methods include, but are not limited to, gel permeation chromatography, differential scanning calorimetry, and atomic force microscopy.

[0101] In some of these examples, the evaluation method for gel aggregation in the extrudate includes the following steps:

[0102] (1) Two different low-density polyethylene base materials and antioxidants were selected as raw materials for the preparation of cable insulation materials. (2) The main machine adopts a reciprocating single-screw or twin-screw extruder. After plasticizing, melt blending and extrusion, the raw materials are obtained as extruded material. The extruded material melt is filtered by a high-precision filter screen and granulated underwater to prepare insulation particles. The process parameters of melt blending and extrusion include: rotation speed 300rpm~500rpm, screw temperature 80℃~120℃, barrel temperature 140℃~170℃, and material temperature 165℃~180℃. The mesh size of the intermediate layer filter screen is 300 mesh~500 mesh. (3) The crystallinity of the first extruded material on the feed side of the filter screen and the second extruded material on the discharge side of the filter screen are tested by X-ray diffraction. Based on the difference between the crystallinity of the second extruded material on the discharge side of the filter screen and the crystallinity of the first extruded material on the feed side of the filter screen, the gel aggregation in different cable insulation materials is determined. In this example, by studying the crystallization differences on the feed and discharge sides of the filter screens made of two different base materials, it is possible to indirectly evaluate the amount of macromolecular gels in different base materials during processing and whether they are suitable for high-voltage cable base materials, which facilitates the control of the composition of the raw materials.

[0103] In other examples, the evaluation method for gel aggregation in the extrudate includes the following steps:

[0104] (1) Select the same low-density polyethylene base material and antioxidant as raw materials for the preparation of cable insulation material. (2) The main machine adopts a reciprocating single screw or twin screw extruder. After plasticizing the raw materials, different melt blending and extrusion process parameters are used to obtain extruded material. The extruded material is filtered by a high-precision filter screen and granulated underwater to prepare insulation material particles. Among them, the different melt blending and extrusion process parameters include: rotation speed 300rpm~500rpm, screw temperature 80℃~120℃, barrel temperature 140℃~170℃, and material temperature 165℃~180℃. The mesh size of the intermediate layer filter screen is 300 mesh~500 mesh. (3) X-ray diffraction method is used to test the crystallinity of the first extruded material on the feed side of the filter screen and the second extruded material on the discharge side of the filter screen. Based on the difference between the crystallinity of the second extruded material on the discharge side of the filter screen and the crystallinity of the first extruded material on the feed side of the filter screen, the gel aggregation in the cable insulation material with the same composition is judged. In this example, by studying the crystallization differences on the feed and discharge sides of the filter screen surface under different melt blending and extrusion conditions for the same base material, the influence of processing technology on gel aggregation can be indirectly evaluated, providing technical guidance for determining the optimal processing parameters of the base material.

[0105] In some examples, the evaluation method for gel aggregation in the extrudate includes the following steps:

[0106] (1) Select the first shielding material, cross-linked polyethylene insulation material, and second shielding material for cables to be used to prepare the conductor shielding layer, the main insulation layer, and the insulation shielding layer, respectively. (2) Based on the CCV catenary cross-linking production line or the VCV vertical cross-linking production line, a three-layer co-extrusion extruder is used to co-extrude the first shielding material, cross-linked polyethylene insulation material, and second shielding material to prepare the cable insulation core. The cross-linked polyethylene insulation material is melt-plasticized, melt-homogenized, and impurity-filtered to obtain the extruded material which enters the die head. Among them, the diameter of the insulating single screw extruder is 175~200 mm, the screw length-to-diameter ratio is 25:1, the temperature of each section of the screw is 110℃~120℃, the screw speed is 10~20 rpm, and the melt temperature is 130℃~140℃. The mesh size of the intermediate layer filter screen is 300 mesh~500 mesh. (3) The crystallinity of the first extruded material on the feed side and the second extruded material on the discharge side of the filter screen was tested by X-ray diffraction. Based on the difference between the crystallinity of the second extruded material on the discharge side and the crystallinity of the first extruded material on the feed side, the gel aggregation of cross-linked polyethylene insulation material under different extrusion times was determined. In this example, by studying the crystallinity difference between the feed side and the discharge side of the filter screen surface under different extrusion times, the influence of extrusion time on the formation of macromolecular gel can be indirectly evaluated, which facilitates the control of extrusion time.

[0107] A second aspect of this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements at least one step of the method for evaluating gel aggregation in extruded material according to any one of the first aspects of this application.

[0108] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. The following are also provided as examples of more readily implementable and detailed embodiments and comparative examples. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0109] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0110] Unless otherwise specified, the raw materials used in the following experiments can be purchased from the market.

[0111] Example 1-1, Example 1-2

[0112] This study evaluates the gel content during the preparation of cross-linked insulation materials using low-density polyethylene as a base material, providing technical guidance for the mass production of insulation materials.

[0113] (1) Preparation of insulating material in Example 1-1: raw materials and formulation components: polyethylene matrix resin 1 (weight average molecular weight of 98,000, number average molecular weight of 16,200, and weight average molecular weight to number average molecular weight ratio of 6.05) and antioxidant 4,4'-thiobis(6-tert-butyl-m-cresol), wherein the polyethylene matrix and antioxidant are in a weight ratio of 1:0.002.

[0114] Example 1-2 Preparation of insulation material raw materials and formulation components: polyethylene matrix resin 2 (weight average molecular weight of 104,000, number average molecular weight of 16,100, weight average molecular weight to number average molecular weight ratio of 6.46) and antioxidant 4,4'-thiobis(6-tert-butyl-m-cresol), wherein the polyethylene matrix and antioxidant are in a weight ratio of 1:0.2%.

[0115] The main difference between Examples 1-1 and 1-2 is that the raw materials used in the preparation are different, but the following steps are the same.

[0116] (2) Melt blending and extrusion: A reciprocating single-screw extruder or twin-screw extruder is used. Polyethylene base material and antioxidant are fed into the extruder through a gravity feeder. The materials are processed sequentially through plasticizing, melt blending, extrusion, melt filtration, and underwater pelletizing to prepare insulating material particles. In the melt blending and extrusion steps, the extruder screw speed is 400 rpm, and the temperature settings for each section of the extruder are 90℃, 170℃, 173℃, 165℃, 158℃, 157℃, and 154℃, respectively. The screw temperature is 95℃, and the material temperature is 175℃. In the precision filtration step, a 5-layer filter structure is used (from the feed side to the discharge side, the filter screens are 80 mesh, 250 mesh, 500 mesh, 250 mesh, and 50 mesh, respectively). The first extruded material from the feed side and the second extruded material from the discharge side are collected from the 500 mesh filter screen.

[0117] (3) X-ray diffraction detection: The 5-layer filter screen was heated to the melting temperature of the insulating material. The multiple layers of filter screen were peeled off layer by layer using tweezers, taking care to avoid mechanical damage during the peeling process. A 1cm × 1cm square area was randomly selected from the feed and discharge sides of the peeled 500-mesh filter screen as the X-ray diffraction test sample. The sample was continuously scanned using an X-ray diffractometer. Test parameters: 2θ range 18°~26°, step size 0.02°; instrument parameters: Cu target, wavelength 0.154 nm, tube voltage 40 kV, current 40 mA. The corresponding XRD patterns of the first extruded material on the feed side and the second extruded material on the discharge side of the filter screen are shown below. Figure 1 As shown. Figure 1 (a) is the XRD pattern of the first extruded material on the feed side of the filter screen and the second extruded material on the discharge side of the filter screen obtained from the test in Example 1-1; Figure 1 (b) is the XRD pattern of the first extruded material on the feed side and the second extruded material on the discharge side of the filter screen obtained from the tests in Examples 1-2.

[0118] The formulas for calculating the crystallinity of the first extruded material on the feed side of the filter screen and the second extruded material on the discharge side of the filter screen are as follows:

[0119] X c =A c / (A c +A a )×100%;

[0120] Among them, X c Indicates the crystallinity of the first extrusion / second extrusion; A c A represents the diffraction intensity of the first / second extruded material at the characteristic peak of the crystalline region; a This represents the diffraction intensity of the first / second extruded material at the characteristic peak in the amorphous region. Figure 1In the figure, the characteristic peaks of 2θ at 21°~22° are characteristic peaks of the crystalline region; the characteristic peaks of 2θ at 23.5°~25° are characteristic peaks of the amorphous region.

[0121] In this embodiment, the crystallinity of the extruded material on the feed / discharge side of the filter screen is calculated as shown in Table 1.

[0122] Table 1

[0123]

[0124] (4) The crystallinity of the test in step (3) was verified by atomic force microscopy: a 1×1cm square area was randomly selected on the filter screen as the AFM test sample. The sample was placed on the AFM test platform, and its morphology and modulus distribution were tested using the AFM-QNM mode. The effective scanning area of ​​the AFM probe was 10μm×10μm, the scanning resolution was 256×256, and the scanning frequency was 0.5 Hz. Generally, the crystallinity of the area with higher surface modulus is also relatively higher. By comparing the difference in surface modulus on both sides of the filter screen, it was inferred that the crystallinity on both sides was different, and the XRD results were further verified. The corresponding Young's modulus diagrams of the first extruded material on the feed side and the second extruded material on the discharge side of the filter screen obtained by the test are shown in the figure. Figure 2 As shown. Figure 2 (a) is the Young's modulus diagram of the first extruded material on the feed side of the filter screen obtained by testing in Example 1-1; Figure 2 (b) is the Young's modulus diagram of the second extruded material on the filter screen outlet side obtained from the test in Example 1-1; Figure 2 (c) is the Young's modulus diagram of the first extruded material on the feed side of the filter screen obtained from the tests in Examples 1-2; Figure 2 (d) is the Young's modulus diagram of the second extruded material on the filter screen discharge side obtained from the test in Examples 1-2.

[0125] Furthermore, the Young's modulus of the first extruded material on the feed side and the second extruded material on the discharge side of the filter screen obtained by the test is shown in Table 2.

[0126] Table 2

[0127]

[0128] As shown in Table 2, the changes in Young's modulus obtained by atomic force microscopy are consistent with the changes in crystallinity obtained by XRD. Both show a trend that the crystallinity of the second extruded material on the discharge side is higher than that of the first extruded material on the feed side, and the crystallinity of the first extruded material on the feed side in Example 1-1 is higher than that in Example 1-2.

[0129] (5) Evaluation of gel aggregation in extruded material: According to the difference between the crystallinity of the second extruded material on the filter screen discharge side and the crystallinity of the first extruded material on the filter screen feed side in Table 2, the extruded material of Examples 1-2 has less gel aggregation, that is, the molecular weight of the gel aggregates is low.

[0130] (6) The above evaluation method was verified by gel permeation chromatography: A filter screen (500 mesh) was placed on a constant temperature hot stage and the temperature was set to 130°C to soften the insulating material on the filter screen. Then, a scraper was used to scrape the softened first and second extruded materials from both sides of the filter screen along the plane of the filter screen. Using a high-temperature gel permeation chromatography system with trichlorobenzene as the eluent, the number-average molecular weight (Mn) of the insulating material was determined under high-temperature conditions. n ) and dispersion factor PDI=M W / M n Sample preparation process: The test sample prepared from the first extrusion material / second extrusion material was dissolved in trichlorobenzene to prepare a 3 mg / ml solution. After filtration through a 0.4 μm filter membrane, the molecular weight and PDI value of the insulating material on both sides of the filter were analyzed. The corresponding test results are shown in Table 3.

[0131] Table 3

[0132]

[0133] As shown in Table 3, the molecular weight Mn on the discharge side is lower than that on the feed side. Comparing the Mn in Examples 1-1 and 1-2, the molecular weight of the first extruded material on the feed side of Example 1-1 is higher, indicating that the gel aggregates in the extruded material of Example 1-1 are larger and the degree of gel aggregation is higher; this is consistent with step (4). Furthermore, in Table 2, the difference between the crystallinity of the second extruded material on the discharge side and the crystallinity of the first extruded material on the feed side is ≤10%, which indicates that the degree of gel aggregation in the extruded material is level 0. At this time, the degree of gel aggregation in the extruded material is low. It has been verified that the extruded materials of Examples 1-1 and 1-2 can achieve stable extrusion for 36 hours.

[0134] Examples 1-3

[0135] Examples 1-3 are basically the same as Example 1-1, the main difference being that steps (1) and (2) of Examples 1-3 are different from those of Example 1-1. Steps (1) and (2) of Examples 1-3 are as follows:

[0136] (1) Preparation of insulating material in Example 1-1: raw materials and formulation components: polyethylene matrix resin 1 (weight average molecular weight is 111969, number average molecular weight is 15950, and the ratio of weight average molecular weight to number average molecular weight is 7.02) and antioxidant is 4,4'-thiobis(6-tert-butyl-m-cresol), wherein the polyethylene matrix and antioxidant are in a weight ratio of 1:0.002.

[0137] (2) Melt blending and extrusion: A reciprocating single-screw extruder or twin-screw extruder is used. Polyethylene base material and antioxidant are fed into the extruder through a gravity feeder. The materials are processed sequentially through plasticizing, melt blending, extrusion, melt filtration, and underwater pelletizing to prepare insulating particles. In the melt blending and extrusion steps, the extruder speed is 350 rpm, and the temperature settings for each section of the extruder are 95℃, 175℃, 178℃, 170℃, 163℃, 163℃, and 158℃, respectively. The screw temperature is 108℃, and the material temperature is 180℃. In the precision filtration step, a 5-layer filter structure is used (from the feed side to the discharge side, the filter screens are 80 mesh, 250 mesh, 500 mesh, 250 mesh, and 50 mesh, respectively). The first extruded material from the feed side and the second extruded material from the discharge side are collected from the 500 mesh filter screen.

[0138] In this embodiment, the calculated crystallinity of the first extruded material on the feed side of the filter screen and the second extruded material on the discharge side is shown in Table 4. The XRD patterns of the first extruded material on the feed side and the second extruded material on the discharge side of the filter screen obtained from tests in Examples 1-3 are shown below. Figure 1 As shown in (c).

[0139] Table 4

[0140]

[0141] The above evaluation method was verified using gel permeation chromatography as described in Examples 1-1 and 1-2: the molecular weight and PDI value of the insulating materials on both sides of the filter screen were analyzed. The corresponding test results are shown in Table 5.

[0142] Table 5

[0143]

[0144] As shown in Table 4, the difference in crystallinity between the second extruded material on the discharge side and the first extruded material on the feed side is greater than 10%, indicating that the gel aggregation degree in the extruded material is level 1, which is a relatively high degree of gel aggregation. Verification shows that the stable extrusion time for the extruded materials of Examples 1-3 is 24 hours.

[0145] Examples 1-4 and 1-5

[0146] This study evaluates the gel content during continuous production of cable insulation cores using cross-linked polyethylene insulation material, providing technical guidance for cable insulation extrusion.

[0147] The main difference between Examples 1-4 and Examples 1-5 lies in the continuous extrusion time of the cable insulation core; the following steps are the same. A commercially available cross-linked polyethylene insulation material with a density of 0.920 g / cm³ was selected. 2The melt flow index is 2.0±0.1 g / 10min, and it is matched with conductor shielding (first shielding material) and insulation shielding (second shielding material). The cable structure conforms to ZA-YJLW02-Z 127 / 220kV, and the nominal thickness of the insulation layer is 25.0 mm. Based on the VCV vertical cross-linking production line, a three-layer co-extrusion extruder is used to co-extrude the first shielding material, cross-linked polyethylene insulation material, and second shielding material to prepare the cable insulation core. The cross-linked polyethylene insulation material is melt-plasticized and melt-homogenized to obtain the extrudate, which is then filtered for impurities and fed into the die head. The insulation single-screw extruder has a diameter of 175 mm, a screw length-to-diameter ratio of 25:1, and the screw is divided into 7 sections with temperatures of 114℃, 115℃, 116℃, 117℃, 118℃, 118℃, and 118℃, respectively. The insulating material melt undergoes five layers of precision filtration (from the feed side to the discharge side, these include filters with mesh sizes of 80 mesh, 250 mesh, 500 mesh, 250 mesh, and 50 mesh, respectively). Specifically, the insulating materials in Examples 1-4 were continuously extruded for 240 hours, and those in Examples 1-5 for 280 hours. After the production line was shut down, the first-stage material before the 500-mesh filter feed side and the second-stage material after the 500-mesh filter discharge side were collected. The XRD patterns of the first extruded material on the filter feed side and the second extruded material on the filter discharge side of Examples 1-4, obtained using the X-ray diffraction method described in Example 1-1, are shown below. Figure 1 As shown in (d). The XRD patterns of the first extruded material on the feed side and the second extruded material on the discharge side of the filter screen obtained from tests in Examples 1-5 are shown in (d). Figure 1 As shown in (e). The crystallinity of Examples 1-4 and 1-5 is shown in Table 6.

[0148] Table 6

[0149]

[0150] As shown in Table 6, in Examples 1-4, the difference in crystallinity between the secondary material after the discharge side screen and the primary material before the feed side screen is <10%, indicating that the gel aggregation degree in the extruded material is level 0, which is low and the insulation layer quality meets the requirements. In Examples 1-5, after extending the continuous production time to 280 hours and disassembling the filter screen after shutdown, the difference in crystallinity between the secondary material after the discharge side screen and the primary material before the feed side screen is >10%, indicating that the gel aggregation degree in the extruded material is level 1, which is high, and obvious impurity particles appeared at the filter screen discharge test.

[0151] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0152] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A method for evaluating gel aggregation in extruded materials, characterized in that, Includes the following steps: The raw materials for cable insulation are melt-blended and extruded to prepare extruded materials; or the cable insulation material is melt-plasticized and homogenized to prepare extruded materials. The extruded material is filtered through a filter screen, and the first extruded material from the feed side of the filter screen and the second extruded material from the discharge side of the filter screen are collected respectively. The crystallinity of the first extruded material on the feed side of the filter screen and the second extruded material on the discharge side of the filter screen is obtained; The gel aggregation status in the extruded material is obtained based on the difference between the crystallinity of the second extruded material on the filter screen discharge side and the crystallinity of the first extruded material on the filter screen feed side.

2. The method for evaluating gel aggregation in extruded materials according to claim 1, characterized in that, The steps for obtaining the gel aggregation status in the extrudate include: The lower the difference in crystallinity between the second extruded material on the filter screen discharge side and the first extruded material on the filter screen feed side, the less gel aggregation occurs in the extruded material. The mesh size of the filter screen is 300 to 500 mesh.

3. The method for evaluating gel aggregation in extruded materials according to claim 2, characterized in that, The step of obtaining the gel aggregation status in the extrudate further includes: Based on the difference between the crystallinity of the second extruded material on the filter screen discharge side and the crystallinity of the first extruded material on the filter screen feed side, the gel aggregation in the extruded material is determined to be level 0 and level 1. If the difference between the crystallinity of the second extruded material on the filter screen discharge side and the crystallinity of the first extruded material on the filter screen feed side is ≤10%, then the gel aggregation of the extruded material is confirmed as level 0. When the difference between the crystallinity of the second extruded material on the filter screen discharge side and the crystallinity of the first extruded material on the filter screen feed side is greater than 10%, the gel aggregation of the extruded material is confirmed as level 1. Among them, the gel aggregation of the extrudate confirmed as grade 0 is lower than that of the extrudate confirmed as grade 1.

4. The method for evaluating gel aggregation in extruded materials according to any one of claims 1 to 3, characterized in that, The steps for obtaining the crystallinity of the first extruded material on the feed side of the filter screen and the second extruded material on the discharge side of the filter screen include: The first extruded material is stripped off from the feed side of the filter screen, and the second extruded material is stripped off from the discharge side of the filter screen; X-ray diffraction was used to test the first extruded material and the second extruded material to obtain the crystallinity of the first extruded material on the feed side of the filter screen and the second extruded material on the discharge side of the filter screen.

5. The method for evaluating gel aggregation in extruded materials according to claim 4, characterized in that, The detection parameters of X-ray diffraction have one or more of the following characteristics: (1) The angle 2θ between the incident direction and the diffraction direction of the X-rays is 5°~90°; (2) The step size is 0.01°~0.03°; (3) The target material used to generate X-rays is a copper target; (4) The wavelength of X-rays is 0.15 nm to 0.16 nm; (5) The tube voltage is 35kV~45kV; (6) The current is 35mA~45mA.

6. The method for evaluating gel aggregation in extruded materials according to claim 4, characterized in that, The first extrusion crystallinity on the feed side of the filter screen and / or the second extrusion crystallinity on the discharge side of the filter screen are calculated using the following formula: X c =A c / (A c +A a )×100%; Among them, X c Indicates the crystallinity of the first extrudate and / or the second extrudate; A c A represents the diffraction intensity of the first extruded material and / or the second extruded material at the characteristic peak of the crystalline region; a This represents the diffraction intensity of the first extruded material and / or the second extruded material at the characteristic peak in the amorphous region.

7. The method for evaluating gel aggregation in extruded materials according to claim 4, characterized in that, In the step of testing the first extrudate and the second extrudate using X-ray diffraction, the area of ​​the sample to be tested made from the first extrudate and / or the second extrudate is 1 cm². 2 ~4cm 2 The thickness of the test sample made from the first extrusion and / or the second extrusion is 1 μm to 100 μm.

8. The method for evaluating gel aggregation in extruded materials according to any one of claims 1 to 3, characterized in that, The raw materials for preparing the cable insulation material include polyethylene matrix resin and functional additives; And / or, the cable insulation material is cross-linked polyethylene insulation material.

9. The method for evaluating gel aggregation in extruded materials according to claim 8, characterized in that, The polyethylene matrix resin has one or more of the following characteristics: (1) The weight-average molecular weight of the polyethylene matrix resin is 60,000 to 110,000; (2) The number average molecular weight of the polyethylene matrix resin is 12,000 to 20,000; (3) The ratio of the weight-average molecular weight to the number-average molecular weight of the polyethylene matrix resin is 3 to 7.

5.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements at least one step in the method for evaluating gel aggregation in extruded material according to any one of claims 1 to 9.

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