Degassing by-product detection method, degassing by-product detection device and application of degassing by-product detection method and degassing by-product detection device

Abstract

The invention relates to the technical field of wires and cables, and discloses a degassing by-product detection method, a degassing by-product detection device and application of the degassing by-product detection method and the degassing by-product detection device. The detection method comprises the following steps: in a closed vacuum environment, a sample to be detected is subjected to at least two sections of degassing treatment, and in two adjacent sections of degassing treatment, the conditions of the first section and the later section of degassing treatment are at least partially different; the conditions of the degassing treatment are as follows: the temperature is-80 DEG C to 250 DEG C, the pressure is-0.2 MPa to 0.1 MPa, and the time is 0.5 to 72 hours; and calculating the total content of the removed by-products in each gram of the sample to be detected according to the following formula: A = [(G * (100%-VG) / VG + L * (100%-VL) / VL)] / m. According to the method, temperature and pressure control in the degassing treatment process is realized, the composition and content of a gas-phase byproduct and a liquid-phase byproduct are accurately tested, and a reference is provided for optimization of an insulating material formula according to a byproduct index A.

Description

Technical Field

[0001] This invention relates to the field of wire and cable technology, and specifically to a method for detecting degassing byproducts, a device for detecting degassing byproducts, and their applications. Background Technology

[0002] High-voltage cables play a vital role in modern society, serving as a key component of power transmission and distribution systems. Cross-linked polyethylene (XLPE) cables are widely used in high-voltage cables due to their excellent electrical properties and mechanical strength. However, the byproducts generated during the production of high-voltage cables, particularly those arising from the cross-linking system, have been a persistent challenge.

[0003] Existing research suggests that the main components of by-products are methane, acetophenone, styrene, and small molecule cracking products, but their specific types are complex, and clear qualitative and quantitative methods are lacking. Currently, in industry, the level of by-products in cables is mainly reflected by detecting the methane concentration in the air surrounding the cable. However, this method cannot directly quantify the cable itself and ignores the influence of other by-products. Other studies have attempted to collect cable by-products using methods such as gas sampling bags, but this method can only be performed after the cable has been formed and placed in a sealed bag for testing. It cannot quantitatively analyze the state of the cable before and during vulcanization, or the changes under different temperatures / pressures, thus failing to provide technical reference for cable formulation optimization. In summary, the main problems faced by existing technologies include: the temperature for detecting degassing by-products in cables is limited to room temperature; the pressure for detecting degassing by-products in cables is limited to atmospheric pressure; and the qualitative and quantitative methods are singular and inaccurate.

[0004] Therefore, it is of great significance to research and develop a detection method for degassing byproducts of high-voltage cables. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies, such as the limitation of temperature to below 100°C and pressure to atmospheric pressure during degassing detection in traditional cable degassing byproduct detection methods, which cannot accelerate byproduct release through high temperature and vacuum conditions, and the inability to accurately obtain the specific content and composition of liquid-phase byproducts. This invention provides a method and device for detecting degassing byproducts, and their applications. This method can achieve temperature and pressure control during the degassing process, accurately test the composition and content of gaseous and liquid-phase byproducts, and provide a reference for optimizing insulation material formulations based on the byproduct index A.

[0006] To achieve the above objectives, a first aspect of the present invention provides a method for detecting degassing byproducts, the detection method comprising: (1) In a closed vacuum environment, the sample to be tested is subjected to at least two stages of degassing treatment, and the conditions of the first stage and the second stage of degassing treatment are at least partially different in the two adjacent stages of degassing treatment; The degassing conditions include: a temperature of -80°C to 250°C, a pressure of -0.2 MPa to 0.1 MPa, and a time of 0.5 h to 72 h. (2) The gaseous byproducts after degassing were tested to obtain their composition and content; (3) After the solid product after degassing is subjected to gradient washing and / or soaking treatment, solid-liquid separation is performed; (4) The liquid obtained in step (3) is analyzed by liquid phase infrared analysis and gas chromatography-flame ionization detection in sequence to obtain the composition and content of liquid phase byproducts; The total content of byproducts removed per gram of the sample to be tested is calculated using the following formula: A = [(G × (100% - V)] G )÷V G +L×(100%-V) L )÷V L )] / m, Where A is the byproduct index, mL / g; G represents the calibration gas volume, in mL; L represents the calibration liquid volume, in mL; V G The percentage of calibration gas among all gases, expressed as % . V L The percentage of calibration liquid in the total liquid content, expressed as % . m is the total mass of the sample to be tested, in grams.

[0007] Preferably, the degassing process consists of ≥3 stages, and the conditions for each stage of the degassing process are at least partially different.

[0008] Preferably, the degassing conditions include: a temperature of -30°C to 220°C, a pressure of -0.2 MPa to 0.1 MPa, and a time of 0.5 to 48 hours.

[0009] A second aspect of the present invention provides a device for detecting degassing byproducts, the device comprising a sample processing system, a gas detection system, and a liquid detection system; The sample processing system is used to degas the sample to be tested, send the gaseous byproducts after degassing to the gas detection system, and perform gradient washing and / or soaking on the solid products after degassing, and send the liquid to the liquid detection system after solid-liquid separation. The sample processing system is connected to a temperature control system that controls the temperature from -80℃ to 250℃, and a pressure control system that controls the pressure from -0.2MPa to 0.1MPa. The gas detection system is used to detect the composition and content of gaseous byproducts; The liquid detection system includes a liquid phase infrared analyzer (8) and a gas chromatograph-flame ionization detector (Y3) for detecting the composition and content of liquid phase byproducts.

[0010] The third aspect of the present invention provides the application of the detection device described in the second aspect above in a method for detecting degassing byproducts.

[0011] Compared with the prior art, the present invention has the following beneficial effects through the above technical solution: (1) In the prior art, the temperature can only be controlled at 20-100℃ when detecting cable degassing by-products, while the present invention achieves a large temperature control range from -80 to 250℃; (2) In the prior art, the detection of cable degassing byproducts only supports atmospheric pressure environment, while the present invention achieves a wide pressure control range from -0.2MPa to 0.1MPa; (3) The present invention can realize the detection of the types and contents of the degassing byproducts of the entire process of cable, not limited to the finished cable section after cutting, and can perform detection and analysis on the products at the front, middle and rear ends of the cable under different temperatures and pressures to obtain the detailed composition and contents of gaseous and liquid phase byproducts. (4) The present invention can simultaneously collect gaseous and liquid phase by-products, and analyze and classify all by-products at the same time. The number of by-products detected is ≥7, or even ≥10; while the traditional method detects ≤3 types of by-products. (5) The present invention obtains “byproduct index A” by calibrating gas and calibrating liquid and combining chromatographic test ratio, and provides a reference for optimizing the insulation material formula based on byproduct index A; (6) The detection methods in the prior art have low accuracy and the degassing process is uncontrollable. The method of the present invention has a detection accuracy of <1ppb and the degassing process is controllable. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the device for degassing byproducts provided by the present invention; Figure 2 This is a schematic diagram of the process flow for the degassing by-product method provided by the present invention; Figure 3 These are the quality change curves of the finished and semi-finished cables of this invention.

[0013] Explanation of reference numerals in the attached figures 1- High borosilicate glass box; 2- Sample inlet; 3-Vacuum pump; 4-Calibration gas storage tank; 5-Calibration liquid storage tank; 6-Liquid collection pool; 7-Heating and insulation layer; 8-Liquid phase infrared analyzer; Y1-Gas Infrared Analyzer; Y2-Gas Chromatography-Mass Spectrometry Analyzer; Y3-Gas Chromatography-Flame Ionization Detector. Detailed Implementation

[0014] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0015] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this invention are based on weight, unless being based on weight would not be in accordance with the common understanding of those skilled in the art.

[0016] This invention provides a first method for detecting degassing byproducts, the method comprising: (1) In a closed vacuum environment, the sample to be tested is subjected to at least two stages of degassing treatment, and the conditions of the first stage and the second stage of degassing treatment are at least partially different in the two adjacent stages of degassing treatment; The degassing conditions include: a temperature of -80°C to 250°C, a pressure of -0.2 MPa to 0.1 MPa, and a time of 0.5 h to 72 h. (2) The gaseous byproducts after degassing were tested to obtain their composition and content; (3) After the solid product after degassing is subjected to gradient washing and / or soaking treatment, solid-liquid separation is performed; (4) The liquid obtained in step (3) is analyzed by liquid phase infrared analysis and gas chromatography-flame ionization detection in sequence to obtain the composition and content of liquid phase byproducts; The total content of byproducts removed per gram of the sample to be tested is calculated using the following formula: A = [(G × (100% - V)] G )÷V G +L×(100%-V) L )÷V L )] / m, Where A is the byproduct index, mL / g; G represents the calibration gas volume, in mL; L represents the calibration liquid volume, in mL; V G The percentage of calibration gas among all gases, expressed as % . V L The percentage of calibration liquid in the total liquid content, expressed as % . m is the total mass of the sample to be tested, in grams.

[0017] According to the present invention, preferably, the degassing process consists of ≥3 stages, and the conditions for each stage of the degassing process are at least partially different.

[0018] It should be noted that the present invention does not have a particular limitation on the number of degassing stages, as long as the final degassing stage can ensure that the composition and content of gaseous byproducts are 0. For example, it can be 3 stages, 4 stages, 5 stages, 6 stages, 7 stages, 8 stages, 9 stages, 10 stages, etc.

[0019] In this invention, those skilled in the art can select the degassing time for each segment according to their needs, which is beneficial for obtaining the degassing results of the sample at any time.

[0020] In this invention, the phrase "the conditions of the degassing treatment in the first stage and the degassing treatment in the second stage are at least partially different" means that there are differences in the degassing temperature and pressure between the two adjacent degassing treatments, that is, the degassing treatment conditions of the two adjacent stages are not completely consistent.

[0021] In this invention, the "time from 0.5 h to 72 h" refers to the time required for each degassing process.

[0022] Specifically, it can be one of the following situations: The temperature in the first segment can be different from that in the second segment, but the pressure can be the same. For example, the first segment has a temperature of -50℃ and a pressure of -0.1MPa, while the second segment has a temperature of 30℃ and a pressure of -0.1MPa.

[0023] The pressure in the first segment may differ from that in the second segment, but the temperature may be the same. For example, the first segment may have a temperature of 100℃ and a pressure of -0.05MPa, while the second segment may have a temperature of 100℃ and a pressure of -0.15MPa.

[0024] The temperature and pressure in the first section are different from those in the second section. For example, the temperature in the first section is 20℃ and the pressure is -0.08MPa, while the temperature in the second section is 80℃ and the pressure is -0.12MPa.

[0025] The present invention has a wide range of specific detection parameters for analysis using liquid phase infrared analysis and gas chromatography-flame ionization detection in step (4). As long as the composition and content of liquid phase by-products can be obtained, it is well known to those skilled in the art.

[0026] In this invention, the purpose of setting different degassing conditions is to achieve segmented detection and to study the qualitative and quantitative changes of cable by-products under different degassing temperatures and times.

[0027] It should be noted that in this invention, "the first stage" and "the second stage" refer to the order of the multi-stage degassing process, and are used to clarify the temporal relationship between two adjacent degassing processes.

[0028] "First stage" refers to the degassing process performed first among two adjacent degassing processes. For example, if two degassing processes are performed, the first stage is the "first stage"; if three degassing processes are performed, the first stage is the "first stage" relative to the second stage, and the second stage is also the "first stage" relative to the third stage.

[0029] "In the later stage" refers to the later degassing process among two adjacent degassing processes. For example, in a two-stage degassing process, the second stage is "in the later stage"; in a three-stage degassing process, the second stage is "in the later stage" relative to the first stage, and the third stage is "in the later stage" relative to the second stage.

[0030] According to the present invention, preferably, the degassing treatment conditions include: a temperature of -30°C to 220°C, a pressure of -0.2 MPa to 0.1 MPa, and a time of 0.5 to 48 h.

[0031] The inventors of this invention have discovered that the main problems faced by the prior art include: the temperature of traditional methods for detecting degassing byproducts in cables is limited to below 100°C, the pressure state during degassing is limited to atmospheric pressure, the qualitative and quantitative methods are singular and inaccurate, the inability to detect the cable vulcanization process in situ, and the lack of quantitative indicator parameters.

[0032] In detail: (C-1) Temperature and pressure limitations: Traditional methods use atmospheric pressure ovens / degassing chambers for treatment, with a temperature limit of only 100℃, which cannot simulate the high-temperature stage (180-250℃) of the cross-linking reaction and the low-temperature storage conditions (below -10℃); existing gas sampling devices (such as GB / T 2951.32) only support atmospheric pressure environments and cannot accelerate the release of by-products through vacuum conditions.

[0033] (C-2) Poor sample adaptability: Industrial testing methods are only applicable to finished cable sections and cannot be used to test granular materials or vulcanized sample sections.

[0034] (C-3) Limitations of the detection method: The single methane detection method ignores high-boiling-point byproducts such as acetophenone and α-methylstyrene, resulting in insufficient basis for formula optimization.

[0035] Thermogravimetric analysis (TGA) cannot distinguish between gaseous and liquid phase byproducts.

[0036] (C-4) Lack of dynamic monitoring: Existing technologies can only perform static sampling after vulcanization is complete, and cannot capture the dynamic gas release patterns during the crosslinking reaction process.

[0037] (C-5) Quantitative indicator parameters are missing: Existing technologies lack unified quantitative indicator parameters, making it impossible to compare multiple methods to indicate the amount of by-product residues.

[0038] Based on this, the inventors of this invention employ the method of this invention to perform staged degassing under high temperature and vacuum conditions, and to qualitatively and quantitatively analyze the types and contents of by-products at each stage. Specifically, for the first time, dynamic detection and by-product tracking of the entire process from pre-crosslinking (granules) to crosslinking (semi-finished products) to post-crosslinking (cables) are achieved. Samples before crosslinking are placed in a sealed vacuum environment and can be directly heated. At this time, the samples undergo crosslinking within the sealed vacuum environment, enabling in-situ detection of the crosslinking process at different stages. Furthermore, a dual-mode approach of "gas adsorption + liquid extraction" is used to cover both volatile and non-volatile by-products (detection limit less than 1 ppb). In addition, the total degassing amount of each crosslinking system is evaluated by combining the by-product index A, providing a reference for optimizing insulation material formulations. Analysis is performed sequentially using liquid phase infrared analysis and gas chromatography-flame ionization detection, avoiding the shortcomings of traditional thermogravimetric analysis methods and maximizing non-destructive testing and analysis data. It also achieves combined quantitative and qualitative analysis of liquid phase by-products, realizing simultaneous analysis of liquid / gas phase by-products throughout the entire process, avoiding the defects of single detection in traditional methods.

[0039] According to the present invention, preferably, the formulation optimization applicable to 330kV and above ultra-high voltage cables increases the number of by-products to be detected to 7 or more, and the total content of removed by-products is controllable.

[0040] According to the present invention, preferably, the sealed vacuum environment is formed by a high borosilicate glass container, which realizes the fully sealed treatment of the sample to be tested, provides a sealed environment or different pressure environments for the sample to be tested, can be vacuumed to -0.2MPa to 0.1MPa, and can work stably in the temperature range of -180℃ to 250℃.

[0041] According to the present invention, preferably, the high borosilicate glass container serves as the reaction chamber, combined with a polytetrafluoroethylene plug, to ensure airtightness throughout the entire process. This invention marks the first time a vacuum degassing simulation process has been implemented, providing technical support for the development of insulating materials.

[0042] According to the present invention, the sample to be tested can be a sample before cross-linking, during cross-linking, or after cross-linking. Preferably, the sample to be tested is selected from one or more of cable insulation materials, semi-finished cables, and finished cables.

[0043] According to the present invention, the sample to be tested can be in various forms. Preferably, the sample to be tested is one or more of the following shapes: granular, blocky, plate-like, and columnar.

[0044] According to the present invention, preferably, the composition and content of gaseous byproducts in step (2) are 0, and the degassing is determined to be completed.

[0045] According to the present invention, preferably, the calibration gas is one or more of nitrogen, argon, carbon dioxide, and hydrogen.

[0046] According to the present invention, preferably, the instruments used for detection in step (2) are a gas infrared analyzer and a gas chromatography-flame ionization detector, or a gas infrared analyzer and a gas chromatography-mass spectrometry analyzer. Preferably, the gas infrared analyzer and the gas chromatography-flame ionization detector are used in sequence, which is more conducive to ensuring the accuracy of the determination of the types of by-products and can realize the segmented quantitative detection of by-products.

[0047] According to the present invention, preferably, the resolution of the gas infrared analyzer is ≤4cm. -1 .

[0048] The present invention has a wide range of specific detection parameters for the instrument used in step (2), as long as the composition and content of the gas phase byproducts can be obtained, which is well known to those skilled in the art.

[0049] According to the present invention, preferably, the present invention combines the above-mentioned gas-phase by-product detector and liquid-phase product detector to establish a by-product fingerprint library covering C1-C1. 20 Compounds are more conducive to accurately testing the composition and content of products.

[0050] According to the present invention, preferably, the gas-phase byproduct is a C1-C20 compound.

[0051] In this invention, C1-C20 compounds refer to compounds containing 1 to 20 carbon atoms in their molecules, including but not limited to C1-C20 alkanes, C1-C20 alkenes, C1-C20 alkynes, and C1-C20 derivatives containing functional groups.

[0052] According to the present invention, preferably, the gaseous byproducts include C1-C6 alkanes, methanol, ethanol, propanol, acetone, butanone, n-butene, and isoprene, more preferably one or more of n-hexane, 2-methylpentane, 3-methylpentane, and 2,3-dimethylbutane.

[0053] According to the present invention, preferably, the gradient flushing includes the following steps: (S1) Solvent A is used to extract low polarity substances and the first liquid phase is collected.

[0054] The low-polarity product is a decomposition product of polyethylene.

[0055] (S2) Extract the polar residue from the remaining solid in step (S1) using solvent B and collect the second liquid phase.

[0056] The polar residue is a cross-linking agent byproduct.

[0057] In this invention, solvent A is selected from at least one of n-hexane, n-heptane, and petroleum ether.

[0058] In this invention, solvent B is selected from at least one of DMSO, dichloromethane, and chloroform.

[0059] This invention offers a wide range of options for the amounts of solvent A and solvent B. Preferably, solvent A is used first to remove low-polarity substances, and then solvent B is used to extract crosslinking byproducts. By employing the gradient rinsing method described above, the problem that liquid-phase byproducts can only be detected by total internal reflection infrared (ATR) testing of cable sheets in traditional methods is avoided. This method is more conducive to the quantification of byproducts and avoids the influence of polyethylene decomposition products, resulting in a more accurate byproduct index A to guide formulation development.

[0060] According to the present invention, preferably, the calibration liquid is one or more of benzene, toluene, and xylene.

[0061] According to the present invention, preferably, the liquid phase byproduct includes one or more of acetophenone, α-methylstyrene, 2-phenyl-2-propanol, 2,4-dimethyl-undecane, 2,4-diphenyl-4-methyl-2(E)-pentene, 2-butyl-1-octanol, cumene, methyl methoxyphenylacetate, and 1-phenyl-1,2-propanedione.

[0062] According to the present invention, preferably, the total time for the method is 18-720 hours, more preferably 18-72 hours.

[0063] In this invention, the "total time" refers to the time required to complete the entire process of detecting the composition and content of gaseous and liquid phase byproducts.

[0064] In this invention, the total time required for the method described is much shorter than that of the prior art, which greatly improves the accuracy and shortens the evaluation and development cycle of new formulas.

[0065] According to a particularly preferred embodiment of the present invention, Figure 2 This is a schematic diagram of the process flow for the degassing by-product method provided by the present invention, as shown below. Figure 2 As shown, a method for detecting degassing byproducts includes: (1) In a 10L high borosilicate glass box 1, 100-5000g of the sample to be tested is subjected to at least two stages of degassing treatment. The high borosilicate glass box 1 is connected to a vacuum pump 3 to achieve a vacuum pressure of -0.2MPa to 0.1MPa, and the ambient temperature is set from -30℃ to 220℃. The temperature is maintained for 0.5-48h. In the two adjacent stages of degassing treatment, the conditions of the first stage and the second stage of degassing treatment are at least partially different. After each specified time (e.g., 6h, 12h, 24h, 48h, etc.), 50mL of gas is extracted from the bottle. Then the gas is subjected to gas infrared analysis and gas chromatography-mass spectrometry analysis for component analysis. The composition and content of gaseous byproducts are 0, indicating that degassing is complete; After the solid product is degassed, it is subjected to gradient washing and / or soaking treatment, followed by solid-liquid separation. The collected liquid is analyzed sequentially by liquid phase infrared analysis and gas chromatography-flame ionization detection to obtain the composition and content of liquid phase by-products. The total content of byproducts removed per gram of the sample to be tested is calculated using the following formula: A = [(G × (100% - V)] G )÷V G +L×(100%-V) L )÷V L )] / m, Where A is the byproduct index, mL / g; G represents the calibration gas volume, in mL; L represents the calibration liquid volume, in mL; V G The percentage of calibration gas among all gases, expressed as % . V L The percentage of calibration liquid in the total liquid content, expressed as % . m is the total mass of the sample to be tested, in grams.

[0066] A second aspect of the present invention provides a device for detecting degassing byproducts, the device comprising a sample processing system, a gas detection system, and a liquid detection system; The sample processing system is used to degas the sample to be tested, send the gaseous byproducts after degassing to the gas detection system, and perform gradient washing and / or soaking on the solid products after degassing, and send the liquid to the liquid detection system after solid-liquid separation. The sample processing system is connected to a temperature control system that controls the temperature from -80℃ to 250℃, and a pressure control system that controls the pressure from -0.2MPa to 0.1MPa. The gas detection system is used to detect the composition and content of gaseous byproducts; The liquid detection system includes a liquid phase infrared analyzer (8) and a gas chromatograph-flame ionization detector (Y3) for detecting the composition and content of liquid phase byproducts.

[0067] In this invention, the above-mentioned detection device for degassing byproducts is used to detect the sample to be tested. It has high accuracy, can control the degassing process, obtains "byproduct index A", and provides a reference for optimizing the insulation material formula based on byproduct index A.

[0068] According to the present invention, preferably, the sample processing system includes a borosilicate glass box 1, a vacuum pump 3, a calibration gas storage box 4, a calibration liquid storage box 5, a liquid collection pool 6, and a heating and insulation layer 7; Vacuum pump 3, calibration gas storage tank 4, calibration liquid storage tank 5, and liquid collection pool (6) are each independently connected to high borosilicate glass box 1; The high borosilicate glass box 1 is equipped with a sample inlet 2 and a heating and insulation layer 7 around it; A stopcock is provided between the vacuum pump 3 and the high borosilicate glass box 1.

[0069] According to the present invention, in a preferred embodiment, a vacuum control system (mechanical pump + PTFE stopcock combination) is designed. The vacuum pump is connected to a borosilicate glass tube via a silicone hose, and the connection is sealed with silicone oil. The vacuum level is controlled by the PTFE stopcock, and the vacuum level is monitored in real time using a vacuum pressure gauge. During the evacuation phase, a pressure gradient within the chamber is maintained, and multi-time-point sampling is achieved via a rotary valve.

[0070] According to the present invention, preferably, the gas detection system includes a gas infrared analyzer Y1 connected in sequence to a borosilicate glass box 1, and a gas chromatograph-mass spectrometer (Y2) or a gas chromatograph-flame ionization detector (Y3).

[0071] According to the present invention, preferably, the liquid detection system further includes a liquid collection tank 6, which is connected to a gas chromatograph-flame ionization detector Y3.

[0072] It should be noted that in this invention, the gas chromatograph-mass spectrometer Y2 and the gas chromatograph-flame ionization detector Y3 can be an integrated device or independent devices.

[0073] Specifically, Figure 1 This is a schematic diagram of the detection device for degassing byproducts provided by the present invention. Figure 1As can be seen, in this invention, different types of test samples are placed in a borosilicate glass box 1 through the sample inlet 2. A heating and insulation layer 7 and a vacuum pump 3 are used to control the temperature and pressure during the sample testing process. After each testing stage, calibration gas is first added to the calibration gas storage tank 4, and then the gas is sent to a gas infrared analyzer Y1 to obtain an infrared spectrum for preliminary determination of the composition of gaseous byproducts. The gas is then further sent to a gas chromatograph-mass spectrometer Y2 or a gas chromatograph-flame ionization detector Y3, and the data are cross-compared to obtain the accurate composition and content of the gaseous byproducts. When the composition and content of the gaseous byproducts are 0, degassing is considered complete, meaning the collection of gaseous byproducts is finished. Calibration liquid is then added to the calibration liquid storage tank 5 and collected through a liquid collection pool 6. The collected liquid is then sent to a liquid infrared analyzer 8 to determine the composition of the liquid byproducts, and then further sent to a gas chromatograph-flame ionization detector Y3, and the data are cross-compared to obtain the accurate composition and content of the liquid byproducts. Finally, by measuring the final content of by-products, the by-product index A is calculated to obtain the total content of by-products removed per gram of sample.

[0074] The third aspect of the present invention provides the application of the detection device described in the second aspect above in a method for detecting degassing byproducts.

[0075] The parameter A provided in this invention can accurately determine the total amount of by-products per gram of sample, enabling rapid assessment of formula reliability during formulation development, shortening the R&D cycle, and improving R&D efficiency. It also allows for accurate evaluation of industrial cables, providing preliminary predictions based on by-product content before subsequent cable experiments. Excessively high by-product content often leads to cable breakdown and other problems, thus reducing experimental costs during cable extrusion. Furthermore, it enables comparison of samples from different countries and manufacturers. Through the by-product index, the by-product content of different insulation materials can be compared, allowing for pre-production evaluation of cable insulation performance.

[0076] The present invention will be described in detail below through embodiments.

[0077] In the following examples and comparative examples, the contents of gas phase and liquid phase byproducts were tested by gas chromatography-flame ionization detector (company: Shimadzu Corporation, model: Shimadzu GCMS-QP2020NX instrument, with GS-GasPro60m column for sample separation). Specifically, the sample was injected at 25 °C, held at 50 °C for two minutes, and then heated to 200 °C at a rate of 20 °C per minute, and held for 20 minutes. In the following examples and comparative examples, the types of gaseous byproducts were determined by gas infrared analyzer, specifically, the scanning range was 4000-400 cm⁻¹. -1 The resolution is 4 cm. -1 64 scans; In the following examples and comparative examples, the types of liquid phase byproducts were determined by liquid phase infrared spectroscopy, specifically, the scanning range was 3500-600 cm⁻¹. -1 The resolution is 8 cm. -1 64 scans; In the following examples and comparative examples, the LDPE base material parameters used were: density 0.920 g / cm³. 3 Weight-average molecular weight: 102,000 Daltons; Molecular weight distribution: 5; Melt flow rate: 2.1 g / 10 min.

[0078] In Examples 1-4 and Comparative Examples 1-4 below, the raw materials for cable insulation, semi-finished cables, and finished cables are all commercially available 500kV AC cable insulation materials with the brand name QL8205(YJ-500) produced by Zibo Qilu High Voltage Insulation Materials Co., Ltd.

[0079] In Example 5 below, the cable insulation material was prepared by a blending extrusion process. LDPE, crosslinking agent, and antioxidant were added sequentially to a twin-screw extruder with a conventional screw diameter of 40 mm, a length-to-diameter ratio of 44, a screw speed of 180 rpm, and a nine-zone temperature control system with temperatures of 120, 130, 140, 145, 150, 155, 160, 165, and 170 °C, and then mixed and extruded to obtain the cable insulation material.

[0080] Unless otherwise specified, all examples and comparative examples below are conventional methods; the reagents, materials and instruments used are commercially available and / or prepared using methods known in the art, unless otherwise specified.

[0081] In the following examples and comparative examples, the gradient rinsing method was as follows: Heptane was used for immersion at a ratio of 2 mL per gram of sample for 5 minutes, followed by removal of the solvent. Then, toluene or benzene (selected according to the actual solvent used in the examples and comparative examples below) was added, also acting as a calibrator, at a ratio of 2 mL per gram of sample for 15 minutes. The resulting liquid was then subjected to subsequent analysis to obtain quantitative and qualitative data, and the byproduct index A was obtained.

[0082] In the following examples and comparative examples, phr refers to the percentage of mass per 100 samples.

[0083] In the following examples and comparative examples, specifically, A = [(stage I gas phase byproducts) G1 × (100% - V)] G1 )÷V G1 + (Stage II gas phase byproducts) G2 × (100% - V) G2 )÷V G2 + (stage n gas phase byproducts) G n ×(100%-VGn )÷V Gn + (liquid phase byproducts) L×(100%-V) L )÷V L )] / m; Equation (a); Where A is the byproduct index, mL / g; G1, G2, G n These represent the calibration gas volumes, in mL, for stages I, II, and n, respectively. V G1 V G2 V Gn These represent the percentages of calibration gases in Stage I, Stage II, and Stage n, respectively, out of the total gas content, in % . L represents the calibration liquid volume, in mL; V L The percentage of calibration liquid in the total liquid content, expressed as % . m is the total mass of the sample to be tested, in grams.

[0084] Example 1 This embodiment 1 illustrates the use of the detection method of the present invention to detect degassing byproducts of finished cables.

[0085] Experimental item: Finished cable Experimental sample condition: after cross-linking Cable specifications: Insulation thickness 9 mm Cable formulation: LDPE base: 97.8 phr; DCP: 2.0 phr; Antioxidant 300: 0.2 phr Degassing procedure: Stage I: Vacuum degassing at 80 ℃ (-0.2 MPa) for 12 h Phase II: Degas at 120℃ and atmospheric pressure (0.1 MPa) for 12 hours. Stage III: Vacuum degassing at 210 ℃ (-0.05 MPa) for 6 h Sample weight: 600 g Table 1 shows the gaseous byproducts (stage I), with 50 mL of argon gas used as a calibrator.

[0086] Table 1

[0087] Table 2 shows the gaseous byproducts (stage II), with 50 mL of argon gas used as a calibrator.

[0088] Table 2

[0089] Table 3 shows the gaseous byproducts (stage III), with 50 mL of argon gas used as a calibrator.

[0090] Table 3

[0091] Table 4 shows the liquid phase byproducts, with 15 mL of toluene used as a calibrator.

[0092] Table 4

[0093] Byproduct index A = [(Stage I gas phase byproducts) 50 × (100% - 81.35%) ÷ 81.35% + (Stage II gas phase byproducts) 50 × (100% - 76.42%) ÷ 76.42% + (Stage III gas phase byproducts) 50 × (100% - 100%) ÷ 100% + 15 × (100% - 0.98%) ÷ 0.98%) mL] / 600 g = 2.57 mL / g.

[0094] The total time taken was 30 hours.

[0095] Experimental conclusion: (1) After the first, second and third stages of degassing treatment, the gas phase byproducts were completely removed, achieving complete degassing; (2) The degassing temperature in stage II is higher than that in stage I, resulting in a greater variety of degassing byproducts, indicating that the device has the effect of efficiently adjusting the degassing temperature to explore the degassing time. (3) The byproduct index A of Example 1 is 2.57 mL / g, indicating that 2.57 mL of byproducts are generated per gram under this formulation.

[0096] Example 2 This embodiment 2 illustrates the use of the detection method of the present invention to detect degassing byproducts of plate-shaped samples.

[0097] Experimental item: Semi-finished cable Experimental sample status: In the process of cross-linking Sample dimensions: 17 cm × 21 cm × 1 mm Sample formulation: LDPE base: 97.8 phr; DCP: 2.0 phr; Antioxidant 300: 0.2 phr Degassing procedure: Stage I: Degassing at 80℃ under low vacuum (-0.02 MPa) for 6 hours Phase II: Degassing at 80℃ and atmospheric pressure (0.1 MPa) for 24 hours Stage III: Degassing at 80℃ under medium vacuum (-0.05 MPa) for 6 hours Stage IV: Degassing at 80℃ and atmospheric pressure (0.1 MPa) for 24 hours Stage V: Degassing at 80℃ under high vacuum (-0.2 MPa) for 6 hours Sample weight: 35 g sample Table 5 shows the gaseous byproducts (stage I), with 20 mL of argon gas used as a calibrator.

[0098] Table 5

[0099] Table 6 shows the gaseous byproducts (stage II), with 20 mL of argon gas used as a calibrator.

[0100] Table 6

[0101] Table 7 shows the gaseous byproducts (stage III), with 20 mL of argon gas used as a calibrator.

[0102] Table 7

[0103] Table 8 shows the gaseous byproducts (stage IV), with 20 mL of argon gas used as a calibrator.

[0104] Table 8

[0105] Table 9 shows the gaseous byproducts (stage V), with 20 mL of argon gas used as a calibrator.

[0106] Table 9

[0107] Table 10 shows the liquid phase byproducts, with 5 mL of toluene used as a calibrator.

[0108] Table 10

[0109] Byproduct index A = [(Stage I gas phase byproducts) 20 × (100% - 84.65%) ÷ 84.65% + (Stage II gas phase byproducts) 20 × (100% - 92.54%) ÷ 92.54% + (Stage III gas phase byproducts) 20 × (100% - 82.61%) ÷ 82.61% + (Stage IV gas phase byproducts) 20 × (100% - 74.58%) ÷ 74.58% + (Stage V gas phase byproducts) 20 × (100% - 100%) ÷ 100% + 5 × (100% - 5.83%) ÷ 5.83% mL] / 35g = 2.77 mL / g.

[0110] The total time taken was 66 hours.

[0111] Experimental conclusion: (1) Example 2 underwent multiple degassing processes with different vacuum levels. It can be seen that the content of its by-products gradually increased until they disappeared (only argon was present in the gas phase by-products in stage V). This indicates that the device can achieve the degassing effect by changing different vacuum levels and degassing times. (2) The degassing time in this embodiment is significantly reduced, with a total degassing time of 66 hours, which indicates that the device can significantly shorten the degassing time and improve the degassing efficiency; (3) The byproduct index A of the sample tested by the device was 2.77 mL / g, which indicates that 2.77 mL of byproducts were generated per gram under this formula, which is similar to the test results of the cable, indicating the reliability and repeatability of the test method.

[0112] Example 3 This embodiment 3 illustrates the use of the detection method of the present invention to detect degassing byproducts of cable insulation material.

[0113] Experimental material: Cable insulation Experimental sample condition: before crosslinking Sample specifications: Cable insulation material Sample formulation: LDPE base: 97.8 phr; DCP: 2.0 phr; Antioxidant 300: 0.2 phr Degassing procedure: Stage I: Degassing at 120℃ under low vacuum (-0.02 MPa) for 30 min Stage II: Degassing at 180℃ under low vacuum (-0.02 MPa) for 30 min Stage III: Degassing at 80℃ under high vacuum (-0.2 MPa) for 12 h Stage IV: Degassing at 80℃ under low vacuum (-0.02 MPa) for 6 hours Sample weight: 300 g sample Table 11 shows the gaseous byproducts (stage I), with 50 mL of argon gas used as a calibrator.

[0114] Table 11

[0115] Table 12 shows the gaseous byproducts (stage II), with 50 mL of argon gas used as a calibrator.

[0116] Table 12

[0117] Table 13 shows the gaseous byproducts (stage III), with 50 mL of argon gas used as a calibrator.

[0118] Table 13

[0119] Table 14 shows the gaseous byproducts (stage IV), with 50 mL of argon gas used as a calibrator.

[0120] Table 14

[0121] Table 15 shows the liquid phase byproducts, of which 15 mL of toluene was used as a calibrator.

[0122] Table 15

[0123] Byproduct index A = [(Stage I gas phase byproducts) 50 × (100% - 91.26%) ÷ 91.26% + (Stage II gas phase byproducts) 50 × (100% - 89.51%) ÷ 89.51% + (Stage III gas phase byproducts) 50 × (100% - 70.29%) ÷ 70.29% + (Stage IV gas phase byproducts) 50 × (100% - 100%) ÷ 100% + 15 × (100% - 1.74%) ÷ 1.74% mL] / 300g = 2.93 mL / g.

[0124] The total time taken was 19 hours.

[0125] Experimental conclusion: (1) In Example 3, the insulating granules were heated in situ to simulate the vulcanization process. The byproducts of the vulcanization process were collected. The GCMS results showed that a small amount of gaseous byproducts were volatilized during the vulcanization process, which could not be achieved in the previous device, indicating the advantages of the device. (2) In this Example 3, the byproduct index A is 2.93 mL / g, which means that 2.93 mL of byproducts are generated per gram under this formula. This is similar to the test results of the cable and the sample, indicating the reliability and repeatability of the test method. At the same time, this value is slightly larger than that of the sample, indicating that a small amount of byproducts will also volatilize during the vulcanization process. This was not directly observed in previous studies. This device provides a quantitative means.

[0126] Example 4 This embodiment 4 illustrates the use of the detection method of the present invention to detect degassing byproducts of cable insulation material.

[0127] Experimental material: Cable insulation Experimental sample condition: before crosslinking Sample specifications: Cable insulation material Sample formulation: LDPE base: 97.8 phr; DCP: 2.0 phr; Antioxidant 300: 0.2 phr Degassing procedure: Stage I: Degassing at 120℃ under low vacuum (-0.02 MPa) for 30 min Stage II: Degassing at 180℃ under low vacuum (-0.02 MPa) for 30 min Stage III: Degassing at 80℃ under high vacuum (-0.2 MPa) for 12 h Stage IV: Degassing at 80℃ under low vacuum (-0.02 MPa) for 6 hours Sample weight: 300 g sample Table 16 shows the gaseous byproducts (stage I), with 50 mL of carbon dioxide used as a calibrator.

[0128] Table 16

[0129] Table 17 shows the gaseous byproducts (stage II), with 50 mL of hydrogen gas used as a calibrator.

[0130] Table 17

[0131] Table 18 shows the gaseous byproducts (stage III), with 50 mL of nitrogen gas used as a calibrator.

[0132] Table 18

[0133] Table 19 shows the gaseous byproducts (stage IV), with 50 mL of argon gas used as a calibrator.

[0134] Table 19

[0135] Table 20 shows the liquid phase byproducts, with 15 mL of benzene used as a calibrator.

[0136] Table 20

[0137] Byproduct index A = [(Stage I gas phase byproducts) 50 × (100% - 75.61%) ÷ 75.61% + (Stage II gas phase byproducts) 50 × (100% - 86.90%) ÷ 86.90% + (Stage III gas phase byproducts) 50 × (100% - 76.97%) ÷ 76.97% + (Stage IV gas phase byproducts) 50 × (100% - 100%) ÷ 100% + 15 × (100% - 1.72%) ÷ 1.72% mL] / (sample mass) 300 g = 2.99 mL / g.

[0138] The total time taken was 19 hours.

[0139] Experimental conclusion: In Example 4, an in-situ heating and degassing experiment was conducted on the granules using different calibrators. The final byproduct index A was 2.99 mL / g, which was basically the same as the result obtained in Example 3 using argon. This indicates that the calibrator does not affect the reliability of the experimental method, and the quantitative concentration of byproducts can be obtained using simple non-reactive gases / liquids.

[0140] Example 5 Example 5 illustrates the use of the detection method of the present invention to detect degassing byproducts of finished cables under different formulations.

[0141] Experimental item: Finished cable Experimental sample condition: after cross-linking Sample formulation: LDPE base: 48.6 phr; DCP: 27.5 phr; bis(tert-butylperoxyisopropylbenzene): 13.6 phr; Antioxidant 300: 10.3 phr Degassing procedure: Stage I: Degassing at 120℃ under low vacuum (-0.02 MPa) for 30 min Stage II: Degassing at 180℃ under low vacuum (-0.02 MPa) for 30 min Stage III: Degassing at 120℃ under high vacuum (-0.2 MPa) for 12 h Stage IV: Degassing at -30℃ under high vacuum (-0.2 MPa) for 72 hours Stage V: Degassing at 80℃ under low vacuum (-0.02 MPa) for 4 hours Sample weight: 300 g Sample size: Table 21 shows the gaseous byproducts (stage I), with 50 mL of carbon dioxide used as a calibrator.

[0142] Table 21

[0143] Table 22 shows the gaseous byproducts (stage II), with 50 mL of hydrogen gas used as a calibrator.

[0144] Table 22

[0145] Table 23 shows the gaseous byproducts (stage III), with 50 mL of nitrogen gas used as a calibrator.

[0146] Table 23

[0147] Table 24 shows the gaseous byproducts (stage IV), with 50 mL of argon gas used as a calibrator.

[0148] Table 24

[0149] Table 25 shows the gaseous byproducts (stage V), with 50 mL of argon gas used as a calibrator.

[0150] Table 25

[0151] Table 26 shows the liquid phase byproducts, with 15 mL of benzene used as a calibrator.

[0152] Table 26

[0153] Byproduct index A = [(Stage I gas phase byproducts) 50 × (100% - 73.85%) ÷ 73.85% + (Stage II gas phase byproducts) 50 × (100% - 62.54%) ÷ 62.54% + (Stage III gas phase byproducts) 50 × (100% - 75.69%) ÷ 75.69% + (Stage IV gas phase byproducts) 50 × (100% - 92.39%) ÷ 92.39% + (Stage V gas phase byproducts) 50 × (100% - 100%) ÷ 100% + 15 × (100% - 1.05%) ÷ 1.05% mL] / 300 g = 4.94 mL / g.

[0154] The total time taken was 19 hours.

[0155] Comparative Example 1 Comparative Example 1 is intended to illustrate the degassing experiment and analysis of finished cables at industrial temperatures.

[0156] Experimental item: Finished cable Experimental sample condition: after cross-linking Sample specifications: 9 mm insulation thickness cable section Sample formulation: XLPE base: 97.8 phr; DCP: 2.0 phr; Antioxidant 300: 0.2 phr Degassing procedure: Stage I: Degassing at 80℃ and atmospheric pressure (0.1 MPa) for 240 h Stage II: Degassing at 80℃ and atmospheric pressure (0.1 MPa) for 240 h Stage III: Degassing at 80℃ and atmospheric pressure (0.1 MPa) for 240 h Stage IV: Degassing at 80℃ and atmospheric pressure (0.1 MPa) for 240 h Stage V: Degassing at 80℃ and atmospheric pressure (0.1 MPa) for 240 h Sample weight: 600 g sample Table 27 shows the gaseous byproducts (stage I), with 50 mL of argon gas used as a calibrator.

[0157] Table 27

[0158] Table 28 shows the gaseous byproducts (stage II), with 50 mL of argon gas used as a calibrator.

[0159] Table 28

[0160] Table 29 shows the gaseous byproducts (stage III), with 50 mL of argon gas used as a calibrator.

[0161] Table 29

[0162] Table 30 shows the gaseous byproducts (stage IV), with 50 mL of argon gas used as a calibrator.

[0163] Table 30

[0164] Table 31 shows the gaseous byproducts (stage V), with 50 mL of argon gas used as a calibrator.

[0165] Table 31

[0166] The treatment method for liquid phase byproducts is the same as in Example 1.

[0167] Table 32 shows the liquid phase byproducts, with 15 mL of toluene used as a calibrator.

[0168] Table 32

[0169] Byproduct index A = [(Stage I gas phase byproducts) 50 × (100% - 84.69%) ÷ 84.69% + (Stage II gas phase byproducts) 50 × (100% - 86.21%) ÷ 86.21% + (Stage III gas phase byproducts) 50 × (100% - 87.65%) ÷ 87.65% + (Stage IV gas phase byproducts) 50 × (100% - 90.67%) ÷ 90.67% + (Stage V gas phase byproducts) 50 × (100% - 100%) ÷ 100% + 15 × (100% - 1.19%) ÷ 1.19% mL] / 600g = 2.12 mL / g.

[0170] The total time taken was 960 hours.

[0171] Experimental conclusion: (1) Comparative Example 1 adopted traditional industrial degassing conditions (atmospheric pressure, 80℃), and the degassing time of general cables needs to reach 20 days or more; under the crosslinking agent content in this experiment, the cable can be completely degassed within 40 days, which is consistent with the actual cable experiment. (2) In Comparative Example 1, the relative content of methane gradually decreased over time, while the content of other types of byproducts gradually increased, indicating that the chemical structure of the byproducts changed, which reflects the advantage of in-situ detection in exploring the transformation of byproducts. (3) Under the test conditions, the byproduct index A is 2.12 mL / g, which means that 2.12 mL of byproducts are produced per gram under this formula. This is similar to the byproduct index in Example 1, indicating that the byproduct index under different test conditions is similar, which verifies the reliability of the method. At the same time, the degassing time can be shortened by changing the pressure and temperature.

[0172] Comparative Example 2 Comparative Example 2 illustrates the degassing experiment and analysis of semi-finished cables at industrial temperatures.

[0173] Experimental item: Semi-finished cable Experimental sample status: In the process of cross-linking Sample dimensions: 17 cm × 21 cm × 1 mm Sample formulation: XLPE base: 97.8 phr; DCP: 2.0 phr; Antioxidant 300: 0.2 phr Degassing procedure: Stage I: Degassing at 80℃ and atmospheric pressure (0.1 MPa) for 240 h Stage II: Degassing at 80℃ and atmospheric pressure (0.1 MPa) for 240 h Stage III: Degassing at 80℃ and atmospheric pressure (0.1 MPa) for 240 h Stage IV: Degassing at 80℃ and atmospheric pressure (0.1 MPa) for 240 h Stage V: Degassing at 80℃ and atmospheric pressure (0.1 MPa) for 240 h Sample weight: 35 g sample Table 33 shows the gaseous byproducts (stage I), with 20 mL of argon gas used as a calibrator.

[0174] Table 33

[0175] Table 34 shows the gaseous byproducts (stage II), with 20 mL of argon gas used as a calibrator.

[0176] Table 34

[0177] Table 35 shows the gaseous byproducts (stage III), with 20 mL of argon gas used as a calibrator.

[0178] Table 35

[0179] Table 36 shows the gaseous byproducts (stage IV), with 20 mL of argon gas used as a calibrator.

[0180] Table 36

[0181] Table 37 shows the gaseous byproducts (stage V), with 20 mL of argon gas used as a calibrator.

[0182] Table 37

[0183] The treatment method for liquid phase byproducts is the same as in Example 2.

[0184] Table 38 shows the liquid phase byproducts, with 5 mL of toluene used as a calibrator.

[0185] Table 38

[0186] Byproduct index A = [(Stage I gas phase byproducts) 20 × (100% - 84.64%) ÷ 84.64% + (Stage II gas phase byproducts) 20 × (100% - 85.96%) ÷ 85.96% + (Stage III gas phase byproducts) 20 × (100% - 87.74%) ÷ 87.74% + (Stage IV gas phase byproducts) 20 × (100% - 90.54%) ÷ 90.54% + (Stage V gas phase byproducts) 20 × (100% - 100%) ÷ 100% + 5 × (100% - 7.44%) ÷ 7.44% mL] / 35 g = 2.11 mL / g.

[0187] The total time taken was 960 hours.

[0188] Experimental conclusion: (1) Comparative Example 2 adopted traditional industrial degassing conditions (normal pressure, 80℃), and the degassing time of general cables needs to reach 20 days or more; under the crosslinking agent content in this experiment, the semi-finished cable can be completely degassed within 40 days, which is consistent with the actual experiment. (2) Under the test conditions, the byproduct index A was 2.11 mL / g, which means that 2.11 mL of byproducts were produced per gram under this formulation. This is similar to the byproduct index in Example 2, indicating that the byproduct index obtained by this method can be consistent with that under traditional industrial methods, thus verifying the reliability of this method.

[0189] Comparative Example 3 Comparative Example 3 illustrates the degassing experiment and analysis of insulation material for industrial temperature cables.

[0190] Experimental material: Cable insulation Experimental sample condition: before crosslinking Sample formulation: XLPE base: 97.8 phr; DCP: 2.0 phr; Antioxidant 300: 0.2 phr Degassing procedure: Stage I: Degassing at 180℃ under low vacuum (-0.02 MPa) for 30 min Stage II: Degassing at 80℃ and atmospheric pressure (0.1 MPa) for 240 h Stage III: Degassing at 80℃ and atmospheric pressure (0.1 MPa) for 240 h Stage IV: Degassing at 80℃ and atmospheric pressure (0.1 MPa) for 240 h Stage V: Degassing at 80℃ and atmospheric pressure (0.1 MPa) for 240 h Stage VI: Degassing at 80℃ and atmospheric pressure (0.1 MPa) for 240 h Test results (600 g sample): Table 39 shows the gaseous byproducts (stage I), with 50 mL of argon gas used as a calibrator.

[0191] Table 39

[0192] Table 40 shows the gaseous byproducts (stage II), with 50 mL of argon gas used as a calibrator.

[0193] Table 40

[0194] Table 41 shows the gaseous byproducts (stage III), with 50 mL of argon gas used as a calibrator.

[0195] Table 41

[0196] Table 42 shows the gaseous byproducts (stage IV), with 50 mL of argon gas used as a calibrator.

[0197] Table 42

[0198] Table 43 shows the gaseous byproducts (stage V), with 50 mL of argon gas used as a calibrator.

[0199] Table 43

[0200] Table 44 shows the gaseous byproducts (stage VI), with 50 mL of argon gas used as a calibrator.

[0201] Table 44

[0202] The liquid phase byproducts were treated in the same way as in Example 3.

[0203] Table 45 shows the liquid phase byproducts, with 15 mL of toluene used as a calibrator.

[0204] Table 45

[0205] Byproduct index A = [(Stage I gas phase byproducts) 50 × (100% - 98.17%) ÷ 98.17% + (Stage II gas phase byproducts) 50 × (100% - 82.91%) ÷ 82.91% + (Stage III gas phase byproducts) 50 × (100% - 85.99%) ÷ 85.99% + (Stage IV gas phase byproducts) 50 × (100% - 87.57%) ÷ 87.57% + (Stage V gas phase byproducts) 50 × (100% - 90.44%) ÷ 90.44% + (Stage VI gas phase byproducts) 50 × (100% - 100%) ÷ 100% + 15 × (100% - 1.16%) ÷ 1.16% mL] / 600g = 2.18 mL / g.

[0206] The total time taken was 960 hours.

[0207] Experimental conclusion: (1) Comparative Example 3 adopted traditional industrial degassing conditions (normal pressure, 80℃). Generally, the degassing time of cables needs to reach 20 days or more. Under the crosslinking agent content in this experiment, except for the first stage used for vulcanization, the granules can only be completely degassed within 40 days at 80℃, which is consistent with the actual cable experiment. (2) Under the test conditions, the byproduct index A is 2.18 mL / g, which means that 2.18 mL of byproduct is produced per gram under this formula. This is similar to the byproduct index of Examples 3 and 4, indicating that the byproduct index under different test conditions is similar, which verifies the reliability of the method. At the same time, the degassing time can be shortened by changing the pressure and temperature.

[0208] Comparative Example 4 Comparative Example 4 aims to evaluate the reliability of the traditional thermogravimetric analysis (TGA) method by comparing its quantitative results for finished cables / semi-finished cables / granules.

[0209] Experimental materials: Finished cables / semi-finished cables Experimental sample status: Post-crosslinking / In progress Sample specifications: 9 mm insulation thickness cable segment (finished cable), 17 cm × 21 cm × 1 mm (semi-finished cable) Sample formulation: XLPE base: 97.8 phr; DCP: 2.0 phr; Antioxidant 300: 0.2 phr TGA test procedure: The test temperature range is 35-700 ℃, and the heating rate is 10 ℃ / min.

[0210] Sample weight: 10 mg each, test results as follows Figure 3 As shown, from Figure 3As can be seen, the TGA curves of samples with the same formulation show no significant differences, making it impossible to effectively distinguish them.

[0211] Experimental conclusion: (1) Comparative Example 4 used the traditional TGA method to test the finished and semi-finished cables. The test results showed that the TGA curves of samples with the same formulation were not significantly different and could not be effectively distinguished. This method generally uses the weight loss rate of XLPE at 350℃ as the by-product content indicator. The experimental results showed that the weight loss rate of both finished and semi-finished cables was about 0.2%. Therefore, the by-product weight loss per gram of test sample was 2 mg, mainly liquid by-products with a density of 1 g / cm³. 3 Therefore, according to the TGA test method, it is roughly estimated that 2 mL of byproducts are produced per gram of this formulation; (2) The byproduct content obtained by the traditional TGA test method and the new byproduct index A method is similar, but the byproduct index A has higher accuracy, which proves that the method is reliable.

[0212] The results above show that, compared to the comparative example, existing methods can only obtain a rough weight loss rate from the curve, lacking high accuracy. Furthermore, they cannot distinguish between gaseous and liquid byproducts, and cannot achieve real-time detection and control of pressure and temperature. The method provided by this invention allows for changes in test conditions (temperature, time, and pressure), while simultaneously obtaining gaseous and liquid byproducts separately, which are then combined to obtain a unified byproduct index A. This provides a reference for cable development and allows for the investigation of cable insulation materials in different states, with accurate measurement results. This invention solves the shortcomings of existing methods, which are limited to room temperature and atmospheric pressure, and cannot accelerate byproduct release under high temperature and vacuum conditions. It also addresses the inability to accurately determine the specific content and composition of liquid byproducts.

[0213] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for detecting degassing byproducts, characterized in that, The detection method includes: (1) In a closed vacuum environment, the sample to be tested is subjected to at least two stages of degassing treatment, and the conditions of the first stage and the second stage of degassing treatment are at least partially different in the two adjacent stages of degassing treatment; The degassing conditions include: a temperature of -80℃ to 250℃, a pressure of -0.2MPa to 0.1MPa, and a time of 0.5h to 72h. (2) The gaseous byproducts after degassing were tested to obtain their composition and content; (3) After the solid product after degassing is subjected to gradient washing and / or soaking treatment, solid-liquid separation is performed; (4) The liquid obtained in step (3) is analyzed by liquid phase infrared analysis and gas chromatography-flame ionization detection in sequence to obtain the composition and content of liquid phase byproducts; The total content of byproducts removed per gram of the sample to be tested is calculated using the following formula: A=[(G×(100%-V) G )÷V G +L×(100%-V) L )÷V L )] / m, Where A is the byproduct index, mL / g; G represents the calibration gas volume, in mL; L represents the calibration liquid volume, in mL; V G The percentage of calibration gas among all gases, expressed as % . V L The percentage of calibration liquid in the total liquid content, expressed as % . m is the total mass of the sample to be tested, in grams.

2. The detection method according to claim 1, wherein, A sealed vacuum environment is the environment formed by a high borosilicate glass container; And / or, the sample to be tested is selected from one or more of cable insulation materials, semi-finished cables, and finished cables; And / or, the shape of the sample to be tested is one or more of granular, blocky, plate-like and columnar.

3. The detection method according to claim 1 or 2, wherein, The degassing process consists of ≥3 stages, and the conditions for each stage of the degassing process are at least partially different; Preferably, the degassing conditions include: a temperature of -30°C to 220°C, a pressure of -0.2 MPa to 0.1 MPa, and a time of 0.5 to 48 hours. Preferably, the composition and content of gaseous byproducts in step (2) are 0, which indicates that degassing is complete.

4. The detection method according to any one of claims 1-3, wherein, The calibration gas is one or more of nitrogen, argon, carbon dioxide, and hydrogen; And / or, the instruments used for detection in step (2) are, in order, a gas infrared analyzer and a gas chromatograph-flame ionization detector; Preferably, the resolution of the gas infrared analyzer is ≤4cm. -1 .

5. The detection method according to any one of claims 1-4, wherein, Gas-phase byproducts are C1-C20 compounds; Preferably, the gaseous byproducts include C1-C6 alkanes, methanol, ethanol, propanol, acetone, butanone, n-butene, and isoprene, and more preferably include one or more of n-hexane, 2-methylpentane, 3-methylpentane, and 2,3-dimethylbutane.

6. The detection method according to any one of claims 1-5, wherein, The gradient flushing includes the following steps: (S1) Solvent A is used to extract low-polarity substances, and the first liquid phase is collected; The low-polarity product is a decomposition product of polyethylene; (S2) Extract the polar residue from the remaining solid in step (S1) using solvent B and collect the second liquid phase; The polar residue is a cross-linking agent byproduct.

7. The detection method according to any one of claims 1-6, wherein, The calibration liquid is one or more of benzene, toluene, and xylene; And / or, liquid phase byproducts include one or more of acetophenone, α-methylstyrene, 2-phenyl-2-propanol, 2,4-dimethyl-undecane, 2,4-diphenyl-4-methyl-2(E)-pentene, 2-butyl-1-octanol, cumene, methyl methoxyphenylacetate, and 1-phenyl-1,2-propanedione; And / or, the total time for the method to be described is 18-720 hours, preferably 18-72 hours.

8. A device for detecting degassing byproducts, characterized in that, The device includes a sample processing system, a gas detection system, and a liquid detection system; The sample processing system is used to degas the sample to be tested, send the gaseous byproducts after degassing to the gas detection system, and perform gradient washing and / or soaking on the solid products after degassing, and send the liquid to the liquid detection system after solid-liquid separation. The sample processing system is connected to a temperature control system that controls the temperature from -80℃ to 250℃, and a pressure control system that controls the pressure from -0.2MPa to 0.1MPa. The gas detection system is used to detect the composition and content of gaseous byproducts; The liquid detection system includes a liquid phase infrared analyzer (8) and a gas chromatograph-flame ionization detector (Y3) for detecting the composition and content of liquid phase byproducts.

9. The detection device according to claim 8, wherein, The sample processing system includes a high borosilicate glass box (1), a vacuum pump (3), a calibration gas storage box (4), a calibration liquid storage box (5), a liquid collection pool (6), and a heating and insulation layer (7). The vacuum pump (3), calibration gas storage tank (4), calibration liquid storage tank (5), and liquid collection pool (6) are each independently connected to the high borosilicate glass box (1); The high borosilicate glass box (1) is provided with a sample inlet (2) and a heating and insulation layer (7) is provided around it; A stopcock is provided between the vacuum pump (3) and the high borosilicate glass box (1); And / or, the gas detection system includes a gas infrared analyzer (Y1) connected in sequence to the high borosilicate glass box (1), and a gas chromatograph-mass spectrometer (Y2) or a gas chromatograph-flame ionization detector (Y3). And / or, the liquid detection system further includes a liquid collection tank (6), which is connected to a gas chromatograph-flame ionization detector (Y3).

10. The application of the detection device according to claim 8 or 9 in a method for detecting degassing byproducts.

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