Halogen-free environment-friendly electric carbon mark-resistant heat-shrinkable sleeve and preparation method thereof

Abstract

The invention relates to the technical field of heat-shrinkable materials, in particular to a halogen-free environment-friendly electric carbon mark-resistant heat-shrinkable sleeve and a preparation method thereof, and the preparation method comprises the following steps: preparing a sleeve sample from a plurality of raw materials; based on sleeving the sleeve sample on the target copper bar, acquiring a surface image of the sleeve sample on the target copper bar; determining whether the interface adaptability of the sleeve sample and the target copper bar reaches the standard or not based on the interface contact characterization parameters, and determining and adjusting the kneading temperature or the extrusion temperature according to the ratio; determining whether the contact uniformity of the sleeve sample on the target copper bar is qualified or not based on the contact fluctuation characterization value, and determining and adjusting the premixing time according to the difference value; determining whether the contact interface of the sleeve sample and the target copper bar has bubble influence or not based on the bubble area proportion; and determining whether the bubble distribution of the contact interface of the sleeve sample and the target copper bar reaches the standard based on the spatial aggregation degree index, and determining and adjusting the irradiation dose according to the relative difference. According to the invention, the interface adaptability of the halogen-free environment-friendly electric carbon mark-resistant heat-shrinkable sleeve and the copper bar is improved.

Description

Technical Field

[0001] This invention relates to the field of heat-shrinkable materials technology, and in particular to a halogen-free, environmentally friendly, electrostatically resistant carbon-marking heat-shrinkable sleeve and its preparation method. Background Technology

[0002] In electrical insulation products, busbar insulating heat shrink tubing provides insulation protection for copper busbars, preventing accidents caused by exposed live conductors. Existing busbar heat shrink tubing uses EVA-based polyolefin materials. EVA-based materials are prone to oxidative degradation under the influence of electric fields, thermal fields, and ambient humidity, releasing acidic gases such as acetic acid. This reacts electrochemically with the copper busbar, leading to surface oxidation and cross-sectional thinning. This not only increases contact resistance but may also reduce the interfacial bonding between the tubing and the copper busbar due to corrosion product accumulation, ultimately inducing insulation failure. Furthermore, EVA-based materials have low shrinkage stress. When applied to busbars with multiple bends, they cannot fully conform to the complex curves of the busbar during heat shrinking, resulting in residual "air trapping" between the tubing and the copper busbar. Air expands at high temperatures, further exacerbating the risk of interfacial delamination and even causing the tubing to bulge or rupture. Current production processes rely solely on visual inspection to assess the interface quality between the tubing and the copper busbar, lacking quantitative analysis of the interface contact uniformity and distribution characteristics.

[0003] Chinese Patent Application Publication No. CN117711681A discloses a method for preparing a halogen-free flame-retardant environmentally friendly low-voltage cable, comprising multiple wire cores. The wire core located in the middle is provided with an isolation sleeve on its outer side, and the other wire cores are evenly distributed in a ring on the outer side of the isolation sleeve. The isolation sleeve is provided with multiple fixedly connected isolation plates for isolating the wire cores from each other. A fire-resistant sleeve is provided on the outer side of the isolation plate, and a ring-shaped isolation mesh is provided inside the fire-resistant sleeve. An anti-corrosion coating is provided on the outer side of the fire-resistant sleeve.

[0004] However, the existing technology has the following problems: the physical isolation structure design does not quantify the interface contact between the sleeve and the copper busbar, resulting in low uniformity of the contact between the sleeve and the copper busbar, which in turn leads to low interface compatibility between the halogen-free environmentally friendly electrostatic carbon trace heat shrink sleeve and the copper busbar. Summary of the Invention

[0005] To address this issue, the present invention provides a halogen-free, environmentally friendly, electrostatic carbon-track resistant heat shrink tubing and its preparation method, thereby overcoming the problem that the physical isolation structure design in the prior art does not quantify the interface contact between the tubing and the copper busbar, resulting in low uniformity of the contact between the tubing and the copper busbar, which in turn leads to low interface compatibility between the halogen-free, environmentally friendly, electrostatic carbon-track resistant heat shrink tubing and the copper busbar.

[0006] To achieve the above objectives, the present invention provides a method for preparing a halogen-free, environmentally friendly, electrostatically resistant carbon-marking heat shrink tubing, comprising:

[0007] Sleeve samples were prepared based on several raw materials;

[0008] Cut a sleeve sample of a preset length, place the sleeve sample on the target copper busbar, and obtain a surface image of the sleeve sample on the target copper busbar.

[0009] Based on the surface image, the interface contact characterization parameters are determined to determine whether the interface compatibility between the sleeve sample and the target copper busbar meets the standard, and the kneading temperature or extrusion temperature is adjusted according to the ratio of the interface contact characterization parameters to the preset interface contact characterization parameters.

[0010] Based on the surface image, a contact fluctuation characterization value is determined to determine whether the contact uniformity of the sleeve sample on the target copper busbar is qualified, and the premixing time is adjusted according to the difference between the contact fluctuation characterization value and the preset contact fluctuation characterization value.

[0011] Based on the surface image, the bubble area ratio is determined to determine whether there is bubble influence at the contact interface between the sleeve sample and the target copper busbar.

[0012] Based on the surface image with the presence of bubbles, a spatial aggregation index is determined to determine whether the bubble distribution at the interface between the sleeve sample and the target copper busbar meets the standard, and the irradiation dose is adjusted according to the relative difference between the spatial aggregation index and the preset spatial aggregation index.

[0013] Furthermore, the failure of the interface compatibility between the sleeve sample and the target copper busbar to meet the standard is determined based on the comparison results of interface contact characterization parameters being less than or equal to preset interface contact characterization parameters, wherein,

[0014] The interface contact characterization parameters are determined based on the area of ​​the effective contact area and the area of ​​the reference contact area.

[0015] Furthermore, the process of adjusting the kneading temperature or extrusion temperature includes:

[0016] Calculate the ratio of the interface contact characterization parameter to the preset interface contact characterization parameter;

[0017] Based on the comparison results where the ratio is less than or equal to a preset ratio, the kneading temperature is increased by a preset kneading temperature adjustment coefficient.

[0018] Based on the comparison results where the ratio is greater than a preset ratio, the extrusion temperature is increased by a preset extrusion temperature adjustment coefficient.

[0019] Furthermore, the non-compliance of the contact uniformity of the sleeve sample on the target copper busbar is determined based on the comparison result of the contact fluctuation characterization value being greater than the preset contact fluctuation characterization value, wherein,

[0020] The contact fluctuation characterization value is determined based on the standard deviation and average value of the grayscale mean.

[0021] Furthermore, the process of adjusting the premixing time includes:

[0022] Calculate the difference between the contact fluctuation characterization value and the preset contact fluctuation characterization value;

[0023] Based on the comparison results where the difference is less than or equal to a preset difference, the premixing time is increased by a first preset premixing time adjustment coefficient.

[0024] Based on the comparison results where the difference is greater than a preset difference, the premixing time is increased by a second preset premixing time adjustment coefficient.

[0025] Furthermore, the presence of air bubbles at the contact interface between the sleeve sample and the target copper busbar is determined based on a comparison result where the bubble area ratio is greater than a preset bubble area ratio.

[0026] The bubble area ratio is determined based on the area of ​​the contact bubble at the interface between the sleeve sample and the target copper busbar and the area of ​​the interface between the sleeve sample and the target copper busbar.

[0027] Furthermore, the non-compliance of the bubble distribution at the contact interface between the sleeve sample and the target copper busbar is determined based on the comparison result of a spatial aggregation index greater than a preset spatial aggregation index, wherein,

[0028] The spatial aggregation index is determined based on the maximum bubble cluster volume, the total bubble volume, the minimum distance between the bubble cluster and the pipe wall, and the pipe wall thickness.

[0029] Furthermore, the process of adjusting the irradiation dose includes:

[0030] Calculate the relative difference between the spatial clustering index and the preset spatial clustering index;

[0031] Based on the comparison results where the relative difference is less than or equal to the preset relative difference, the irradiation dose is increased by the first preset irradiation dose adjustment coefficient.

[0032] Based on the comparison results where the relative difference is greater than the preset relative difference, the irradiation dose is increased by the second preset irradiation dose adjustment coefficient.

[0033] Furthermore, the process of preparing the sleeve sample includes:

[0034] EMMA, nano-activated magnesium hydroxide, ultrafine activated aluminum hydroxide, ultrafine activated kaolin, antioxidant, organosilicon powder, trimethylolpropane trimethacrylate, polyethylene wax, stearic acid, zinc stearate, and halogen-free color powder are added to a mixer in a preset mass ratio and mixed under preset mixing conditions to obtain a mixture.

[0035] The mixture is granulated by kneading in a kneader under preset kneading conditions, and then granulated again by a twin-screw granulator under preset granulation conditions to obtain granules.

[0036] The granules are extruded through an extruder under preset extrusion conditions to obtain a tube blank;

[0037] The tube blank is irradiated under preset crosslinking conditions and expanded under preset expansion conditions to obtain a sleeve sample;

[0038] The preset mass fractions are 100 parts EMMA, 15 parts nano-activated magnesium hydroxide, 15 parts ultrafine activated aluminum hydroxide, 10 parts ultrafine activated kaolin, 0.5 parts antioxidant, 6 parts organosilicon powder, 1.0 parts trimethylolpropane trimethacrylate, 0.3 parts polyethylene wax, 0.2 parts stearic acid, 0.5 parts zinc stearate, and 1.5 parts halogen-free color powder.

[0039] Another aspect of the present invention provides a halogen-free, environmentally friendly, electrostatically resistant carbon trace heat shrink tubing, comprising: EMMA, nano-activated magnesium hydroxide, ultrafine activated aluminum hydroxide, ultrafine activated kaolin, antioxidant, organosilicon powder, trimethylolpropane trimethacrylate, polyethylene wax, stearic acid, zinc stearate, and halogen-free colorant.

[0040] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention determines whether the interface compatibility between the sleeve sample and the target copper busbar meets the standard by using interface contact characterization parameters. If it does not meet the standard, the kneading temperature or extrusion temperature is adjusted according to the ratio of the interface contact characterization parameters to the preset interface contact characterization parameters. The contact uniformity of the sleeve sample on the target copper busbar is determined according to the contact fluctuation characterization value. If it does not meet the standard, the premixing time is adjusted. It is first determined whether there are bubbles affecting the interface between the sleeve sample and the target copper busbar. If there are bubbles, the distribution of bubbles at the interface between the sleeve sample and the target copper busbar is determined according to the spatial aggregation index. If it does not meet the standard, the irradiation dose is adjusted. Bubble contamination and abnormal distribution are identified in advance according to the bubble area ratio and spatial aggregation index. The material density is optimized by irradiation crosslinking, preventing interface failure and avoiding defects such as interface delamination and peeling. This improves the interface quality between the sleeve and the copper busbar, enhances the stability and reliability of insulation protection, and reduces safety hazards caused by poor contact, bubbles, and other problems. Thus, the interface compatibility between the halogen-free environmentally friendly electrostatic carbon trace heat shrink sleeve and the copper busbar is improved.

[0041] Furthermore, this invention quantifies the interfacial contact performance between the sleeve and the copper busbar, using the effective contact area ratio as an interfacial contact characterization parameter. The compatibility is determined by comparing it with a preset interfacial contact characterization parameter. If the compatibility is not met, the kneading or extrusion temperature is adjusted. Poor interfacial contact is the core cause of subsequent delamination and cracking of the sleeve and copper busbar. When the compatibility is not met, the temperature adjustment is triggered immediately, intervening in the interfacial bonding quality from the process end in advance. This ensures that the process parameters dynamically match the material characteristics, reduces the risk of insulation failure caused by poor interfacial contact, improves the interfacial fit between the sleeve and the copper busbar, reduces contact thermal resistance and electric field concentration, thereby improving the interfacial compatibility between the halogen-free environmentally friendly electrostatic carbon trace heat shrink sleeve and the copper busbar.

[0042] Furthermore, this invention uniformly divides the effective contact area between the bushing and the copper busbar into equal-area sub-regions, calculates the ratio of the standard deviation to the average value of the grayscale mean of each sub-region as the contact fluctuation characterization value, compares the contact fluctuation characterization value with the preset contact fluctuation characterization value to determine whether the contact uniformity is qualified. If it is not qualified, the premixing time is adjusted. Based on the ratio of the standard deviation to the average value of the grayscale mean of the sub-region, the contact uniformity is transformed into a calculable quantitative index, improving the detection accuracy and repeatability. This allows the premixing time adjustment to accurately match the material mixing requirements, avoiding uneven contact or overmixing caused by insufficient premixing, reducing the risk of heat accumulation or electric field distortion caused by poor local contact, and improving the insulation reliability of the product.

[0043] Furthermore, this invention determines the presence of bubble influence by the bubble area ratio. If present, the bubble distribution uniformity is assessed based on the spatial aggregation index. If not met, the irradiation dose is dynamically adjusted based on the relative difference between the spatial aggregation index and the preset value. This avoids bubble aggregation caused by insufficient irradiation dose or material degradation caused by excessive irradiation dose, improves the density of the insulation layer, and the spatial aggregation index reflects the degree of bubble distribution concentration. Adjusting the irradiation dose improves the cross-linking uniformity of the material, reduces the risk of electric field distortion caused by local bubble aggregation, extends the service life of the sleeve, and improves the safety of the electrical system. This improves the interface compatibility between the halogen-free environmentally friendly electrostatic carbon trace heat shrink sleeve and the copper busbar. Attached Figure Description

[0044] Figure 1 This is a flowchart illustrating the preparation method of halogen-free, environmentally friendly, electrostatically resistant carbon trace heat shrink tubing according to an embodiment of the present invention.

[0045] Figure 2 This is a flowchart illustrating whether the interface compatibility between the sleeve sample and the target copper busbar meets the requirements in an embodiment of the present invention.

[0046] Figure 3 This is a flowchart illustrating how to determine whether the contact uniformity of the sleeve sample on the target copper busbar is qualified according to an embodiment of the present invention.

[0047] Figure 4This is a flowchart illustrating how to determine whether air bubbles affect the contact interface between the sleeve sample and the target copper busbar in an embodiment of the present invention. Detailed Implementation

[0048] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0049] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0050] It should be noted that the data in this embodiment are all derived from a comprehensive analysis and evaluation of historical test data and corresponding historical test results from the three months prior to this test. Those skilled in the art will understand that the determination of the above-mentioned parameters for any single item in this invention can be achieved by selecting the value with the highest percentage based on the data distribution as the preset standard parameter, using weighted summation to obtain the value as the preset standard parameter, substituting each historical data point into a specific formula and using the value obtained from that formula as the preset standard parameter, or other selection methods, as long as the invention can clearly define different specific situations in the single-item judgment process through the obtained values.

[0051] Please see Figure 1 As shown, it is a flowchart of the preparation method of halogen-free environmentally friendly electrostatic carbon trace heat shrink tubing according to an embodiment of the present invention.

[0052] The present invention provides a method for preparing halogen-free, environmentally friendly, and electrostatically resistant carbon-tracking heat shrink tubing, comprising:

[0053] Step S1: Prepare a sleeve sample based on several raw materials;

[0054] Step S2: Cut a sleeve sample of a preset length, place the sleeve sample on the target copper busbar, and obtain a surface image of the sleeve sample on the target copper busbar.

[0055] Step S3: Determine the interface contact characterization parameters based on the surface image to determine whether the interface compatibility between the sleeve sample and the target copper busbar meets the standard, and determine the adjustment of the kneading temperature or extrusion temperature according to the ratio of the interface contact characterization parameters to the preset interface contact characterization parameters.

[0056] Step S4: Determine the contact fluctuation characterization value based on the surface image to determine whether the contact uniformity of the sleeve sample on the target copper busbar is qualified, and determine the adjustment of the premixing time based on the difference between the contact fluctuation characterization value and the preset contact fluctuation characterization value.

[0057] Step S5: Determine the bubble area ratio based on the surface image to determine whether there is bubble influence at the contact interface between the sleeve sample and the target copper busbar.

[0058] Step S6: Determine the spatial aggregation index based on the surface image with bubble influence to determine whether the bubble distribution at the contact interface between the sleeve sample and the target copper busbar meets the standard, and determine the adjusted irradiation dose based on the relative difference between the spatial aggregation index and the preset spatial aggregation index.

[0059] Specifically, this invention determines whether the interface compatibility between the bushing sample and the target copper busbar meets the standard by using interface contact characterization parameters. If it does not meet the standard, the kneading temperature or extrusion temperature is adjusted according to the ratio of the interface contact characterization parameters to the preset interface contact characterization parameters. The contact uniformity of the bushing sample on the target copper busbar is determined according to the contact fluctuation characterization value. If it does not meet the standard, the premixing time is adjusted. It is first determined whether there are bubbles affecting the interface between the bushing sample and the target copper busbar. If there are bubbles, the distribution of bubbles at the interface between the bushing sample and the target copper busbar is determined according to the spatial aggregation index. If it does not meet the standard, the irradiation dose is adjusted. Bubble contamination and abnormal distribution are identified in advance according to the bubble area ratio and spatial aggregation index. The material density is optimized by irradiation crosslinking, preventing interface failure and avoiding defects such as interface delamination and peeling. This improves the interface quality between the bushing and the copper busbar, enhances the stability and reliability of insulation protection, and reduces safety hazards caused by poor contact, bubbles, and other problems. This improves the interface compatibility between the halogen-free environmentally friendly electrostatic carbon trace heat shrinkable bushing and the copper busbar.

[0060] This invention also provides a halogen-free, environmentally friendly, electrostatic carbon-track resistant heat shrink tubing, comprising:

[0061] EMMA, nano-activated magnesium hydroxide, ultrafine activated aluminum hydroxide, ultrafine activated kaolin, antioxidant, organosilicon powder, trimethylolpropane trimethacrylate, polyethylene wax, stearic acid, zinc stearate, halogen-free color powder.

[0062] The process of preparing the sleeve sample in this embodiment of the invention includes:

[0063] Step S11: Add EMMA, nano-activated magnesium hydroxide, ultrafine activated aluminum hydroxide, ultrafine activated kaolin, antioxidant, organosilicon powder, trimethylolpropane trimethacrylate, polyethylene wax, stearic acid, zinc stearate, and halogen-free color powder to a mixer in a preset mass ratio, and mix under preset mixing conditions to obtain a mixture.

[0064] Step S12: The mixture is granulated by kneading in a kneader under preset kneading conditions, and then granulated again by a twin-screw granulator under preset granulation conditions to obtain granules.

[0065] Step S13: The granules are extruded through an extruder under preset extrusion conditions to obtain a tube blank;

[0066] Step S14: Irradiate the tube blank under preset crosslinking conditions and expand it under preset expansion conditions to obtain a sleeve sample.

[0067] In this embodiment of the invention, the preset mass parts are 100 parts EMMA, 15 parts ultrafine activated ATH, 15 parts nano MH, 6 parts organosilicon powder, 10 parts ultrafine activated kaolin, 0.5 parts antioxidant, 1.0 parts trimethylolpropane trimethacrylate, 0.3 parts polyethylene wax, 0.2 parts stearic acid, 0.5 parts zinc stearate, and 1.5 parts halogen-free color powder.

[0068] In this embodiment of the invention, the preset mixing conditions include a premixing time of 5 to 10 minutes, preferably 5 minutes, and a premixing temperature of 30 to 50°C, preferably 40°C.

[0069] In this embodiment of the invention, the preset kneading conditions include a kneading time of 20-30 min, preferably 25 min, a kneading machine speed of 20-40 rpm, preferably 30 rpm, a kneading temperature of 140-180℃, preferably 145℃, and preset granulation conditions of a granulation temperature of 170-180℃, preferably 175℃, and a granulator speed of 300-500 rpm, preferably 400 rpm.

[0070] In this embodiment of the invention, the preset extrusion conditions include an extrusion temperature of 160–220°C, preferably 170°C, and an extruder speed of 20–40 rpm, preferably 30 rpm.

[0071] In this embodiment of the invention, the preset crosslinking conditions include an irradiation dose of 4 to 6 Mrad, preferably 5 Mrad, and the preset expansion conditions include a tube blank thermal elongation of 120 to 180%, preferably 150%.

[0072] Specifically, in this embodiment of the invention, under the condition of obtaining the sleeve sample, a sleeve sample of a preset length is cut, the sleeve sample is placed on the target copper busbar, and a surface image of the sleeve sample on the target copper busbar is obtained. The preset length is 10 to 20 cm, preferably 15 cm.

[0073] Please see Figure 2 As shown, it is a flowchart of an embodiment of the present invention for determining whether the interface compatibility between the sleeve sample and the target copper busbar meets the standard.

[0074] Specifically, in this embodiment of the invention, the interface compatibility between the sleeve sample and the target copper busbar is determined based on the comparison result between the interface contact characterization parameters determined by the surface image and the preset interface contact characterization parameters.

[0075] When the interface contact characterization parameter is less than or equal to the preset interface contact characterization parameter, it is determined that the interface compatibility between the sleeve sample and the target copper busbar is not up to standard.

[0076] When the interface contact characterization parameter is greater than the preset interface contact characterization parameter, it is determined that the interface compatibility between the sleeve sample and the target copper busbar meets the standard.

[0077] In this embodiment of the invention, the preset interface contact characterization parameter range is [90%, 98%], preferably 95%, but the above values ​​are not limited to these, and those skilled in the art can adjust the values ​​according to actual needs.

[0078] In this embodiment of the invention, the process of obtaining the interface contact characterization parameter is as follows: an image segmentation algorithm is used to acquire the interface contact area between the sleeve sample and the target copper busbar in the surface image; the area in the interface contact area with a gray value at a preset contact threshold is recorded as the effective contact area; the geometric fit area between the sleeve sample and the target copper busbar is recorded as the reference contact area; the ratio of the area of ​​the effective contact area to the area of ​​the reference contact area is the interface contact characterization parameter, wherein the preset contact threshold is set to 200.

[0079] It is understandable that when the sleeve and the copper busbar are in close contact, the micro-unevenness at the interface is compacted, resulting in a decrease in the optical reflectivity of the local area, which manifests as an increase in grayscale value. If there is a gap, air or contaminants at the interface will form an "optical interface layer," which will also increase reflectivity and manifest as a decrease in grayscale value. Therefore, extracting areas with a grayscale value ≥200 through image segmentation is a capture of the "actual close contact area," quantifying the uniformity of the interface contact. When the contact defect is severe, it indicates that the micro-unevenness on the surface of the copper busbar is not fully filled. Increasing the kneading temperature can make the polymer molecular chains move more easily and penetrate into the tiny unevenness of the copper busbar during subsequent extrusion, thereby increasing the effective contact area. When the contact defect is mild, it indicates that the material flowability has basically met the requirements, but there may be tiny protrusions on the surface of the extrudate, resulting in a loose fit with the copper busbar. Increasing the extrusion temperature can reduce the melt viscosity, reduce the surface tension, and make the surface of the extrudate smoother, thus making the fit with the copper busbar tighter.

[0080] Specifically, in the case where the interface compatibility between the sleeve sample and the target copper busbar is determined to be substandard, the kneading temperature or extrusion temperature is adjusted based on the ratio of the interface contact characterization parameter to the preset interface contact characterization parameter.

[0081] When the ratio is less than or equal to the preset ratio, it is determined that the kneading temperature will be increased to the corresponding value by a preset kneading temperature adjustment coefficient of 1.15.

[0082] When the ratio is greater than the preset ratio, it is determined that the extrusion temperature will be increased to the corresponding value by a preset extrusion temperature adjustment coefficient of 1.28.

[0083] The ratio is the ratio of the interface contact characterization parameter to the preset interface contact characterization parameter.

[0084] In this embodiment of the invention, the preset ratio range is [0.6, 0.7], preferably 0.65, but the above value is not limited to this, and those skilled in the art can adjust the value according to actual needs.

[0085] In this embodiment of the invention, the increased kneading temperature is the product of the kneading temperature and the preset kneading temperature adjustment coefficient, which is set to 1.15; the increased extrusion temperature is the product of the extrusion temperature and the preset extrusion temperature adjustment coefficient, which is set to 1.28. To ensure that the adjusted kneading temperature and extrusion temperature meet the actual requirements, the adjustment range should not be too large, so an adjustment coefficient is set to control the adjustment range.

[0086] Specifically, this invention quantifies the interfacial contact performance between the sleeve and the copper busbar, using the effective contact area ratio as an interfacial contact characterization parameter. The compatibility is determined by comparing it with a preset interfacial contact characterization parameter. If the compatibility is not met, the kneading or extrusion temperature is adjusted. Poor interfacial contact is the core cause of subsequent delamination and cracking of the sleeve and copper busbar. When the compatibility is not met, the temperature adjustment is triggered immediately, intervening in the interfacial bonding quality from the process end in advance. This ensures that the process parameters dynamically match the material characteristics, reduces the risk of insulation failure caused by poor interfacial contact, improves the interfacial fit between the sleeve and the copper busbar, and reduces contact thermal resistance and electric field concentration, thereby improving the interfacial compatibility between the halogen-free environmentally friendly electrostatic carbon trace heat shrink sleeve and the copper busbar.

[0087] Please see Figure 3 As shown, it is a flowchart for determining whether the contact uniformity of the sleeve sample on the target copper busbar is qualified according to an embodiment of the present invention.

[0088] Specifically, in this embodiment of the invention, the contact uniformity of the sleeve sample on the target copper busbar is determined based on the comparison result between the contact fluctuation characterization value and the preset contact fluctuation characterization value.

[0089] When the contact fluctuation characterization value is less than or equal to the preset contact fluctuation characterization value, the contact uniformity of the sleeve sample on the target copper busbar is determined to be qualified.

[0090] When the contact fluctuation characterization value is greater than the preset contact fluctuation characterization value, it is determined that the contact uniformity of the sleeve sample on the target copper busbar is unqualified.

[0091] In this embodiment of the invention, the preset contact fluctuation characterization value range is [5%, 15%], preferably 10%, but the above value is not limited to this, and those skilled in the art can also adjust the value according to actual needs.

[0092] In this embodiment of the invention, the process of obtaining the contact fluctuation characterization value is as follows: an image segmentation algorithm is used to extract the effective contact area between the sleeve sample and the target copper busbar; the effective contact area is uniformly divided into several sub-regions of equal area; the gray mean of each sub-region is calculated; the ratio of the standard deviation of the gray mean of all sub-regions to the average value is the contact fluctuation characterization value.

[0093] It is understandable that when the contact between the sleeve and the copper busbar is uniform, the tightness of the interface is consistent, and the microscopic unevenness filling state is similar. Therefore, the difference in optical reflection characteristics between the sub-regions is small. If the contact is uneven, gaps may appear in local areas due to insufficient material filling, or abnormal reflection characteristics may occur due to excessive extrusion. When the premixing time is insufficient, the polymer matrix and additives are mixed unevenly, resulting in local differences in the fluidity of the melt during extrusion. Areas with poor fluidity are difficult to fill the depressions of the copper busbar, while areas with excessive fluidity may form surface protrusions, ultimately causing uneven contact with the copper busbar. Adjusting the premixing time can improve the material uniformity and ensure a more uniform internal structure of the material, thereby reducing the fluctuation of the contact between the sleeve and the copper busbar after extrusion.

[0094] Specifically, in this embodiment of the invention, when it is determined that the contact uniformity of the sleeve sample on the target copper busbar is unqualified, the premixing time is adjusted based on the difference between the contact fluctuation characterization value and the preset contact fluctuation characterization value.

[0095] When the difference is less than or equal to the preset difference, it is determined that the premixing time will be increased to the corresponding value by the first preset premixing time adjustment coefficient of 1.5.

[0096] When the difference is greater than the preset difference, it is determined that the premixing time will be increased to the corresponding value by the second preset premixing time adjustment coefficient of 1.8.

[0097] The difference is the difference between the contact fluctuation characterization value and the preset contact fluctuation characterization value.

[0098] In this embodiment of the invention, the preset difference value range is [0.01, 0.04], preferably 0.02, but the above value is not limited to this, and those skilled in the art can also adjust the value according to actual needs.

[0099] In this embodiment of the invention, the increased premixing time is the product of the premixing time and the preset premixing time adjustment coefficient. The preset premixing time adjustment coefficient includes a first preset premixing time adjustment coefficient with a value of 1.5 and a second preset premixing time adjustment coefficient with a value of 1.8. In order to ensure that the adjusted premixing time meets the actual needs, the adjustment range should not be too large, so an adjustment coefficient is set to control the adjustment range.

[0100] Specifically, this invention divides the effective contact area between the bushing and the copper busbar into equal-area sub-regions. The ratio of the standard deviation to the average gray value of each sub-region is calculated as the contact fluctuation characterization value. The contact fluctuation characterization value is compared with the preset contact fluctuation characterization value to determine whether the contact uniformity is qualified. If it is not qualified, the premixing time is adjusted. Based on the ratio of the standard deviation to the average gray value of the sub-region, the contact uniformity is transformed into a calculable quantitative index, which improves the detection accuracy and repeatability. The premixing time adjustment is precisely matched with the material mixing requirements, avoiding uneven contact or overmixing caused by insufficient premixing. This reduces the risk of heat accumulation or electric field distortion caused by poor local contact and improves the insulation reliability of the product.

[0101] Please see Figure 4 As shown, it is a flowchart of an embodiment of the present invention for determining whether there are air bubbles affecting the contact interface between the sleeve sample and the target copper busbar.

[0102] Specifically, in this embodiment of the invention, the presence of bubbles at the contact interface between the sleeve sample and the target copper busbar is determined based on the comparison between the bubble area ratio and the preset bubble area ratio.

[0103] When the bubble area ratio is less than or equal to the preset bubble area ratio, it is determined that there is no bubble influence at the contact interface between the sleeve sample and the target copper busbar.

[0104] When the bubble area ratio is greater than the preset bubble area ratio, it is determined that there is a bubble effect at the contact interface between the sleeve sample and the target copper busbar.

[0105] In this embodiment of the invention, the preset bubble area ratio range is [1%, 3%], preferably 2%, but the above value is not limited to this, and those skilled in the art can adjust the value according to actual needs.

[0106] In this embodiment of the invention, the process of obtaining the bubble area ratio is as follows: bubbles whose minimum distance to the copper busbar is less than or equal to 1 / 2 of the sleeve wall thickness are recorded as contact bubbles at the contact interface between the sleeve sample and the target copper busbar; the ratio of the area of ​​the contact bubble to the area of ​​the contact interface between the sleeve sample and the target copper busbar is the bubble area ratio.

[0107] Specifically, in this embodiment of the invention, under the condition that bubbles exist at the contact interface between the sleeve sample and the target copper busbar, the bubble distribution at the contact interface between the sleeve sample and the target copper busbar is determined based on the comparison result between the spatial aggregation index obtained from the surface image and the preset spatial aggregation index.

[0108] When the spatial aggregation index is less than or equal to the preset spatial aggregation index, it is determined that the bubble distribution at the interface between the sleeve sample and the target copper busbar meets the standard.

[0109] When the spatial aggregation index is greater than the preset spatial aggregation index, it is determined that the bubble distribution at the interface between the sleeve sample and the target copper busbar is substandard.

[0110] In this embodiment of the invention, the preset spatial aggregation index range is [0.3, 0.5], preferably 0.4, but the above value is not limited to this, and those skilled in the art can adjust the value according to actual needs.

[0111] In this embodiment of the invention, the spatial aggregation index is the ratio of the maximum bubble cluster volume to the total bubble volume multiplied by the ratio of the minimum distance of the bubble cluster from the pipe wall to the pipe wall thickness.

[0112] Understandably, the presence of contact bubbles directly disrupts interfacial continuity. The air inside the bubbles, acting as a poor conductor, increases local contact thermal resistance, leading to heat accumulation. Simultaneously, the multiple interfaces formed by the bubbles with the bushing and copper busbar can cause electric field distortion, which can easily induce insulation breakdown with long-term use. This bubble problem is usually related to the degree of polymer crosslinking. When the irradiation dose is insufficient, the crosslinking reaction is incomplete, and unexpelled gas is easily left inside the material. Furthermore, the inter-molecular chain bonding is weak, making it easy for bubbles to aggregate. Increasing the irradiation dose can promote full crosslinking of molecular chains, enhance material density, reduce bubble formation, improve structural stability, and inhibit bubble aggregation.

[0113] Specifically, the present invention is implemented under the condition that the bubble distribution at the contact interface between the sleeve sample and the target copper busbar is not up to standard, and determines the irradiation dose based on the comparison result of the relative difference between the spatial aggregation index and the preset spatial aggregation index and the preset relative difference.

[0114] When the relative difference is less than or equal to the preset relative difference, it is determined that the irradiation dose will be increased to the corresponding value by the first preset irradiation dose adjustment coefficient of 1.07.

[0115] When the relative difference is greater than the preset relative difference, it is determined that the irradiation dose will be increased to the corresponding value by the second preset irradiation dose adjustment coefficient of 1.12;

[0116] The relative difference is the relative difference between the spatial clustering index and the preset spatial clustering index.

[0117] In this embodiment of the invention, the preset relative difference range is [0.15, 0.25], preferably 0.2, but the above value is not limited to this, and those skilled in the art can adjust the value according to actual needs.

[0118] In this embodiment of the invention, the increased irradiation dose is the product of the irradiation dose and the preset irradiation dose adjustment coefficient. The preset irradiation dose adjustment coefficient includes a first preset irradiation dose adjustment with a value of 1.07 and a second preset irradiation dose adjustment coefficient with a value of 1.12. In order to ensure that the adjusted irradiation dose meets the actual needs, the adjustment range should not be too large, so an adjustment coefficient is set to control the adjustment range.

[0119] Specifically, this invention determines the presence of bubbles by measuring the bubble area ratio. If bubbles are present, the uniformity of bubble distribution is assessed based on the spatial aggregation index. If the standard is not met, the irradiation dose is dynamically adjusted based on the relative difference between the spatial aggregation index and the preset value. This avoids bubble aggregation caused by insufficient irradiation dose or material degradation caused by excessive irradiation dose, improves the density of the insulation layer, and the spatial aggregation index reflects the degree of bubble distribution concentration. Adjusting the irradiation dose improves the uniformity of material crosslinking, reduces the risk of electric field distortion caused by local bubble aggregation, extends the service life of the sleeve, and improves the safety of the electrical system. This improves the interface compatibility between the halogen-free environmentally friendly electrostatic carbon trace heat shrink tubing and the copper busbar.

[0120] Specifically, in this embodiment of the invention, a halogen-free, environmentally friendly, electrostatic carbon trace resistant heat shrink tubing is prepared under the condition that the bubble distribution at the contact interface between the tubing sample and the target copper busbar meets the standard.

[0121] In this embodiment of the invention, the halogen-free, environmentally friendly, and electrostatically resistant carbon trace heat shrink tubing prepared is not prone to cracking even with minor defects, such as a 5mm longitudinal crack, under long-term high-temperature operation.

[0122] Specifically, in this embodiment of the invention, under the condition that the halogen-free, environmentally friendly, electrostatic carbon-track resistant heat shrink tubing has been successfully manufactured, a performance testing experiment is conducted on the halogen-free, environmentally friendly, electrostatic carbon-track resistant heat shrink tubing. The experimental environment is a temperature of 23±5℃ and a relative humidity of 60±10%RH, including:

[0123] Melt flow index test: The halogen-free environmentally friendly electrostatic carbon trace heat shrink tubing was tested on an XNR-400 melt flow rate tester according to GB / T3682-2000 standard.

[0124] Breakdown strength test: Halogen-free environmentally friendly electrostatic carbon trace heat shrink tubing was tested on a GJW-100kV computer-controlled voltage breakdown tester according to ADTM D2671 standard.

[0125] Mechanical property testing: The halogen-free environmentally friendly electrostatic carbon trace heat shrink tubing was made into dumbbell-shaped specimens using a standard mold. The tensile strength and elongation at break of the specimens were tested on a TY8000 series electronic universal testing machine according to GB / T1040.3—2006 standard, with a tensile rate of 200 mm / min.

[0126] Volume resistivity was tested using a ZC-36 high-resistivity meter on a halogen-free, environmentally friendly, electrostatically resistant carbon trace heat shrink tubing according to GB1410-2006 standard.

[0127] Hardness testing was performed on an XHS type Shore hardness tester according to GB2401-80 standard for halogen-free environmentally friendly electrostatic carbon trace heat shrink tubing.

[0128] Heat aging test: Halogen-free environmentally friendly electrostatic carbon trace resistant heat shrink tubing was tested on a WGL-230B electric heating drying oven according to ASTM-D2671 standard.

[0129] Low-temperature flexibility test: Halogen-free environmentally friendly electrostatic carbon trace resistant heat shrink tubing was tested on a GJW-150 high and low temperature test chamber according to ASTM-D2671 standard.

[0130] Thermal shock test: Halogen-free environmentally friendly electrostatic carbon trace resistant heat shrink tubing was tested on a WGL-230B electric heating drying oven according to ASTM-D2671 standard.

[0131] To test the heat shrinkage rate, prepare a 100mm sample tube, measure the inner diameter of the sample tube, place the sample tube in a 160℃ electric drying oven for preheating, and after it has completely shrunk, take it out and cool it, and measure the inner diameter and length of the sample tube again.

[0132] Radial shrinkage rate formula: (shrinkage sample tube inner diameter - inner diameter after free shrinkage) / inner diameter before shrinkage * 100%;

[0133] The formula for longitudinal shrinkage rate is: (length of tube before shrinkage - length of tube after free shrinkage) / length of tube before shrinkage * 100%.

[0134] Halogen-free environmental protection test: Halogen-free environmental protection electrostatic carbon trace heat shrink tubing was tested on an EDX-8800 energy dispersive X-ray fluorescence spectrometer according to RoHS / halogen-free standards (Cl<900ppm, Br<900ppm, Cl+Br<1500ppm).

[0135] Electrostatic carbon trace resistance test: Halogen-free environmentally friendly electrostatic carbon trace resistant heat shrink tubing tested according to ASTM-D2303 standard.

[0136] Example 1:

[0137] Step S11: Add EMMA, nano-activated magnesium hydroxide, ultrafine activated aluminum hydroxide, ultrafine activated kaolin, antioxidant, organosilicon powder, trimethylolpropane trimethacrylate, polyethylene wax, stearic acid, zinc stearate, and halogen-free color powder to a mixer in a preset mass ratio, and mix under preset mixing conditions to obtain a mixture.

[0138] Step S12: The mixture is granulated by kneading in a kneader under preset kneading conditions, and then granulated again by a twin-screw granulator under preset granulation conditions to obtain granules.

[0139] Step S13: The granules are extruded through an extruder under preset extrusion conditions to obtain a tube blank;

[0140] Step S14: Irradiate the tube blank under preset crosslinking conditions and expand it under preset expansion conditions to obtain a sleeve sample.

[0141] In Example 1, the preset mass percentages are 100 parts EMMA, 15 parts ultrafine activated ATH, 15 parts nano MH, 6 parts organosilicon powder, 10 parts ultrafine activated kaolin, 0.5 parts antioxidant, 1.0 parts trimethylolpropane trimethacrylate, 0.3 parts polyethylene wax, 0.2 parts stearic acid, 0.5 parts zinc stearate, and 1.5 parts halogen-free color powder.

[0142] In Example 1, the premixing time was 5 min, the premixing temperature was 40°C, the kneading time was 25 min, the kneader speed was 30 rpm, the kneading temperature was 145°C, the granulation temperature was 175°C, the granulator speed was 400 rpm, the extrusion temperature was 170°C, the extruder speed was 30 rpm, the irradiation dose was 5 Mrad, and the thermal extension of the billet was 150%.

[0143] Example 2:

[0144] In Example 2, the conditions were the same as in Example 1, except that the mass fraction of organosilicon powder was 0.

[0145] Example 3:

[0146] In Example 3, the conditions were the same as in Example 1, except that the mass fraction of ultrafine activated kaolin was 0.

[0147] Example 4:

[0148] In Example 4, the kneading temperature was 166°C, and the other conditions were the same as in Example 1.

[0149] Example 5:

[0150] In Example 5, the conditions were the same as in Example 1, except that the extrusion temperature was 200°C.

[0151] Example 6:

[0152] In Example 6, the conditions were the same as in Example 1, except that the premixing time was 7.5 min.

[0153] Example 7:

[0154] In Example 7, the conditions were the same as in Example 1, except that the irradiation dose was 5.35 Mrad.

[0155] Comparative Example 1:

[0156] In Comparative Example 1, the conditions were the same as in Example 1, except that EMMA was replaced with PE.

[0157] Comparative Example 2:

[0158] In Comparative Example 2, the conditions were the same as in Example 1, except that there was no nano-activated magnesium hydroxide and no ultrafine activated aluminum hydroxide.

[0159] Table 1. Results of machining and mechanical performance tests.

[0160]

[0161] Table 1 shows that, compared to Example 2, the addition of silicone powder in Example 1 increases the melt flow index and improves the material's processing fluidity. Simultaneously, the tensile strength and elongation at break are both higher, indicating that silicone powder enhances mechanical properties, reduces processing stress through lubrication, and improves molecular chain integrity. Compared to Example 3, the absence of kaolin in Example 1 leads to a decrease in elongation at break and a drop in Shore hardness, indicating that kaolin, as a filler, can enhance the material's toughness and rigidity, improving mechanical properties through interfacial bonding with the matrix. Compared to Examples 4 and 5, the kneading and extrusion temperatures have little impact on performance, with only slight fluctuations in melt flow index and elongation at break, indicating good stability of the system over a wide temperature range. Compared to Examples 6 and 7, the extended premixing time slightly increases melt flow index and elongation at break, resulting in more uniform mixing. Increased irradiation dose improves tensile strength and crosslinking density. Comparative Examples 1 and 2 compared to Example 1. In Comparative Example 1, PE was used to replace EMMA, and all properties decreased significantly. Comparative Example 2 lacked nano-activated magnesium hydroxide and ultrafine activated ATH, and its performance was the worst. This indicates that the two are not only flame retardants, but also have a synergistic effect on enhancing mechanical properties.

[0162] Table 2. Electrical and weather resistance test results.

[0163]

[0164] Table 2 shows that, compared to Example 2, removing the silicone powder in Example 1 resulted in a decrease in breakdown strength and volume resistivity. The silicone powder, acting as a surface modifier, improved the dispersibility and interfacial bonding of the inorganic filler in the EMMA matrix. The absence of silicone powder led to filler agglomeration, forming localized conductive channels. Compared to Example 3, removing kaolin resulted in a decrease in breakdown strength and volume resistivity. The flake-like kaolin extended the leakage path, and simultaneously activated the surface to capture charge carriers, reducing charge migration resistance after its removal. Compared to Example 4, with increasing temperature, the breakdown strength and volume resistivity decreased. The volume resistivity remained basically the same, and moderate heating promoted the dispersion of the filler. Compared with Comparative Example 1, the PE matrix, due to the non-polarity of its molecular chains, had poor compatibility with the nanofiller. The interface defects became charge traps, resulting in a decrease in breakdown strength and volume resistivity, and failure of tracking resistance. Compared with Comparative Example 2, Comparative Example 2 proved that nano-activated magnesium hydroxide and ultrafine activated aluminum hydroxide are not only flame retardants, but also the pillars of insulation performance, blocking the conductive path and inhibiting tracking carbonization. Without nano-activated magnesium hydroxide and ultrafine activated aluminum hydroxide, the volume resistivity and breakdown strength decreased, and tracking resistance failed.

[0165] Table 3. Test results of heat shrinkage and environmental performance.

[0166]

[0167] Table 3 shows that silicone powder and kaolin can stabilize the radial shrinkage rate because the fillers restrict the thermal movement of molecular chains, reducing shrinkage deviation; the axial shrinkage rate changes little, indicating low anisotropy of the system. Examples 1-7 all passed low-temperature flexibility and thermal shock tests, while Comparative Examples 1 and 2 showed cracking and dripping. EMMA has better low-temperature resistance than PE and can resist brittle fracture at low temperatures; the flame-retardant effect of nano-magnesium hydroxide and ATH is the core of passing the thermal shock test, while silicone powder can enhance dimensional stability at high temperatures. Processing temperature and premixing time have minimal impact on thermal shrinkage and weather resistance; only the increase in irradiation dose slightly reduces the axial shrinkage rate because the increased crosslinking density restricts molecular chain relaxation.

[0168] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a halogen-free, environmentally friendly, electrostatically resistant carbon-marking heat shrink tubing, characterized in that, include: Sleeve samples were prepared based on several raw materials; Cut a sleeve sample of a preset length, place the sleeve sample on the target copper busbar, and obtain a surface image of the sleeve sample on the target copper busbar. Based on the surface image, the interface contact characterization parameters are determined to determine whether the interface compatibility between the sleeve sample and the target copper busbar meets the standard, and the kneading temperature or extrusion temperature is adjusted according to the ratio of the interface contact characterization parameters to the preset interface contact characterization parameters. Based on the surface image, a contact fluctuation characterization value is determined to determine whether the contact uniformity of the sleeve sample on the target copper busbar is qualified, and the premixing time is adjusted according to the difference between the contact fluctuation characterization value and the preset contact fluctuation characterization value. Based on the surface image, the bubble area ratio is determined to determine whether there is bubble influence at the contact interface between the sleeve sample and the target copper busbar. Based on the surface image with the presence of bubbles, a spatial aggregation index is determined to determine whether the bubble distribution at the interface between the sleeve sample and the target copper busbar meets the standard, and the irradiation dose is adjusted according to the relative difference between the spatial aggregation index and the preset spatial aggregation index.

2. The method for preparing halogen-free, environmentally friendly, electrostatically resistant carbon-marking heat shrink tubing according to claim 1, characterized in that, The failure of the interface compatibility between the sleeve sample and the target copper busbar to meet the standard is determined based on the comparison results of interface contact characterization parameters being less than or equal to preset interface contact characterization parameters, wherein, The interface contact characterization parameters are determined based on the area of ​​the effective contact area and the area of ​​the reference contact area.

3. The method for preparing halogen-free, environmentally friendly, electrostatically resistant carbon-marking heat shrink tubing according to claim 2, characterized in that, The process of adjusting the kneading temperature or extrusion temperature includes: Calculate the ratio of the interface contact characterization parameter to the preset interface contact characterization parameter; Based on the comparison results where the ratio is less than or equal to a preset ratio, the kneading temperature is increased by a preset kneading temperature adjustment coefficient. Based on the comparison results where the ratio is greater than a preset ratio, the extrusion temperature is increased by a preset extrusion temperature adjustment coefficient.

4. The method for preparing halogen-free, environmentally friendly, electrostatically resistant carbon-marking heat shrink tubing according to claim 3, characterized in that, The non-compliance of the contact uniformity of the sleeve sample on the target copper busbar was determined based on the comparison result of the contact fluctuation characterization value being greater than the preset contact fluctuation characterization value, wherein, The contact fluctuation characterization value is determined based on the standard deviation and average value of the grayscale mean.

5. The method for preparing halogen-free, environmentally friendly, electrostatically resistant carbon-marking heat shrink tubing according to claim 4, characterized in that, The process of adjusting the premixing time includes: Calculate the difference between the contact fluctuation characterization value and the preset contact fluctuation characterization value; Based on the comparison results where the difference is less than or equal to a preset difference, the premixing time is increased by a first preset premixing time adjustment coefficient. Based on the comparison results where the difference is greater than a preset difference, the premixing time is increased by a second preset premixing time adjustment coefficient.

6. The method for preparing halogen-free, environmentally friendly, electrostatically resistant carbon-marking heat shrink tubing according to claim 5, characterized in that, The presence of air bubbles at the interface between the sleeve sample and the target copper busbar is determined based on a comparison of bubble area percentages exceeding a preset bubble area percentage. The bubble area ratio is determined based on the area of ​​the contact bubble at the interface between the sleeve sample and the target copper busbar and the area of ​​the interface between the sleeve sample and the target copper busbar.

7. The method for preparing halogen-free, environmentally friendly, electrostatically resistant carbon-marking heat shrink tubing according to claim 6, characterized in that, The substandard bubble distribution at the interface between the sleeve sample and the target copper busbar was determined based on a comparison result where the spatial aggregation index was greater than a preset spatial aggregation index. The spatial aggregation index is determined based on the maximum bubble cluster volume, the total bubble volume, the minimum distance between the bubble cluster and the pipe wall, and the pipe wall thickness.

8. The method for preparing halogen-free, environmentally friendly, electrostatically resistant carbon-marking heat shrink tubing according to claim 7, characterized in that, The process of adjusting the irradiation dose includes: Calculate the relative difference between the spatial clustering index and the preset spatial clustering index; Based on the comparison results where the relative difference is less than or equal to the preset relative difference, the irradiation dose is increased by the first preset irradiation dose adjustment coefficient. Based on the comparison results where the relative difference is greater than the preset relative difference, the irradiation dose is increased by the second preset irradiation dose adjustment coefficient.

9. The method for preparing halogen-free, environmentally friendly, electrostatically resistant carbon-marking heat shrink tubing according to claim 8, characterized in that, The process of preparing the sleeve sample includes: EMMA, nano-activated magnesium hydroxide, ultrafine activated aluminum hydroxide, ultrafine activated kaolin, antioxidant, organosilicon powder, trimethylolpropane trimethacrylate, polyethylene wax, stearic acid, zinc stearate, and halogen-free color powder are added to a mixer in a preset mass ratio and mixed under preset mixing conditions to obtain a mixture. The mixture is granulated by kneading under preset kneading conditions in a kneader, and then granulated again by twin-screw granulator under preset granulation conditions to obtain granules. The granules are extruded through an extruder under preset extrusion conditions to obtain a tube blank; The tube blank is irradiated under preset crosslinking conditions and expanded under preset expansion conditions to obtain a sleeve sample; The preset mass fractions are 100 parts EMMA, 15 parts nano-activated magnesium hydroxide, 15 parts ultrafine activated aluminum hydroxide, 10 parts ultrafine activated kaolin, 0.5 parts antioxidant, 6 parts organosilicon powder, 1.0 parts trimethylolpropane trimethacrylate, 0.3 parts polyethylene wax, 0.2 parts stearic acid, 0.5 parts zinc stearate, and 1.5 parts halogen-free color powder.

10. A halogen-free, environmentally friendly, electrostatic carbon-track resistant heat shrink tubing, comprising the method for preparing the halogen-free, environmentally friendly, electrostatic carbon-track resistant heat shrink tubing according to any one of claims 1-9, characterized in that, include: EMMA, nano-activated magnesium hydroxide, ultrafine activated aluminum hydroxide, ultrafine activated kaolin, antioxidants, organosilicon powder, trimethylolpropane trimethacrylate, polyethylene wax, stearic acid, zinc stearate, and halogen-free color powder.

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