Crystallization control type cold shrink tube raw material, preparation method and C type cold shrink tube

Abstract

The invention discloses a crystallization control type cold shrink tube raw material, a preparation method and a C type cold shrink tube. The crystallization control type cold shrink tube is prepared from the following raw materials in parts by weight: 100 parts of a high-crystallinity polymer, 0-2 parts of an antioxidant, 0-2 parts of an irradiation sensitizer, 0-3 parts of an extrusion aid and 0-1 part of color master batch. According to the crystallization control type cold shrink tube raw material, the preparation method and the C-type cold shrink tube provided by the invention, the C-type cold shrink tube can spontaneously generate an inward locking force after being locked through the crystallization internal stress of the material, so that the leakproofness and reliability of a connector box are improved, and the material can be widely applied.

Description

Technical Field

[0001] The invention relates to the field of power cable accessories, and in particular to a crystallization controlled cold shrink tube raw material, a preparation method and a C-type cold shrink tube. Background Art

[0002] In the field of power transmission, different types of power tubes play different roles in different power facilities. Conventional C-tubes are used to lock the edge of the joint box, and the edge of the joint box is locked through the notch structure. However, the conventional C-tube has no locking force after locking the joint box, and may even become loose over time. Therefore, the conventional C-tube is modified. Through the crystalline internal stress of the material itself, the C-tube spontaneously generates an inward locking force after locking, thereby improving the airtightness and reliability of the joint box. Summary of the invention

[0003] In view of the above-mentioned deficiencies in the prior art, the present invention proposes a crystallization-controlled cold shrink tube raw material, a preparation method and a C-type cold shrink tube, aiming to solve the problem of looseness of the current traditional C-type tube locking joint box.

[0004] To achieve the above-mentioned purpose, the present invention proposes a crystallization-controlled cold shrink tube raw material, and the ingredients of the crystallization-controlled cold shrink tube raw material, measured by weight, include: 100 parts of high crystalline polymer, 0-2 parts of antioxidant, 0-2 parts of radiation sensitizer, 0-3 parts of extrusion aid, and 0-1 part of masterbatch.

[0005] Optionally, the high crystalline polymer is at least one of high-density polyethylene, medium-density polyethylene, isotactic polypropylene, polystyrene, polyamide and polyethylene terephthalate.

[0006] Optionally, the high crystalline polymer has a crystallinity of 50%-80%.

[0007] Optionally, the antioxidant is at least one of a hindered phenol antioxidant and a phosphite antioxidant.

[0008] Optionally, the extrusion aid is at least one of stearic acid and zinc stearate.

[0009] Optionally, the radiation sensitizer is at least one of triallyl cyanurate (TAIC), triacetin cyanurate (TAC), trimethylolpropane trimethacrylate (TMPTM) and trimethylolpropane triacrylate (TMPTA).

[0010] In order to achieve the above-mentioned purpose, the present invention also proposes a method for preparing a crystallization-controlled cold shrink tube raw material, comprising the following steps: mixing the highly crystalline polymer, antioxidant, radiation sensitizer, extrusion aid and masterbatch and then kneading, granulating through a twin-screw extruder, and using the extruder to extrude the granules into a tube; the extruded crystallization-controlled cold shrink tube is rapidly cooled, and the rapid cooling allows the crystallization-controlled cold shrink tube to quickly complete crystallization, so that a large temperature difference occurs between the inside and outside of the crystallization-controlled cold shrink tube, and a large crystalline internal stress is generated in the tube, and then irradiating, and then cutting the tube with a ring-shaped cross-section along the axial direction of the tube to form a cutting portion and a C-shaped tube portion.

[0011] Optionally, the irradiation source is a high-energy electron accelerator or a cobalt source, and the irradiation dose is 4-10 MeV.

[0012] Optionally, the tube with a ring-shaped cross section is cut along the axial direction of the tube, and the cut portion is connected to the C-shaped tube portion.

[0013] In order to achieve the above-mentioned purpose, the present invention also proposes a C-type cold shrink tube for use in power transmission, wherein the C-type cold shrink tube is prepared by the above-mentioned preparation method.

[0014] Beneficial effects of the present invention: In the present invention, a high crystalline polymer is used as the base material of the C-type cold shrink tube, which ensures the high crystallinity of the material, and the antioxidant, radiation sensitizer and extrusion aid are coordinated to enable the crystallization-controlled cold shrink tube raw material to be smoothly formed.

[0015] The present invention also uses the above-mentioned crystallization controlled cold shrink tube raw material to prepare C-type cold shrink tube. During the crystallization process of high-crystalline polymer extrusion, rapid cooling can enable it to complete crystallization quickly. Rapid cooling will cause a large temperature difference between the inside and outside of the C-type cold shrink tube. The crystallinity inside and outside the C-type cold shrink tube is quite different, thereby generating a large crystalline internal stress in the tube, while the internal stress balance of the circular tube can be maintained. The irradiated tube is cut to form a cutting portion and a C-type cold shrink tube. When the cutting portion is removed, the internal stress balance of the tube is broken, and the remaining C-type cold shrink tube portion will slowly close due to the existence of crystalline internal stress until the two sides of the C-type cold shrink tube contact each other to form a nearly circular structure again. Since the internal stress of the C-type cold shrink tube will continue to exist, a compressive stress perpendicular to the seam will continue to be generated at the joint where the two sides of the C-type cold shrink tube contact each other, so that the C-type cold shrink tube has a greater locking force and is not easy to fail during actual use. Therefore, the C-type cold shrink tube not only has excellent cold shrinkage ability, but the existence of internal stress will make the shrinkage force always maintained, ensuring the locking force of the C-type cold shrink tube and improving the airtightness and reliability of the joint box. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0017] Figure 1 A schematic diagram of cutting a crystallization controlled cold shrink tube according to an embodiment of the present invention;

[0018] Figure 2 A schematic diagram of a C-shaped tube portion according to an embodiment of the present invention;

[0019] Figure 3 A cross-sectional view of a C-shaped tube portion according to an embodiment of the present invention;

[0020] Figure 4 This is an installation diagram of a C-shaped pipe and a joint box according to an embodiment of the present invention.

[0021] Description of Figure Numbers

[0022] 1. Crystallization controlled cold shrink tube; 11. Cutting section; 12. C-type tube section; 2. Joint box. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. It should be understood that the following embodiments are only used to explain the present invention and are not used to limit the present invention.

[0024] Unless defined otherwise, all technical and scientific terms used herein have the common meaning in the art to which the claimed subject matter belongs.

[0025] In the field of power transmission, different types of power tubes play different roles in different power facilities. Conventional C-tubes are used to lock the edge of the joint box, and the edge of the joint box is locked through the notch structure. However, the conventional C-tube has no locking force after locking the joint box, and may even become loose over time. Therefore, the conventional C-tube is modified. Through the crystalline internal stress of the material itself, the C-tube spontaneously generates an inward locking force after locking, thereby improving the airtightness and reliability of the joint box.

[0026] To solve the above problems, the present invention proposes a crystallization-controlled cold shrink tube raw material. The ingredients of the crystallization-controlled cold shrink tube raw material, measured in parts by weight, include: 100 parts of high crystalline polymer, 0-2 parts of antioxidant, 0-2 parts of radiation sensitizer, 0-3 parts of extrusion aid, and 0-1 part of masterbatch.

[0027] In the present invention, a high crystalline polymer is used as the base material of the C-type cold shrink tube to ensure the high crystallinity of the material. The antioxidant, radiation sensitizer and extrusion aid are coordinated to enable the crystallization-controlled cold shrink tube raw material to be smoothly formed.

[0028] In some embodiments, the ingredients of the crystallization controlled cold shrink tube raw material preferably include, by weight, 100 parts of a high crystalline polymer, 0-2 parts of an antioxidant, 0-2 parts of a radiation sensitizer, 0-3 parts of an extrusion aid, and 0-1 part of a masterbatch.

[0029] Furthermore, the high crystalline polymer is at least one of high-density polyethylene, medium-density polyethylene, isotactic polypropylene, polystyrene, polyamide and polyethylene terephthalate.

[0030] In some embodiments, the highly crystalline polymer is preferably high density polyethylene.

[0031] In some embodiments, the high crystalline polymer is preferably a combination of high density polyethylene and medium density polyethylene.

[0032] Furthermore, the high crystalline polymer has a crystallinity of 50%-80%.

[0033] In some embodiments, the highly crystalline polymer has a crystallinity of 60% to 70%.

[0034] Furthermore, the antioxidant is at least one of a hindered phenol antioxidant and a phosphite antioxidant.

[0035] In some embodiments, the antioxidant is preferably a hindered phenolic antioxidant.

[0036] In some embodiments, the antioxidant is preferably at least one of 1010 antioxidant, 1098 antioxidant, 1330 antioxidant, and 1076 antioxidant.

[0037] In some embodiments, the antioxidant is preferably a mixture of a hindered phenol antioxidant and a phosphite antioxidant.

[0038] In some embodiments, the antioxidant is preferably at least one of 168 antioxidant, 626 antioxidant, and 9228 antioxidant.

[0039] Furthermore, the extrusion aid is at least one of stearic acid and zinc stearate.

[0040] In some embodiments, the extrusion aid is preferably a mixture of stearic acid and zinc stearate.

[0041] In some embodiments, the extrusion aid is preferably stearic acid.

[0042] Further, the radiation sensitizer is at least one of triallyl cyanurate (TAIC), triacetin cyanurate (TAC), trimethylolpropane trimethacrylate (TMPTM) and trimethylolpropane triacrylate (TMPTA).

[0043] In some embodiments, the radiation sensitizer is preferably triallyl cyanurate.

[0044] In some embodiments, the radiation sensitizer is preferably a mixture of triacetin cyanurate and trimethylolpropane triacrylate.

[0045] In order to solve the above problems, the present invention also provides a method for preparing a crystallization controlled cold shrink tube raw material, comprising the following steps:

[0046] S1: Highly crystalline polymer, antioxidant, radiation sensitizer, extrusion aid and masterbatch are mixed and kneaded, granulated by a twin-screw extruder, and the granules are extruded into a tube by the extruder;

[0047] In this scheme, a highly crystalline polymer, an antioxidant, a radiation sensitizer, an extrusion aid and a masterbatch are mixed and then kneaded at a temperature of 120-140° C. for 8-15 minutes.

[0048] S2: The extruded crystallization controlled cold shrink tube is subjected to rapid cooling, which allows the crystallization of the crystallization controlled cold shrink tube to be completed quickly, resulting in a large temperature difference between the inside and outside of the crystallization controlled cold shrink tube, and a large crystal internal stress is generated in the tube. The tube is then irradiated, and the tube with a circular cross section is cut along the axial direction of the tube to form a cutting portion and a C-shaped tube portion.

[0049] Furthermore, the irradiation source is a high-energy electron accelerator or a cobalt source, and the irradiation dose is 4-10 MeV.

[0050] In some embodiments, the irradiation source is a high energy electron accelerator, and the irradiation dose is 8 MeV.

[0051] Furthermore, the tube with a ring-shaped cross section is cut along the axial direction of the tube, and the cut portion is connected to the C-shaped tube portion.

[0052] In order to solve the above problems, the present invention also proposes a C-type cold shrink tube, which is applied to power transmission. The C-type cold shrink tube is prepared by the above preparation method.

[0053] The content of the present invention is explained below through specific examples and data.

[0054] Embodiment 1:

[0055] The base material is put into the internal mixer for internal mixing, and when the internal mixing reaches 120°C, it is taken out of the pot and then enters the twin-screw extruder for granulation. The granules are extruded, and the temperature of the extruder head is set to 150°C, and the cooling water temperature is 60°C. The extruded pipe is irradiated, and the irradiation source is selected as a high-energy electron beam, and the irradiation dose is 5MeV. Then it is cut, and the incision width is about 3cm.

[0056] The matrix material is 100 parts of high-density polyethylene Sabic 5933, 1 part of 1010 antioxidant, 1 part of radiation sensitizer TAIC, 1 part of stearic acid, and 3 parts of brown masterbatch.

[0057] Embodiment 2:

[0058] The base material is put into the internal mixer for internal mixing, and when the internal mixing reaches 125°C, it is taken out of the pot and then enters the twin-screw extruder for granulation. The pellets are extruded, and the extruder head temperature is set to 160°C, and the cooling water temperature is 50°C. The extruded pipe is irradiated, and the irradiation source is selected as a high-energy electron beam, and the irradiation dose is 4MeV. It is then cut, and the incision width is about 3cm.

[0059] Among them, the base material is 100 parts of high-density polyethylene Sinopec 5000s, 2 parts of 1098 antioxidant, 2 parts of radiation sensitizer TAC, 1 part of zinc stearate, and 3 parts of brown masterbatch.

[0060] Embodiment 3:

[0061] The base material is put into the internal mixer for internal mixing, and when the internal mixing reaches 130°C, it is taken out of the pot and then enters the twin-screw extruder for granulation. The granules are extruded, and the extruder head temperature is set to 170°C, and the cooling water temperature is 25°C. The extruded pipe is irradiated, and the irradiation source is selected as a high-energy electron beam, and the irradiation dose is 6MeV. Then it is cut, and the incision width is about 3cm.

[0062] The matrix material is 100 parts of high-density polyethylene (Sinopec TR201T), 2 parts of 1330 antioxidant, 2 parts of radiation sensitizer TMPTM, 1 part of zinc stearate, and 3 parts of brown masterbatch.

[0063] Embodiment 4:

[0064] The base material is put into the internal mixer for internal mixing, and when the internal mixing reaches 130°C, it is taken out of the pot and then enters the twin-screw extruder for granulation. The granules are extruded, and the temperature of the extruder head is set to 150°C, and the cooling water temperature is 35°C. The extruded pipe is irradiated, and the irradiation source is selected as a high-energy electron beam, and the irradiation dose is 4MeV. It is then cut, and the incision width is about 3cm.

[0065] Among them, SK medium density polyethylene DX800 100 parts, 1076 antioxidant 1 part, radiation sensitizer TMPTM 1 part, zinc stearate 1 part, brown masterbatch 3 parts.

[0066] Embodiment 5:

[0067] The base material is put into the internal mixer for internal mixing, and when the internal mixing temperature reaches 150°C, it is taken out of the pot and then enters the twin-screw extruder for granulation. The granules are extruded, and the extruder head temperature is set to 180°C, and the cooling water temperature is 50°C. The extruded pipe is irradiated, and the irradiation source is selected as a high-energy electron beam, and the irradiation dose is 7MeV. It is then cut, and the incision width is about 3cm.

[0068] Among them, the base material is 100 parts of Lotte Chemical isotactic polypropylene JM-350, 1 part of 1010 antioxidant, 1 part of radiation sensitizer TAIC, 1 part of stearic acid, and 3 parts of brown masterbatch.

[0069] Embodiment 6:

[0070] The base material is put into the internal mixer for internal mixing, and when the internal mixing reaches 190°C, it is taken out of the pot and then enters the twin-screw extruder for granulation. The granules are extruded, and the extruder head temperature is set to 210°C, and the cooling water temperature is 80°C. The extruded pipe is irradiated, and the irradiation source is selected as a high-energy electron beam, and the irradiation dose is 7MeV, and then it is cut, and the incision width is about 3cm.

[0071] The matrix material is 100 parts of polystyrene FC9412G, 1 part of 1010 antioxidant, 1 part of radiation sensitizer TAIC, 1 part of stearic acid, and 3 parts of brown masterbatch.

[0072] Embodiment 7:

[0073] The base material is put into the internal mixer for internal mixing, and when the internal mixing reaches 190°C, it is taken out of the pot and then enters the twin-screw extruder for granulation. The granules are extruded, and the extruder head temperature is set to 210°C, and the cooling water temperature is 80°C. The extruded pipe is irradiated, and the irradiation source is selected as a high-energy electron beam, and the irradiation dose is 7MeV, and then it is cut, and the incision width is about 3cm.

[0074] The matrix material is 100 parts of polyamide, 1 part of 1010 antioxidant, 1 part of radiation sensitizer TAIC, 1 part of stearic acid, and 3 parts of brown masterbatch.

[0075] Embodiment 8:

[0076] The base material is put into the internal mixer for internal mixing, and when the internal mixing reaches 190°C, it is taken out of the pot and then enters the twin-screw extruder for granulation. The granules are extruded, and the extruder head temperature is set to 210°C, and the cooling water temperature is 80°C. The extruded pipe is irradiated, and the irradiation source is selected as a high-energy electron beam, and the irradiation dose is 7MeV, and then it is cut, and the incision width is about 3cm.

[0077] The matrix material is 100 parts of polyethylene terephthalate, 1 part of 1010 antioxidant, 1 part of radiation sensitizer TAIC, 1 part of stearic acid, and 3 parts of brown masterbatch.

[0078] Comparative Example 1:

[0079] The base material is put into the internal mixer for internal mixing, and is taken out of the pot when the internal mixing reaches 115°C, and then enters the twin-screw extruder for granulation. The granules are extruded, and the extruder head temperature is set to 130°C, and the cooling water temperature is 60°C. The extruded pipe is irradiated, and the irradiation source is selected as a high-energy electron beam, and the irradiation dose is 5MeV.

[0080] The matrix material is 100 parts of ethylene vinyl acetate EVA 18-3, 1 part of 1010 antioxidant, 1 part of radiation sensitizer TAIC, 1 part of stearic acid, and 3 parts of brown masterbatch.

[0081] Comparative Example 2:

[0082] The base material is put into the internal mixer for internal mixing, and is taken out of the pot when the internal mixing reaches 115°C, and then enters the twin-screw extruder for granulation. The granules are extruded, and the extruder head temperature is set to 130°C, and the cooling water temperature is 60°C. The extruded pipe is irradiated, and the irradiation source is selected as a high-energy electron beam, and the irradiation dose is 5MeV.

[0083] The base material is 100 parts of ExxonMobil POE 7256, 1 part of 1010 antioxidant, 1 part of radiation sensitizer TAIC, 1 part of stearic acid, and 3 parts of brown masterbatch.

[0084] Comparative Example 3:

[0085] The base material is put into the internal mixer for internal mixing, and is taken out of the pot when the internal mixing reaches 120°C, and then enters the twin-screw extruder for granulation. The granules are extruded, and the extruder head temperature is set to 130°C, and the cooling water temperature is 60°C. The extruded pipe is irradiated, and the irradiation source is selected as a high-energy electron beam, and the irradiation dose is 5MeV.

[0086] The matrix material is 100 parts of low-density polyethylene LD600, 1 part of 1010 antioxidant, 1 part of radiation sensitizer TAIC, 1 part of stearic acid, and 3 parts of brown masterbatch.

[0088] Comparative Example 4:

[0089] The base material is put into the internal mixer for internal mixing, and is taken out of the pot when the internal mixing reaches 120°C, and then enters the twin-screw extruder for granulation. The granules are extruded, and the extruder head temperature is set to 130°C, and the cooling water temperature is 60°C. The extruded pipe is irradiated, and the irradiation source is selected as a high-energy electron beam, and the irradiation dose is 5MeV.

[0090] The matrix material is 100 parts of polytrifluorochloroethylene Sigma-Aldrich, 1 part of 1010 antioxidant, 1 part of radiation sensitizer TAIC, 1 part of stearic acid, and 3 parts of brown masterbatch.

[0091] The components of Examples 1-8 and Comparative Examples 1-4 and important preparation variables are summarized in Table 1.

[0092] Table 1. Summary of components and important preparation variables for Examples 1-8 and Comparative Examples 1-4 of the present invention

[0093]

[0094] According to the test specified in (test standard or specification to be determined), the time taken for the tube opening to be completely shrunk was tested for the C-type cold shrink tubes in the above-mentioned Examples 1-8 and Comparative Examples 1-4, and the test results were recorded in the following Table 2:

[0095] Table 2. Performance of Examples 1-8 and Comparative Examples 1-4

[0096] Test items Time taken for the nozzle to fully shrink / min Example 1 10 Example 2 8 Example 3 5 Example 4 15 Example 5 12 Example 6 9 Example 7 9 Example 8 9 Comparative Example 1 Cannot shrink Comparative Example 2 Cannot shrink Comparative Example 3 >120 Comparative Example 4 Cannot be squeezed out smoothly

[0097] According to the above test results, it can be seen that in Examples 1-8, in Example 1 and Example 2, the difference between the temperature of the cooling water and the extrusion temperature of the extruder is 90°C and 110°C, respectively, while the temperature of the cooling water used in Example 3 is room temperature 25°C, which is 145°C different from the extrusion temperature of the extruder 170°C. The time taken for the nozzles of Examples 1, 2 and 3 to shrink completely is measured. The time taken for the nozzle of Example 3 to shrink completely is the shortest, which is 5min. The time taken for the nozzle of Example 1 to shrink completely is 10min, and the time taken for the nozzle of Example 2 to shrink completely is 8min. In Examples 6-8, the extruder head temperature and the cooling water temperature are both 210°C and 80°C, and the temperature difference is 130°C. The time taken for the nozzles of Examples 6-8 to shrink completely is all 9min. It can be seen that when the cooling water cools the pipe, the greater the temperature difference between the inside and outside of the pipe, the faster the inside The greater the difference in external crystallinity, the greater the crystalline internal stress generated in the tube. When the crystallization-controlled cold shrink tube is cut, the C-type cold shrink tube part will slowly close due to the larger crystalline internal stress in the body. The greater the crystalline internal stress in the body, the shorter the closing time of the C-type cold shrink tube; in Comparative Examples 1-2, the base material is a low-crystalline polymer, and the texture of the tube is soft after extrusion, and the hardness is low at room temperature, which does not meet the requirements for the use of C-type cold shrink tubes at room temperature, and the soft texture cannot be cut; in Comparative Example 3, the base material is low-density polyethylene, and the actual shrinkage effect of the tube after extrusion is small, which does not meet the shrinkage characteristics of the C-type tube, and the joint box cannot be fixed. The base material in Comparative Example 4 is polytrifluorochloroethylene, and its crystallinity is 85%-90%. When the crystallinity is too high, it cannot be extruded smoothly like other embodiments and comparative examples during extrusion, and therefore the self-locking of the prepared C-type tube cannot be achieved. Therefore, the C-type cold shrink tube made from crystallization-controlled cold shrink tube raw materials has the advantage of self-locking. The material shrinkage time is short after locking, and its shrinkage force is strong. It can complete the locking of the joint box and avoid safety accidents such as loosening, and can be widely used.

[0098] The above are only preferred embodiments of the present invention, and do not limit the patent scope of the present invention. For those skilled in the art, the present invention may have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the patent protection scope of the present invention.

Claims

1. A crystallization controlled cold shrink tube raw material, characterized in that: The ingredients of the crystallization controlled cold shrink tube raw material are measured by weight and include: 100 parts of highly crystalline polymer; Antioxidants 0-2 parts; Radiation sensitizer 0-2 parts; Extrusion aid 0-3 parts; Masterbatch 0-1 part.

2. The crystallization controlled cold shrink tube raw material according to claim 1, characterized in that: The high crystalline polymer is at least one of high-density polyethylene, medium-density polyethylene, isotactic polypropylene, polystyrene, polyamide and polyethylene terephthalate.

3. The crystallization controlled cold shrink tube raw material according to claim 1, characterized in that: The high crystalline polymer has a crystallinity of 50%-80%.

4. The crystallization controlled cold shrink tube raw material according to claim 1, characterized in that: The antioxidant is at least one of a hindered phenol antioxidant and a phosphite antioxidant and at least one of a phosphite antioxidant.

5. The crystallization controlled cold shrink tube raw material according to claim 1, characterized in that: The extrusion aid is at least one of stearic acid and zinc stearate.

6. The crystallization controlled cold shrink tube raw material according to claim 1, characterized in that: The radiation sensitizer is at least one of triallyl cyanurate (TAIC), triacetin cyanurate (TAC), trimethylolpropane trimethacrylate (TMPTM) and trimethylolpropane triacrylate (TMPTA).

7. A method for preparing a crystallization-controlled cold shrink tube raw material, characterized in that: The following steps are involved: The highly crystalline polymer, antioxidant, radiation sensitizer, extrusion aid and masterbatch are mixed and then kneaded, and granulated by a twin-screw extruder. The granules are extruded into a pipe by the extruder; the extruded crystallization controlled cold shrink tube is rapidly cooled, and the rapid cooling allows the crystallization controlled cold shrink tube to quickly complete crystallization, so that a large temperature difference occurs between the inside and outside of the crystallization controlled cold shrink tube, and a large crystalline internal stress is generated in the tube, and then irradiated, and then the tube with a ring-shaped cross section is cut along the axial direction of the tube to form a cutting portion and a C-shaped tube portion.

8. The method for preparing the crystallization controlled cold shrink tube raw material according to claim 7, characterized in that: The irradiation source is a high-energy electron accelerator or a cobalt source, and the irradiation dose is 4-10 MeV.

9. The method for preparing the crystallization controlled cold shrink tube raw material according to claim 7, characterized in that: The tube with a ring-shaped cross section is cut along the axial direction of the tube, and the cut portion is connected to the C-shaped tube portion.

10. A C-type cold shrink tube, characterized in that: Applied to power transmission, the C-type cold shrink tube is prepared by the preparation method of claim 7.

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