Coating material for optical fiber, preparation method of coating material, optical fiber insulator and preparation method of optical fiber insulator

Abstract

The invention discloses a coating material for an optical fiber, a preparation method of the coating material, an optical fiber insulator and a preparation method of the optical fiber insulator. The coating material is prepared from the following raw material components in parts by weight: 40-60 parts of tetrahydrofuran acrylate, 30-50 parts of carboxyl modified polyurethane acrylate oligomer, 5-15 parts of organic silicon modified epoxy acrylate bifunctional coupling agent, 2-5 parts of vinyl silane surface modified SiO2 nano-particles, 1-5 parts of organic silicon modified epoxy acrylate, 1-5 parts of organic silicon modified epoxy acrylate, 1-5 parts of organic silicon modified epoxy acrylate, 1-5 parts of organic silicon modified epoxy acrylate and 1-5 parts of organic silicon modified epoxy acrylate. 0.1 to 1 part by weight of a triaryl sulfonium hexafluoroantimonate cationic initiator and 0.5 to 4 parts by weight of a TPO free radical photoinitiator. According to the embodiment of the invention, active chemical bonding of the optical fiber coating layer and the alicyclic epoxy resin sheath is realized through the organic silicon modified epoxy acrylate bifunctional coupling agent in the coating layer, and mismatch of physical gaps and thermal stress of a multi-material interface is reduced; therefore, the interface strength, the internal insulation performance and the long-term reliability of the optical fiber insulator can be fundamentally improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of optical fiber sensing and power equipment, and particularly relates to a coating material for optical fibers, a preparation method thereof, an optical fiber insulator and a preparation method thereof. BACKGROUND

[0002] With the continuous increase of voltage level, higher requirements are put forward for the insulation performance and reliability of power equipment. As a key component in the power transmission and monitoring system, the performance of the optical fiber insulator is directly related to the safe and stable operation of the power grid.

[0003] At present, cycloaliphatic epoxy resin can be applied to the insulation material of high-voltage optical fiber insulators due to its excellent electrical insulation performance and mechanical strength. However, the existing optical fiber coating materials on the market (such as acrylate and polyimide) are mainly aimed at low-voltage and low-electric-field scenes, and there is a large difference in the thermal expansion coefficient and a problem of insufficient chemical compatibility between the traditional optical fiber coating layer and the cycloaliphatic epoxy resin material. This makes it easy to produce physical microcracks between the coating layer and the sheath under the long-term action of high voltage, high field strength and the influence of temperature changes, and further causes partial discharge and accelerates the deterioration of the insulation performance. At the same time, this thermal stress mismatch can also cause the coating layer to peel off from the sheath, damaging the overall structure of the optical fiber insulator and seriously affecting its service life and reliability. SUMMARY

[0004] The embodiments of the application provide a coating material for optical fibers, a preparation method thereof, an optical fiber insulator and a preparation method thereof. The special optical fiber coating material can be applied to high-voltage and high-electric-field conditions, and the optical fiber insulator can be applied to 500kV-1100kV AC / DC environments, so as to at least solve the problems of physical microcracks and thermal stress mismatch caused by poor interfacial compatibility between the traditional coating layer and the cycloaliphatic epoxy resin sheath in the optical fiber insulator in the related art.

[0005] In a first aspect, the embodiments of the application provide a coating material for optical fibers, and the preparation raw materials of the coating material include the following components according to weight parts:

[0006] tetrahydrofuran acrylate 40-60 parts by weight,

[0007] carboxyl-modified polyurethane acrylate oligomer 30-50 parts by weight,

[0008] silicone-modified epoxy acrylate bifunctional linker 5-15 parts by weight,

[0009] vinyl silane surface-modified SiO2 nanoparticles 2-5 parts by weight,

[0010] triaryl sulfonium hexafluoroantimonate cationic initiator 0.1-1 part by weight,

[0011] TPO free radical photoinitiator 0.5-4 parts by weight.

[0012] Optionally, the organic silicon modified epoxy acrylate bifunctional linker contains acryloyloxy and epoxy groups.

[0013] In a second aspect, the embodiments of the present application provide a preparation method of the coating material for optical fibers according to any one of the embodiments of the first aspect, and the method comprises the following steps:

[0014] S110, mixing tetrahydrofuran acrylate and carboxyl modified polyurethane acrylate oligomer to obtain a base resin solution;

[0015] S120, mixing the base resin solution obtained in step S110 and the organic silicon modified epoxy acrylate bifunctional linker under nitrogen protection, then adding vinyl silane surface modified SiO2 nanoparticles and performing ultrasonic dispersion treatment, and then mixing with triaryl sulfonium hexafluoroantimonate cationic initiator and TPO free radical photoinitiator to obtain a coating material.

[0016] Optionally, the mixing of tetrahydrofuran acrylate and carboxyl modified polyurethane acrylate oligomer in step S110 is carried out under constant temperature of 50-70°C and stirring condition of 400-600 r / min.

[0017] Optionally, the mixing with triaryl sulfonium hexafluoroantimonate cationic initiator and TPO free radical photoinitiator in step S120 is carried out under light shielding and stirring condition of 150-250 r / min.

[0018] In a third aspect, the embodiments of the present application provide a preparation method of an optical fiber insulator, and the method comprises the following steps:

[0019] S210, coating the coating material according to any one of the embodiments of the first aspect on an optical fiber;

[0020] S220, attaching the optical fiber to the surface of a mandrel;

[0021] S230, pressing a sheath and an umbrella skirt on the surface of the mandrel by injection molding process, so that the sheath and the umbrella skirt are integrally formed on the surface of the mandrel to obtain an optical fiber insulator; wherein the sheath is a cycloaliphatic epoxy resin sheath.

[0022] Optionally, the step S210 comprises:

[0023] plasma activation treatment is performed on the surface of the optical fiber;

[0024] the coating material is coated on the surface of the optical fiber by high-speed wire drawing under nitrogen protection;

[0025] UV curing is performed under ultraviolet light conditions to form a primary solid coating layer with residual epoxy active groups.

[0026] Optionally, the step S230 comprises:

[0027] In the aliphatic epoxy resin sheath injection molding stage, the residual epoxy active groups are synchronously triggered to react with the ring-opening crosslinking of the sheath by using the sheath curing heat energy, realizing the covalent bonding of the coating layer and the sheath interface and the integrated molding of the interpenetrating network IPN structure.

[0028] In a fourth aspect, the embodiments of the present application provide an optical fiber insulator prepared by the preparation method of the optical fiber insulator according to any one of the embodiments of the third aspect.

[0029] The coating material for optical fibers, the preparation method thereof, the optical fiber insulator and the preparation method thereof provided in the embodiments of the present application realize the active chemical bonding of the optical fiber coating layer and the aliphatic epoxy resin sheath by using the organic silicon-modified epoxy acrylate bifunctional linker in the coating layer, reduce the physical gap and thermal stress mismatch of the multi-material interface; and in combination with the vinyl silane-modified SiO2 nanoparticles to fill the micro pores and block the growth of the electrical tree, the signal loss increment after thermal cycling is far below the industry failure threshold; thereby the interface strength, the internal insulation performance and the long-term reliability of the optical fiber insulator can be fundamentally improved. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly introduced, and other drawings can be obtained by those of ordinary skill in the art without creative labor on the premise of not paying creative labor.

[0031] Figure 1 is a flowchart of a preparation method of a coating material for optical fibers provided in the embodiments of the present application;

[0032] Figure 2 is a flowchart of a preparation method of an optical fiber insulator provided in the embodiments of the present application;

[0033] Figure 3 is a structural schematic diagram of an optical fiber insulator provided in the embodiments of the present application.

[0034] REFERENCE SIGNS:

[0035] Sheath 1, umbrella skirt 2, optical fiber 3, mandrel 4. DETAILED DESCRIPTION

[0036] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples.

[0037] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0038] In this application, when numerical intervals (i.e., numerical ranges) are involved, unless otherwise specified, the distribution of selectable numerical values ​​within the numerical interval is considered continuous, and includes the two endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every numerical value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that numerical interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed in this application should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include percentage intervals, ratio intervals, proportion intervals, etc.

[0039] Currently, the optical fiber composite insulator for high-voltage power transmission is facing a serious interface failure problem. There is a significant difference in the thermal expansion coefficient and a lack of chemical compatibility between the traditional optical fiber coating layer (such as acrylate or polyimide) and the alicyclic epoxy resin material of the insulator sheath, which leads to the generation of micro-cracks and delamination at the interface between the coating layer and the sheath under the action of temperature cycling, humid environment or mechanical stress; such interface defects not only destroy the stability of the optical fiber sensing signal, but also cause partial discharge and insulation resistance degradation, which continuously reduces the insulation performance of the insulator, eventually significantly shortens the service life of the equipment, and becomes a key bottleneck restricting the reliability of the high-voltage power transmission system.

[0040] In order to solve the problems of the related art, the optical fiber coating material and its preparation method, and the optical fiber insulator and its preparation method provided by the embodiments of the present application are provided, which relate to the fields of optical fiber sensing technology and power equipment technology.

[0041] The embodiments of the present application upgrade the coating layer from a "passive protective layer" to an "active interface bonding layer" through material chemical bonding and process synergy, which solves the core problem of multi-material interface synergy. It aims to solve the problems of physical micro-gap, thermal stress mismatch and process defects caused by the poor interface compatibility between the traditional coating layer and the alicyclic epoxy resin sheath in the optical fiber insulator. By innovatively designing an organic silicon hybrid coating layer material with double reactive groups (acryloyloxy and epoxy), combining plasma activation pretreatment and UV / thermal dual-mode gradient curing process, forming a basic protective structure through free radical polymerization during the coating layer curing stage, and triggering the covalent bonding reaction between the residual epoxy group of the coating layer and the alicyclic epoxy resin during the sheath thermal curing process, an interpenetrating network interface structure is simultaneously constructed, which completely eliminates the physical gap at the interface, inhibits the risk of thermal expansion and peeling, and eliminates the leakage risk of the traditional filling glue process, thereby significantly improving the interface strength, internal insulation voltage resistance and long-term signal transmission stability of the optical fiber insulator, meeting the demand of high-voltage power grid for monitoring reliability and more than 30 years of life.

[0042] The reagents or materials used in the following examples can be purchased from conventional manufacturers, and the specific manufacturers and models are shown in Table 1:

[0043] Table 1

[0044]

[0045] Firstly, the optical fiber coating material and its preparation method provided by the embodiments of the present application are described in detail through specific examples and their application scenarios.

[0046] Examples 1-3

[0047] An optical fiber coating material, the specific components are shown in Table 2, and the amount of each component is "parts by weight":

[0048] Table 2

[0049]

[0050] The molecular structure of the organosilicon-modified epoxy acrylate bifunctional linker contains acryloyloxy and epoxy groups.

[0051] Reference Figure 1 The preparation method of the optical fiber coating material provided in Embodiments 1-3 can include the following steps S110-S120:

[0052] S110, mixing tetrahydrofuran acrylate and carboxyl-modified polyurethane acrylate oligomer to obtain a base resin solution.

[0053] In specific implementation, the tetrahydrofuran acrylate and the carboxyl-modified polyurethane acrylate oligomer are placed in a reaction kettle, mixed under constant temperature at 60°C and stirring at a speed of 500 r / min to form a homogeneous transparent solution.

[0054] S120, mixing the base resin solution obtained in step S110 and the organosilicon-modified epoxy acrylate bifunctional linker under nitrogen protection, then adding vinyl silane surface-modified SiO2 nanoparticles and performing ultrasonic dispersion treatment, and then mixing with triaryl sulfonium hexafluoroantimonate cationic initiator and TPO free radical photoinitiator to obtain a coating material.

[0055] In specific implementation, steps S121-S123 are included:

[0056] S121, under nitrogen protection, adding the organosilicon-modified epoxy acrylate bifunctional linker, continuously stirring for 30 minutes to ensure molecular dispersion and prevent pre-reaction of the epoxy group;

[0057] S122, adding vinyl silane surface-modified SiO2 nanoparticles, eliminating agglomerates through ultrasonic dispersion for 20 minutes, and embedding the modified SiO2 in the polymer chain in ultrasonic dispersion, migrating to the interface area during thermal curing to form a "pore filling + electric field homogenization" dual barrier;

[0058] S123, under light protection, adding triaryl sulfonium hexafluoroantimonate cationic initiator and TPO free radical photoinitiator, stirring at a speed of 200 r / min for 10 minutes to completely mix, to obtain a functional hybrid coating material that can trigger dual-mode curing (ultraviolet polymerization + thermal ring-opening crosslinking).

[0059] The temperature, speed, stirring time, and ultrasonic dispersion time parameters of S110, S121, S122, and S123 in Embodiments 1-3 are as follows in Table 3:

[0060] Table 3

[0061]

[0062] Comparative Example 1

[0063] A coating material for optical fiber, which is different from Example 1 in that it does not contain the silicone-modified epoxy acrylate bifunctional linker, and other components, amounts and preparation methods are the same as Example 1.

[0064] Comparative Example 2

[0065] A coating material for optical fiber, which is different from Example 1 in that it lacks the vinyl silane surface-modified SiO2nanoparticles, and other components, amounts and preparation methods are the same as Example 1.

[0066] Comparative Example 3

[0067] A coating material for optical fiber, which is different from Example 1 in that the silicone-modified epoxy acrylate bifunctional linker is 25 parts by weight, and other components, amounts and preparation methods are the same as Example 1.

[0068] Performance Test:

[0069] (1) Interfacial peeling strength test: 90° peeling test, test speed 50 mm / min, ambient temperature 25℃, each group of samples tested 5 times and averaged.

[0070] (2) Signal loss test after thermal cycling: 500 cycles (12 hours per cycle) in the range of -40℃ to 80℃, using an optical time domain reflectometer (OTDR) to measure the signal loss increment at 1550nm wavelength.

[0071] (3) Inner insulation breakdown voltage test: oil immersion method, voltage rise rate 1kV / s, ambient temperature 25℃, relative humidity 50%, record the voltage value at the moment of breakdown.

[0072] (4) Electrical tree growth inhibition test: apply a direct current electric field of 10kV / mm for 72 hours, observe the length of the electrical tree by microscope, each group of samples tested 3 parallel samples.

[0073] The coating materials for optical fiber obtained from Examples 1-3 and Comparative Examples 1-3 were tested according to the above test methods, and the test results are shown in Table 4:

[0074] Table 4

[0075]

[0076]

[0077] According to the data in Table 4, it can be seen that the coating material for optical fiber provided by the application can covalently bond with the alicyclic epoxy resin sheath through the reaction of the bifunctional connecting agent to form an interpenetrating network structure, thereby greatly improving the interfacial peeling strength. In terms of thermal stability, the ethenylsilane surface modified SiO2 nanoparticles can fill the micro pores and block the growth path of the electrical tree, thereby effectively inhibiting the thermal stress damage. In terms of insulation performance, the synergistic effect of the covalent bonding structure constructed by the bifunctional connecting agent and the nanoparticles can significantly improve the inner insulation breakdown voltage.

[0078] Specifically, it can be found from Comparative Example 1, Comparative Example 2 and Example 1 that the interfacial peeling strength of Comparative Example 1 is only 3.2 N / cm due to the lack of the organosilicon modified epoxy acrylate bifunctional connecting agent, which is far lower than 8.6 N / cm of Example 1; the signal loss increment after thermal cycling is as high as 0.82 dB / km, which is 16.4 times of Example 1; the inner insulation breakdown voltage is only 65 kV, which is less than half of Example 1; and the maximum length of the electrical tree is 150 μm, which is 6 times of Example 1. Comparative Example 2 lacks the ethenylsilane surface modified SiO2 nanoparticles, and the interfacial peeling strength is 6.8 N / cm, which is 79.1% of Example 1; the signal loss increment after thermal cycling is 0.35 dB / km, which is 7 times of Example 1; the inner insulation breakdown voltage is 92 kV, which is only 71.9% of Example 1; and the maximum length of the electrical tree is 80 μm, which is 3.2 times of Example 1. This shows that the organosilicon modified epoxy acrylate bifunctional connecting agent and the ethenylsilane surface modified SiO2 nanoparticles play an important role in improving the performance of the optical fiber coating material.

[0079] It can be found from Comparative Example 1, Example 2 and Example 3 that with the increase of the addition amount of the organosilicon modified epoxy acrylate bifunctional connecting agent and the ethenylsilane surface modified SiO2 nanoparticles, the performance of the material changes. The interfacial peeling strength of Example 2 is 9.2 N / cm, which is higher than 8.6 N / cm of Example 1 and 8.9 N / cm of Example 3; the signal loss increment after thermal cycling is 0.04 dB / km, which is lower than 0.05 dB / km of Example 1 and 0.06 dB / km of Example 3; the inner insulation breakdown voltage is 135 kV, which is higher than 128 kV of Example 1 and 130 kV of Example 3; and the maximum length of the electrical tree is 20 μm, which is lower than 25 μm of Example 1 and 22 μm of Example 3. This shows that within a certain range, increasing the addition amount of the two core materials can further optimize the performance of the material.

[0080] It can be found from Comparative Example 1 and Comparative Example 3 that the addition amount of the silicone-modified epoxy acrylate bifunctional linker in Comparative Example 3 exceeds the set range, the interfacial peeling strength is 5.1 N / cm, which is lower than 8.6 N / cm of Example 1; the signal loss increment after thermal cycling is 0.58 dB / km, which is 11.6 times of Example 1; the inner insulation breakdown voltage is 80 kV, which is only 62.5% of Example 1; and the maximum length of the electrical tree is 110 μm, which is 4.4 times of Example 1. This shows that the addition amount of the silicone-modified epoxy acrylate bifunctional linker needs to be controlled within a reasonable range, and exceeding the range will lead to a decrease in material performance.

[0081] Therefore, through the silicone-modified epoxy acrylate bifunctional linker in the coating layer, active chemical bonding of the optical fiber coating layer and the alicyclic epoxy resin sheath can be achieved, and the physical gap and thermal stress mismatch of the multi-material interface are reduced; and in combination with the vinyl silane-modified SiO2 nanoparticles to fill the micro pores and block the growth of the electrical tree, the signal loss increment after thermal cycling is far lower than the industry failure threshold; thereby the interface strength, the inner insulation performance and the long-term reliability of the optical fiber insulator can be fundamentally improved.

[0082] Further, the application also provides a preparation method of the optical fiber insulator. It should be noted that the preparation method of the optical fiber insulator can be applied to the coating material for optical fibers in any of the above embodiments.

[0083] It can be understood that the optical fiber insulator is a key carrier of the power transmission line monitoring system, and there is a significant interface compatibility problem between the traditional coating layer of the internal optical fiber and the alicyclic epoxy resin material of the external sheath, which leads to weak physical combination, lack of chemical bonding, causes interface micro gap and aggravates the risk of surface discharge; at the same time, the difference in thermal expansion coefficient of the materials induces interface peeling and moisture intrusion in the temperature alternating environment, accelerates interface deterioration and affects the stability of optical fiber signal transmission.

[0084] In addition, the existing coating process has defects such as insufficient curing and poor coating uniformity, and the passive scheme of relying on filling glue to compensate the interface gap is easy to cause local electric field distortion, which ultimately leads to a decrease in the inner insulation performance of the insulator, a decrease in the mechanical strength and a difficulty in meeting the long-term operation demand of the high-voltage power grid.

[0085] Figure 2 A flowchart of the preparation method of the optical fiber insulator of the embodiment of the application is shown. As shown in Figure 2 The preparation method of the optical fiber insulator can specifically include the following steps:

[0086] S210, coating the coating material prepared in any of the above embodiments on the optical fiber;

[0087] S220, attaching the optical fiber to the surface of the mandrel;

[0088] S230, a jacket and a skirt are pressed on the surface of the core rod by using an injection molding process, so that the jacket and the skirt are integrally formed on the surface of the core rod, to obtain an optical fiber insulator; wherein the jacket is a alicyclic epoxy resin jacket.

[0089] The specific implementation of each step is described below.

[0090] In some embodiments, in S210, the surface of the optical fiber is subjected to plasma activation treatment; the coating material is coated on the surface of the optical fiber by high-speed drawing under nitrogen protection; and UV curing is performed under ultraviolet light to form a primary solid coating layer with residual epoxy active groups.

[0091] In specific implementation, first, the surface of the bare optical fiber is treated by argon / oxygen low-temperature plasma to generate highly active silicon hydroxyl groups (—Si—OH); then, the hybrid coating material is applied in a nitrogen protection environment, and UV curing is completed by using ultraviolet light to trigger free radical polymerization, to form a primary solid coating layer with epoxy active groups.

[0092] In this way, by plasma pretreatment, silicon hydroxyl groups (—Si—OH) are generated to improve the adhesion of the optical fiber coating layer; by using double-mode gradient curing, UV curing under nitrogen protection avoids oxidation interference, and chemical bonding is triggered in the jacket heat curing stage to eliminate the risk of leakage; by introducing modified SiO2 nanoparticles, the compactness of the coating layer and the electrical tracking resistance level are improved.

[0093] In some embodiments, in S220, the optical fiber is wound on the surface of the core rod, so that the optical fiber is attached to the cylindrical surface of the core rod.

[0094] In some embodiments, in S230, in the alicyclic epoxy resin jacket injection molding stage, the residual epoxy active groups and the jacket are simultaneously triggered to undergo ring-opening crosslinking reaction by using the heat energy of the jacket curing, to realize the covalent bonding of the coating layer and the jacket interface and the integrated molding of the interpenetrating network (IPN) structure.

[0095] In this way, by using the organosilicon modified epoxy acrylate bifunctional linker (containing acryloyloxy and epoxy groups) in the coating layer, ring-opening polymerization occurs between the alicyclic epoxy resin in the jacket heat curing stage (150–180℃), to form a covalently bonded “molecular bridging” structure, which completely eliminates the interface micro-cracks and eliminates the surface discharge.

[0096] Therefore, by using the synergistic process of plasma activation-gradient curing (UV primary solidification + heat synergistic curing), the residual epoxy groups of the coating layer are crosslinked with the jacket resin when the jacket is formed, to form an interpenetrating network (IPN) structure, which synchronously matches the thermal expansion behaviors of the two, to inhibit peeling.

[0097] Thus, the embodiment of the present application uses a silicone hybrid resin containing double reactive groups (acryloxy and epoxy) as the core component of the coating layer, forms a basic protective layer by photocuring during the coating stage, and triggers the ring-opening reaction of the epoxy group during the subsequent thermal curing process of the sheath aliphatic epoxy resin, to realize the direct covalent bond connection between the coating layer and the sheath interface; simultaneously, the plasma surface activation pretreatment and the staged gradient curing process are combined to eliminate the physical gap at the interface and construct an integrated interpenetrating network structure; the functional nanofiller is used to enhance the compactness of the coating layer, to fundamentally solve the reliability problems caused by poor interface compatibility, thermal stress mismatch and process defects, and to significantly improve the interface strength, electrical resistance and long-term stability of the insulator.

[0098] In addition, the present application also provides an optical fiber insulator. It should be noted that the optical fiber insulator of the embodiment of the present application is prepared by using the preparation method of the optical fiber insulator of any of the above embodiments.

[0099] Reference Figure 3 is a structural schematic diagram of the optical fiber insulator of the embodiment of the present application. As shown in Figure 3 , the optical fiber insulator is composed of a core rod 4, an optical fiber 3, a sheath 1 and a shed 2.

[0100] In summary, the embodiment of the present application proposes a high interface stability optical fiber insulator coating layer material and a preparation method, and a coating process for a special optical fiber coating layer material of an optical fiber composite insulator, aiming to realize the elimination of the physical gap at the interface and the construction of an integrated interpenetrating network structure by optimizing the interface chemical bonding between the optical fiber coating layer and the sheath aliphatic epoxy resin based on the molecular bridging chemical bonding mechanism, to significantly improve the insulation performance and long-term stability of the insulator, and to realize the online monitoring function. Specifically, through material formula innovation (silicone-epoxy hybrid acrylate system) and process breakthrough (plasma activation-gradient curing synergy), the coating layer is upgraded from a “passive protective layer” to an “active bonding functional layer”, solving the long-existing multi-material interface synergy failure problem of the optical fiber coating layer and the sheath. The core of the revolution is: molecular level interface design, double functional group linker to realize the covalent bond bridging between the coating layer and the sheath, breaking through the limitations of traditional physical adhesion; process-material synergy, integrated interpenetrating network formed by plasma activation and gradient curing, synchronous optimization of thermal matching and compactness; full life cycle improvement, from interface strength, electrical resistance to signal stability, systematically meeting the stringent requirements of ultra-high voltage power grid on monitoring reliability.

[0101] It is to be understood that the foregoing description is descriptive only, and that other embodiments within the scope of the application are possible, and that all such embodiments are intended to be included within the scope of the claims. Where technical features mentioned in any of the claims are followed by notation for emphasis (e.g., "must include, "must implement," "must have"), those features are described as being "essential" to the application or "essential" to an embodiment thereof. However, no requirement exists in the application that any or all of the features be "essential" or that the features be "essential" to the application or to an embodiment thereof. Terms used

[0102] Reference throughout this application to "various embodiments" or "one embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase "in various embodiments" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily referring to a common or all embodiments.

[0103] In the description of the application, it is to be understood that the terms "mounting", "connected", "connecting", "attach", "attached", "connection" should be construed broadly in accordance with the principles of equivalence in the art, for example, it can be fixed connection, or detachable connection, or integrally connected, can be directly connected, or indirectly connected through an intermediate medium, can be the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0104] In the embodiments of the present application, the same reference signs represent the same parts, and for the sake of brevity, detailed description of the same parts is omitted in different embodiments. It should be understood that the thickness, length and width of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length and width of the integrated device, are only exemplary and should not constitute any limitation on the present application.

[0105] "Multiple" appearing in the present application refers to two or more (including two).

[0106] Although the present application has been described with reference to the preferred embodiments, various modifications can be made to it without departing from the scope of the present application, and equivalent parts can be substituted for the parts thereof, especially, the technical features mentioned in each embodiment can be combined in any way as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0107] It should also be noted that the exemplary embodiments mentioned in the present application describe some methods or systems based on a series of steps or devices. However, the present application is not limited to the order of the above steps, that is, the steps can be performed in the order mentioned in the embodiments, or in an order different from the embodiments, or several steps can be performed simultaneously.

[0108] The above is only a specific implementation of the present application, and those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the system, module and unit described above can refer to the corresponding process in the foregoing method embodiments, which will not be described here. It should be understood that the protection scope of the present application is not limited to this, and any person skilled in the art can easily think of various equivalent modifications or replacements within the technical range disclosed in the present application, and these modifications or replacements should be covered within the protection scope of the present application.

Claims

1. A coating material for optical fibers, characterized in that, The raw materials for preparing the coating material include the following components in parts by weight: 40-60 parts by weight of tetrahydrofuran acrylate 30-50 parts by weight of carboxyl-modified polyurethane acrylate oligomer, 5-15 parts by weight of silicone-modified epoxy acrylate bifunctional binder 2-5 parts by weight of vinylsilane-modified SiO2 nanoparticles. 0.1-1 parts by weight of triarylthionium hexafluoroantimonate cationic initiator 0.5 to 4 parts by weight of TPO free radical photoinitiator.

2. The coating material according to claim 1, characterized in that, The organosilicon-modified epoxy acrylate bifunctional linker contains acryloyloxy and epoxy groups.

3. A method for preparing a coating material for optical fibers as described in any one of claims 1-2, characterized in that, The method includes the following steps: S110. Tetrahydrofuran acrylate and carboxyl-modified polyurethane acrylate oligomer are mixed to obtain a matrix resin solution. S120. Under nitrogen protection, the matrix resin solution obtained in step S110 is mixed with the organosilicon-modified epoxy acrylate bifunctional binder, then vinyl silane surface-modified SiO2 nanoparticles are added and ultrasonically dispersed, and then mixed with triarylthionium hexafluoroantimonate cationic initiator and TPO free radical photoinitiator to obtain the coating material.

4. The method for preparing the coating material according to claim 3, characterized in that, In step S110, tetrahydrofuran acrylate and carboxyl-modified polyurethane acrylate oligomers are mixed under constant temperature of 50-70°C and stirring conditions of 400-600 r / min.

5. The method for preparing the coating material according to claim 3, characterized in that, In step S120, the mixture is prepared by mixing the triarylthionium hexafluoroantimonate cationic initiator and the TPO free radical photoinitiator under light-protected conditions and stirring at a speed of 150-250 r / min.

6. A method for preparing an optical fiber insulator, characterized in that, The method includes the following steps: S210. Apply the coating material as described in any one of claims 1-2 onto the optical fiber; S220. Attach the optical fiber to the surface of the core rod; S230. An sheath and a shed are pressed onto the surface of the core rod using an injection molding process, so that the sheath and the shed are integrally formed on the surface of the core rod to obtain an optical fiber insulator; wherein, the sheath is an alicyclic epoxy resin sheath.

7. The method for preparing an optical fiber insulator according to claim 6, characterized in that, Step S210 includes: Plasma activation treatment is applied to the surface of the optical fiber; The coating material is applied to the surface of an optical fiber by high-speed drawing under nitrogen protection conditions. UV curing is performed under ultraviolet light to form a preliminary coating with residual epoxy active groups.

8. The method for preparing an optical fiber insulator according to claim 7, characterized in that, Step S230 includes: During the injection molding stage of the alicyclic epoxy resin sheath, the curing heat of the sheath is used to simultaneously trigger the ring-opening crosslinking reaction between the residual epoxy active groups and the sheath, thereby achieving covalent bonding between the coating layer and the sheath interface and the integrated molding of the interpenetrating network (IPN) structure.

9. An optical fiber insulator, characterized in that, It is prepared by the method for preparing optical fiber insulators as described in any one of claims 6-8.

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