Scorch test device and scorch test method

Abstract

The present disclosure relates to a scorch test device and a scorch test method, and relates to the field of polymer processing technology. The scorch test device includes: an extrusion module and a scorch module. A feed port is provided on the extrusion module. An extrusion port is provided at one end of the extrusion module. The scorch module includes a scorch mold. The inlet end of the scorch mold is connected to the extrusion port. The outlet end of the scorch mold is connected to the discharge port. The extrusion module is used to melt the material to be tested, and extrude the melted material to be tested into the scorch mold. The scorch mold is used to control the cross-linking and curing reaction of the material to be tested. The present disclosure can accurately evaluate the scorch performance of the material to be tested and the sensitivity of scorch to temperature, and thus accurately evaluate the long-term extrusion stability of the material to be tested.

Description

Technical Field

[0001] The present disclosure relates to the technical field of polymer processing, and in particular to a scorch test device and a scorch test method. Background Art

[0002] With the steady progress of domestic insulation material research and development, land cable insulation materials have gradually begun to be domestically applied. However, long-length submarine cables have put forward higher requirements on the long-term extrusion stability of insulation materials.

[0003] Verifying the long-term extrusion performance of insulating materials through actual extrusion of model cables or even real cables will cost a lot of money and cause waste of resources. Therefore, it is very important to evaluate the laboratory-level extrusion stability of insulating materials. Moreover, since the scorch performance of insulating materials directly affects their long-term extrusion stability, how to accurately evaluate the scorch performance of materials and then accurately evaluate the long-term extrusion stability of materials is an urgent problem to be solved. Summary of the invention

[0004] Based on this, it is necessary to provide a scorch test device and a scorch test method to accurately evaluate the scorch performance of the material, and then accurately evaluate the long-term extrusion stability of the material.

[0005] On the one hand, an embodiment of the present disclosure provides a scorch test device, comprising: an extrusion module and a scorch module. A feed port is provided on the extrusion module. An extrusion port is provided at one end of the extrusion module. The scorch module comprises a scorch mold extending along a first direction. The inlet end of the scorch mold is connected to the extrusion port. The outlet end of the scorch mold is connected to the discharge port. The extrusion module is used to melt the material to be tested, and continuously extrude the melted material to be tested into the scorch mold;

[0006] The scorch mold is used to provide a place for the melted material to undergo a cross-linking and curing reaction; as the extrusion time of the material to be tested increases, the material to be tested gradually undergoes a cross-linking and curing reaction in the scorch mold to adhere to the inner wall of the scorch mold to form a scorch layer.

[0007] In the embodiment of the present disclosure, the inlet end of the scorch mold is connected to the extrusion port of the extrusion module, so that the extrusion module can control the melted material to be tested to be continuously extruded from the extrusion port to the scorch mold, so that the material to be tested undergoes a cross-linking and curing reaction in the scorch mold, and the cross-linked and cured material to be tested gradually adheres to the inner wall of the scorch mold to form a scorch layer, and the uncross-linked and cured material to be tested is discharged from the discharge port through the outlet end of the scorch mold. In this way, the scorch test device provided by the present disclosure can accurately evaluate the scorch performance of the material to be tested and the sensitivity of scorch to temperature by calculating the scorch ratio of the material to be tested in the scorch mold, that is, the cross-linking ratio of the material to be tested, and then accurately evaluate the long-term extrusion stability of the material to be tested.

[0008] According to some embodiments, the scorch mold includes an upper mold and a lower mold of the same shape. The upper mold and the lower mold are buckled together to form a mold cavity in the scorch mold.

[0009] According to some embodiments, the scorch module further comprises: a first heat conducting unit, a second heat conducting unit and at least two heating modules. The first heat conducting unit covers the surface of the upper mold away from the mold cavity. The second heat conducting unit covers the surface of the lower mold away from the mold cavity. At least one heating module is arranged on the surface of the first heat conducting unit away from the scorch mold. At least another heating module is arranged on the surface of the second heat conducting unit away from the scorch mold.

[0010] According to some embodiments, the scorch test device further includes: at least one temperature measurement and control module. The temperature measurement and control module is disposed on the surface of the first heat conducting unit, and / or the temperature measurement and control module is disposed on the surface of the second heat conducting unit; the temperature measurement and control module is connected to the heating module. In this way, the temperature of the scorch mold can be accurately controlled, which is conducive to accelerating the cross-linking and curing reaction of the material to be tested in the scorch mold.

[0011] According to some embodiments, the mold cavity includes a cylindrical mold cavity and a conical mold cavity that are connected. One end face of the cylindrical mold cavity is connected to the extrusion port. The wide end face of the conical mold cavity is connected to the other end face of the cylindrical mold cavity, and the narrow end face of the conical mold cavity is connected to the discharge port.

[0012] According to some embodiments, the inner diameter of the discharge port ranges from 0.5 mm to 5 mm. The size of the discharge port along the first direction ranges from 50 mm to 80 mm.

[0013] According to some embodiments, the size range of the cylindrical mold cavity along the first direction includes: 80 mm~110 mm; the cone angle range of the conical mold cavity includes: 30°~60°.

[0014] According to some embodiments, the scorch test device further includes: a feeding module. The outlet end of the feeding module is connected to the feed port, and is used to deliver the material to be tested to the extrusion module through the feed port.

[0015] On the other hand, the embodiment of the present disclosure further provides a scorch test method, which is performed based on the scorch test device in the above embodiment. The scorch test method includes:

[0016] The material to be tested is transported to the extrusion module for melting, and the melted material to be tested is continuously extruded into the scorch die;

[0017] The material to be tested undergoes a cross-linking and curing reaction in the scorching mold, and gradually adheres to the inner wall of the scorching mold to form a scorching layer, and the material to be tested is discharged from the outlet end of the scorching mold; wherein, the time for the material to be tested to be continuously extruded into the scorching mold is not less than 5 hours;

[0018] The thermoplastic material is conveyed to the extrusion module for melting, and the melted thermoplastic material is continuously extruded to the scorch die until the thermoplastic material is discharged from the outlet end of the scorch die;

[0019] After the scorched mold is cooled to room temperature, the sample to be tested retained in the mold cavity is obtained, and the scorched percentage of the material to be tested is obtained based on the sample to be tested; the sample to be tested includes a scorched layer after the material to be tested is scorched and a thermoplastic material located inside the scorched layer.

[0020] In the disclosed embodiment, the extrusion module controls the melted material to be tested to be extruded from the extrusion port to the scorch mold, so that the material to be tested undergoes a cross-linking and curing reaction in the scorch mold, and the cross-linked material to be tested gradually adheres to the inner wall of the scorch mold to form a scorch layer. Then, the thermoplastic material is conveyed to the extrusion module, and the uncross-linked material to be tested is removed to retain the scorch layer, and finally the sample to be tested is obtained. In this way, by calculating the proportion of the scorch layer in the sample to be tested, the scorch proportion of the material to be tested can be obtained, and the scorch performance of the material to be tested can be accurately evaluated, and then the long-term extrusion stability of the material to be tested can be accurately evaluated.

[0021] According to some embodiments, the thermoplastic material includes a colored thermoplastic material. Obtaining the sample to be tested retained in the mold cavity and obtaining the scorch percentage of the material to be tested based on the sample to be tested includes:

[0022] Open the scorch mold and obtain the sample to be tested in the scorch mold;

[0023] Selecting at least one interception position along the extending direction of the sample to be tested, and intercepting the sample to be tested from the interception position along a direction perpendicular to the extending direction of the sample to be tested, so as to obtain a plurality of sub-samples to be tested;

[0024] The scorch percentage of the material to be tested is obtained based on the cross section of the sub-sample to be tested.

[0025] According to some embodiments, obtaining the scorch percentage of the material to be tested based on the cross section of the sub-sample to be tested includes:

[0026] Get the area of ​​the scorched layer in the cross section;

[0027] Get the area of ​​the cross section;

[0028] The scorch percentage of the material to be tested is obtained based on the following formula:

[0029] σ=S1 / S*100%, where σ is the scorch percentage of the material to be tested, S1 is the area of ​​the scorch layer in the cross section, and S is the area of ​​the cross section.

[0030] According to some embodiments, a plurality of interception positions are selected along the direction in which the sample to be tested extends, and the sample to be tested is intercepted from each interception position along a direction perpendicular to the direction in which the sample to be tested extends, so as to obtain a plurality of sub-samples to be tested; the charring percentage of the material to be tested in each sub-sample to be tested is obtained based on the cross-section of each sub-sample to be tested; and the average value of the charring percentages of the material to be tested in all the sub-samples to be tested is taken as the charring percentage of the material to be tested in the sample to be tested. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 It is a schematic cross-sectional structure diagram of a scorch test device provided in an embodiment of the present disclosure;

[0033] Figure 2 It is a structural schematic diagram of another scorch test device provided in an embodiment of the present disclosure;

[0034] Figure 3 It is a structural schematic diagram of a scorching mold provided in an embodiment of the present disclosure; Figure 3 (a) Figure 3 The structure shown is a cross-sectional schematic diagram on section AA'; Figure 3 (b) Figure 3 The structure shown is a schematic cross-sectional view on section BB'; Figure 3 (c) Figure 3 The structure shown is a schematic cross-sectional view at section CC';

[0035] Figure 4 A flow chart of a scorch test method provided in an embodiment of the present disclosure;

[0036] Figure 5 for Figure 4 A schematic flow chart of step S400 in the scorch test method shown;

[0037] Figure 6 for Figure 5 FIG. 1 is a flow chart of step S403 in the scorch test method shown.

[0038] Description of reference numerals:

[0039] 1-extrusion module; 10-feeding port; 11-extrusion port; 2-scorching module; 20-discharging port; 21-scorching mold; 211-inlet end of the scorching mold; 212-outlet end of the scorching mold; 213-upper mold; 214-lower mold; 215-mold cavity; 2151-cylindrical mold cavity; 2152-conical mold cavity; 22-first heat conduction unit; 23-second heat conduction unit; 24-heating module; 25-temperature measurement and control module; 26-fixing device; 3-feeding module; 31-outlet end of the feeding module; 201a-first thermoplastic material; 201b-second thermoplastic material; 201c-third thermoplastic material; 202a-first scorched layer; 202b-second scorched layer; 202c-third scorched layer. DETAILED DESCRIPTION

[0040] In order to facilitate understanding of the present disclosure, the present disclosure will be described more fully below with reference to the relevant drawings. Embodiments of the present disclosure are given in the drawings. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present disclosure more thorough and comprehensive.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present disclosure. The terms used in the specification of the present disclosure herein are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure.

[0042] It should be understood that when an element or layer is referred to as being "on, adjacent to, connected to or coupled to other elements or layers, it may be directly on, adjacent to, connected to or coupled to other elements or layers, or there may be intervening elements or layers. In contrast, when an element is referred to as being "directly on, directly adjacent to, directly connected to or directly coupled to other elements or layers, there may be no intervening elements or layers. It should be understood that, although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present disclosure, the first element, component, region, layer or part discussed below may be represented as a second element, component, region, layer or part.

[0043] Spatially relative terms such as "under," "beneath," "below," "under," "above," "above," and the like may be used herein to describe the relationship of an element or feature shown in the figures to other elements or features. It should be understood that, in addition to the orientations shown in the figures, spatially relative terms also include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is flipped, an element or feature described as "under other elements" or "under it" or "under it" will be oriented as being "above" the other elements or features. Thus, the exemplary terms "under" and "under" may include both upper and lower orientations. In addition, the device may also include additional orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptors used herein are interpreted accordingly.

[0044] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that when the terms "consisting of" and / or "comprising" are used in this specification, the presence of the features, integers, steps, operations, elements and / or parts can be determined, but the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups is not excluded. At the same time, when used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0045] Embodiments of the invention are described herein with reference to cross-sectional illustrations that are schematic illustrations of idealized embodiments (and intermediate structures) of the present disclosure, and variations from the illustrated shapes as a result, for example, of manufacturing techniques and / or tolerances are to be expected. Thus, embodiments of the present disclosure should not be limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing techniques.

[0046] Imported high-voltage cross-linked polyethylene insulation has achieved 15 days of continuous extrusion in 500kV AC submarine cable projects. In recent years, the research and development of domestic insulation materials has made steady progress, and cross-linked polyethylene insulation materials for AC 110kV, 220kV and 500kV for land cables and cross-linked polyethylene insulation materials for DC 100kV, 320kV and 500kV have been developed. At present, domestic 110kV insulation products are relatively mature and have been verified in many cable projects, but the continuous extrusion time is usually no more than 10 days. The insulation materials used for high-voltage and long-length submarine cables have higher requirements for long-term extrusion stability.

[0047] It will cost a lot of money and waste resources to verify the long-term extrusion resistance of new products of self-developed insulation materials through actual extrusion of model cables or even real cables. Therefore, it is very important to carry out laboratory-level extrusion stability evaluation of insulation materials. Since the scorch performance of insulation materials directly affects their long-term extrusion stability, the industry is currently generally concerned about the scorch performance of materials, especially the scorch time (the time required for the torque to reach a certain increment). From the perspective of the test principle, the material in the mold cavity will undergo changes in torque and material temperature under a certain temperature and shear force. When the material is completely plasticized, the shear heat causes the cross-linking agent to decompose under heat to produce free radicals, which promotes the formation of a cross-linked network, thereby increasing the torque and viscosity, and the insulation material undergoes premature cross-linking (scorch) phenomenon. Referring to the group standard T / SHPTA 032.1-2022 and GB / T 16584-1996, the group standard T / SHPTA 032.1-2022 uses T1 (rotorless rheometer) as the determination of scorch time, which is defined as the time required for the torque to reach 1dN•m. GB / T 16584-1996 uses TSX as the determination of scorch time, but does not specify the specific value of x (the industry uses T10), which is defined as the time corresponding to the torque reaching ML+10(MH-ML) / 100.

[0048] The industry uses torque rheometers and rotorless rheometers to evaluate the scorch performance of materials. The torque rheometer mainly includes a computer measurement control system, a sensor drive system and an internal mixer (i.e., a mixing unit), which can be used to test the rheological behavior of materials, including the plasticization and cross-linking characteristics of resins. The rotorless rheometer mainly includes a pressurized sealed double-cone cavity system (i.e., an upper cavity and a lower cavity), a DC brushless motor drive system and a torque sensor. For the torque rheometer, in addition to the ejector pressure, the material is also subjected to the kneading, axial tumbling, kneading and other effects generated by a pair of counter-rotating rotors, as well as shearing, stirring and extrusion between the rotor surface and the mixing chamber wall. For the rotorless rheometer, after the material is placed in the closed double-cone cavity, the lower cavity oscillates sinusoidally according to the set strain, frequency and temperature. The oscillation causes the material to produce shear strain, and the torque sensor located in the upper cavity detects the torque response transmitted from the lower cavity through the material.

[0049] However, in the above two scorch performance test methods, the stress of the material is still different from the actual cable production process, and it is difficult to fully simulate the impact of the actual stress during cable extrusion on the scorch performance of the material. Therefore, how to accurately evaluate the scorch performance of the material is an urgent problem to be solved.

[0050] Based on this, the embodiments of the present disclosure provide a scorch test device and a scorch test method to accurately evaluate the scorch performance of a material.

[0051] See also Figure 1Some embodiments of the present disclosure provide a scorch test device, including: an extrusion module 1 and a scorch module 2. A feed port 10 is provided on the extrusion module 1. An extrusion port 11 is provided at one end of the extrusion module 1. The scorch module 2 includes a scorch mold 21 extending along a first direction (for example, an X direction). An inlet end 211 of the scorch mold 21 is connected to the extrusion port 11. An outlet end 212 of the scorch mold 21 is connected to a discharge port 20. The extrusion module 1 is used to melt the material to be tested, and continuously extrude the melted material to be tested into the scorch mold 21. The scorch mold 21 is used to provide a place for the melted material to be tested to undergo a cross-linking and curing reaction; as the continuous extrusion time of the material to be tested increases, the material to be tested gradually undergoes a cross-linking and curing reaction in the scorch mold 21, so as to adhere to the inner wall of the scorch mold to form a scorch layer.

[0052] Here, it should be particularly noted that the material to be tested undergoes a cross-linking and curing reaction in the scorching mold 21 . After being extruded for several hours, the pre-cross-linked material to be tested adheres to the inner wall of the scorching mold 21 , and the cross-linked material to be tested gradually accumulates on the inner wall of the scorching mold 21 .

[0053] In the embodiment of the present disclosure, the inlet end 211 of the scorch die 21 is connected to the extrusion port 11 of the extrusion module 1, so that the extrusion module 1 can control the melted material to be tested to be continuously extruded from the extrusion port 11 to the scorch die 21, so that the material to be tested undergoes a cross-linking and curing reaction in the scorch die 21, and the cross-linked and cured material to be tested gradually adheres to the inner wall of the scorch die 21 to form a scorch layer, and the uncross-linked and cured material to be tested is discharged from the discharge port 20 via the outlet end 212 of the scorch die. In this way, the scorch test device provided by the present disclosure can accurately evaluate the scorch performance of the material to be tested and the sensitivity of scorch to temperature by calculating the scorch ratio of the material to be tested in the scorch die 21, that is, the cross-linking ratio of the material to be tested, and further accurately evaluate the long-term extrusion stability of the material to be tested.

[0054] Here, it should be particularly noted that the cross-linking reaction of the material to be tested in the scorch mold 21 can be accelerated by controlling the shear rate, temperature range and other parameters of the extrusion module 1, and combining with the scorch mold 21, so that the material to be tested produces a certain degree of scorch in a short time. In addition, by controlling the residence time of the material to be tested in the scorch mold 21, that is, controlling the continuous extrusion of the extrusion module 1 for a preset time, the test efficiency can be improved. Compared with the traditional extrusion method of the material to be tested, which takes several days or even longer to accumulate, the scorch test device provided by the present disclosure reduces the test time of the scorch performance of the material to be tested and improves the evaluation efficiency of the scorch performance of the material to be tested.

[0055] In some examples, the extrusion module 1 includes a laboratory-grade single-screw extruder, so that it can be ensured that the extrusion method of the extrusion module 1 can simulate the extrusion of a real cable, that is, the extrusion module 1 can simulate the real stress conditions during the cable extrusion process.

[0056] In some examples, the material to be tested includes polyethylene insulation.

[0057] In some embodiments, please refer to Figure 1 The scorch test device further includes: a feeding module 3. An outlet end 31 of the feeding module 3 is connected to the feed port 10, and is used to transport the material to be tested to the extrusion module 1 through the feed port 10.

[0058] For example, the running time of the feeding module 3 is not less than 5 hours. That is, the material to be tested is continuously added to the extrusion module 1 through the feeding module 3, and the continuous running time is not less than 5 hours.

[0059] In some embodiments, please refer to Figure 1 The scorch mold 21 includes an upper mold 213 and a lower mold 214 of the same shape. The upper mold 213 and the lower mold 214 are buckled together to form a mold cavity 215 in the scorch mold 21.

[0060] In some embodiments, see Figure 1 and Figure 2 The scorch module 2 further includes: a first heat conducting unit 22, a second heat conducting unit 23 and at least two heating modules 24. The first heat conducting unit 22 covers the surface of the upper mold 213 away from the mold cavity 215. The second heat conducting unit 23 covers the surface of the lower mold 214 away from the mold cavity 215. At least one heating module 24 is arranged on the surface of the first heat conducting unit 22 away from the scorch mold 21. At least another heating module 24 is arranged on the surface of the second heat conducting unit 23 away from the scorch mold 21.

[0061] In some embodiments, please refer to Figure 2 The scorch test device further includes: at least one temperature measurement and control module 25. The temperature measurement and control module 25 is disposed on the surface of the first heat conducting unit 22, and / or the temperature measurement and control module 25 is disposed on the surface of the second heat conducting unit 23. The temperature measurement and control module 25 is connected to the heating module 24.

[0062] In some examples, the scorch test device further includes: a fixing device 26. For example, the fixing device 26 can be a screw or a bolt.

[0063] In some embodiments, see Figure 3 The mold cavity 215 includes a cylindrical mold cavity 2151 and a conical mold cavity 2152 which are connected. One end face of the cylindrical mold cavity 2151 is connected to the extrusion port 11. The wide end face of the conical mold cavity 2152 is connected to the other end face of the cylindrical mold cavity 2151, and the narrow end face of the conical mold cavity 2152 is connected to the discharge port 20 through the outlet end 212.

[0064] In some embodiments, the inner diameter size range of the discharge port 20 includes: 0.5mm~5mm. For example, the inner diameter size of the discharge port 20 can be 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm or 5mm, etc. The size range of the discharge port 20 along the first direction (for example, the X direction) includes: 50mm~80mm. For example, the size of the discharge port 20 along the first direction (for example, the X direction) can be 50mm, 55mm, 60mm, 65mm, 70mm, 75mm or 80mm, etc.

[0065] In some embodiments, the size of the cylindrical mold cavity 2151 along the first direction (eg, X direction) ranges from 80 mm to 110 mm. For example, the size of the cylindrical mold cavity 2151 along the first direction (eg, X direction) may be 80 mm, 85 mm, 90 mm, 95 mm, 100 mm, 105 mm, or 110 mm, etc.

[0066] The cone angle of the conical mold cavity 2152 ranges from 30° to 60°. For example, the cone angle of the conical mold cavity 2152 can be 30°, 35°, 40°, 45°, 50°, 55° or 60°, etc.

[0067] See also Figure 4 The embodiment of the present disclosure also provides a scorch test method, which is performed based on the scorch test device in the above embodiment. The scorch test method includes steps S100 to S400.

[0068] S100: conveying the material to be tested to an extrusion module for melting, and continuously extruding the melted material to be tested to a scorching die.

[0069] S200: The material to be tested undergoes a cross-linking and curing reaction in the scorching mold, and gradually adheres to the inner wall of the scorching mold to form a scorching layer, and the material to be tested is discharged from the outlet end of the scorching mold. The time for the material to be tested to be continuously extruded into the scorching mold is not less than 5 hours.

[0070] S300: conveying the thermoplastic material to the extrusion module for melting, and continuously extruding the melted thermoplastic material to the scorch die until the thermoplastic material is discharged from the outlet end of the scorch die.

[0071] S400: After the scorch mold is cooled to room temperature, the sample to be tested retained in the scorch mold is obtained, and the scorch percentage of the material to be tested is obtained based on the sample to be tested; the sample to be tested includes a scorch layer after the scorch of the material to be tested and a thermoplastic material located inside the scorch layer.

[0072] In the disclosed embodiment, the extrusion module controls the melted material to be tested to be extruded from the extrusion port to the scorch mold, so that the material to be tested undergoes a cross-linking and curing reaction in the scorch mold, and the cross-linked material to be tested gradually adheres to the inner wall of the scorch mold to form a scorch layer. Then, the thermoplastic material is conveyed to the extrusion module, and the uncross-linked material to be tested is removed to retain the scorch layer, and finally the sample to be tested is obtained. In this way, by calculating the proportion of the scorch layer in the sample to be tested, the scorch proportion of the material to be tested can be obtained, and the scorch performance of the material to be tested can be accurately evaluated, and then the long-term extrusion stability of the material to be tested can be accurately evaluated.

[0073] Here, it should be particularly noted that the cross-linking reaction of the material to be tested in the scorch mold can be accelerated by controlling the shear rate, temperature range and other parameters of the extrusion module, and combining the scorch mold, so that the material to be tested produces a certain degree of scorch in a short time. In addition, by controlling the residence time of the material to be tested in the scorch mold, that is, controlling the continuous extrusion preset time of the extrusion module, the test efficiency can be improved. Compared with the traditional extrusion method of the material to be tested, which takes several days or even longer to accumulate, the scorch test method provided by the present disclosure reduces the test time of the scorch performance of the material to be tested and improves the evaluation efficiency of the scorch performance of the material to be tested.

[0074] In some embodiments, the thermoplastic material comprises a colored thermoplastic material. Figure 5 Step S400 obtains the sample to be tested retained in the scorch mold, and obtains the scorch percentage of the material to be tested based on the sample to be tested, including steps S401~S403.

[0075] S401: Open the scorch mold and obtain the sample to be tested in the scorch mold.

[0076] S402: selecting at least one interception position along the extending direction of the sample to be tested, and intercepting the sample to be tested from the interception position along a direction perpendicular to the extending direction of the sample to be tested to obtain a plurality of sub-samples to be tested.

[0077] S403: Obtaining the scorch percentage of the material to be tested based on the cross section of the sub-sample to be tested.

[0078] In some embodiments, see Figure 6 Step S403 obtains the scorch percentage of the material to be tested based on the cross section of the sub-sample to be tested, including steps S4031~S4033.

[0079] S4031: Obtain the area of ​​the scorched layer in the cross section.

[0080] S4032: Get the area of ​​the cross section.

[0081] S4033: The scorch percentage of the material to be tested is obtained based on the following formula: σ=S1 / S*100%, wherein σ is the scorch percentage of the material to be tested, S1 is the area of ​​the scorch layer in the cross section, and S is the area of ​​the cross section.

[0082] In some embodiments, a plurality of interception positions are selected along the direction in which the sample to be tested extends, and the sample to be tested is intercepted from each interception position along a direction perpendicular to the direction in which the sample to be tested extends, to obtain a plurality of sub-samples to be tested; the char percentage of the material to be tested in each sub-sample to be tested is obtained based on the cross-section of each sub-sample to be tested; and the average value of the char percentages of the material to be tested in all the sub-samples to be tested is taken as the char percentage of the material to be tested in the sample to be tested.

[0083] In some embodiments, in order to more clearly illustrate the scorch test method provided by the embodiments of the present disclosure, the following is combined with Figure 1~Figure 3 (c) Some possible implementations of the scorch test method are described in detail.

[0084] In step S100, refer to Figure 1 , the material to be tested is transported to the extrusion module for melting, and the melted material to be tested is continuously extruded into the scorch die.

[0085] In some examples, the material to be tested includes polyethylene insulation.

[0086] In some examples, the extrusion module 1 includes a laboratory-grade single-screw extruder, so that it can be ensured that the extrusion method of the extrusion module 1 can simulate the extrusion of a real cable, that is, the extrusion module 1 can simulate the real stress conditions during the cable extrusion process.

[0087] For example, before step S100, the material to be tested can be continuously transported to the extrusion module 1 by the feeding module 3, and the continuous operation time is not less than 5 hours. For example, the continuous operation time of the feeding module 3 continuously transporting the material to be tested to the extrusion module 1 includes: 5 hours, 6 hours, 7 hours, 8 hours, 9 hours or 10 hours, etc.

[0088] Here, it should be particularly noted that the continuous operation time is related to the design size of the scorching mold 21, and usually the continuous operation time is more than 5 hours.

[0089] For example, the set temperature of the extrusion module 1 includes: 110°C to 130°C. For example, the set temperature of the extrusion module 1 can be 110°C, 115°C, 120°C, 125°C or 130°C, etc. The screw speed of the extrusion module 1 includes: 5rpm-40rpm. For example, the screw speed of the extrusion module 1 can be 5rpm, 10rpm, 15rpm, 20rpm, 25rpm, 30rpm, 35rpm or 40rpm, etc.

[0090] In step S200, refer to Figure 2 The material to be tested undergoes a cross-linking and curing reaction in the scorching mold 21, and gradually adheres to the inner wall of the scorching mold 21 to form a scorching layer, and the material to be tested is discharged from the outlet end of the scorching mold 21. The time for the material to be tested to be continuously extruded into the scorching mold is not less than 5 hours.

[0091] For example, the time for the material to be tested to be continuously extruded into the scorch mold 21 includes: 5 hours, 6 hours, 7 hours, 8 hours, 9 hours or 10 hours, etc.

[0092] Here, it should be particularly noted that the material to be tested undergoes a cross-linking and curing reaction in the scorch mold 21. After being extruded for several hours, the pre-cross-linked material to be tested adheres to the inner wall of the scorch mold 21, and the cross-linked material to be tested gradually accumulates on the inner wall of the scorch mold 21. As the extrusion time increases, the material to be tested discharged per unit area at the outlet end 212 of the scorch mold 21 will gradually decrease, and the scorch layer will gradually become thicker.

[0093] For example, the set temperature of the scorch mold 21 includes: 130° C. to 160° C. For example, the set temperature of the scorch mold 21 can be 130° C., 140° C., 150° C. or 160° C., etc.

[0094] In step S300, refer to Figure 2 The thermoplastic material is transported to the extrusion module 1 for melting, and the melted thermoplastic material is continuously extruded to the scorch die 21 until the thermoplastic material is discharged from the outlet end 212 of the scorch die 21 .

[0095] For example, the thermoplastic material can be continuously conveyed to the extrusion module 1 through the feeding module 3 to remove the uncrosslinked material to be tested and retain the crosslinked material to be tested (ie, the charred layer).

[0096] In some embodiments, the thermoplastic material includes a colored thermoplastic material.

[0097] Illustratively, the colored thermoplastic material includes a polyethylene or polyethylene derivative based semiconductive shielding material.

[0098] In step S401, refer to Figure 2 and Figure 3 , open the scorch mold 21 and obtain the sample to be tested in the scorch mold 21.

[0099] By way of example, the scorch mould 21 can be opened by removing the fixing device 26 .

[0100] In step S402, refer to Figure 3, selecting at least one interception position along the extending direction of the sample to be tested, and intercepting the sample to be tested along the direction perpendicular to the extending direction of the sample to be tested from the interception position to obtain a plurality of sub-samples to be tested.

[0101] Here, it should be particularly noted that the scorch percentage of the sample to be tested increases from the inlet end 211 of the scorch mold 21 to the outlet end 212 of the scorch mold 21 , and a fixed position should be selected for calculation when comparing the scorch content of different samples to be tested.

[0102] In some embodiments, see Figure 3 The mold cavity 215 includes a cylindrical mold cavity 2151 and a conical mold cavity 2152 which are connected. One end face of the cylindrical mold cavity 2151 is connected to the extrusion port 11. The wide end face of the conical mold cavity 2152 is connected to the other end face of the cylindrical mold cavity 2151, and the narrow end face of the conical mold cavity 2152 is connected to the discharge port 20 through the outlet end 212.

[0103] For example, selecting at least one interception position along the direction in which the sample to be tested extends includes: based on the sample to be tested in the cylindrical mold cavity 2151 , selecting at least one interception position along the direction in which the sample to be tested extends.

[0104] For example, three interception positions may be selected along the extending direction of the sample to be tested, for example: an AA' interception position, a BB' interception position, and a CC' interception position.

[0105] In step S4031, refer to Figure 3 (a) ~ Figure 3 (c), obtain the area of ​​the scorched layer in the cross section.

[0106] For example, obtaining the area of ​​the scorched layer in the cross section includes:

[0107] See also Figure 3 (a), obtaining the area of ​​the first scorched layer 202a in the cross section corresponding to the AA' cut position;

[0108] See also Figure 3 (b), obtaining the area of ​​the second scorched layer 202b in the cross section corresponding to the BB' interception position;

[0109] See also Figure 3 (c) Obtain the area of ​​the third scorched layer 202c in the cross section corresponding to the CC' cutting position.

[0110] S4032: Please refer to Figure 3 (a) ~ Figure 3 (c), obtain the area of ​​the cross section.

[0111] For example, obtaining the area of ​​the scorched layer in the cross section includes:

[0112] See also Figure 3 (a), obtain the area of ​​the cross section corresponding to the AA' interception position;

[0113] For example, the area of ​​the cross section corresponding to the AA′ cutting position is the sum of the area of ​​the first scorched layer 202a and the area of ​​the first thermoplastic material 201a.

[0114] See also Figure 3 (b), obtain the area of ​​the cross section corresponding to the interception position of BB';

[0115] For example, the area of ​​the cross section corresponding to the BB′ cutting position is the sum of the area of ​​the second scorched layer 202b and the area of ​​the second thermoplastic material 201b.

[0116] See also Figure 3 (c) Obtain the area of ​​the cross section corresponding to the CC' interception position.

[0117] For example, the area of ​​the cross section corresponding to the CC′ cutting position is the sum of the area of ​​the third scorched layer 202c and the area of ​​the third thermoplastic material 201c.

[0118] S4033: Please refer to Figure 3 (a) ~ Figure 3 (c) The scorch percentage of the material to be tested is obtained based on the following formula: σ=S1 / S*100%, wherein σ is the scorch percentage of the material to be tested, S1 is the area of ​​the scorch layer in the cross section, and S is the area of ​​the cross section.

[0119] For example, the scorch percentage of the material to be tested is obtained based on the following formula: σ=S1 / S*100% includes:

[0120] Based on the cross section corresponding to the AA' interception position, the first scorch percentage of the material to be tested is calculated according to the formula σ=S1 / S*100%; wherein S1 is the area of ​​the first scorch layer 202a; S is the sum of the area of ​​the first scorch layer 202a and the area of ​​the first thermoplastic material 201a;

[0121] Based on the cross section corresponding to the BB' interception position, the second scorch percentage of the material to be tested is calculated according to the formula σ=S1 / S*100%; wherein S1 is the area of ​​the second scorch layer 202b; S is the sum of the area of ​​the second scorch layer 202b and the area of ​​the second thermoplastic material 201b;

[0122] Based on the cross section corresponding to the CC' interception position, the third scorch percentage of the material to be tested is calculated according to the formula σ=S1 / S*100%; wherein S1 is the area of ​​the third scorch layer 202c; S is the sum of the area of ​​the third scorch layer 202c and the area of ​​the third thermoplastic material 201c;

[0123] The average of the first scorch percentage, the second scorch percentage and the third scorch percentage is calculated as the scorch percentage of the material to be tested in the sample to be tested.

[0124] In the description of this specification, the technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features of the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0125] The above-described embodiments only express several implementation methods of the present disclosure, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present disclosure, and these all belong to the protection scope of the present disclosure. Therefore, the protection scope of the patent of the present disclosure shall be subject to the attached claims.

Claims

1. A scorch test device, characterized in that: include: Extrusion module and scorch module; The extrusion module is provided with a feed port; an extrusion port is provided at one end of the extrusion module; the scorch module comprises a scorch die extending along a first direction; the inlet end of the scorch die is connected to the extrusion port; the outlet end of the scorch die is connected to a discharge port; wherein the inner diameter size range of the discharge port includes: 0.5mm~5mm; the size range of the discharge port along the first direction includes: 50mm~80mm; The extrusion module is used to melt the material to be tested, and continuously extrude the melted material to be tested into the scorch mold; The scorch mold is used to provide a place for the melted material to undergo a cross-linking and curing reaction; as the extrusion time of the material to be tested increases, the material to be tested gradually undergoes a cross-linking and curing reaction in the scorch mold, so as to adhere to the inner wall of the scorch mold to form a scorch layer; The scorch mold comprises an upper mold and a lower mold of the same shape; the upper mold and the lower mold are buckled together to form a mold cavity in the scorch mold; The mold cavity comprises a cylindrical mold cavity and a conical mold cavity which are connected; one end surface of the cylindrical mold cavity is connected to the extrusion port; The wide end face of the conical mold cavity is connected to the other end face of the cylindrical mold cavity, and the narrow end face of the conical mold cavity is connected to the discharge port; The size range of the cylindrical mold cavity along the first direction includes: 80mm~110mm; the cone angle range of the conical mold cavity includes: 30°~60°.

2. The scorch test device according to claim 1, characterized in that: The scorch module further comprises: a first heat conduction unit, a second heat conduction unit and at least two heating modules; The first heat conducting unit covers the surface of the upper mold away from the mold cavity; The second heat conducting unit covers the surface of the lower mold away from the mold cavity; At least one of the heating modules is disposed on a surface of the first heat conducting unit that is away from the scorching mold; and at least another of the heating modules is disposed on a surface of the second heat conducting unit that is away from the scorching mold.

3. The scorch test device according to claim 2, characterized in that: Also includes: At least one temperature measurement and control module; The temperature measurement and control module is arranged on the surface of the first heat conducting unit, and / or the temperature measurement and control module is arranged on the surface of the second heat conducting unit; the temperature measurement and control module is connected to the heating module.

4. The scorch test device according to claim 1, characterized in that: Also includes: Feeding module; the outlet end of the feeding module is connected to the feed port, and is used to transport the material to be tested to the extrusion module through the feed port.

5. A scorch test method, characterized in that: The scorch test method is performed based on the scorch test device according to any one of claims 1 to 4, and the scorch test method comprises: The material to be tested is transported to the extrusion module for melting, and the melted material to be tested is continuously extruded to the scorch die; The material to be tested undergoes a cross-linking and curing reaction in the scorching mold, and gradually adheres to the inner wall of the scorching mold to form a scorching layer, and the material to be tested is discharged from the outlet end of the scorching mold; wherein the material to be tested is continuously extruded into the scorching mold for not less than 5 hours; The thermoplastic material is conveyed to the extrusion module for melting, and the melted thermoplastic material is continuously extruded to the scorch die until the thermoplastic material is discharged from the outlet end of the scorch die; After the scorch mold is cooled to room temperature, the sample to be tested retained in the scorch mold is obtained, and the scorch percentage of the material to be tested is obtained based on the sample to be tested; the sample to be tested includes a scorch layer after the material to be tested is scorched and the thermoplastic material located inside the scorch layer.

6. The scorch test method according to claim 5, characterized in that: The thermoplastic material includes a colored thermoplastic material; the step of obtaining the sample to be tested retained in the scorch mold and obtaining the scorch percentage of the material to be tested based on the sample to be tested includes: Opening the scorch mold and obtaining the sample to be tested in the scorch mold; Selecting at least one interception position along the extending direction of the sample to be tested, and intercepting the sample to be tested from the interception position along a direction perpendicular to the extending direction of the sample to be tested, so as to obtain a plurality of sub-samples to be tested; The scorch percentage of the material to be tested is obtained based on the cross section of the sub-sample to be tested.

7. The scorch test method according to claim 6, characterized in that: The step of obtaining the scorch percentage of the material to be tested based on the cross section of the sub-sample to be tested comprises: Obtaining the area of ​​the scorched layer in the cross section; obtaining the area of ​​the cross section; The scorch percentage of the material to be tested is obtained based on the following formula: σ=S1 / S*100%, wherein σ is the scorch percentage of the material to be tested, S1 is the area of ​​the scorch layer in the cross section, and S is the area of ​​the cross section.

8. The scorch test method according to claim 7, characterized in that: A plurality of interception positions are selected along the direction in which the sample to be tested extends, and the sample to be tested is intercepted from each of the interception positions along a direction perpendicular to the direction in which the sample to be tested extends, so as to obtain a plurality of sub-samples to be tested; based on the cross-section of each sub-sample to be tested, the scorch percentage of the material to be tested in each sub-sample to be tested is obtained; and the average value of the scorch percentages of the material to be tested in all the sub-samples to be tested is taken as the scorch percentage of the material to be tested in the sample to be tested.

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