Water-blocking glue, preparation method thereof and large-section direct-current submarine cable molded line water-blocking conductor

Abstract

The invention discloses water-blocking glue, a preparation method thereof and a large-section direct-current submarine cable molded line water-blocking conductor, and belongs to the technical field of submarine cables. The large-section direct-current submarine cable molded line water-blocking conductor prepared by the invention comprises a central conductor, and a first elliptical single line layer, a second elliptical single line layer, a third elliptical single line layer, a fourth elliptical single line layer, a fifth elliptical single line layer and a sixth elliptical single line layer which are sequentially coated outside the central conductor from inside to outside, the water-blocking glue is filled between the central conductor and each elliptical single wire layer; the water-blocking glue is obtained by compounding high-water-absorption water-blocking powder, silicone oil, white carbon black, a first cross-linking agent, a catalyst and organic silicon, and the high-water-absorption water-blocking powder is obtained by compounding an acrylic copolymer, a sulfonic acid type polyurethane prepolymer, melamine and a second cross-linking agent.

Description

Technical Field

[0001] The invention relates to the technical field of submarine cables, in particular to a water-blocking adhesive and a preparation method thereof, and a large-section DC submarine cable-shaped wire water-blocking conductor. Background Art

[0002] With the rapid development of the marine economy and the growing demand for power transmission, large-section DC submarine cables have been widely used in the field of cross-sea power transmission due to their high transmission capacity and low loss characteristics. However, in actual application, due to the complex and changeable seabed environment, such as the strong corrosiveness of seawater and the mechanical stress caused by the undulating seabed terrain, higher requirements are placed on the protection of cables. Especially for large-section submarine cables, the gaps between the internal conductors are large, and how to effectively prevent moisture intrusion and maintain long-term stable operation of the cable has become a technical problem that needs to be solved urgently.

[0003] The water-blocking materials used in large-section submarine cable conductors on the market generally have insufficient longitudinal water-blocking performance. On the one hand, these materials often cannot effectively prevent moisture from penetrating along the longitudinal direction of the cable, affecting the insulation performance of the cable; on the other hand, most of the existing water-blocking adhesive materials do not have good salt resistance and are prone to aging and failure when immersed in seawater for a long time. In addition, since submarine cables need to undergo multiple bends during the laying process, the existing water-blocking adhesive materials also have the problem of being not resistant to bending and are prone to cracking after repeated bending, thereby reducing their water-blocking effect.

[0004] On the other hand, traditional water-blocking adhesive materials are often difficult to completely fill the gaps between large-section submarine cable conductors, especially when there are complex geometries or tiny gaps between the conductors. Bubbles or unfilled areas are easily formed. These defects will cause the overall performance of the water-blocking adhesive to deteriorate.

[0005] Therefore, developing a water-blocking adhesive and a large-section DC submarine cable-shaped water-blocking conductor can not only improve the longitudinal water-blocking performance of the large-section DC submarine cable, enhance the salt resistance and bending resistance, but also ensure that the water-blocking adhesive can be evenly and completely filled between the conductors. Summary of the invention

[0006] The purpose of the present invention is to provide a water-blocking adhesive and a preparation method thereof, and a large-section DC submarine cable-type water-blocking conductor, 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] A water-blocking adhesive comprises, by weight, 35 to 45 parts of highly water-absorbing water-blocking powder, 20 to 30 parts of silicone oil, 10 to 15 parts of white carbon black, 0.5 to 0.7 parts of a first cross-linking agent, 0.15 to 0.17 parts of a catalyst, and 100 parts of organic silicon.

[0009] Furthermore, the raw material components of the highly water-absorbent and water-resistant powder include 80 to 130 parts by weight of acrylic copolymer, 20 to 40 parts by weight of sulfonic acid type polyurethane prepolymer, 10 to 30 parts by weight of melamine, and 0.3 to 0.7 parts by weight of a second crosslinking agent.

[0010] Furthermore, the acrylic copolymer is obtained by copolymerizing acrylic acid, acrylamide and sodium methacrylic acid sulfonate.

[0011] Furthermore, the second cross-linking agent includes N,N'-methylenebisacrylamide.

[0012] Furthermore, the first cross-linking agent includes vinyltrimethoxysilane and 3-(methacryloyloxy)propyltrimethoxysilane.

[0013] The present invention also provides a method for preparing a water-blocking adhesive, and the preparation steps are as follows: under moisture-proof conditions, 100 parts by mass of silicone, 35 to 45 parts by mass of highly water-absorbent water-blocking powder, 10 to 15 parts by mass of white carbon black, and 0.15 to 0.17 parts by mass of a catalyst are mixed to obtain a water-blocking adhesive primary mixture, and the water-blocking adhesive primary mixture is mixed with 0.5 to 0.7 parts by mass of a first cross-linking agent to obtain a water-blocking adhesive.

[0014] Furthermore, the preparation method of the highly water-absorbent and water-resistant powder is as follows: 80 to 130 parts by weight of an acrylic copolymer is added to a 1M sodium hydroxide solution for neutralization, with a neutralization degree of 40 to 70%, followed by adding 20 to 40 parts by weight of a sulfonic acid type polyurethane prepolymer, 10 to 30 parts by weight of melamine, and 0.1 to 0.12 parts by weight of ammonium persulfate, heating to 70 to 80° C. under nitrogen protection, keeping warm for 1.5 to 2.5 hours, then adding 0.3 to 0.7 parts by weight of a second cross-linking agent N,N'-methylenebisacrylamide, continuing the warm reaction for 0.5 to 1 hour, and then dehydrating, drying, and crushing to obtain a highly water-absorbent and water-resistant powder.

[0015] Furthermore, the preparation method of the acrylic copolymer is as follows: under ice water bath conditions, 1M sodium hydroxide aqueous solution is added to 40 parts by mass of acrylic acid to neutralize to a neutralization degree of 65-75%, then 5-7 parts by mass of acrylamide and 5-7 parts by mass of sodium methyl propylene sulfonate are added, and after mixing evenly, the mixture is placed in a reactor and heated to 70-80° C., nitrogen is introduced, and then 0.06-0.064 parts by mass of ammonium persulfate is added dropwise, and after keeping the temperature for 2 hours, the acrylic copolymer is obtained after multiple washing with deionized water and ethanol, drying and pulverization.

[0016] Furthermore, the preparation method of the sulfonic acid type polyurethane prepolymer is as follows: 35 to 45 parts by weight of polyetherimide, 5 to 15 parts by weight of polycarbonate diol, and 2 to 2.4 parts by weight of dimethylol propionic acid are placed in a reaction kettle for vacuum dehydration at 105° C. for 1 hour, and then the vacuum is removed, the temperature is lowered to 68 to 72° C., 30 to 40 parts by weight of isophorone diisocyanate are added dropwise, and the addition is completed within 1 hour, 0.03 to 0.05 parts by weight of catalyst dibutyl dilaurate are added, and the reaction is kept warm until the -NCO value reaches 0.5 to 7%, triethylamine is added for neutralization for 20 minutes, and 2 to 2.4 parts by weight of sodium ethylenediamine polyethylene glycol sulfonate are added and stirred at a speed of 800 rpm for 1 hour to obtain a sulfonic acid type polyurethane prepolymer.

[0017] The present invention also provides a large-section DC submarine cable-type water-blocking conductor, comprising a central conductor, a first elliptical single-wire layer, a second elliptical single-wire layer, a third elliptical single-wire layer, a fourth elliptical single-wire layer, a fifth elliptical single-wire layer, and a sixth elliptical single-wire layer sequentially coated on the outside of the central conductor from the inside to the outside, and a water-blocking glue filled between the central conductor and the elliptical single-wire layers; the first elliptical single-wire layer, the second elliptical single-wire layer, the third elliptical single-wire layer, the fourth elliptical single-wire layer, the fifth elliptical single-wire layer, and the sixth elliptical single-wire layer are The elliptical single-line layer and the sixth elliptical single-line layer are both composed of elliptical conductor single lines, and the number of elliptical conductor single lines in each layer is 6, 12, 18, 24, 30, and 36 respectively; the angles corresponding to the elliptical conductor single lines of the first elliptical single-line layer, the second elliptical single-line layer, the third elliptical single-line layer, the fourth elliptical single-line layer, the fifth elliptical single-line layer, and the sixth elliptical single-line layer are 59.5°, 29.5°, 19.5°, 14.6°, 11.7°, and 9.7° respectively.

[0018] By adopting the above technical solution, the present invention has the following beneficial effects:

[0019] (1) The water-blocking adhesive of the present invention is prepared by compounding highly water-absorbing water-blocking powder, silicone oil, white carbon black, a first cross-linking agent, a catalyst, and organic silicon. The highly water-absorbing water-blocking powder absorbs water and swells to form a gel-like substance, thereby preventing moisture from entering the interior of the cable and protecting the electrical and mechanical properties of the cable. The highly water-absorbing water-blocking powder has excellent salt resistance, water absorption and swelling properties, and bending resistance.

[0020] (2) The highly water-absorbent and water-blocking powder of the present invention is obtained by compounding an acrylic copolymer, a sulfonic acid polyurethane prepolymer, melamine, and a second crosslinking agent. Active groups on the acrylic copolymer, such as carboxyl groups, active groups on the sulfonic acid polyurethane prepolymer, such as isocyanate groups, and amino groups on melamine react to form a hyperbranched structure with melamine as a rigid skeleton and sulfonic acid polyurethane prepolymer and acrylic copolymer as elastic side chains. This structure significantly increases the contact area between the molecular chains with hydrophilic groups (such as amino groups and sulfonic acid groups) and water or salt water, thereby improving the water absorption rate of the water-blocking powder. When the highly water-absorbent and water-blocking powder absorbs water, it will expand rapidly, and the presence of highly elastic side chains makes it expand to a greater extent, effectively avoiding the decrease in water absorption rate due to limited expansion height. In addition, under the synergistic effect of the rigid skeleton melamine and the elastic side chain sulfonic acid polyurethane prepolymer and acrylic copolymer, the highly water-absorbent and water-blocking powder exhibits better mechanical properties.

[0021] (3) The acrylic copolymer of the present invention is obtained by copolymerizing acrylic acid, acrylamide and sodium methacrylic acid sulfonate. Hydrophilic and salt-resistant sulfonic acid groups and amide groups are introduced into the acrylic copolymer, thereby enhancing the water absorption and salt resistance of the acrylic copolymer, and further enhancing the water absorption and salt resistance of the highly water-absorbent and water-blocking powder.

[0022] (4) The angles of the elliptical conductor single wires of each layer of the large-section DC submarine cable type water-blocking conductor of the present invention from the inside to the outside are 59.5°, 29.5°, 19.5°, 14.6°, 11.7°, and 9.7°, respectively, forming appropriate gaps between the conductors, resulting in a larger heat dissipation area for the conductors, and appropriate gaps can increase the flexibility of the conductors; and the existence of the gaps ensures that the water-blocking glue can be evenly and completely filled between the conductors, thereby enhancing the longitudinal water-blocking performance of the conductors. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] 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

[0024] Figure 1 It is a conductor cross-sectional view of the large-section DC submarine cable profiled special-shaped water-blocking conductor of the present invention.

[0025] The numbers in the accompanying drawings are: center conductor 1, first elliptical single wire layer 2, second elliptical single wire layer 3, third elliptical single wire layer 4, fourth elliptical single wire layer 5, fifth elliptical single wire layer 6, sixth elliptical single wire layer 7, elliptical conductor single wire 8, and water-blocking glue 9. DETAILED DESCRIPTION

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] Overall embodiment

[0033] See Figure 1A large-section DC submarine cable profiled water-blocking conductor, comprising, from inside to outside, a central conductor 1, a first elliptical single-wire layer 2, a second elliptical single-wire layer 3, a third elliptical single-wire layer 4, a fourth elliptical single-wire layer 5, a fifth elliptical single-wire layer 6, a sixth elliptical single-wire layer 7, and a water-blocking glue 9 filled between the central conductor and each elliptical single-wire layer;

[0034] In this embodiment, the first elliptical single-line layer 2, the second elliptical single-line layer 3, the third elliptical single-line layer 4, the fourth elliptical single-line layer 5, the fifth elliptical single-line layer 6, and the sixth elliptical single-line layer 7 are all composed of elliptical conductor single lines 8, and the number of elliptical conductor single lines 8 in each layer is 6, 12, 18, 24, 30, and 36 respectively;

[0035] The angles corresponding to the elliptical conductor single wire 8 of the first elliptical single wire layer 2, the second elliptical single wire layer 3, the third elliptical single wire layer 4, the fourth elliptical single wire layer 5, the fifth elliptical single wire layer 6, and the sixth elliptical single wire layer 7 of this embodiment are 59.5°, 29.5°, 19.5°, 14.6°, 11.7°, and 9.7° respectively; the large-section DC submarine cable profiled water-blocking conductor of the present invention adopts 6 layers of elliptical single wire layers to wrap the central conductor, which can achieve 3000mm 2 The above conductor cross-sections have good water-blocking properties. The angles corresponding to the elliptical conductor single wires 8 of each layer of the large-section DC submarine cable profiled water-blocking conductor of this embodiment are 59.5°, 29.5°, 19.5°, 14.6°, 11.7°, and 9.7°, respectively. Appropriate gaps are formed between the conductors, and the heat dissipation area of ​​the conductors is large. Appropriate gaps can increase the flexibility of the conductors, and the presence of gaps ensures that the water-blocking glue can be evenly and completely filled between the conductors, thereby enhancing the longitudinal water-blocking properties of the conductors.

[0036] The central conductor 1 of this embodiment is a circular compressed conductor; the circular compressed conductor is obtained by compressing five layers of circular compressed conductor monofilaments, and the number of circular compressed conductor monofilaments in each layer is 1, 6, 12, 18, and 24, respectively.

[0037] The diameter of the circular compressed conductor of this embodiment is 2.92 mm.

[0038] The diameter of the large-section DC submarine cable profiled water-blocking conductor of this embodiment is 4.38-4.41 mm.

[0039] The central conductor 1 of this embodiment adopts a round compact conductor with a diameter of 2.92mm, and the diameter of the large-section DC submarine cable profile water-blocking conductor is 4.38-4.41mm, which can achieve 3000mm 2 The conductor cross section above.

[0040] Both sides of the elliptical conductor single wire of this embodiment are semicircles with a radius of 0.5 mm. The four corners of the elliptical conductor single wire of the present invention are arc-shaped chamfers with a radius of 0.5 mm, taking into account both production and processing needs and filling factor requirements.

[0041] A method for preparing a water-blocking adhesive, the preparation steps are as follows:

[0042] Under moisture-proof conditions, 100 parts by mass of silicone, 35-45 parts by mass of highly water-absorbing water-blocking powder, 10-15 parts by mass of white carbon black, and 0.15-0.17 parts by mass of a catalyst are mixed to obtain a preliminary mixture of a water-blocking adhesive. The preliminary mixture of the water-blocking adhesive is mixed with 0.5-0.7 parts by mass of a first cross-linking agent to obtain a water-blocking adhesive.

[0043] Silicone is a combination of methyl silicone oil, epoxy silicone oil and ester silicone oil in a mass ratio of 1:1:1. These silicone substances have good adhesion, heat resistance, corrosion resistance and weather resistance.

[0044] Silicone oil is polydimethylsiloxane. Its main function in glue is to act as a carrier, which can adjust the viscosity and fluidity of the glue, thereby affecting the coating performance and use effect of the glue. In addition, silicone oil can also improve the adhesion and weather resistance of the glue, improve the water resistance and heat resistance of the glue, thereby enhancing the waterproof performance and service life of the glue.

[0045] Silica generally has good adsorption, dispersibility, thickening, whitening and reinforcing properties.

[0046] The first cross-linking agent is a combination of vinyl trimethoxy silane and 3-(methacryloyloxy)propyl trimethoxy silane in a mass ratio of 1:1.

[0047] The catalyst used is dibutyltin dilaurate.

[0048] The preparation method of the highly water-absorbent and water-resistant powder of this embodiment is as follows: 80 to 130 parts by weight of an acrylic copolymer is added to a 1M sodium hydroxide solution for neutralization, with a neutralization degree of 40 to 70%, followed by adding 20 to 40 parts by weight of a sulfonic acid type polyurethane prepolymer, 10 to 30 parts by weight of melamine, and 0.1 to 0.12 parts by weight of ammonium persulfate, and heating to 70 to 80° C. under nitrogen protection, and after keeping warm for 1.5 to 2.5 hours, 0.3 to 0.7 parts by weight of a second cross-linking agent N,N'-methylenebisacrylamide is added, and the reaction is continued by keeping warm for 0.5 to 1 hour, followed by dehydration, drying, and pulverization to obtain a highly water-absorbent and water-resistant powder.

[0049] The preparation method of the acrylic copolymer of the present embodiment is as follows: under ice water bath conditions, 1M sodium hydroxide aqueous solution is added to 40 parts by weight of acrylic acid to neutralize to a neutralization degree of 65-75%, then 5-7 parts by weight of acrylamide and 5-7 parts by weight of sodium methyl propylene sulfonate are added, the mixture is evenly mixed, the mixture is placed in a reactor, heated to 70-80° C., nitrogen is introduced, and then 0.06-0.064 parts by weight of ammonium persulfate is added dropwise. After the mixture is kept warm for 2 hours, the acrylic copolymer is obtained by multiple washing with deionized water and ethanol, drying and pulverization.

[0050] The preparation method of the sulfonic acid polyurethane prepolymer of the present embodiment is as follows: 35-45 parts by weight of polyetherimide, 5-15 parts by weight of polycarbonate diol, and 2-2.4 parts by weight of dimethylol propionic acid are placed in a reaction kettle, vacuum dehydrated at 105° C. for 1 hour, and then the vacuum is removed, the temperature is lowered to 68-72° C., 30-40 parts by weight of isophorone diisocyanate are added dropwise, and the addition is completed within 1 hour, 0.03-0.05 parts by weight of catalyst dibutyl dilaurate are added, and the reaction is kept warm until the -NCO value reaches 0.5-7%, triethylamine is added for neutralization for 20 minutes, and 2-2.4 parts by weight of sodium ethylenediamine polyethylene glycol sulfonate are added and stirred at 800 rpm for 1 hour to obtain a sulfonic acid polyurethane prepolymer.

[0051] The number average molecular weight of the polyetherimide is 1500; the number average molecular weight of the polycarbonate diol is 2000; the sodium ethylenediamine polyethylene glycol sulfonate is obtained from Beijing Baiyuan Company, and the solid content is 90%.

[0052] Example 1

[0053] Based on the raw materials of the general embodiment, a method for preparing a water-blocking adhesive in this embodiment has the following preparation steps:

[0054] Under moisture-proof conditions, 100 parts by mass of silicone, 35 parts by mass of highly water-absorbing water-blocking powder, 10 parts by mass of white carbon black, and 0.15 parts by mass of a catalyst are mixed to obtain a preliminary mixture of a water-blocking adhesive. The preliminary mixture of the water-blocking adhesive is mixed with 0.5 parts by mass of a first cross-linking agent to obtain a water-blocking adhesive.

[0055] The preparation method of the highly water-absorbent and water-resistant powder of this embodiment is as follows: 80 parts by mass of an acrylic copolymer is added to a 1M sodium hydroxide solution for neutralization with a neutralization degree of 40%, followed by adding 20 parts by mass of a sulfonic acid type polyurethane prepolymer, 10 parts by mass of melamine, and 0.1 parts by mass of ammonium persulfate, and heating to 70° C. under nitrogen protection, and after keeping warm for 1.5 hours, 0.3 parts by mass of a second cross-linking agent N,N'-methylenebisacrylamide is added, and the reaction is continued by keeping warm for 0.5 hours, followed by dehydration, drying, and pulverization to obtain a highly water-absorbent and water-resistant powder.

[0056] The preparation method of the acrylic copolymer of this embodiment is as follows: under ice water bath conditions, 1M sodium hydroxide aqueous solution is added to 40 parts by mass of acrylic acid to neutralize to a neutralization degree of 65%, then 5 parts by mass of acrylamide and 5 parts by mass of sodium methyl acrylate sulfonate are added, the mixture is evenly mixed, the mixture is placed in a reactor, heated to 70° C., nitrogen is introduced, and then 0.06 parts by mass of ammonium persulfate is added dropwise. After keeping the mixture warm for 2 hours, the acrylic copolymer is obtained by multiple washing with deionized water and ethanol, drying and pulverization.

[0057] The preparation method of the sulfonic acid polyurethane prepolymer of this embodiment is as follows: 35 parts by mass of polyetherimide, 5 parts by mass of polycarbonate diol, and 2 parts by mass of dimethylol propionic acid are placed in a reactor and vacuum dehydrated at 105° C. for 1 hour, then the vacuum is removed, the temperature is lowered to 68° C., 30 parts by mass of isophorone diisocyanate are added dropwise, and the addition is completed within 1 hour, 0.03 parts by mass of catalyst dibutyl dilaurate is added, and the reaction is kept warm until the -NCO value reaches 0.5%, triethylamine is added for neutralization for 20 minutes, and 2 parts by mass of sodium ethylenediamine polyethylene glycol sulfonate are added and stirred at 800 rpm for 1 hour to obtain a sulfonic acid polyurethane prepolymer.

[0058] Example 2

[0059] Based on the raw materials of the general embodiment, a method for preparing a water-blocking adhesive in this embodiment has the following preparation steps:

[0060] Under moisture-proof conditions, 100 parts by mass of silicone, 40 parts by mass of highly water-absorbent water-blocking powder, 12 parts by mass of white carbon black, and 0.16 parts by mass of a catalyst are mixed to obtain a preliminary mixture of a water-blocking adhesive. The preliminary mixture of the water-blocking adhesive is mixed with 0.6 parts by mass of a first cross-linking agent to obtain a water-blocking adhesive.

[0061] The preparation method of the highly water-absorbent and water-resistant powder of this embodiment is as follows: 100 parts by mass of an acrylic copolymer is added to a 1M sodium hydroxide solution for neutralization with a neutralization degree of 55%, and then 30 parts by mass of a sulfonic acid type polyurethane prepolymer, 20 parts by mass of melamine, and 0.11 parts by mass of ammonium persulfate are added, and heated to 75° C. under nitrogen protection. After keeping warm for 2 hours, 0.5 parts by mass of a second cross-linking agent N,N'-methylenebisacrylamide is added, and the reaction is continued by keeping warm for 0.7 hours, followed by dehydration, drying, and pulverization to obtain a highly water-absorbent and water-resistant powder.

[0062] The preparation method of the acrylic acid copolymer of this embodiment is as follows: under ice water bath conditions, 1M sodium hydroxide aqueous solution is added to 40 parts by mass of acrylic acid to neutralize to a neutralization degree of 70%, then 6 parts by mass of acrylamide and 6 parts by mass of sodium methyl acrylate sulfonate are added, the mixture is evenly mixed, the mixture is placed in a reactor, heated to 75° C., nitrogen is introduced, and 0.062 parts by mass of ammonium persulfate is added dropwise. After the mixture is kept warm for 2 hours, the acrylic acid copolymer is obtained by multiple washing with deionized water and ethanol, drying and pulverization.

[0063] The preparation method of the sulfonic acid polyurethane prepolymer of this embodiment is as follows: 40 parts by mass of polyetherimide, 10 parts by mass of polycarbonate diol, and 2.2 parts by mass of dimethylol propionic acid are placed in a reactor and vacuum dehydrated at 105° C. for 1 hour, then the vacuum is removed, the temperature is lowered to 70° C., 35 parts by mass of isophorone diisocyanate are added dropwise, and the addition is completed within 1 hour, 0.04 parts by mass of catalyst dibutyl dilaurate are added, and the reaction is kept warm until the -NCO value reaches 4%, triethylamine is added for neutralization for 20 minutes, and 2.2 parts by mass of sodium ethylenediamine polyethylene glycol sulfonate are added and stirred at 800 rpm for 1 hour to obtain a sulfonic acid polyurethane prepolymer.

[0064] Example 3

[0065] Based on the raw materials of the general embodiment, a method for preparing a water-blocking adhesive in this embodiment has the following preparation steps:

[0066] Under moisture-proof conditions, 100 parts by mass of silicone, 45 parts by mass of highly water-absorbing water-blocking powder, 15 parts by mass of white carbon black, and 0.17 parts by mass of a catalyst are mixed to obtain a preliminary mixture of a water-blocking adhesive. The preliminary mixture of the water-blocking adhesive is mixed with 0.7 parts by mass of a first cross-linking agent to obtain a water-blocking adhesive.

[0067] The preparation method of the highly water-absorbent and water-resistant powder of this embodiment is as follows: 130 parts by mass of an acrylic copolymer is added to a 1M sodium hydroxide solution for neutralization with a neutralization degree of 70%, followed by adding 40 parts by mass of a sulfonic acid type polyurethane prepolymer, 30 parts by mass of melamine, and 0.12 parts by mass of ammonium persulfate, and heating to 80° C. under nitrogen protection, and after keeping warm for 2.5 hours, 0.7 parts by mass of a second cross-linking agent N,N'-methylenebisacrylamide is added, and the reaction is continued by keeping warm for 1 hour, followed by dehydration, drying, and pulverization to obtain a highly water-absorbent and water-resistant powder.

[0068] The preparation method of the acrylic copolymer of this embodiment is as follows: under ice water bath conditions, 1M sodium hydroxide aqueous solution is added to 40 parts by mass of acrylic acid to neutralize to a neutralization degree of 75%, then 7 parts by mass of acrylamide and 7 parts by mass of sodium methyl propylene sulfonate are added, the mixture is evenly mixed, the mixture is placed in a reactor, heated to 80° C., nitrogen is introduced, and then 0.064 parts by mass of ammonium persulfate is added dropwise. After keeping the mixture warm for 2 hours, the acrylic copolymer is obtained by washing with deionized water and ethanol for multiple times, drying and pulverizing.

[0069] The preparation method of the sulfonic acid polyurethane prepolymer of this embodiment is as follows: 45 parts by mass of polyetherimide, 15 parts by mass of polycarbonate diol, and 2.4 parts by mass of dimethylol propionic acid are placed in a reactor and vacuum dehydrated at 105° C. for 1 hour, then the vacuum is removed, the temperature is lowered to 72° C., 40 parts by mass of isophorone diisocyanate are added dropwise, and the addition is completed within 1 hour, 0.05 parts by mass of catalyst dibutyl dilaurate are added, and the reaction is kept warm until the -NCO value reaches 7%, triethylamine is added for neutralization for 20 minutes, and 2.4 parts by mass of sodium ethylenediamine polyethylene glycol sulfonate are added and stirred at 800 rpm for 1 hour to obtain a sulfonic acid polyurethane prepolymer.

[0070] Comparative Example 1

[0071] The difference between Comparative Example 1 and Example 2 is that the highly water-absorbent and water-resistant powder is compounded from acrylic acid, sulfonic acid type polyurethane prepolymer, melamine, and a second crosslinking agent; the remaining steps and components are the same as those of Example 2.

[0072] Comparative Example 2

[0073] The difference between Comparative Example 2 and Example 2 is that the highly water-absorbent and water-resistant powder is compounded from acrylic copolymer, sodium lignin sulfonate, melamine, and a second cross-linking agent; the remaining steps and components are the same as those of Example 2.

[0074] Comparative Example 3

[0075] The difference between Comparative Example 3 and Example 2 is that the highly water-absorbent and water-resistant powder is compounded from acrylic copolymer, sulfonic acid type polyurethane prepolymer, urea, and a second crosslinking agent; the remaining steps and components are the same as those of Example 2.

[0076] Effect example

[0077] Water absorption, expansion height: The water absorption and expansion height of the water-blocking adhesives prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were tested according to the test method in the YD / T1115.3-201X industry standard:

[0078] A. The liquid absorbed by the water-blocking powder is water, and the water absorption and swelling height are recorded accordingly;

[0079] B. The liquid absorbed by the water-blocking powder is seawater (salinity is 35‰), and the water absorption and swelling height are recorded accordingly;

[0080] C. The liquid absorbed by the water-blocking powder is seawater (salinity is 60‰), and the water absorption and swelling height are recorded accordingly;

[0081] Water seepage length: According to the method F5B of 23.2.2 of GB / T7424.2-2008, the large-section DC submarine cable profile water-blocking conductor samples filled with water-blocking glue prepared in Examples 1 to 3 and Comparative Examples 1 to 3 and extruded with insulating layers of the same thickness were immersed in different liquids for 10 weeks, and the water seepage length was tested. The test conditions were

[0082] Bending and unbending longitudinal water-blocking performance: According to the test method of GB / T 31489.1-2015, the large-section DC submarine cable profiled water-blocking conductors filled with water-blocking glue and extruded with the same thickness of insulating layer prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were divided into two groups of samples according to the relevant methods of high-voltage DC submarine cables. One group was coiled and bent according to GB / T7424.2-2008, and the other group was not subjected to any operation. The two groups of samples were subjected to a longitudinal water permeability test, and 30m of large-section DC submarine cable profiled water-blocking conductors extruded with the same thickness of insulating layer were selected, and the water pressure was 2MPa.

[0083] Table 1 below shows the performance test results of the water-blocking adhesives and the large-section DC submarine cable profiled water-blocking conductors filled with the water-blocking adhesive and extruded with the same thickness of insulating layers prepared in Examples 1 to 3 of the present invention and Comparative Examples 1 to 3:

[0084] Table 1

[0085]

[0086]

[0087] As can be seen from Table 1 above, compared with Comparative Examples 1 to 3, Examples 1 to 3 can be obtained that the highly water-absorbent water-blocking powder obtained by compounding an acrylic copolymer, a sulfonic acid polyurethane prepolymer, melamine, and a second crosslinking agent is used to prepare a water-blocking adhesive. The water absorption and swelling height of the prepared water-blocking adhesive are good, and the salt resistance is good. On the one hand, the sulfonic acid polyurethane prepolymer and the acrylic copolymer introduce more hydrophilic and salt-resistant groups (such as amino groups and sulfonic acid groups, etc.) into the water-blocking adhesive. After the acrylic copolymer, the sulfonic acid polyurethane prepolymer, and melamine react, a highly water-absorbent water-blocking powder with melamine as a rigid skeleton and melamine as a crosslinking agent is formed. Sulfonic acid polyurethane prepolymer and acrylic copolymer are hyperbranched structures with elastic branches, which significantly increase the contact area between the molecular chain with hydrophilic groups (such as amino and sulfonic acid groups) and water or brine, further increasing the water absorption, expansion height and salt resistance of the water-blocking adhesive. On the other hand, under the synergistic effect of rigid skeleton melamine and elastic branched sulfonic acid polyurethane prepolymer and acrylic copolymer, the highly water-absorbent water-blocking powder exhibits good bending resistance, avoiding the problem of cracking of the water-blocking adhesive due to bending and winding of the submarine cable during use, resulting in a sharp drop in the longitudinal water-blocking performance of the submarine cable.

[0088] 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 scope of protection of the present invention.

Claims

1. A water-blocking adhesive, characterized in that: The raw material components include 35-45 parts by weight of highly water-absorbing and water-blocking powder, 20-30 parts by weight of silicone oil, 10-15 parts by weight of white carbon black, 0.5-0.7 parts by weight of a first crosslinking agent, 0.15-0.17 parts by weight of a catalyst, and 100 parts by weight of silicone.

2. The water-blocking adhesive according to claim 1, characterized in that: The raw material components of the highly water-absorbent and water-resistant powder include 80 to 130 parts by weight of acrylic copolymer, 20 to 40 parts by weight of sulfonic acid type polyurethane prepolymer, 10 to 30 parts by weight of melamine, and 0.3 to 0.7 parts by weight of a second crosslinking agent.

3. The water-blocking adhesive according to claim 2, characterized in that: The acrylic acid copolymer is obtained by copolymerizing acrylic acid, acrylamide and sodium methacrylic acid sulfonate.

4. The water-blocking adhesive according to claim 2, characterized in that: The second cross-linking agent includes N,N'-methylenebisacrylamide.

5. The water-blocking adhesive according to claim 1, characterized in that: The first cross-linking agent includes any one of vinyl trimethoxy silane and 3-(methacryloyloxy)propyl trimethoxy silane or a combination of the two.

6. A method for preparing a water-blocking adhesive as claimed in any one of claims 1 to 5, characterized in that: The preparation steps are as follows: Under moisture-proof conditions, 100 parts by mass of silicone, 35-45 parts by mass of highly water-absorbing water-blocking powder, 10-15 parts by mass of white carbon black, and 0.15-0.17 parts by mass of a catalyst are mixed to obtain a preliminary mixture of a water-blocking adhesive; the preliminary mixture of the water-blocking adhesive is mixed with 0.5-0.7 parts by mass of a first cross-linking agent to obtain a water-blocking adhesive.

7. The method for preparing the water-blocking adhesive according to claim 6, characterized in that: The preparation method of the highly water-absorbent and water-resistant powder is as follows: 80 to 130 parts by weight of an acrylic copolymer is added to a 1M sodium hydroxide solution for neutralization, with a neutralization degree of 40 to 70%, followed by adding 20 to 40 parts by weight of a sulfonic acid type polyurethane prepolymer, 10 to 30 parts by weight of melamine, and 0.1 to 0.12 parts by weight of ammonium persulfate, heating to 70 to 80° C. under nitrogen protection, keeping the temperature for 1.5 to 2.5 hours, then adding 0.3 to 0.7 parts by weight of a second cross-linking agent, N,N'-methylenebisacrylamide, continuing the heat preservation reaction for 0.5 to 1 hour, and then dehydrating, drying, and pulverizing to obtain the highly water-absorbent and water-resistant powder.

8. The method for preparing the water-blocking adhesive according to claim 7, characterized in that: The preparation method of the acrylic acid copolymer is as follows: under ice water bath conditions, 1M sodium hydroxide aqueous solution is added to 40 parts by weight of acrylic acid to neutralize to a neutralization degree of 65-75%, then 5-7 parts by weight of acrylamide and 5-7 parts by weight of sodium methyl propylene sulfonate are added, the mixture is evenly mixed, the mixture is placed in a reaction kettle, heated to 70-80° C., nitrogen is introduced, and 0.06-0.064 parts by weight of ammonium persulfate is added dropwise, the mixture is kept warm for 2 hours, and then the acrylic acid copolymer is obtained by multiple washing with deionized water and ethanol, drying and pulverization.

9. The method for preparing the water-blocking adhesive according to claim 7, characterized in that: The preparation method of the sulfonic acid type polyurethane prepolymer is as follows: 35-45 parts by weight of polyetherimide, 5-15 parts by weight of polycarbonate diol, and 2-2.4 parts by weight of dimethylol propionic acid are placed in a reaction kettle for vacuum dehydration at 105° C. for 1 hour, and then the vacuum is removed, the temperature is lowered to 68-72° C., 30-40 parts by weight of isophorone diisocyanate is added dropwise, and the addition is completed within 1 hour, 0.03-0.05 parts by weight of catalyst dibutyl dilaurate is added, and the temperature is kept to react until the -NCO value reaches 0.5-7%, triethylamine is added for neutralization for 20 minutes, and 2-2.4 parts by weight of sodium ethylenediamine polyethylene glycol sulfonate is added and stirred at a speed of 800 rpm for 1 hour to obtain the sulfonic acid type polyurethane prepolymer.

10. A large-section DC submarine cable type water-blocking conductor, characterized in that: The invention comprises a central conductor (1), a first elliptical single-wire layer (2), a second elliptical single-wire layer (3), a third elliptical single-wire layer (4), a fourth elliptical single-wire layer (5), a fifth elliptical single-wire layer (6), and a sixth elliptical single-wire layer (7) sequentially wrapped around the central conductor from the inside to the outside, and a water-blocking glue as claimed in any one of claims 1 to 5 filled between the central conductor (1) and the elliptical single-wire layers; the first elliptical single-wire layer (2), the second elliptical single-wire layer (3), the third elliptical single-wire layer (4), the fourth elliptical single-wire layer (5), the fifth elliptical single-wire layer (6), and the sixth elliptical single-wire layer (7) The first elliptical single wire layer (2), the second elliptical single wire layer (3), the third elliptical single wire layer (4), the fourth elliptical single wire layer (5), the fifth elliptical single wire layer (6), and the sixth elliptical single wire layer (7) are all composed of elliptical conductor single wires (8), and the number of elliptical conductor single wires in each layer is 6, 12, 18, 24, 30, and 36, respectively; the angles corresponding to the elliptical conductor single wires (8) of the first elliptical single wire layer (2), the second elliptical single wire layer (3), the third elliptical single wire layer (4), the fourth elliptical single wire layer (5), the fifth elliptical single wire layer (6), and the sixth elliptical single wire layer (7) are 59.5°, 29.5°, 19.5°, 14.6°, 11.7°, and 9.7°, respectively.

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