A 220KV submarine cable resistant to deep water pressure and its manufacturing method

Abstract

This invention relates to the field of cable technology and discloses a 220KV submarine cable resistant to deep water pressure and its preparation method. The submarine cable is composed of a conductor, an insulation layer, a water-blocking tape, a sheath layer, a waterproof polypropylene tape inner lining layer, an armor layer, and a waterproof polypropylene tape outer sheath layer. This invention involves mixing polypropylene, polypropylene-modified silicone oil, and a lubricant, followed by extrusion, casting, stretching and orientation, and slitting. The resulting waterproof polypropylene tape exhibits good tensile strength, while significantly improving elongation at break and flexibility. The polypropylene-modified silicone oil contains strongly hydrophobic perfluoroalkyl chains and polysiloxane structures, which improves the water contact angle and surface hydrophobicity of the polypropylene tape, enhancing its waterproof performance. As the inner lining and outer sheath layer of the cable, it is beneficial for improving the cable's waterproof and water-resistant performance, and has good practical applications in submarine cables and other fields.

Description

Technical Field

[0001] This invention relates to the field of cable technology, specifically to a 220KV submarine cable resistant to deep water pressure and its manufacturing method. Background Technology

[0002] In recent years, my country's offshore wind power industry has developed rapidly, leading to increasing demand for submarine cables. Facing the complex high-salt, high-pressure seabed environment, higher performance requirements are being placed on cables, making it crucial to improve their waterproof and pressure-resistant properties. Polypropylene, with its high strength, abrasion resistance, and corrosion resistance, is widely used in cable filler ropes, sheathing materials, and insulation layers.

[0003] Traditional polypropylene materials for cables have poor toughness and low hydrophobicity, which is not conducive to improving the flexibility and waterproof performance of cables, thus limiting the practical application of polypropylene in submarine cables. Patent CN118248414B discloses the modification of polypropylene with modified basalt fiber to prepare a high-temperature resistant, flame-retardant, and waterproof layer. Then, a protective coating based on fluorinated organosilicon modified polyurethane is coated on the surface of the waterproof layer. The resulting cable has good high-temperature resistance and waterproof performance, but this patent does not improve the flexibility of polypropylene. Summary of the Invention

[0004] (i) This invention solves the problem of low toughness and waterproof performance of polypropylene materials for cables.

[0005] (II) The technical solution of the present invention is: a 220KV submarine cable resistant to deep water pressure and its preparation method, which includes preparing a submarine cable by means of a conductor, an insulation layer, a water-blocking tape, a lead sheath, a sheath layer, a filling layer, a wrapping tape, an inner lining layer, an armor layer, and an outer sheath layer.

[0006] The inner lining and outer sheath are made of waterproof polypropylene tape, and the preparation method of the waterproof polypropylene tape includes:

[0007] S1. Methacryloxy-2-hydroxypropyl perfluorooctanoate grafted polypropylene is added to N,N-dimethylformamide, heated and stirred, and then hydroxyl silicone oil and dibutyltin dilaurate are added. The mixture is stirred and reacted, cooled and filtered, and washed successively with N,N-dimethylformamide and chloroform, and dried to obtain polypropylene modified silicone oil.

[0008] S2. Polypropylene, polypropylene-modified silicone oil, and lubricant are mixed, extruded and cast into sheets using a screw extruder, stretched and oriented using a multi-roll stretching machine, heat-set, and then twisted. Finally, the sheets are cut into strips using a strip cutter to obtain waterproof polypropylene tape.

[0009] Preferably, the conductor is a copper conductor.

[0010] Preferably, the insulation layer is a cross-linked polyethylene layer.

[0011] Preferably, the sheath layer is a polyethylene sheath layer or a polyvinyl chloride sheath layer.

[0012] Preferably, the filler layer is a polyethylene filler strip.

[0013] Preferably, the strap is made of polypropylene nonwoven fabric.

[0014] Preferably, the armor layer is made of copper wire.

[0015] Preferably, the reaction in S1 is stirred at 145-155℃ for 6-10 hours.

[0016] Preferably, the mass ratio of methacryloyloxy-2-hydroxypropyl perfluorooctanoate grafted polypropylene, hydroxy silicone oil, and dibutyltin dilaurate in S1 is (10-30):100:(0.4-1.5).

[0017] Preferably, the mass ratio of polypropylene, polypropylene-modified silicone oil, and lubricant in S2 is (75-90):(10-25):(0.1-0.2).

[0018] Preferably, the lubricant in S2 is calcium stearate or zinc stearate.

[0019] Preferably, the temperature of each section of the screw extruder is 150-190℃, and the screw speed is 40-100 r / min.

[0020] Preferably, the stretching ratio during stretching orientation is 4-6 times.

[0021] Preferably, the heat setting temperature is 120-140℃ and the heat setting time is 15-20s.

[0022] Preferably, the preparation method of methacryloyloxy-2-hydroxypropyl perfluorooctanoate grafted polypropylene is as follows: polypropylene, methacryloyloxy-2-hydroxypropyl perfluorooctanoate, and dicumyl peroxide are added to xylene to carry out the grafting reaction. After cooling, the mixture is filtered, and the precipitate is added to chloroform. After heating and stirring, the mixture is filtered again, and the precipitate is dried to obtain methacryloyloxy-2-hydroxypropyl perfluorooctanoate grafted polypropylene.

[0023] Preferably, the ratio of polypropylene, methacryloyloxy-2-hydroxypropyl perfluorooctanoate, and dicumyl peroxide is 100g:(50-300)mmol:(0.8-5)mmol.

[0024] Preferably, the grafting reaction is carried out by stirring at 120-135°C for 1-3 hours.

[0025] (III) Beneficial technical effects: Under the action of dicumyl peroxide initiator, the present invention grafts methacryloyloxy-2-hydroxypropyl perfluorooctanoate onto polypropylene to obtain grafted polypropylene containing hydroxyl and perfluoroalkyl chains. Then, using dibutyltin dilaurate as catalyst, the hydroxyl groups of polypropylene and hydroxyl silicone oil undergo a dehydration condensation reaction to obtain polypropylene-modified silicone oil. Finally, it is blended with polypropylene, stretched and oriented, stranded, and cut into strips to obtain waterproof polypropylene tape, which serves as the inner lining and outer sheath of the cable. The silicone oil grafts polypropylene molecular chains, and after blending with polypropylene, its compatibility with the polypropylene matrix is ​​improved, and its impact on the mechanical strength of polypropylene is minimal. Furthermore, its flexible polysiloxane has a better toughening effect, enabling polypropylene to maintain good tensile strength, while significantly improving elongation at break and flexibility.

[0026] The polypropylene modified silicone oil of this invention contains highly hydrophobic perfluoroalkyl chains and polysiloxane structures, which are uniformly dispersed in the polypropylene matrix. This improves the water contact angle and surface hydrophobicity of the polypropylene tape, enhancing its waterproof performance. As an inner lining and outer sheath of a cable, it helps to improve the cable's waterproof and water-resistant performance. The high-strength copper wire armor layer set in the inner lining and outer sheath as a supporting skeleton helps to improve the cable's structural stability and resistance to deep water pressure, and has better practical applications in submarine cables and other fields. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the submarine cable structure.

[0028] Figure 2 This is the infrared spectrum of polypropylene modified silicone oil from Example 1. Detailed Implementation

[0029] To make the content of this invention easier to understand, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention.

[0030] The following polypropylene model is Zhonghai PP HP565S, sourced from Dongguan Jinyuan Rongsheng New Materials Co., Ltd. The hydroxyl silicone oil model is PMX-0156, with the following structural formula: This information originates from Nanjing Hekai Chemical Technology Co., Ltd.

[0031] Methacryloxy-2-hydroxypropyl perfluorooctanoate was prepared according to the method described in the journal article Polymer 54 (2013) 3047-3054, "Fluorinated poly(isobornylmethacrylateecoebutyl acrylate) coreeshell latex nanoparticles: Synthesis, morphology and wettability of films". 24 g of perfluorooctanoic acid, 16 g of glycidyl methacrylate, and 0.12 g of tetrabutylammonium bromide catalyst were added to 30 mL of 1,4-dioxane. The mixture was heated to 100 °C and stirred for 8 h. The reaction solution was washed successively with saturated sodium carbonate solution and water. The organic phase was dried over anhydrous magnesium sulfate. After filtration, the filtrate was distilled under reduced pressure, and the fraction collected at 70 °C under 9 mmHg pressure yielded methacryloxy-2-hydroxypropyl perfluorooctanoate, with the structural formula [insert structural formula here]. .

[0032] Example 1: A 220KV submarine cable resistant to deep water pressure, comprising a copper conductor, a cross-linked polyethylene insulation layer, a water-blocking tape, a lead sheath, a polyethylene sheath layer, a polyethylene filler strip, a polypropylene non-woven fabric, a waterproof polypropylene tape inner lining layer, a copper wire armor layer, and a waterproof polypropylene tape outer sheath layer.

[0033] The preparation method of waterproof polypropylene tape is as follows:

[0034] (1) Add 5g of polypropylene to 60mL of xylene, heat to 125℃, stir, add 2.5mmol of methacryloyloxy-2-hydroxypropyl perfluorooctanoate and 0.04mmol of dicumyl peroxide, stir and reflux for 1h, cool and filter, add the precipitate to chloroform, heat to 60℃, stir and filter, dry the precipitate to obtain methacryloyloxy-2-hydroxypropyl perfluorooctanoate grafted polypropylene.

[0035] (2) Add 2g of methacryloyloxy-2-hydroxypropyl perfluorooctanoate grafted polypropylene to 30mL of N,N-dimethylformamide, heat to 150℃, stir, add 20g of hydroxyl silicone oil and 0.08g of dibutyltin dilaurate, stir and reflux for 7h, filter after cooling, wash with N,N-dimethylformamide and chloroform in sequence, dry to obtain polypropylene modified silicone oil. Figure 2 The infrared spectrum shows 2934-2867 cm⁻¹ -1 The absorption peak of the polypropylene alkane backbone is at 1727 cm⁻¹. -1 It is the absorption peak of C=O in the ester group, 1201 cm⁻¹. -1 The absorption peak is for the CF bond, 1176-1152 cm⁻¹. -1It is the absorption peak of Si-O-Si in silicone oil, at 1245 cm⁻¹. -1 It is the deformation vibration peak of the methyl group in Si-CH3 in silicone oil.

[0036] (3) Mix 900g polypropylene, 100g polypropylene modified silicone oil and 2g calcium stearate, and extrude them through a screw extruder. The temperatures of each section are 150℃, 175℃, 190℃, 190℃ and 180℃, and the screw speed is 40r / min to obtain polypropylene granules. After casting, the granules are stretched and oriented by a multi-roll stretching machine with a stretching ratio of 6. They are then heat-set at 120℃ for 20s, twisted, and finally cut into strips by a strip cutter to obtain waterproof polypropylene tape.

[0037] Comparative Example 1: A 220KV submarine cable resistant to deep water pressure, comprising a copper conductor, a cross-linked polyethylene insulation layer, a water-blocking tape, a lead sheath, a polyethylene sheath layer, a polyethylene filler strip, a polypropylene non-woven fabric, a polypropylene tape inner lining layer, a copper wire armor layer, and a polypropylene tape outer sheath layer.

[0038] The preparation method of polypropylene tape is as follows:

[0039] (1) Mix 1kg of polypropylene and 2g of calcium stearate, and extrude them through a screw extruder. The temperatures of each section are 150℃, 175℃, 190℃, 190℃ and 180℃, and the screw speed is 40r / min to obtain polypropylene granules. After casting, the granules are stretched and oriented by a multi-roll stretching machine with a stretching ratio of 6. They are then heat-set at 120℃ for 20s, twisted, and finally cut into strips by a strip cutter to obtain polypropylene strips.

[0040] Comparative Example 2: A 220KV submarine cable resistant to deep water pressure, consisting of a copper conductor, a cross-linked polyethylene insulation layer, a water-blocking tape, a lead sheath, a polyethylene sheath layer, a polyethylene filler strip, a polypropylene non-woven fabric, a polypropylene tape inner lining layer, a copper wire armor layer, and a polypropylene tape outer sheath layer.

[0041] The preparation method of polypropylene tape is as follows:

[0042] (1) Mix 900g polypropylene, 100g hydroxyl silicone oil and 2g calcium stearate, and extrude them through a screw extruder. The temperatures of each section are 150℃, 175℃, 190℃, 190℃ and 180℃, and the screw speed is 40r / min to obtain polypropylene granules. After casting, the granules are stretched and oriented by a multi-roll stretching machine with a stretching ratio of 6. They are then heat-set at 120℃ for 20s, twisted, and finally cut into strips by a strip cutter to obtain polypropylene strips.

[0043] Comparative Example 3: A 220KV submarine cable resistant to deep water pressure, consisting of a copper conductor, a cross-linked polyethylene insulation layer, a water-blocking tape, a lead sheath, a polyethylene sheath layer, a polyethylene filler strip, a polypropylene non-woven fabric, a polypropylene tape inner lining layer, a copper wire armor layer, and a polypropylene tape outer sheath layer.

[0044] The preparation method of polypropylene tape is as follows:

[0045] (1) Add 5g of polypropylene to 60mL of xylene, heat to 125℃, stir, add 2.5mmol of hydroxyethyl methacrylate and 0.04mmol of dicumyl peroxide, stir and reflux for 1h, cool and filter, add the precipitate to chloroform, heat to 60℃, stir and filter, dry the precipitate to obtain hydroxyethyl methacrylate grafted polypropylene.

[0046] (2) Add 2g of hydroxyethyl methacrylate-grafted polypropylene to 30mL of N,N-dimethylformamide, heat to 150℃, stir, add 20g of hydroxyl silicone oil and 0.08g of dibutyltin dilaurate, stir and reflux for 7h, filter after cooling, wash with N,N-dimethylformamide and chloroform in sequence, dry to obtain polypropylene modified silicone oil.

[0047] (3) Mix 900g polypropylene, 100g polypropylene modified silicone oil and 2g calcium stearate, and extrude them through a screw extruder. The temperatures of each section are 150℃, 175℃, 190℃, 190℃ and 180℃, and the screw speed is 40r / min to obtain polypropylene granules. After casting, the granules are stretched and oriented by a multi-roll stretching machine with a stretching ratio of 6. They are then heat-set at 120℃ for 20s, twisted, and finally cut into strips by a strip cutter to obtain polypropylene strips.

[0048] Comparative Example 4: A 220KV submarine cable resistant to deep water pressure, consisting of a copper conductor, a cross-linked polyethylene insulation layer, a water-blocking tape, a lead sheath, a polyethylene sheath layer, a polyethylene filler strip, a polypropylene non-woven fabric, a polypropylene tape inner lining layer, a copper wire armor layer, and a polypropylene tape outer sheath layer.

[0049] The preparation method of polypropylene tape is as follows:

[0050] (1) Add 5g of polypropylene to 60mL of xylene, heat to 125℃, stir, add 2.5mmol of tridecylfluorooctyl methacrylate (CAS No. 2144-53-8) and 0.04mmol of dicumyl peroxide, stir, reflux and cool for 1h, filter after cooling, add the precipitate to chloroform, heat to 60℃, stir and filter, dry the precipitate to obtain tridecylfluorooctyl methacrylate grafted polypropylene.

[0051] (2) Add 2g of tridecyl methacrylate grafted polypropylene to 30mL of N,N-dimethylformamide, heat to 150℃, stir, add 20g of hydroxyl silicone oil and 0.08g of dibutyltin dilaurate, stir, reflux for 7h, and distill under reduced pressure to obtain a blend of grafted polypropylene and hydroxyl silicone oil.

[0052] (3) Mix 900g of polypropylene, 100g of grafted polypropylene-hydroxy silicone oil blend and 2g of calcium stearate, and extrude them through a screw extruder. The temperatures of each section are 150℃, 175℃, 190℃, 190℃ and 180℃, and the screw speed is 40r / min to obtain polypropylene granules. After casting, the granules are stretched and oriented by a multi-roll stretching machine with a stretching ratio of 6. They are then heat-set at 120℃ for 20s, twisted, and finally cut into strips by a strip cutter to obtain polypropylene strips.

[0053] Example 2: A 220KV submarine cable resistant to deep water pressure, comprising a copper conductor, a cross-linked polyethylene insulation layer, a water-blocking tape, a lead sheath, a polyethylene sheath layer, a polyethylene filler strip, a polypropylene non-woven fabric, a waterproof polypropylene tape inner lining layer, a copper wire armor layer, and a waterproof polypropylene tape outer sheath layer.

[0054] The preparation method of waterproof polypropylene tape is as follows:

[0055] (1) Add 5g of polypropylene to 80mL of xylene, heat to 135℃, stir, add 6.5mmol of methacryloyloxy-2-hydroxypropyl perfluorooctanoate and 0.1mmol of dicumyl peroxide, stir and reflux for 2h, cool and filter, add the precipitate to chloroform, heat to 60℃, stir and filter, dry the precipitate to obtain methacryloyloxy-2-hydroxypropyl perfluorooctanoate grafted polypropylene.

[0056] (2) Add 3g of methacryloyloxy-2-hydroxypropyl perfluorooctanoate grafted polypropylene to 60mL of N,N-dimethylformamide, heat to 150℃, stir, add 20g of hydroxyl silicone oil and 0.14g of dibutyltin dilaurate, stir and reflux for 10h, cool and filter, wash with N,N-dimethylformamide and chloroform in sequence, dry to obtain polypropylene modified silicone oil.

[0057] (3) Mix 850g polypropylene, 150g polypropylene modified silicone oil and 1.3g zinc stearate, and extrude them through a screw extruder. The temperatures of each section are 150℃, 175℃, 190℃, 190℃ and 180℃, and the screw speed is 100r / min to obtain polypropylene granules. After casting, the granules are stretched and oriented by a multi-roll stretching machine with a stretching ratio of 4. They are then heat-set at 130℃ for 20s, twisted, and finally cut into strips by a strip cutter to obtain waterproof polypropylene tape.

[0058] Example 3: A 220KV submarine cable resistant to deep water pressure, consisting of a copper conductor, a cross-linked polyethylene insulation layer, a water-blocking tape, a lead sheath, a polyvinyl chloride sheath layer, a polyethylene filler strip, a polypropylene non-woven fabric, a waterproof polypropylene tape inner lining layer, a copper wire armor layer, and a waterproof polypropylene tape outer sheath layer.

[0059] The preparation method of waterproof polypropylene tape is as follows:

[0060] (1) Add 5g of polypropylene to 80mL of xylene, heat to 125℃, stir, add 10.5mmol of methacryloyloxy-2-hydroxypropyl perfluorooctanoate and 0.17mmol of dicumyl peroxide, stir and reflux for 3h, cool and filter, add the precipitate to chloroform, heat to 60℃, stir and filter, dry the precipitate to obtain methacryloyloxy-2-hydroxypropyl perfluorooctanoate grafted polypropylene.

[0061] (2) Add 4.5g of methacryloyloxy-2-hydroxypropyl perfluorooctanoate grafted polypropylene to 80mL of N,N-dimethylformamide, heat to 140℃, stir, add 20g of hydroxyl silicone oil and 0.23g of dibutyltin dilaurate, stir and reflux for 6h, filter after cooling, wash with N,N-dimethylformamide and chloroform in sequence, dry to obtain polypropylene modified silicone oil.

[0062] (3) Mix 800g polypropylene, 200g polypropylene modified silicone oil and 1g calcium stearate, and extrude them through a screw extruder. The temperatures of each section are 150℃, 175℃, 190℃, 190℃ and 180℃, and the screw speed is 60r / min to obtain polypropylene granules. After casting, the granules are stretched and oriented by a multi-roll stretching machine with a stretching ratio of 6 times. They are then heat-set at 140℃ for 15s, twisted, and finally cut into strips by a strip cutter to obtain waterproof polypropylene tape.

[0063] Example 4: A 220KV submarine cable resistant to deep water pressure, consisting of a copper conductor, a cross-linked polyethylene insulation layer, a water-blocking tape, a lead sheath, a polyvinyl chloride sheath layer, a polyethylene filler strip, a polypropylene non-woven fabric, a waterproof polypropylene tape inner lining layer, a copper wire armor layer, and a waterproof polypropylene tape outer sheath layer.

[0064] The preparation method of waterproof polypropylene tape is as follows:

[0065] (1) Add 5g of polypropylene to 80mL of xylene, heat to 120℃, stir, add 15mmol of methacryloyloxy-2-hydroxypropyl perfluorooctanoate and 0.25mmol of dicumyl peroxide, stir and reflux for 3h, cool and filter, add the precipitate to chloroform, heat to 60℃, stir and filter, dry the precipitate to obtain methacryloyloxy-2-hydroxypropyl perfluorooctanoate grafted polypropylene.

[0066] (2) Add 6g of methacryloyloxy-2-hydroxypropyl perfluorooctanoate grafted polypropylene to 80mL of N,N-dimethylformamide, heat to 155℃, stir, add 20g of hydroxyl silicone oil and 0.3g of dibutyltin dilaurate, stir and reflux for 6h, filter after cooling, wash with N,N-dimethylformamide and chloroform in sequence, dry to obtain polypropylene modified silicone oil.

[0067] (3) Mix 750g polypropylene, 250g polypropylene modified silicone oil and 1g calcium stearate, and extrude them through a screw extruder. The temperatures of each section are 150℃, 175℃, 190℃, 190℃ and 180℃, and the screw speed is 60r / min to obtain polypropylene granules. After casting, the granules are stretched and oriented by a multi-roll stretching machine with a stretching ratio of 5 times. They are then heat-set at 140℃ for 15s, twisted, and finally cut into strips by a strip cutter to obtain waterproof polypropylene tape.

[0068] The water contact angle of the polypropylene tape was tested according to GB / T 30693-2014. Polypropylene granules were injection molded into strips, and their tensile properties were tested according to GB / T 1040.1-2025.

[0069] Table 1 Properties of Polypropylene Tape

[0070]

[0071] Compared with Comparative Example 1, the polypropylene material in Example 1 incorporated polypropylene-modified silicone oil. The silicone oil introduced polypropylene molecular chains, improving compatibility with the polypropylene resin matrix. It had minimal impact on the mechanical strength of polypropylene and provided better toughening, maintaining good tensile strength and significantly improving elongation at break. The polypropylene-modified silicone oil contained highly hydrophobic perfluoroalkyl chains and polysiloxane structures, which were uniformly dispersed in the polypropylene matrix, improving the water contact angle and surface hydrophobicity of the polypropylene tape and enhancing its waterproof performance.

[0072] The silicone oil added in Comparative Example 2 has poor compatibility with polypropylene, resulting in a significant decrease in the tensile strength of polypropylene and poor toughening effect on polypropylene, with a low elongation at break. Furthermore, the silicone oil does not contain perfluoroalkyl chains, and the water contact angle of the polypropylene is lower than that in Example 1, which is not conducive to improving its waterproof performance.

[0073] The hydroxyethyl methacrylate-grafted polypropylene of Comparative Example 3 and the polypropylene-modified silicone oil prepared therefrom do not contain perfluoroalkyl chains. The water contact angle of the polypropylene is lower than that of Example 1, which is not conducive to improving its waterproof performance.

[0074] The tridecyl fluorooctyl methacrylate-grafted polypropylene in Comparative Example 4 does not contain hydroxyl groups and cannot react with hydroxyl silicone oil. The hydroxyl silicone oil in the blend is not introduced into the polypropylene molecular chain, resulting in poor compatibility between the hydroxyl silicone oil and polypropylene. Consequently, the tensile strength and elongation at break of the polypropylene material are lower than those in Example 1.

[0075] The above description is only a preferred 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 within the protection scope of the present invention.

Claims

1. A method of preparing a 220 KV submarine cable resistant to deep water pressure, characterized in that, Submarine cables are made by preparing conductors, insulation layers, water-blocking tapes, lead sheaths, sheath layers, filling layers, wrapping tapes, inner lining layers, armor layers, and outer sheath layers. The inner lining and outer sheath are made of waterproof polypropylene tape; The method for preparing the waterproof polypropylene tape includes: S1. Methacryloxy-2-hydroxypropyl perfluorooctanoate grafted polypropylene was added to N,N-dimethylformamide, heated and stirred, and then hydroxyl silicone oil and dibutyltin dilaurate were added. The mixture was stirred and reacted, cooled and filtered, the product was washed and dried to obtain polypropylene modified silicone oil. S2. Polypropylene, polypropylene-modified silicone oil, and lubricant are mixed, extruded and cast into sheets using a screw extruder, stretched and oriented using a multi-roll stretching machine, heat-set, and then twisted. Finally, the sheets are cut into strips using a strip cutter to obtain waterproof polypropylene tape.

2. The method of manufacturing a 220 KV subsea cable resistant to deep water pressure according to claim 1, characterized in that, The conductor is a copper conductor; the insulation layer is a cross-linked polyethylene layer; the sheath layer is a polyethylene sheath layer or a polyvinyl chloride sheath layer; the filler layer is a polyethylene filler strip; the wrapping tape is a polypropylene non-woven fabric; and the armor layer is a copper wire.

3. The method of manufacturing a 220 KV subsea cable resistant to deep water pressure according to claim 1, characterized in that, The reaction in S1 is stirred at 145-155℃ for 6-10 hours.

4. The method of claim 1, wherein the 220 KV subsea cable is prepared to withstand deep water pressure, and The mass ratio of methacryloyloxy-2-hydroxypropyl perfluorooctanoate grafted polypropylene, hydroxy silicone oil, and dibutyltin dilaurate in S1 is (10-30):100:(0.4-1.5).

5. The method of manufacturing a 220 KV subsea cable resistant to deep water pressure according to claim 4, characterized in that, The preparation method of the methacryloyloxy-2-hydroxypropyl perfluorooctanoate grafted polypropylene is as follows: add polypropylene, methacryloyloxy-2-hydroxypropyl perfluorooctanoate, and dicumyl peroxide in a ratio of 100g:(50-300)mmol:(0.8-5)mmol to xylene, heat to 120-135℃, stir and react for 1-3h, cool and filter, add the precipitate to chloroform, heat and stir and filter, dry the precipitate to obtain methacryloyloxy-2-hydroxypropyl perfluorooctanoate grafted polypropylene.

6. The method of manufacturing a 220 KV subsea cable resistant to deep water pressure according to claim 1, characterized in that, The mass ratio of polypropylene, polypropylene-modified silicone oil, and lubricant in S2 is (75-90):(10-25):(0.1-0.2).

7. The method of manufacturing a 220 KV subsea cable resistant to deep water pressure according to claim 6, characterized in that, The lubricant is calcium stearate or zinc stearate.

8. The method of claim 1, wherein the 220 KV subsea cable is resistant to deep water pressure. The temperature of each section of the screw extruder is 150-190℃, and the screw speed is 40-100 r / min.

9. The method of claim 1, wherein the 220 KV subsea cable is prepared to withstand deep water pressure. The stretching ratio during stretching and orientation is 4-6 times, the heat setting temperature is 120-140℃, and the heat setting time is 15-20s.

10. A 220KV submarine cable resistant to deep-water pressure, obtained by the preparation method according to any one of claims 1-9.

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