Insulating material for light submarine cable, preparation method of insulating material and light submarine cable

Abstract

The invention discloses an insulating material for a light submarine cable, a preparation method of the insulating material and the light submarine cable, and relates to the technical field of submarine cables. The insulation material for the light submarine cable prepared by the invention is prepared from the following raw material components in parts by weight: 65.4 to 65.6 parts by mass of modified polypropylene, 13 to 15 parts by mass of modified boron nitride, 19 to 21 parts by mass of a composite flame retardant and 0.4 to 0.6 part by mass of an antioxidant, wherein the modified polypropylene is obtained by modifying polypropylene with allyl-terminated cyclotriphosphazene; the modified boron nitride is obtained by modifying hydroxylated hexagonal boron nitride with vinyl trimethoxy silane; the composite flame retardant is prepared by compounding 12.92 to 14.28 parts by mass of ammonium polyphosphate and 6.08 to 6.72 parts by mass of melamine; the insulating material prepared by the invention is relatively good in flame retardance, thermal conductivity and mechanical property.

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 and a preparation method thereof, and a light submarine cable. Background Art

[0002] With the vigorous development of the global Internet, Internet of Things, big data and other industries, as well as the in-depth development of marine resources, the demand for submarine cables (hereinafter referred to as "submarine cables") has shown a continuous growth trend. At the same time, the competition in the industry has become increasingly fierce. Therefore, how to reduce costs and increase efficiency while ensuring product quality has become an important issue facing submarine cable manufacturers.

[0003] At present, traditional submarine cables usually use copper as the conductor material and lead as the outer sheath material. Although this design can provide good electrical performance, the high density of copper and lead leads to a large overall weight of the submarine cable, which not only increases the difficulty of the production process, but also brings great challenges in the laying and transportation of submarine cables. In particular, as marine development activities continue to advance to deeper and farther waters, the application advantages of traditional heavy submarine cables are gradually weakening.

[0004] In addition, when considering the use of lower-cost aluminum as an alternative conductor material, since the conductivity of aluminum is lower than that of copper, in order to achieve the same current carrying capacity, the diameter of the aluminum conductor must be increased. This not only increases the amount of material used, but also increases the overall diameter of the submarine cable, which in turn leads to an increase in production and laying costs.

[0005] In order to solve the above problems, technicians have found that by modifying polypropylene insulation materials, their thermal conductivity can be effectively improved, thereby reducing the cost of materials and the weight of submarine cables while ensuring the current carrying capacity of submarine cables, thereby achieving the goal of reducing costs and increasing efficiency. Therefore, the present application provides an insulation material for a light submarine cable, a preparation method thereof, and a light submarine cable. Summary of the invention

[0006] The purpose of the present invention is to provide an insulating material for a light submarine cable and 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 prepared by compounding 12.92 to 14.28 parts by mass of ammonium polyphosphate and 6.08 to 6.72 parts by mass of melamine.

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

[0015] (1) Ingredients: weigh the aforementioned raw material components and their weight proportions;

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

[0017] Furthermore, the preparation method of the modified polypropylene is as follows: pre-dry the polypropylene resin in an 80° C. forced air drying oven for 2 hours. After drying, accurately weigh 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 and mix them evenly, then extrude them through a twin-screw extruder and granulate them through 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 reaction is cooled to room temperature, followed by vacuum filtration, and the filter residue is rinsed with ethanol for 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; a fan-shaped filling is provided between every two adjacent electrical units and the inner sheath layer, and a plurality of fan-shaped fillings are provided in each fan-shaped filling, and an optical unit is provided in each fan-shaped filling; 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 in sequence; the insulating layer is made by extruding the insulating material for the light submarine cable outside 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 connected in pairs.

[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 the present 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 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 making the submarine cable light in weight; 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, preventing crack expansion like an "anchor", 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 insulating material.

[0026] (4) Hexaphenoxy cyclotriphosphazene in terminal allyl cyclotriphosphazene 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 the compatibility with polypropylene base materials and synergizes with terminal allyl cyclotriphosphazene 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 shielding supplemented by a lead-plastic composite tape longitudinal wrapping design, which greatly reduces the weight and outer diameter of the submarine cable while ensuring the short-circuit capacity 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 the lead-plastic composite tape and the 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 according to 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 numbers in the accompanying drawings are: cable core 1, electrical unit 1-1, conductor 1-1-1, conductor shielding layer 1-1-2, insulating layer 1-1-3, insulating 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 filling strip 1-3, inner sheath layer 2, composite armor layer 3, non-magnetic copper wire 3-1, PE filling 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 solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0033] 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 in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0034] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0036] In the description of the embodiments of the present invention, it should be understood that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is conventionally placed when used, or are the orientations or positional relationships conventionally understood by those skilled in the art. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0037] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "installed", "connected" and "connected" 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 the internal connection of 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 in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the scope of protection of the present invention.

[0038] (Lightweight submarine cable embodiment)

[0039] See Figure 1 A light submarine cable 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.

[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 1-3 between every two adjacent electrical units 1-1 and the inner sheath layer 2, and each fan-shaped filling 1-3 is provided with multiple, and each fan-shaped filling is provided 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; adding copper wire after the insulating shielding and wrapping the copper tape shielding to increase the short-circuit capacity, and wrapping the semi-circuit shielding layer after the shielding Conductive waterproof tape further improves 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 thickness of the lead tape is 0.05mm. Commonly used plastic films include polyethylene, semi-conductive polyethylene or ethylene-acrylic acid copolymer, etc., with a thickness of 0.05-0.1mm; 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 sheaths; the lead-plastic composite tape is passed through a tape unwinding device, a horn mold forming device of different sizes, and a sizing mold, and then is 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 a 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 to 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; 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 a non-magnetic steel with a corrosion-resistant coating, and the magnetic permeability of the non-magnetic steel is low, which can reduce the energy loss in the armor layer caused by the cable magnetic field, and the corrosion-resistant coating on the non-magnetic steel provides excellent corrosion resistance, which can avoid the occurrence of pitting and crevice corrosion, and is suitable for use in marine environments.

[0043] Embodiment of insulating material for light submarine cable

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

[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, and then 78 parts by mass of acetone solution containing 40.2 parts by mass of 2-allylphenol is added dropwise at 30°C. After the addition is completed, the temperature is raised and refluxed for reaction for 11 hours. The reaction is completed when HPLC is detected. After cooling, the mixture is filtered, and the filtrate is distilled to recover the solvent. Then, 300 parts by mass of toluene are added to the filter residue to dissolve it, and the residue is washed with 5% sodium hydroxide solution, 2% hydrochloric acid solution and distilled water in sequence until it is neutral, dried with anhydrous sodium sulfate, filtered, and the solvent is removed 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 cleaning machine, and finally vacuum dried at 50°C to obtain hydroxylated hexagonal boron nitride.

[0047] Example 1

[0048] A method for preparing an insulating material for a light submarine cable comprises the following preparation steps:

[0049] (1) Ingredients: The following raw material components and corresponding weight parts are weighed and prepared: 65.6 parts by weight of modified polypropylene, 15 parts by weight of modified boron nitride, 12.92 parts by weight of ammonium polyphosphate, 6.08 parts by weight of melamine, and 0.4 parts by weight of antioxidant 1010;

[0050] (2) adding the raw material components weighed in step (1) into a high-speed mixer and mixing them thoroughly for 9 to 11 minutes, and then putting them 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.

[0051] The preparation method of the modified polypropylene is as follows: pre-drying a polypropylene resin in an 80° C. forced air drying oven for 2 hours, and 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 mixing them uniformly, and then extruding through a twin-screw extruder and then granulating through water-cooling to obtain the modified polypropylene; wherein the screw barrel temperature of the twin-screw extruder according to the material forward direction is: 80, 100, 130, 170, 180, 180, 180, 190, 190, 190, 190° C.; the main engine speed is 80 r / min, and the feeding speed is 8 r / min.

[0052] 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 room temperature is cooled, and then vacuum filtration is performed, and the filter residue is rinsed with ethanol for multiple times to remove xylene and unreacted vinyltrimethoxysilane to obtain modified boron nitride.

[0053] Example 2

[0054] A method for preparing an insulating material for a light submarine cable comprises the following preparation steps:

[0055] (1) Ingredients: Weigh and prepare the following raw material components and their corresponding weight parts: 65.5 parts by weight of modified polypropylene, 15 parts by weight of modified boron nitride, 12.6 parts by weight of ammonium polyphosphate, 6.4 parts by weight of melamine, and 0.5 parts by weight of antioxidant 1010;

[0056] (2) adding the raw material components weighed in step (1) into a high-speed mixer and mixing them thoroughly for 9 to 11 minutes, and then putting them 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.

[0057] The preparation method of the modified polypropylene is as follows: pre-drying a polypropylene resin in an 80° C. forced air drying oven for 2 hours, and 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 mixing them uniformly, and then extruding through a twin-screw extruder and then granulating through water-cooling to obtain the modified polypropylene; wherein the screw barrel temperature of the twin-screw extruder according to the material forward direction is: 80, 100, 130, 170, 180, 180, 180, 190, 190, 190, 190° C.; the main engine speed is 80 r / min, and the feeding speed is 8 r / min.

[0058] 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 room temperature is cooled, and then vacuum filtration is performed, and the filter residue is rinsed with ethanol for multiple times to remove xylene and unreacted vinyltrimethoxysilane to obtain modified boron nitride.

[0059] Example 3

[0060] A method for preparing an insulating material for a light submarine cable comprises the following preparation steps:

[0061] (1) Ingredients: The following raw material components and corresponding weight parts are weighed and prepared: 65.6 parts by weight of modified polypropylene, 13 parts by weight of modified boron nitride, 14.28 parts by weight of ammonium polyphosphate, 6.72 parts by weight of melamine, and 0.4 parts by weight of antioxidant 1010;

[0062] (2) adding the raw material components weighed in step (1) into a high-speed mixer and mixing them thoroughly for 9 to 11 minutes, and then putting them 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.

[0063] The preparation method of the modified polypropylene is as follows: pre-drying a polypropylene resin in an 80° C. forced air drying oven for 2 hours, and 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 mixing them uniformly, and then extruding through a twin-screw extruder and then granulating through water-cooling to obtain the modified polypropylene; wherein the screw barrel temperature of the twin-screw extruder according to the material forward direction is: 80, 100, 130, 170, 180, 180, 180, 190, 190, 190, 190° C.; the main engine speed is 80 r / min, and the feeding speed is 8 r / min.

[0064] 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 room temperature is cooled, and then vacuum filtration is performed, and the filter residue is rinsed with ethanol for multiple times to remove xylene and unreacted vinyltrimethoxysilane to obtain modified boron nitride.

[0065] Comparative Example 1

[0066] The only difference between Comparative Example 1 and Example 2 is that the raw material components of the insulating material for the light submarine cable only use modified polypropylene, boron nitride, ammonium polyphosphate, melamine, and antioxidant 1010, and the remaining steps are the same as those in Example 2.

[0067] Comparative Example 2

[0068] 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 Example 2.

[0069] Effect example

[0070] Table 1 below shows the performance effects of the insulating materials for light submarine cables obtained in Examples 1 to 3 and Comparative Examples 1 to 2:

[0071]

[0072] Comparison of the performance data in the above table shows that the insulating materials for light submarine cables prepared in Examples 1 to 3 have strong flame retardancy and impact resistance.

[0073] 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 description is only a specific embodiment of the present invention and is 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 protection scope of the present invention.

Claims

1. An insulating material for a light submarine cable, characterized in that: In terms of weight, the raw material components include 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.

2. The insulating material for light submarine cable according to claim 1, characterized in that: The modified polypropylene is obtained by modifying terminal allyl cyclotriphosphazene polypropylene; wherein the terminal allyl cyclotriphosphazene is obtained by reacting hexachlorocyclotriphosphazene with 2-allylphenol.

3. The insulating material for light submarine cable according to claim 1, characterized in that: The modified boron nitride is obtained by modifying and hydroxylating hexagonal boron nitride with vinyltrimethoxysilane.

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

5. A method for preparing the insulating material for a light submarine cable as described in any one of 1 to 4, characterized in that: The method comprises the following preparation steps: (1) Ingredients: weighing the raw material components and the weight proportions of the raw material components according to any one of claims 1 to 4; (2) Preparation of insulating material: The raw material components weighed in step (1) are added to a high-speed mixer and mixed thoroughly for 9 to 11 minutes, followed by extrusion granulation to obtain insulating material.

6. The method for preparing the insulating material for light submarine cable according to claim 5, characterized in that: The preparation method of the modified polypropylene is as follows: pre-drying the polypropylene resin in an 80° C. forced air drying oven for 2 hours, and 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 mixing them uniformly, and then extruding through a twin-screw extruder and then granulating through water-cooling to obtain the modified polypropylene.

7. The method for preparing the insulating material for light submarine cable according to claim 5, characterized in that: 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 room temperature is cooled, and then vacuum filtration is performed, and the filter residue is rinsed with ethanol for multiple times to remove xylene and unreacted vinyltrimethoxysilane to obtain modified boron nitride.

8. 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) is provided between each two adjacent electrical units (1-1) and the inner sheath layer (2). Filling (1-3), each sector-shaped filling (1-3) is provided with a plurality of them, and each sector-shaped filling is provided with an optical unit (1-2); 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 light submarine cables according to any one of claims 1 to 4 on the outside of the conductor shielding layer (1-1-2).

9. The light submarine cable according to claim 8, 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.

10. The light submarine cable according to claim 8, 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 arranged in pairs.

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