Lightweight submarine cable insulating material, its preparation method and lightweight submarine cable

Abstract

The application discloses light submarine cable insulating material and a preparation method thereof and light submarine cable, and relates to the technical field of submarine cables; the light submarine cable insulating material prepared by the application comprises raw material components in proportion by mass fraction, wherein the raw material components comprise 65.4-65.6 mass parts of modified polypropylene, 13-15 mass parts of modified boron nitride, 19-21 mass parts of a composite flame retardant, and 0.4-0.6 mass parts of an antioxidant; wherein the modified polypropylene is obtained by modifying polypropylene with terminal allyl cyclotriphosphazene; the modified boron nitride is obtained by modifying hydroxylated hexagonal boron nitride with vinyltrimethoxysilane; and the composite flame retardant is obtained by compounding 12.92-14.28 mass parts of ammonium polyphosphate and 6.08-6.72 mass parts of melamine; the insulating material prepared by the application has good flame retardance, heat conductivity and mechanical properties.

Description

Technical Field

[0001] The present invention relates to the technical field of submarine cables, and in particular to an insulating material for a light submarine cable, a preparation method thereof, and a light submarine cable. Background Art

[0002] With the booming global growth of industries like the internet, the Internet of Things, and big data, as well as the in-depth development of marine resources, demand for submarine cables (hereinafter referred to as "submarine cables") continues to grow. At the same time, competition in the industry is becoming increasingly fierce. Therefore, how to reduce costs and increase efficiency while ensuring product quality has become a key challenge for submarine cable manufacturers.

[0003] Currently, traditional submarine cables typically use copper as the conductor material and lead as the outer sheath material. While this design provides good electrical performance, the high density of copper and lead results in a relatively heavy cable. This not only increases the difficulty of production but also poses significant challenges during cable laying and transportation. As marine development continues to expand into deeper and more distant waters, the advantages of traditional heavy submarine cables are gradually diminishing.

[0004] Furthermore, when considering using lower-cost aluminum as an alternative conductor material, since aluminum has lower conductivity than copper, the diameter of the aluminum conductor must be increased to achieve the same current-carrying capacity. This not only increases material usage but also increases the overall diameter of the submarine cable, leading to higher production and installation costs.

[0005] To address these issues, researchers have discovered that modifying polypropylene insulation can effectively improve its thermal conductivity, thereby reducing material costs and weight while maintaining the cable's current carrying capacity, thereby achieving the goal of cost reduction and efficiency improvement. Therefore, the present application provides an insulation material for lightweight submarine cables, a preparation method thereof, and a lightweight submarine cable. Summary of the Invention

[0006] The object of the present invention is to provide an insulating material for a light submarine cable, a preparation method thereof, and a light submarine cable, so as to solve the technical problems mentioned in the above background technology.

[0007] The technical solution for achieving the purpose of the present invention is:

[0008] An insulating material for a light submarine cable comprises, by weight, 65.4 to 65.6 parts by weight of modified polypropylene, 13 to 15 parts by weight of modified boron nitride, 19 to 21 parts by weight of a composite flame retardant, and 0.4 to 0.6 parts by weight of an antioxidant.

[0009] Furthermore, the modified polypropylene is obtained by modifying polypropylene with terminal allyl cyclotriphosphazene; wherein the terminal allyl cyclotriphosphazene is obtained by reacting hexachlorocyclotriphosphazene with 2-allylphenol.

[0010] Among them, the reaction mechanism of hexachlorocyclotriphosphazene and 2-allylphenol is as follows:

[0011]

[0012] Furthermore, the modified boron nitride is obtained by modifying hydroxylated hexagonal boron nitride with vinyltrimethoxysilane.

[0013] Furthermore, the composite flame retardant is obtained by compounding 12.92-14.28 parts by mass of ammonium polyphosphate and 6.08-6.72 parts by mass of melamine.

[0014] The present invention also provides a method for preparing an insulating material for a lightweight submarine cable, comprising the following preparation steps:

[0015] (1) Ingredients: weigh the raw materials and their weight proportions as described above;

[0016] (2) Preparation of insulating material: The raw material components weighed in step (1) are added to a high-speed mixer and fully mixed for 9 to 11 minutes, followed by extrusion and granulation to obtain insulating material.

[0017] Furthermore, the preparation method of the modified polypropylene is as follows: the polypropylene resin is placed in an 80° C. forced air drying oven and dried for 2 hours. After drying, 100 parts by mass of the polypropylene resin, 0.2 parts by mass of the cross-linking agent di-tert-butyl peroxyisopropylbenzene, 0.3 parts by mass of sulfur, and 1 part by mass of terminal allyl cyclotriphosphazene are accurately weighed and mixed evenly, and then extruded through a twin-screw extruder and granulated by water-cooling to obtain the modified polypropylene.

[0018] Furthermore, the preparation method of the modified boron nitride is as follows: 1 part by mass of hydroxylated hexagonal boron nitride is added to 200 parts by mass of xylene solution and mixed evenly, vinyltrimethoxysilane is slowly added at 90°C, stirred, and refluxed for 11 to 13 hours to complete the reaction, and after the reaction is completed, the mixture is cooled to room temperature, followed by vacuum filtration, and the filter residue is rinsed with ethanol multiple times to remove xylene and unreacted vinyltrimethoxysilane to obtain modified boron nitride.

[0019] The present invention also provides a light submarine cable, comprising a cable core, an inner sheath layer arranged on the outside of the cable core, an outer sheath layer arranged on the outside of the inner sheath layer, and a composite armor layer arranged between the inner sheath layer and the outer sheath layer; the cable core comprises an electrical unit, an optical unit, and a fan-shaped filling strip; a plurality of electrical units are provided, and the plurality of electrical units are distributed in a ring array around the axis of the submarine cable, and two adjacent electrical units are closely adjacent to each other; a fan-shaped filling strip is provided between each two adjacent electrical units and the inner sheath layer, a plurality of fan-shaped filling strips are provided, and an optical unit is provided in each fan-shaped filling strip; the electrical unit comprises, from the inside to the outside, a conductor, a conductor shielding layer, an insulating layer, an insulating shielding layer, a first water-blocking tape layer, a composite shielding layer, and a second water-blocking tape layer; the insulating layer is made by extruding the insulating material for the light submarine cable onto the outside of the conductor shielding layer.

[0020] Furthermore, the composite shielding layer includes a copper wire layer woven on the outside of the first water-blocking tape layer, a copper tape shielding layer wrapped around the outside of the copper wire layer, and a lead-plastic composite tape longitudinally wrapped around the outside of the copper tape shielding layer.

[0021] Furthermore, the composite armor layer includes non-magnetic copper wires, PE filling strips, and reinforced non-magnetic steel wires arranged circumferentially on the outer wall of the inner sheath layer, and the non-magnetic copper wires, PE filling strips, and reinforced non-magnetic steel wires are closely adjacent to each other.

[0022] By adopting the above technical solution, the present invention has the following beneficial effects:

[0023] (1) Boron nitride (BN) is an inorganic non-metallic material with excellent properties. Its main advantages include high thermal conductivity, good electrical insulation performance, good chemical stability and high temperature resistance. Adding boron nitride to the polypropylene insulation material in this application can effectively improve the thermal conductivity and heat resistance of the insulation material for light submarine cables, thereby increasing the current carrying capacity of the light submarine cables.

[0024] (2) The modified polypropylene of the present invention is obtained by modifying polypropylene with terminal allyl cyclotriphosphazene; terminal allyl cyclotriphosphazene is grafted onto polypropylene through unsaturated bonds to form a hyperbranched polypropylene. The polypropylene with this structure forms more voids and open spaces inside the insulating material for light submarine cables. These voids reduce the density of the material, thereby reducing the mass of the material under the same volume, thereby achieving a light-weight effect for the submarine cable; at the same time, by providing multi-path energy dispersion and stress distribution, the impact resistance and toughness of the insulating material for light submarine cables are enhanced. At the same time, the branch points in the hyperbranched polypropylene increase the intermolecular interaction force, which acts like an "anchor" to prevent crack expansion, thereby improving the tensile strength and modulus of the insulating material for light submarine cables.

[0025] (3) Hexagonal boron nitride (h-BN) can be used in insulating materials for light submarine cables to improve their thermal conductivity due to its excellent thermal conductivity and electrical insulation properties. However, unmodified h-BN is poorly dispersed in the polymer matrix, which limits its performance. The present invention uses vinyltrimethoxysilane to modify hydroxylated hexagonal boron nitride, which can promote the dispersion of hexagonal boron nitride in the insulating material, enhance the interfacial interaction between hexagonal boron nitride and the polypropylene matrix, and improve the tensile strength of the material through the "bridging" effect, thereby significantly improving the comprehensive performance of the submarine cable insulation material.

[0026] (4) Hexaphenoxycyclotriphosphazene in terminal allylcyclotriphosphazene can catalyze the formation of additional carbon residues during the thermal decomposition of submarine cable insulation materials. These carbon residues act as physical barriers to prevent the further release of volatile substances such as CH and C=C. Modified boron nitride improves its compatibility with the polypropylene base material and synergizes with terminal allylcyclotriphosphazene to promote the formation of a more compact nanostructured carbon layer. This dense carbon layer not only reduces the release of pyrolysis substances, achieving the effect of gas phase flame retardancy and smoke suppression, but also hinders the contact between oxygen and the matrix, protects the matrix, and inhibits the release of toxic smoke particles, thereby reducing the risk of fire.

[0027] (5) The present invention changes the traditional lead sheath into a copper wire and copper tape shield supplemented by a lead-plastic composite tape longitudinal wrapping design. While ensuring the short-circuit capacity of the submarine cable, it greatly reduces the weight and outer diameter of the submarine cable, thereby saving costs. Compared with the traditional extruded lead sheath, this new design not only simplifies the production process and reduces the production cost, but also further shortens the production cycle by adopting a linkage production method of lead-plastic composite tape and semi-conductive PE sheath.

[0028] (6) The composite armor layer of the present invention adopts non-magnetic copper wire, PE filling strip and reinforced non-magnetic steel wire arranged at intervals, which not only reduces the eddy current loss of the armor layer, but also reduces the weight of the armor layer itself; under the same current conditions, the temperature of the copper wire armor is lower than that of the steel wire armor, and the electromagnetic loss is reduced, thereby reducing the weight of the cable while increasing its current carrying capacity; adopting this structure not only reduces the cost and weight of the submarine cable, but also improves the transmission capacity of the submarine cable to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments and in conjunction with the accompanying drawings, wherein

[0030] Figure 1 It is a schematic structural diagram of the light submarine cable of the present invention.

[0031] The labels in the drawings are as follows: cable core 1, electrical unit 1-1, conductor 1-1-1, conductor shielding layer 1-1-2, insulation layer 1-1-3, insulation shielding layer 1-1-4, first water-blocking tape layer 1-1-5, composite shielding layer 1-1-6, copper wire layer 1-1-6-1, copper tape shielding layer 1-1-6-2, lead plastic composite tape 1-1-6-3, second water-blocking tape layer 1-1-7, optical unit 1-2, fan-shaped filler strip 1-3, inner sheath layer 2, composite armor layer 3, non-magnetic copper wire 3-1, PE filler strip 3-2, reinforced non-magnetic steel wire 3-3, outer sheath layer 4. DETAILED DESCRIPTION

[0032] In order to better understand the above technical solutions, the above technical solutions will be described in detail below in combination with the drawings of the specification and specific embodiments.

[0033] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0034] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor are within the scope of protection of the present application.

[0035] It should be noted that: similar labels and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0036] In the description of the embodiments of the present application, it should be understood that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly placed when the product of the present application is used, or the orientation or positional relationship commonly understood by those skilled in the art, and are only for the convenience of describing the present application and simplifying the description, and are not intended to indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0037] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise clearly specified and limited, the terms "setting", "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be internal communication between two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The present invention is further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are not intended to limit the scope of protection of the present invention.

[0038] (Lightweight submarine cable example)

[0039] See Figure 1 A lightweight submarine cable includes a cable core 1, an inner sheath layer 2 arranged outside the cable core 1, an outer sheath layer 4 arranged outside the inner sheath layer 2, and a composite armor layer 3 arranged between the inner sheath layer 2 and the outer sheath layer 4.

[0040] The cable core 1 includes an electrical unit 1-1, an optical unit 1-2, and a fan-shaped filling strip 1-3; there are multiple electrical units 1-1, and the multiple electrical units 1-1 are distributed in a ring array around the axis of the submarine cable, and two adjacent electrical units 1-1 are closely adjacent to each other; there is a fan-shaped filling strip 1-3 between each two adjacent electrical units 1-1 and the inner sheath layer 2, there are multiple fan-shaped filling strips 1-3, and each fan-shaped filling strip is equipped with an optical unit 1-2.

[0041] The electrical unit 1-1 includes, from the inside to the outside, a conductor 1-1-1, a conductor shielding layer 1-1-2, an insulating layer 1-1-3, an insulating shielding layer 1-1-4, a first water-blocking tape layer 1-1-5, a composite shielding layer 1-1-6, and a second water-blocking tape layer 1-1-7; the composite shielding layer includes a copper wire layer 1-1-6-1 woven on the outside of the first water-blocking tape layer, a copper tape shielding layer 1-1-6-2 wrapped around the outside of the copper wire layer, and a lead-plastic composite tape 1-1-6-3 longitudinally wrapped around the outside of the copper tape shielding layer; copper wire is added after the insulating shielding and the copper tape shielding is wrapped to increase the short-circuit capacity, and a semi-conductive water-blocking tape is wrapped after the shielding to further improve the water-blocking performance; the lead-plastic composite tape is made of lead tape as the base material and double-sided laminated plastic film, the lead tape thickness is 0.05mm, and commonly used plastic films include polyethylene, semi-conductive polyethylene or ethylene-acrylic acid copolymer, etc., with a thickness of 0.05~0.1 mm; the lead-plastic composite tape is more corrosion-resistant and bending-resistant than the lead-plastic composite tape, and is used for longitudinal wrapping to make bonding sheath; the lead-plastic composite tape passes through the tape unwinding device, the horn mold forming device of different sizes, and the sizing die, and is then rounded and wrapped on the cable surface. The film on the surface of the longitudinal wrap joint of the lead-plastic composite tape is melted with a high-temperature blow gun, and then passed through the mold to make it tightly bonded together.

[0042] The composite armor layer 3 includes non-magnetic copper wires, PE filling strips, and reinforced non-magnetic steel wires arranged circumferentially on the outer wall of the inner sheath layer 2, and the non-magnetic copper wires, PE filling strips, and reinforced non-magnetic steel wires are close together in pairs; wherein, the twisting pitch is 10~13 (D+d), D is the outer diameter of the cable after lining, and d is the diameter of the copper wire, steel wire, and filling strip; the total number of roots is π(D+d) / d / k rounded to the nearest integer; k is the twisting coefficient of the copper wire, steel wire, and filling strip, which is 1.08; the reinforced non-magnetic steel wire adopts Bekaert's non-magnetic armor steel wire with a tensile strength of 1450 or 1650 MPa; the non-magnetic armor steel wire is non-magnetic steel with a corrosion-resistant coating. The non-magnetic steel has a low magnetic permeability, which can reduce the energy loss in the armor layer caused by the cable magnetic field. The corrosion-resistant coating on the non-magnetic steel provides excellent corrosion resistance, which can avoid the occurrence of pitting corrosion and crevice corrosion, and is suitable for use in marine environments.

[0043] Example of insulation material for light submarine cable

[0044] Hexagonal boron nitride powder (h-BN, purity ≥99.9%, average particle size: 50~100 nm).

[0045] The preparation steps of terminal allyl cyclotriphosphazene are as follows: 17.4 parts by mass of hexachlorocyclotriphosphazene and 82.8 parts by mass of anhydrous potassium carbonate are added to 156 parts by mass of acetone and mixed uniformly; then, 78 parts by mass of an acetone solution containing 40.2 parts by mass of 2-allylphenol is added dropwise at 30°C; after completion of the addition, the mixture is heated and refluxed for 11 hours; the reaction is completed after HPLC detection; the mixture is cooled and filtered; the filtrate is distilled to recover the solvent; the filter residue is then dissolved in 300 parts by mass of toluene, washed with 5% sodium hydroxide solution, 2% hydrochloric acid solution and distilled water in sequence until neutral, dried over anhydrous sodium sulfate, filtered, and desolvated to obtain terminal allyl cyclotriphosphazene.

[0046] The preparation method of modified boron nitride is as follows: hexagonal boron nitride powder is mixed with 30% hydrogen peroxide solution at a ratio of 0.1 g / mL and stirred at a speed of 600 r / min for 24 hours, and then the mixture is placed in a reactor and maintained at a temperature of 100°C for 24 hours; after the reactor is cooled to room temperature, the mixture is taken out and centrifuged and washed three times with deionized water, and then ultrasonicated for 2 hours using an ultrasonic cleaner, and finally vacuum dried at 50°C to obtain hydroxylated hexagonal boron nitride. Example

[0047] A method for preparing an insulating material for a lightweight submarine cable comprises the following steps:

[0048] (1) Ingredients: Weigh and prepare the following raw materials according to their corresponding weight parts: 65.6 parts by mass of modified polypropylene, 15 parts by mass of modified boron nitride, 12.92 parts by mass of ammonium polyphosphate, 6.08 parts by mass of melamine, and 0.4 parts by mass of antioxidant 1010;

[0049] (2) The raw material components weighed in step (1) are added to a high-speed mixer and fully mixed for 9 to 11 minutes, and then put into a twin-screw extruder for extrusion granulation to obtain an insulating material; wherein, the screw barrel temperature of the twin-screw extruder according to the forward direction of the material is: 80, 100, 130, 170, 180, 180, 190, 190, 190, 190°C; the main engine speed is 80 r / min, and the feeding speed is 8 r / min.

[0050] The modified polypropylene is prepared as follows: pre-drying a polypropylene resin in an 80° C. forced air drying oven for 2 hours; after drying, accurately weighing 100 parts by mass of the polypropylene resin, 0.2 parts by mass of a cross-linking agent, di-tert-butyl peroxyisopropylbenzene, 0.3 parts by mass of sulfur, and 1 part by mass of terminal allyl cyclotriphosphazene, and uniformly mixing the mixture; then extruding the mixture through a twin-screw extruder and pelletizing the mixture through water-cooling to obtain the modified polypropylene; wherein the screw barrel temperatures of the twin-screw extruder according to the material forward direction are: 80, 100, 130, 170, 180, 180, 180, 190, 190, 190, 190° C.; the main engine speed is 80 r / min, and the feeding rate is 8 r / min.

[0051] The modified boron nitride is prepared as follows: 1 part by mass of hydroxylated hexagonal boron nitride is added to 200 parts by mass of a xylene solution and mixed evenly; vinyltrimethoxysilane is slowly added at 90° C., stirred, and refluxed for 11 to 13 hours to complete the reaction; after the reaction is completed, the solution is cooled to room temperature, followed by vacuum filtration; and the filter residue is rinsed multiple times with ethanol to remove xylene and unreacted vinyltrimethoxysilane to obtain the modified boron nitride. Example

[0052] A method for preparing an insulating material for a lightweight submarine cable comprises the following steps:

[0053] (1) Ingredients: Weigh and prepare the following raw materials according to their corresponding weight parts: 65.5 parts by mass of modified polypropylene, 15 parts by mass of modified boron nitride, 12.6 parts by mass of ammonium polyphosphate, 6.4 parts by mass of melamine, and 0.5 parts by mass of antioxidant 1010;

[0054] (2) The raw material components weighed in step (1) are added to a high-speed mixer and fully mixed for 9 to 11 minutes, and then put into a twin-screw extruder for extrusion granulation to obtain an insulating material; wherein, the screw barrel temperature of the twin-screw extruder according to the forward direction of the material is: 80, 100, 130, 170, 180, 180, 190, 190, 190, 190°C; the main engine speed is 80 r / min, and the feeding speed is 8 r / min.

[0055] The modified polypropylene is prepared as follows: pre-drying a polypropylene resin in an 80° C. forced air drying oven for 2 hours; after drying, accurately weighing 100 parts by mass of the polypropylene resin, 0.2 parts by mass of a cross-linking agent, di-tert-butyl peroxyisopropylbenzene, 0.3 parts by mass of sulfur, and 1 part by mass of terminal allyl cyclotriphosphazene, and uniformly mixing the mixture; then extruding the mixture through a twin-screw extruder and pelletizing the mixture through water-cooling to obtain the modified polypropylene; wherein the screw barrel temperatures of the twin-screw extruder according to the material forward direction are: 80, 100, 130, 170, 180, 180, 180, 190, 190, 190, 190° C.; the main engine speed is 80 r / min, and the feeding rate is 8 r / min.

[0056] The modified boron nitride is prepared as follows: 1 part by mass of hydroxylated hexagonal boron nitride is added to 200 parts by mass of a xylene solution and mixed evenly; vinyltrimethoxysilane is slowly added at 90° C., stirred, and refluxed for 11 to 13 hours to complete the reaction; after the reaction is completed, the solution is cooled to room temperature, followed by vacuum filtration; and the filter residue is rinsed multiple times with ethanol to remove xylene and unreacted vinyltrimethoxysilane to obtain the modified boron nitride. Example

[0057] A method for preparing an insulating material for a lightweight submarine cable comprises the following steps:

[0058] (1) Ingredients: Weigh and prepare the following raw materials according to their corresponding weight parts: 65.6 parts by mass of modified polypropylene, 13 parts by mass of modified boron nitride, 14.28 parts by mass of ammonium polyphosphate, 6.72 parts by mass of melamine, and 0.4 parts by mass of antioxidant 1010;

[0059] (2) The raw material components weighed in step (1) are added to a high-speed mixer and fully mixed for 9 to 11 minutes, and then put into a twin-screw extruder for extrusion granulation to obtain an insulating material; wherein, the screw barrel temperature of the twin-screw extruder according to the forward direction of the material is: 80, 100, 130, 170, 180, 180, 190, 190, 190, 190°C; the main engine speed is 80 r / min, and the feeding speed is 8 r / min.

[0060] The modified polypropylene is prepared as follows: pre-drying a polypropylene resin in an 80° C. forced air drying oven for 2 hours; after drying, accurately weighing 100 parts by mass of the polypropylene resin, 0.2 parts by mass of a cross-linking agent, di-tert-butyl peroxyisopropylbenzene, 0.3 parts by mass of sulfur, and 1 part by mass of terminal allyl cyclotriphosphazene, and uniformly mixing the mixture; then extruding the mixture through a twin-screw extruder and pelletizing the mixture through water-cooling to obtain the modified polypropylene; wherein the screw barrel temperatures of the twin-screw extruder according to the material forward direction are: 80, 100, 130, 170, 180, 180, 180, 190, 190, 190, 190° C.; the main engine speed is 80 r / min, and the feeding rate is 8 r / min.

[0061] The modified boron nitride is prepared as follows: 1 part by mass of hydroxylated hexagonal boron nitride is added to 200 parts by mass of a xylene solution and mixed evenly; vinyltrimethoxysilane is slowly added at 90° C., stirred, and refluxed for 11 to 13 hours to complete the reaction; after the reaction is completed, the solution is cooled to room temperature, followed by vacuum filtration; and the filter residue is rinsed multiple times with ethanol to remove xylene and unreacted vinyltrimethoxysilane to obtain the modified boron nitride.

[0062] Comparative Example 1

[0063] The only difference between Comparative Example 1 and Example 2 is that the raw material components of the insulating material for light submarine cables only use modified polypropylene, boron nitride, ammonium polyphosphate, melamine, and antioxidant 1010, and the remaining steps are the same as Example 2.

[0064] Comparative Example 2

[0065] The only difference between Comparative Example 2 and Example 2 is that the raw material components of the insulating material for light submarine cables only use polypropylene, modified boron nitride, ammonium polyphosphate, melamine, and antioxidant 1010, and the remaining steps are the same as in Example 2.

[0066] Effect Examples

[0067] Table 1 below shows the performance of the insulating materials for lightweight submarine cables prepared in Examples 1 to 3 and Comparative Examples 1 to 2:

[0068]

[0069] From the comparison of the performance data in the above table, it can be seen that the insulating materials for lightweight submarine cables prepared in Examples 1 to 3 have strong flame retardancy and impact resistance.

[0070] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A lightweight submarine cable insulation material, characterized in that: The raw material components include, by weight, 65.4 to 65.6 parts by weight of modified polypropylene, 13 to 15 parts by weight of modified boron nitride, 19 to 21 parts by weight of a composite flame retardant, and 0.4 to 0.6 parts by weight of an antioxidant; the modified polypropylene is obtained by modifying polypropylene with terminal allyl cyclotriphosphazene; wherein the terminal allyl cyclotriphosphazene is obtained by reacting hexachlorocyclotriphosphazene and 2-allylphenol; and the modified boron nitride is obtained by modifying hydroxylated hexagonal boron nitride with vinyltrimethoxysilane.

2. The insulating material for light submarine cable according to claim 1, characterized in that: The composite flame retardant is obtained by compounding 12.92-14.28 parts by mass of ammonium polyphosphate and 6.08-6.72 parts by mass of melamine.

3. A method for preparing the insulating material for a lightweight submarine cable according to any one of items 1 to 2, characterized in that: The method comprises the following preparation steps: (1) Ingredients: weigh the raw material components and the weight proportions of the raw material components according to any one of claims 1 to 2; (2) Preparation of insulating material: The raw material components weighed in step (1) are added to a high-speed mixer and fully mixed for 9 to 11 minutes, followed by extrusion and granulation to obtain insulating material.

4. The method for preparing the insulating material for light submarine cables according to claim 3, characterized in that: The modified polypropylene is prepared as follows: polypropylene resin is placed in a forced air drying oven at 80° C. and dried for 2 hours. After drying, 100 parts by mass of polypropylene resin, 0.2 parts by mass of a cross-linking agent, di-tert-butyl peroxyisopropylbenzene, 0.3 parts by mass of sulfur, and 1 part by mass of terminal allyl cyclotriphosphazene are accurately weighed and uniformly mixed. The mixture is then extruded through a twin-screw extruder and then pelletized through water-cooling to obtain the modified polypropylene.

5. The method for preparing the insulating material for light submarine cable according to claim 3, characterized in that: The modified boron nitride is prepared as follows: 1 part by mass of hydroxylated hexagonal boron nitride is added to 200 parts by mass of a xylene solution and mixed evenly; vinyltrimethoxysilane is slowly added at 90° C., stirred, and refluxed for 11 to 13 hours to complete the reaction; after the reaction is completed, the solution is cooled to room temperature, followed by vacuum filtration; and the filter residue is rinsed multiple times with ethanol to remove xylene and unreacted vinyltrimethoxysilane to obtain the modified boron nitride.

6. A light submarine cable, characterized in that: The invention comprises a cable core (1), an inner sheath layer (2) arranged outside the cable core (1), an outer sheath layer (4) arranged outside the inner sheath layer (2), and a composite armor layer (3) arranged between the inner sheath layer (2) and the outer sheath layer (4); the cable core (1) comprises an electrical unit (1-1), an optical unit (1-2), and a fan-shaped filling strip (1-3); a plurality of electrical units (1-1) are provided, and the plurality of electrical units (1-1) are distributed in a ring array around the axis of the submarine cable, and two adjacent electrical units (1-1) are closely adjacent; a fan-shaped filling strip ( 1-3), a plurality of fan-shaped filling strips (1-3) are provided, and an optical unit (1-2) is provided in each fan-shaped filling strip (1-3); the electrical unit (1-1) comprises, from the inside to the outside, a conductor (1-1-1), a conductor shielding layer (1-1-2), an insulating layer (1-1-3), an insulating shielding layer (1-1-4), a first water-blocking tape layer (1-1-5), a composite shielding layer (1-1-6), and a second water-blocking tape layer (1-1-7); the insulating layer (1-1-3) is made by extruding the insulating material for a light submarine cable according to any one of claims 1 to 2 on the outside of the conductor shielding layer (1-1-2).

7. The light submarine cable according to claim 6, characterized in that: The composite shielding layer comprises a copper wire layer (1-1-6-1) woven on the outside of a first water-blocking tape layer, a copper tape shielding layer (1-1-6-2) wrapped around the outside of the copper wire layer, and a lead-plastic composite tape (1-1-6-3) longitudinally wrapped around the outside of the copper tape shielding layer.

8. The light submarine cable according to claim 6, characterized in that: The composite armor layer (3) comprises non-magnetic copper wires, PE filling strips, and reinforced non-magnetic steel wires arranged circumferentially on the outer wall of the inner sheath layer (2), wherein the non-magnetic copper wires, PE filling strips, and reinforced non-magnetic steel wires are closely adjacent to each other.

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