Corrosion-resistant direct-current charging pile connecting cable and preparation method thereof

Abstract

The invention discloses a corrosion-resistant direct-current charging pile connecting cable and a preparation method thereof, belongs to the technical field of cable preparation, and is used for solving the technical problem that the corrosion resistance and ultraviolet resistance of a charging pile connecting cable need to be further improved in the prior art. And the corrosion-resistant layer is obtained by coating the exterior of the cable base body with a powder coating and then carrying out thermocuring. According to the invention, 4, 4 '-bis (methoxymethyl) biphenyl and 4-allylphenol are condensed to obtain an intermediate I, and the intermediate I is grafted by epoxy chloropropane and subjected to a substitution reaction with participation of tetramethylammonium bromide and sodium hydroxide to form modified epoxy resin containing rich epoxy groups and an allyl structure, so that the corrosion resistance of a connecting cable is improved, and the service life of the connecting cable is prolonged. The ultraviolet resistance and the mechanical property are also improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cable preparation, in particular to a corrosion-resistant direct-current charging pile connecting cable and a preparation method thereof. BACKGROUND

[0002] With the large-scale promotion of new energy vehicles and charging infrastructure, the working conditions of charging pile connecting cables used in outdoor environments for a long time are increasingly harsh, especially in coastal, high-humidity, high-salt fog and strong ultraviolet radiation areas, and the cable materials face serious environmental aging and corrosion risks.

[0003] To improve the corrosion resistance and ultraviolet resistance of the cable, cross-linked polyethylene (XLPE), thermoplastic polyurethane (TPU), chlorinated polyethylene (CPE) and the like are often used as sheath materials, and small molecule additives such as ultraviolet absorbers, antioxidants and metal passivators are also used;

[0004] In addition, by adding inorganic fillers such as nano-zinc oxide, titanium dioxide, kaolin and silane-modified calcium carbonate, the barrier property and stability of the sheath layer can be enhanced to a certain extent, and these modification strategies have achieved certain results in improving the overall weather resistance of the material and have become the mainstream direction in the current industry.

[0005] However, the traditional materials and modification methods still have many limitations: first, the physical filler enhancement of the sheath layer itself depends on the barrier property of the material, and lacks clear interface densification or chemical passivation structure design, which is prone to interface penetration, internal corrosion and performance degradation in a continuous high-humidity and high-salt environment; second, conventional additives are prone to migration and failure during long-term thermal aging or ultraviolet radiation, and cannot provide stable and long-lasting protection; in addition, the traditional polymer sheath cannot effectively balance the mechanical flexibility and extreme environmental protection performance, and lacks a gradient structure design of the external protective layer.

[0006] The root cause of the above-mentioned deficiencies is that the focus is generally on the internal modification of the sheath body material, and the external protection mechanism with a clear chemical corrosion-resistant structure cannot be constructed from the surface layer of the sheath body material, and therefore a solution is proposed. SUMMARY

[0007] The present application relates to the technical field of cable preparation, in particular to a corrosion-resistant direct-current charging pile connecting cable and a preparation method thereof.

[0008] The technical problems to be solved by the present application are to provide a corrosion-resistant direct-current charging pile connecting cable and a preparation method thereof, which can improve the corrosion resistance and ultraviolet resistance of the charging pile connecting cable.

[0009] The corrosion-resistant layer is obtained by coating the powder coating on the outside of the cable base and then heat curing. The present application relates to the technical field of cable preparation, in particular to a corrosion-resistant direct-current charging pile connecting cable and a preparation method thereof.

[0010] The powder coating comprises the following components by weight parts: 65-75 parts of modified epoxy resin, 5-10 parts of composite modified filler, 5-10 parts of curing agent and 1-3 parts of auxiliary additive.

[0011] Further, the curing agent is 4,4'-diaminodiphenyl methane, the auxiliary additive is antioxidant, ultraviolet absorber, initiator and lubricant in a mass ratio of 1:2:1:5, the antioxidant is one or both of N,N'-diphenyl-p-phenylenediamine and 2,6-di-tert-butyl-4-methylphenol, the ultraviolet absorber is one or both of p-t-butylphenyl salicylate and 2-hydroxy-4-n-octyloxybenzophenone, the initiator is benzoyl peroxide, and the lubricant is one or both of oleic acid and fatty acid amide.

[0012] Further, the modified epoxy resin is prepared by the following steps:

[0013] A1, 4,4'-bis(methoxymethyl)diphenyl and N-methylpyrrolidone are placed in a reaction kettle and stirred, 4-allylphenol is added in three equal portions, hydrochloric acid aqueous solution is added, the reaction kettle is heated to 105-115 DEG C, and the reaction is kept for 8-10 h, and the intermediate I is obtained by post-treatment;

[0014] The preparation reaction formula of the intermediate I is:

[0015]

[0016] The preparation reaction principle of the intermediate I is:

[0017] During the reaction, 4,4'-diphenyl dimethyl ether provides two methoxy structures, which can be hydrolyzed to formaldehyde under acidic conditions, and further undergoes polycondensation reaction with the phenolic hydroxyl group of 4-allylphenol to obtain the intermediate I.

[0018] A2, the intermediate I and epichlorohydrin are placed in a reaction kettle and stirred, the reaction kettle is heated to 60-70 DEG C, tetramethylammonium bromide is added, the reaction is kept for 15-30 min, sodium hydroxide is added, the reaction is kept for 2-4 h, and the modified epoxy resin is obtained by post-treatment.

[0019] The preparation reaction formula of the modified epoxy resin is:

[0020]

[0021] The preparation reaction principle of the modified epoxy resin is:

[0022] During the reaction, the phenolic hydroxyl group in intermediate I is deprotonated under alkaline conditions to form a phenoxide with strong nucleophilicity. Since the chlorine atom in epichlorohydrin is on the primary carbon atom, it is extremely susceptible to nucleophilic attack. Therefore, the phenoxide preferentially attacks the C-Cl bond of epichlorohydrin, and an SN2 nucleophilic substitution reaction occurs to obtain the modified epoxy resin.

[0023] Further, in step A1, the use amount ratio of the 4,4'-bis(methoxymethyl)biphenyl, N-methylpyrrolidone, 4-allylphenol and aqueous hydrochloric acid is 4-6 g: 50-100 mL: 5-7 g: 0.5-1 mL, the concentration of the aqueous hydrochloric acid is 35-40 wt%, and the post-treatment step includes: after the reaction is completed, the reaction kettle is heated to 190-200℃, and distilled under reduced pressure until no liquid is collected, to obtain intermediate I; in step A2, the use amount ratio of the intermediate I, epichlorohydrin, tetramethylammonium bromide and sodium hydroxide is 8-10 g: 25-30 mL: 0.1-0.2 g: 0.5-1 g, and the post-treatment step includes: after the reaction is completed, the reaction system is allowed to cool to room temperature, filtered, the filter cake is washed with deionized water for 2-4 times, and then transferred to an oven with a temperature of 50-60℃ for drying until a constant weight is obtained, to obtain the modified epoxy resin.

[0024] Further, the composite modified filler is prepared by the following steps:

[0025] B1, the modified filler, ethanol and deionized water are placed in a reaction kettle, stirred at room temperature for 15-30 min, a mixed salt solution is added, stirred at room temperature for 15-30 min, triethanolamine is added dropwise until the pH is 8-10, and then hydrothermal reaction is performed, and the crude product of the composite modified filler is obtained after post-treatment;

[0026] The preparation reaction principle of the crude product of the composite modified filler is as follows:

[0027] During the reaction, a mixed metal salt solution prepared from magnesium nitrate hexahydrate, aluminum nitrate nonahydrate and deionized water is used, and under the condition that the pH is adjusted to 8-10 by triethanolamine, magnesium ions and aluminum ions are uniformly deposited on the surface of the modified filler through a hydrothermal co-precipitation reaction, to form a layered double hydroxide structure, and thus the crude product of the composite modified filler is obtained.

[0028] B2, the crude product of the composite modified filler, ethanol, γ-methacryloyloxypropyltrimethoxysilane and deionized water are placed in a reaction kettle and stirred, an aqueous acetic acid solution is added, the reaction kettle is heated to 50-60℃, and then incubated for 2-4 h, and the composite modified filler is obtained after post-treatment.

[0029] The preparation reaction principle of the composite modified filler is as follows:

[0030] During the reaction, under the catalysis of acetic acid aqueous solution, γ-methacryloxypropyl trimethoxysilane is hydrolyzed into silanol, which condenses with the hydroxyl groups on the surface of the composite modified filler crude product to form covalent bonds, thereby obtaining the composite modified filler modified by silane coupling agent.

[0031] Further, in step B1, the use amount ratio of the modified filler, ethanol, deionized water and mixed salt solution is 5-10 g:40 mL:40 mL:30-50 mL, the mixed salt solution is prepared from magnesium nitrate hexahydrate, aluminum nitrate nonahydrate and deionized water according to the use amount ratio of 6-8 g:9-11 g:100-150 mL, and the operation steps of the hydrothermal reaction include: transferring the reaction solution to a sealed stainless steel reaction kettle, heating the reaction kettle to 120-150 DEG C, and keeping the temperature for 1-2 h, and then performing post-treatment to obtain the composite modified filler crude product, and the post-treatment steps include: after the reaction is completed, the reaction system is cooled to room temperature, filtration is performed, the filter cake is washed with deionized water until it is neutral, and then the filter cake is transferred to a freeze dryer with a temperature of-60 DEG C, and freeze drying is performed for 4-6 h to obtain the composite modified filler crude product.

[0032] Further, in step B2, the use amount ratio of the composite modified filler crude product, ethanol, γ-methacryloxypropyl trimethoxysilane, deionized water and acetic acid aqueous solution is 4-6 g:60-80 mL:0.5-1 g:5-10 mL:2-4 mL, the concentration of the acetic acid aqueous solution is 0.5-1.0 mol / L, and the post-treatment steps include: after the reaction is completed, the reaction system is cooled to room temperature, filtration is performed, the filter cake is washed with ethanol and deionized water for 2-4 times, the filter cake is transferred to an oven with a temperature of 50-60 DEG C, and drying is performed until the weight is constant to obtain the composite modified filler.

[0033] Further, the modified filler is prepared by the following steps:

[0034] C1, kaolin, potassium hydroxide and deionized water are placed in a reaction kettle and stirred, the reaction kettle is heated to 75-85 DEG C, and stirring is kept for 2-4 h, and then post-treatment is performed to obtain activated kaolin;

[0035] The preparation reaction principle of the activated kaolin is:

[0036] During the reaction, the structure of kaolin is in a sheet layer shape, under the alkaline condition provided by potassium hydroxide, the silicon-aluminum bond is broken to form an amorphous structure, potassium ions are intercalated between the layers to open the sheet structure, surface defects and more hydroxyl groups are introduced, the surface activity is improved, and the activated kaolin is obtained.

[0037] C2, diatomite, concentrated sulfuric acid and deionized water are placed in a reaction kettle and stirred, the reaction kettle is heated to 75-85 DEG C, and stirring is kept for 2-4 h, and then post-treatment is performed to obtain activated diatomite;

[0038] The preparation reaction principle of the activated diatomite is:

[0039] During the reaction, the main component of diatomite is amorphous silicon dioxide, containing metal oxide impurities such as Fe, Ca, Mg, etc. Under the action of aqueous sulfuric acid, the metal oxide impurities in diatomite are dissolved, the surface is corroded to form more micropores, and hydroxyl groups are introduced onto the surface, thereby improving the surface activity, and obtaining activated diatomite.

[0040] C3, the activated kaolin, activated diatomite and polyacrylic acid are placed in a reaction kettle, mixed uniformly, then calcined three times, and treated to obtain a modified filler.

[0041] The reaction principle for preparing the modified filler is as follows:

[0042] During the reaction, the carboxyl group of polyacrylic acid reacts with the active sites of the hydroxyl groups on the surface of the activated kaolin and activated diatomite under alkaline conditions to form a stable effect, thereby improving the uniformity of the raw material mixture and the structural stability. During the first air calcination process, polyacrylic acid pyrolyzes to release small molecule gases and leaves part of the carbon phase, thereby providing structural support for subsequent furfuryl alcohol carbonization and potassium hydroxide activation. After impregnation with furfuryl alcohol, acid-catalyzed polymerization of furfuryl alcohol occurs under the action of aqueous hydrochloric acid, generating a polyfurfuryl alcohol gel. During the second calcination process, the polymer pyrolyzes to release gas, and the remaining carbon skeleton carbonizes to form amorphous or graphitic carbon. After further impregnation with an aqueous potassium hydroxide solution, the metal potassium in the product volatilizes in a reduced state during the third calcination, etching the carbon skeleton and opening up the microporous and mesoporous structures. The generated gas further punches holes, thereby increasing the pore volume and specific surface area of the product. The generated silicon dioxide and aluminum oxide have a supporting effect on the carbon structure, which can limit the excessive collapse of the carbon structure. Ultimately, a modified filler with mesoporous structure is obtained.

[0043] Further, in step C1, the amount of kaolin, potassium hydroxide and deionized water is 2-4 g: 2 g: 6 mL; the amount of diatomite, concentrated sulfuric acid and deionized water is 2-4 g: 2 mL: 8 mL, and the post-treatment step includes: after the reaction is completed, the reaction system is cooled to room temperature, filtered, the filter cake is washed with deionized water until it is neutral, transferred to an oven with a temperature of 70-80°C, dried to a constant weight, ground, and sieved through a 500 mesh sieve to obtain activated kaolin. In step C2, the weight ratio of activated kaolin, activated diatomite and polyacrylic acid is 2-4 g: 1-2 g: 0.5-1 g, and the post-treatment step includes: after the reaction is completed, the reaction system is cooled to room temperature, filtered, the filter cake is washed with deionized water until it is neutral, transferred to an oven with a temperature of 70-80°C, dried to a constant weight, ground, and sieved through a 500 mesh sieve to obtain activated diatomite.

[0044] Further, in step C3, the preparation method of the modified filler is as follows: the activated kaolin, activated diatomite and polyacrylic acid are placed in a reaction kettle, uniformly mixed, then transferred to a muffle furnace for first calcination, the muffle furnace is heated to 800 DEG C at a heating rate of 5 DEG C / min, and kept for 4h, then naturally cooled to room temperature, then immersed in furfuryl alcohol at an impregnation ratio of 1:30-35 for 20-30min, 30wt% hydrochloric acid ethanol solution with a volume of one fifth of the furfuryl alcohol is added, stirred for 15-30min, then transferred to a tube furnace under nitrogen atmosphere for second calcination, the tube furnace is heated to 800 DEG C at a heating rate of 5 DEG C / min, and kept for 4h, then naturally cooled to room temperature, then immersed in 9-10mol / L potassium hydroxide aqueous solution at an impregnation ratio of 1:30-35 for 1-2h, then transferred to a tube furnace under nitrogen atmosphere for third calcination, the tube furnace is heated to 800 DEG C at a heating rate of 5 DEG C / min, and kept for 2h, after the three calcinations, the modified filler crude product is obtained;

[0045] Further, in step C3, the post-treatment step includes: after the three calcinations, the modified filler crude product is cooled to room temperature, then washed with 0.5mol / L hydrochloric acid aqueous solution for 2-4 times, then transferred to an oven with a temperature of 70-80 DEG C, dried to constant weight, and the modified filler is obtained.

[0046] The application further provides a preparation method of the corrosion-resistant DC charging pile connecting cable.

[0047] S1, uniformly mixing modified epoxy resin, composite modified filler, curing agent and auxiliary additive, grinding, passing through a 200 mesh sieve, and obtaining a powder coating;

[0048] S2, after the powder coating is coated on the outer part of the cable substrate, heat curing is performed, and the connecting cable is obtained.

[0049] The application has the following advantages:

[0050] 1. The present application is to activate kaolin and activated diatomite after blending with polyacrylic acid, and then to obtain modified filler with mesoporous structure by three calcinations, the stable inorganic framework structure formed by three calcinations improves the thermal stability and mechanical strength of the modified filler, further improves the tensile strength and toughness of the cable sheath layer, the outer layer of the cable is less likely to deform and break under external impact environment, prolongs the service life of the cable, at the same time, the activated kaolin and diatomite have high specific surface area and lamellar structure, and the Si-O and Al-O inorganic framework of kaolin and diatomite has high ultraviolet reflectivity and absorption capacity, which can effectively block the direct radiation of ultraviolet rays on the connecting cable, improve the ultraviolet resistance of the connecting cable, and the activated kaolin and diatomite as the core of the filler, after the treatment of potassium hydroxide and concentrated sulfuric acid, the surface activity is improved, at the same time, the impurities and structural defects are removed, the chemical stability is improved, the acid and alkali resistance of the modified filler is improved, the corrosion resistance of the connecting cable is further improved, so that it can resist the corrosion of corrosive medium to the cable.

[0051] 2. The present application is to introduce triethanolamine into the modified filler to adjust pH and carry out hydrothermal reaction, and further modify by gamma-methacryloxypropyl trimethoxysilane to obtain composite modified filler, first, the silane coupling agent such as gamma-methacryloxypropyl trimethoxysilane has amphoteric structure, one end contains alkoxy which can react with inorganic filler surface hydroxyl group, the other end contains olefinic unsaturated double bond which can react with modified epoxy resin in the process of thermal curing, forming three-dimensional crosslinked network structure, improving the wear resistance, tensile strength and toughness of the connecting cable, and through the bonding with the hydroxyl group on the surface of the filler, the silane coupling agent forms a stable organic modified layer on the surface of the modified filler, which significantly improves the surface affinity and organic compatibility of the filler, so that it can better disperse in the epoxy resin system and form a stable interface, and the mechanical properties of the cable are enhanced, and the silane molecules form an organic modified layer on the surface of the modified filler, which has excellent hydrophobicity and corrosion resistance, can effectively block the penetration and diffusion of corrosive medium, and improves the corrosion resistance of the connecting cable.

[0052] 3、The application is to condense 4,4'-bis(methoxymethyl) biphenyl with 4-allyl phenol to obtain intermediate I, then grafting with epichlorohydrin and substitution reaction with tetramethylammonium bromide and sodium hydroxide, forming a modified epoxy resin containing rich epoxy groups and allyl structure, the introduced allyl structure in the modified epoxy resin provides additional reactive sites, when reacting with flame-retardant fillers and curing agents, a more compact and uniform three-dimensional crosslinked structure can be formed, the structural stability of the material is enhanced, further resisting the damage of ultraviolet rays to the molecular chain, improving the mechanical properties and ultraviolet resistance of the connecting cable, at the same time, the crack propagation can be effectively inhibited, the impact resistance and tear resistance are improved, in addition, the aromatic structure of 4,4'-bis(methoxymethyl) biphenyl is introduced into the modified epoxy resin, the rigid conjugated backbone has excellent ultraviolet aging resistance, can effectively absorb and disperse ultraviolet radiation, thereby improving the ultraviolet resistance of the outer sheath of the connecting cable, and the biphenyl group also provides excellent chemical resistance and oxidation resistance, can resist the attack of corrosive factors in acid gas, salt spray and humid heat environment, improves the corrosion resistance of the connecting cable, the aromatic backbone and the crosslinked network synergistically act, effectively inhibiting the opening, discoloration and cracking caused by ultraviolet irradiation, delaying the aging speed of the material, and improving the long-term service life and appearance stability of the cable in outdoor or strong light environment. DETAILED DESCRIPTION

[0053] The technical solutions of the present application will be described clearly and completely below in combination with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0054] The kaolin used in the present application is purchased from Hebei Zongrun Mining Product Co., Ltd., with a particle size of 325 mesh, a model of XJT-3000S and a part number of 010;

[0055] The diatomite used in the present application is purchased from Lingshou County Huanlun Mining Product Processing Factory, with a specific surface area of 40-65 m 2 ·g -1 , a model of 325 mesh;

[0056] The cable matrix used in the present application is purchased from Chengdu Chuanyu Shangshang Cable Sales Co., Ltd., with a model of ZC-YJV 3*4, a standard of national standard, a core material of bare copper wire and a sheath material of plastic insulation;

[0057] The commercial bisphenol A type epoxy resin used in the present application is purchased from Shandong Jin Hong New Material Technology Co., Ltd., with a brand of E-44, a part number of 11212 and a model of model 44.

[0058] Example 1

[0059] The embodiment provides a preparation method of a modified filler for a composite modified filler used for a corrosion-resistant direct-current charging pile connecting cable, and the method comprises the following steps:

[0060] Step I, preparation of activated kaolin

[0061] Take 20 g of kaolin, 20 g of potassium hydroxide and 60 mL of deionized water, stir in a reaction kettle, heat the reaction kettle to 75 DEG C, and keep stirring for 2 h, after the reaction is completed, the reaction system is cooled to room temperature, and then filtration is performed, the filter cake is washed to neutral with deionized water, and then the filter cake is transferred to an oven with a temperature of 70 DEG C, dried to constant weight, ground, and then screened through a 500-mesh sieve to obtain the activated kaolin.

[0062] Step II, preparation of activated diatomite

[0063] Take 20 g of diatomite, 20 mL of concentrated sulfuric acid and 80 mL of deionized water, stir in a reaction kettle, heat the reaction kettle to 75 DEG C, and keep stirring for 2 h, after the reaction is completed, the reaction system is cooled to room temperature, and then filtration is performed, the filter cake is washed to neutral with deionized water, and then the filter cake is transferred to an oven with a temperature of 70 DEG C, dried to constant weight, ground, and then screened through a 500-mesh sieve to obtain the activated diatomite.

[0064] Step III, preparation of a modified filler

[0065] Take 20 g of activated kaolin, 10 g of activated diatomite and 5 g of polyacrylic acid, stir in a reaction kettle, uniformly mix, and then transfer the mixture to a muffle furnace for first calcination, the muffle furnace is heated to 800 DEG C at a heating rate of 5 DEG C / min, and then kept for 4 h, after natural cooling to room temperature, the mixture is immersed in furfuryl alcohol at an impregnation ratio of 1:30 for 20 min, 30wt% hydrochloric acid ethanol solution with a volume of one fifth of the furfuryl alcohol is added, and then stirred for 15 min, and then the mixture is transferred to a tubular furnace in a nitrogen atmosphere for second calcination, the tubular furnace is heated to 800 DEG C at a heating rate of 5 DEG C / min, and then kept for 4 h, after natural cooling to room temperature, the mixture is immersed in 9mol / L potassium hydroxide aqueous solution at an impregnation ratio of 1:30 for 1 h, and then transferred to a tubular furnace in a nitrogen atmosphere for third calcination, the tubular furnace is heated to 800 DEG C at a heating rate of 5 DEG C / min, and then kept for 2 h, after the three calcinations are completed, the modified filler crude product is cooled to room temperature, washed with 0.5mol / L hydrochloric acid aqueous solution for two times, and then transferred to an oven with a temperature of 70 DEG C, and dried to constant weight to obtain the modified filler.

[0066] Example 2

[0067] The embodiment provides a preparation method of a modified filler for a composite modified filler used for a corrosion-resistant direct-current charging pile connecting cable, and the method comprises the following steps:

[0068] Step I, preparation of activated kaolin

[0069] Take: kaolin 30g, potassium hydroxide 20g and deionized water 60mL in the reaction kettle stirring, the reaction kettle to 80℃, keep stirring 3h, after the reaction is completed, the reaction system is reduced to room temperature, suction filtration, filter cake with deionized water washing to neutral, transfer to the temperature is 75℃ oven, drying to constant weight, grinding, 500 mesh sieve, get activated kaolin.

[0070] Step II, preparation of activated diatomite

[0071] Take: diatomite 30g, concentrated sulfuric acid 20mL and deionized water 80mL in the reaction kettle stirring, the reaction kettle to 80℃, keep stirring 3h, after the reaction is completed, the reaction system is reduced to room temperature, suction filtration, filter cake with deionized water washing to neutral, transfer to the temperature is 75℃ oven, drying to constant weight, grinding, 500 mesh sieve, get activated diatomite.

[0072] Step III, preparation of modified filler

[0073] Take: activated kaolin 30g, activated diatomite 15g and polyacrylic acid 7g in the reaction kettle, after mixing evenly, transfer to the muffle furnace for the first calcination, muffle furnace with 5℃ / min heating rate to 800℃, keep reaction 4h, natural cooling to room temperature, with 1:32 of the impregnation ratio in the furfuryl alcohol impregnation 25min, the volume of 30wt% hydrochloric acid ethanol solution is one fifth of the furfuryl alcohol, stirring 20min, transfer to the nitrogen atmosphere protection of the tube furnace for the second calcination, tube furnace with 5℃ / min heating rate to 800℃, keep reaction 4h, natural cooling to room temperature, with 1:32 of the impregnation ratio in the 9.5mol / L potassium hydroxide solution impregnation 1.5h, transfer to the nitrogen atmosphere protection of the tube furnace for the third calcination, tube furnace with 5℃ / min heating rate to 800℃, keep reaction 2h, three calcination, after the modified filler crude product is reduced to room temperature, with 0.5mol / L hydrochloric acid solution washing 3 times, transfer to the temperature is 75℃ oven, drying to constant weight, get modified filler.

[0074] Example 3

[0075] The present embodiment provides a kind of preparation method of modified filler for corrosion-resistant direct current charging pile connecting cable composite modified filler, comprising the following steps:

[0076] Step I, preparation of activated kaolin

[0077] Take: kaolin 40g, potassium hydroxide 20g and deionized water 60mL in the reaction kettle stirring, the reaction kettle to 85℃, keep stirring 4h, after the reaction is completed, the reaction system is reduced to room temperature, filter, filter cake is washed to neutral with deionized water, transfer to the oven at a temperature of 80℃, dry to constant weight, grinding, 500 mesh sieve, get activated kaolin.

[0078] Step II, preparation of activated diatomite

[0079] Take: diatomite 40g, concentrated sulfuric acid 20mL and deionized water 80mL in the reaction kettle stirring, the reaction kettle to 85℃, keep stirring 4h, after the reaction is completed, the reaction system is reduced to room temperature, filter, filter cake is washed to neutral with deionized water, transfer to the oven at a temperature of 80℃, dry to constant weight, grinding, 500 mesh sieve, get activated diatomite.

[0080] Step III, preparation of modified filler

[0081] Take: activated kaolin 40g, activated diatomite 20g and polyacrylic acid 10g in the reaction kettle, mix well, then transfer to the muffle furnace for the first calcination, the muffle furnace to 800℃ at a heating rate of 5℃ / min, keep reaction 4h, natural cooling to room temperature, with 1:35 of the impregnation ratio in the furfuryl alcohol for 30min, add 30wt% of hydrochloric acid ethanol solution with a volume of one fifth of the furfuryl alcohol, stirring for 30min, transfer to the tube furnace under the protection of nitrogen atmosphere for the second calcination, the tube furnace to 800℃ at a heating rate of 5℃ / min, keep reaction 4h, natural cooling to room temperature, with 1:35 of the impregnation ratio in 10mol / L potassium hydroxide solution for 2h, transfer to the tube furnace under the protection of nitrogen atmosphere for the third calcination, the tube furnace to 800℃ at a heating rate of 5℃ / min, keep reaction 2h, three times calcination, after the modified filler crude product is reduced to room temperature, washed with 0.5mol / L hydrochloric acid solution for 4 times, then transfer to the oven at a temperature of 80℃, dry to constant weight, get modified filler.

[0082] Example 4

[0083] The embodiment provides a preparation method of a composite modified filler for a corrosion-resistant direct current charging pile connecting cable, comprising the following steps:

[0084] Step 1, preparation of composite modified filler crude product

[0085] Take: magnesium nitrate hexahydrate 60g, aluminum nitrate nonahydrate 90g and deionized water 1000mL, mix well, get mixed salt solution, ready for use;

[0086] Take: modified filler 50g prepared in example 1, ethanol 400mL and deionized water 400mL are placed in the reaction kettle, stirring at room temperature for 15min, adding mixed salt solution 300mL, stirring at room temperature for 15min, adding triethanolamine to pH=8, the reaction liquid is transferred to airtight stainless steel reaction kettle, the reaction kettle is heated to 120℃, and the reaction is kept for 1h. After the reaction is completed, the reaction system is cooled to room temperature, filtered, the filter cake is washed to neutral with deionized water, transferred to a freeze dryer with a temperature of-60℃, and freeze dried for 4h to obtain the composite modified filler crude product.

[0087] Step 2, preparation of composite modified filler

[0088] Take: composite modified filler crude product 40g, ethanol 600mL, γ-methacryloxypropyl trimethoxysilane 5g and deionized water 50mL are placed in the reaction kettle and stirred, 0.5mol / L acetic acid solution 20mL is added, the reaction kettle is heated to 50℃, and the reaction is kept for 2h. After the reaction is completed, the reaction system is cooled to room temperature, filtered, the filter cake is washed with ethanol and deionized water for 2 times, transferred to an oven with a temperature of 50℃, dried to constant weight to obtain the composite modified filler.

[0089] Example 5

[0090] The embodiment provides a preparation method of a composite modified filler for a corrosion-resistant direct current charging pile connecting cable, comprising the following steps:

[0091] Step 1, preparation of composite modified filler crude product

[0092] Take: magnesium nitrate 70g, aluminum nitrate 100g and deionized water 1250mL are mixed uniformly to obtain a mixed salt solution, which is used for standby;

[0093] Take: modified filler 75g prepared in example 2, ethanol 400mL and deionized water 400mL are placed in the reaction kettle, stirring at room temperature for 20min, adding mixed salt solution 400mL, stirring at room temperature for 25min, adding triethanolamine to pH=9, the reaction liquid is transferred to airtight stainless steel reaction kettle, the reaction kettle is heated to 130℃, and the reaction is kept for 1.5h. After the reaction is completed, the reaction system is cooled to room temperature, filtered, the filter cake is washed to neutral with deionized water, transferred to a freeze dryer with a temperature of-60℃, and freeze dried for 5h to obtain the composite modified filler crude product.

[0094] Step 2, preparation of composite modified filler

[0095] Take: 50g of the crude composite modified filler, 700mL of ethanol, 7g of gamma-methacryloxypropyltrimethoxysilane and 75mL of deionized water are placed in a reaction kettle for stirring, 30mL of 1.0mol / L acetic acid aqueous solution is added, the reaction kettle is heated to 55℃, and the reaction is kept for 3h. After the reaction is completed, the reaction system is cooled to room temperature, and then filtered. The filter cake is washed with ethanol and deionized water for 3 times, and then transferred to an oven with a temperature of 55℃ for drying until the weight is constant to obtain the composite modified filler.

[0096] Example 6

[0097] The present embodiment provides a preparation method of a composite modified filler for a corrosion-resistant DC charging pile connecting cable, comprising the following steps:

[0098] Step 1, preparation of the crude composite modified filler

[0099] Take: 80g of magnesium nitrate hexahydrate, 110g of aluminum nitrate nonahydrate and 600mL of deionized water are mixed uniformly to obtain a mixed salt solution, which is used for standby;

[0100] Take: 100g of the modified filler prepared in Example 3, 400mL of ethanol and 400mL of deionized water are placed in a reaction kettle, stirred at room temperature for 30min, 500mL of the mixed salt solution is added, stirred at room temperature for 30min, and triethanolamine is added dropwise until the pH is 10. The reaction liquid is transferred to a closed stainless steel reaction kettle, the reaction kettle is heated to 150℃, and the reaction is kept for 2h. After the reaction is completed, the reaction system is cooled to room temperature, and then filtered. The filter cake is washed with deionized water until it is neutral, and then transferred to a freeze-drying machine with a temperature of -60℃ for freeze-drying for 6h to obtain the crude composite modified filler.

[0101] Step 2, preparation of the composite modified filler

[0102] Take: 60g of the crude composite modified filler, 800mL of ethanol, 10g of gamma-methacryloxypropyltrimethoxysilane and 100mL of deionized water are placed in a reaction kettle for stirring, 40mL of 1.0mol / L acetic acid aqueous solution is added, the reaction kettle is heated to 60℃, and the reaction is kept for 4h. After the reaction is completed, the reaction system is cooled to room temperature, and then filtered. The filter cake is washed with ethanol and deionized water for 4 times, and then transferred to an oven with a temperature of 60℃ for drying until the weight is constant to obtain the composite modified filler.

[0103] Example 7

[0104] The present embodiment provides a preparation method of a modified epoxy resin for a corrosion-resistant DC charging pile connecting cable, comprising the following steps:

[0105] Step 1, preparation of the intermediate I

[0106] Take: 4,4'-bis(methoxymethyl)diphenyl 40 g and N-methyl pyrrolidone 500 mL in the reaction kettle stirring, 4-allyl phenol 50 g in three equal amounts, add 35 wt% hydrochloric acid 5 mL, the reaction kettle to 105 ℃, keep the reaction for 8 h, after treatment to obtain intermediate I.

[0107] Step 2, preparation of modified epoxy resin

[0108] Take: intermediate I 80 g and epichlorohydrin 250 mL in the reaction kettle stirring, the reaction kettle to 60 ℃, add 1 g of tetramethylammonium bromide, keep the reaction for 15 min, add 5 g of sodium hydroxide, keep the reaction for 2 h, after the reaction, the reaction system is reduced to room temperature, filter, filter cake is washed with deionized water 2 times, transfer to the oven at a temperature of 50 ℃, dry to constant weight, to obtain modified epoxy resin.

[0109] Example 8

[0110] The present embodiment provides a preparation method of a modified epoxy resin for a corrosion-resistant DC charging pile connecting cable, comprising the following steps:

[0111] Step 1, preparation of intermediate I

[0112] Take: 4,4'-bis(methoxymethyl)diphenyl 50 g and N-methyl pyrrolidone 750 mL in the reaction kettle stirring, 4-allyl phenol 60 g in three equal amounts, add 38 wt% hydrochloric acid 5 mL, the reaction kettle to 110 ℃, keep the reaction for 9 h, after treatment to obtain intermediate I.

[0113] Step 2, preparation of modified epoxy resin

[0114] Take: intermediate I 90 g and epichlorohydrin 275 mL in the reaction kettle stirring, the reaction kettle to 65 ℃, add 1.5 g of tetramethylammonium bromide, keep the reaction for 20 min, add 7 g of sodium hydroxide, keep the reaction for 3 h, after the reaction, the reaction system is reduced to room temperature, filter, filter cake is washed with deionized water 3 times, transfer to the oven at a temperature of 55 ℃, dry to constant weight, to obtain modified epoxy resin.

[0115] Example 9

[0116] The present embodiment provides a preparation method of a modified epoxy resin for a corrosion-resistant DC charging pile connecting cable, comprising the following steps:

[0117] Step 1, preparation of intermediate I

[0118] Take: 4,4'-bis(methoxymethyl)diphenyl 60 g and N-methyl pyrrolidone 1000 mL in the reaction kettle stirring, 4-allyl phenol 70 g in three equal amounts, add 40 wt% hydrochloric acid 10 mL, the reaction kettle to 115 ℃, keep the reaction for 10 h, after treatment to obtain intermediate I.

[0119] Step 2, preparation of modified epoxy resin

[0120] Take: intermediate I 100 g and epichlorohydrin 300 mL in the reaction kettle stirring, the reaction kettle to 70 ℃, add 2 g of tetramethylammonium bromide, keep the reaction for 30 min, add 10 g of sodium hydroxide, keep the reaction for 4 h, after the reaction, the reaction system is reduced to room temperature, filter, filter cake is washed with deionized water 4 times, transfer to the oven at a temperature of 60 ℃, dry to constant weight, to obtain modified epoxy resin.

[0121] Example 10

[0122] The present embodiment provides a preparation method of a corrosion-resistant direct-current charging pile connecting cable, comprising the following steps:

[0123] Step A, preparation of powder coating

[0124] Mix N,N'-diphenyl-p-phenylenediamine, 2-hydroxy-4-n-octyloxybenzophenone, benzoyl peroxide and fatty acid amide in a mass ratio of 1:2:1:5 to obtain an auxiliary additive, ready for use;

[0125] Take by weight: 75 parts of the modified epoxy resin prepared in example 7, 10 parts of the composite modified filler prepared in example 4 and 10 parts of the auxiliary additive are mixed uniformly, ground and passed through a 200 mesh sieve to obtain a powder coating.

[0126] Step D, preparation of connecting cable

[0127] After the powder coating is coated on the outside of the cable substrate, it is transferred to an oven at a temperature of 90 ℃ for curing for 6 h to obtain a connecting cable.

[0128] Example 11

[0129] The present embodiment provides a preparation method of a corrosion-resistant direct-current charging pile connecting cable, comprising the following steps:

[0130] Step A, preparation of powder coating

[0131] Mix N,N'-diphenyl-p-phenylenediamine, 2-hydroxy-4-n-octyloxybenzophenone, benzoyl peroxide and fatty acid amide in a mass ratio of 1:2:1:5 to obtain an auxiliary additive, ready for use;

[0132] Take by weight parts: 70 parts of modified epoxy resin prepared in Example 8, 7 parts of composite modified filler prepared in Example 5 and 7.5 parts of auxiliary additive are mixed uniformly, ground and sieved through a 200 mesh screen to obtain a powder coating.

[0133] Step ⒝, preparation of connecting cable

[0134] After the powder coating is coated on the outside of the cable substrate, it is transferred to an oven with a temperature of 90℃ for curing for 6h to obtain a connecting cable.

[0135] Example 12

[0136] The present embodiment provides a preparation method of a corrosion-resistant DC charging pile connecting cable, comprising the following steps:

[0137] Step ⒜, preparation of powder coating

[0138] N,N'-diphenyl-p-phenylenediamine, 2-hydroxy-4-n-octyloxybenzophenone, benzoyl peroxide and fatty acid amide are mixed uniformly in a mass ratio of 1:2:1:5 to obtain an auxiliary additive for standby;

[0139] Take by weight parts: 75 parts of modified epoxy resin prepared in Example 9, 10 parts of composite modified filler prepared in Example 6 and 10 parts of auxiliary additive are mixed uniformly, ground and sieved through a 200 mesh screen to obtain a powder coating.

[0140] Step ⒝, preparation of connecting cable

[0141] After the powder coating is coated on the outside of the cable substrate, it is transferred to an oven with a temperature of 90℃ for curing for 6h to obtain a connecting cable.

[0142] Comparative Example 1

[0143] The difference between this comparative example and Example 12 is that in Step ①, the equal proportion of activated diatomite and activated kaolin is used instead of the modified filler in the preparation of the composite modified filler crude product.

[0144] Comparative Example 2

[0145] The difference between this comparative example and Example 12 is that in Step ⒜, the composite modified filler crude product is used instead of the composite modified filler in the preparation of the powder coating.

[0146] Comparative Example 3

[0147] The difference between this comparative example and Example 2 is that in Step ⒜, the commercial bisphenol A type epoxy resin is used instead of the modified epoxy resin in the preparation of the powder coating.

[0148] Performance test:

[0149] Tensile strength and elongation at break of the connecting cable samples prepared in Examples 10-12 and Comparative Examples 1-3 were determined according to the standard XF 306.1-2007 “Flame-retardant and fire-resistant cables - Plastics insulation - Classification and requirements of flame-retardant and fire-resistant cables - Part 1: Flame-retardant cables”;

[0150] The connecting cable samples prepared in Examples 10-12 and Comparative Examples 1-3 were subjected to ultraviolet irradiation test according to the standard GB / T 14522-2008 “Artificial weathering test methods of plastics, paints and rubber materials for mechanical industry products - Fluorescent UV lamp”, and the tensile strength and elongation at break of the connecting cable samples after ultraviolet aging test were determined according to XF 306.1-2007;

[0151] The connecting cable samples prepared in Examples 10-12 and Comparative Examples 1-3 were subjected to salt mist corrosion resistance test according to the standard T / SHPTA 043-2023 “Cable material for salt corrosion resistant and torsion resistant control cable of offshore wind power system”, and the tensile strength and elongation at break of the connecting cable samples after ultraviolet aging test were determined according to XF 306.1-2007, and the specific data are shown in Table 1.

[0152] Table 1 - Performance test data table of each sample

[0153]

[0154] Data analysis:

[0155] Comparative analysis of the data in Table 1 shows that the original tensile strength of the connecting cable prepared by the present application is 19.6 MPa and the elongation at break is 285.5%, the tensile strength after salt mist corrosion resistance test is 18.3 MPa and the elongation at break is 274.9%, and the tensile strength after ultraviolet aging test is 17.2 MPa and the elongation at break is 268.9%, all of which are better than those of the comparative examples;

[0156] The present application is a modified filler with mesoporous structure prepared by blending activated kaolin and activated diatomite with polyacrylic acid and calcining three times, introducing triethanolamine into the modified filler to adjust the pH and performing hydrothermal reaction, further modifying by γ-methacryloyloxypropyltrimethoxysilane to obtain a composite modified filler, condensing 4,4'-bis(methoxymethyl)biphenyl with 4-allylphenol to obtain intermediate I, and then performing substitution reaction with epichlorohydrin grafting and participation of tetramethylammonium bromide and sodium hydroxide to form a modified epoxy resin containing rich epoxy groups and allyl structures, mixing the modified epoxy resin, the composite modified filler, the curing agent and the auxiliary additive uniformly, grinding, sieving to obtain a powder coating; after the powder coating is coated on the outside of the cable matrix and heat cured, a connecting cable is obtained, which not only improves the corrosion resistance of the connecting cable, but also improves its ultraviolet resistance and mechanical properties.

[0157] The preferred embodiments of the application disclosed above are only to facilitate the elucidation of the application. The preferred embodiments do not describe all the details of the application and limit the application to the specific embodiments. Obviously, many modifications and variations can be made in light of the teachings above. The description is chosen and described in order to provide the best illustration of the application principles and their practical application, so that those skilled in the art can well understand and utilize the application. The application is limited only by the claims and their full scope and equivalents.

Claims

1. A corrosion-resistant DC charging pile connection cable, comprising a cable base and a corrosion-resistant layer, characterized in that, The corrosion-resistant layer is obtained by applying powder coating to the outside of the cable substrate and then heat curing it; The powder coating comprises the following components by weight: 65-75 parts modified epoxy resin, 5-10 parts composite modified filler, 5-10 parts curing agent and 1-3 parts auxiliary additives.

2. The corrosion-resistant DC charging pile connection cable according to claim 1, characterized in that, The modified epoxy resin is prepared by the following steps: A1. Place 4,4'-bis(methoxymethyl)biphenyl and N-methylpyrrolidone in a reaction vessel and stir. Add 4-allylphenol in three equal portions, followed by hydrochloric acid aqueous solution. Heat the reaction vessel to 105-115℃ and keep the reaction at this temperature for 8-10 hours. After post-treatment, intermediate I is obtained. A2. Place intermediate I and epichlorohydrin in a reaction vessel and stir. Heat the reaction vessel to 60-70℃, add tetramethylammonium bromide, and keep the reaction at this temperature for 15-30 minutes. Add sodium hydroxide and keep the reaction at this temperature for 2-4 hours. Post-treatment yields the modified epoxy resin.

3. The corrosion-resistant DC charging pile connection cable according to claim 2, characterized in that, In step A1, the ratio of 4,4'-bis(methoxymethyl)biphenyl, N-methylpyrrolidone, 4-allylphenol, and hydrochloric acid aqueous solution is 4-6g:50-100mL:5-7g:0.5-1mL, and the concentration of the hydrochloric acid aqueous solution is 35-40wt%; in step A2, the ratio of intermediate I, epichlorohydrin, tetramethylammonium bromide, and sodium hydroxide is 8-10g:25-30mL:0.1-0.2g:0.5-1g.

4. The corrosion-resistant DC charging pile connection cable according to claim 1, characterized in that, The composite modified filler is prepared by the following steps: B1. Place the modified filler, ethanol and deionized water in a reaction vessel, stir at room temperature for 15-30 min, add the mixed salt solution, stir at room temperature for 15-30 min, add triethanolamine dropwise until pH=8-10, perform hydrothermal reaction, and then process to obtain the crude composite modified filler. B2. The crude composite modified filler, ethanol, γ-methacryloxypropyltrimethoxysilane and deionized water are placed in a reaction vessel and stirred. An aqueous acetic acid solution is added, the reaction vessel is heated to 50-60℃, and the reaction is maintained for 2-4 hours. The composite modified filler is then obtained after post-treatment.

5. The corrosion-resistant DC charging pile connection cable according to claim 4, characterized in that, In step B1, the ratio of the modified filler, ethanol, deionized water, and mixed salt solution is 5-10g:40mL:40mL:30-50mL, and the mixed salt solution is composed of magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, and deionized water in a ratio of 6-8g:9-11g:100-150mL. In step B2, the ratio of the crude composite modified filler, ethanol, γ-methacryloyloxypropyltrimethoxysilane, deionized water, and acetic acid aqueous solution is 4-6g:60-80mL:0.5-1g:5-10mL:2-4mL, and the concentration of the acetic acid aqueous solution is 0.5-1.0mol / L.

6. The corrosion-resistant DC charging pile connection cable according to claim 4, characterized in that, The modified filler is prepared by the following steps: C1. Place kaolin, potassium hydroxide and deionized water in a reaction vessel and stir. Heat the reaction vessel to 75-85℃ and keep it at this temperature for 2-4 hours. Post-treatment yields activated kaolin. C2. Place diatomaceous earth, concentrated sulfuric acid and deionized water in a reaction vessel and stir. Heat the reaction vessel to 75-85℃ and keep it at this temperature for 2-4 hours. Post-treatment yields activated diatomaceous earth. C3. Activated kaolin, activated diatomaceous earth and polyacrylic acid are placed in a reaction vessel, mixed evenly, and then calcined three times. The modified filler is obtained after post-treatment.

7. The corrosion-resistant DC charging pile connection cable according to claim 6, characterized in that, In step C1, the ratio of kaolin, potassium hydroxide and deionized water is 2-4g:2g:6mL; the ratio of diatomaceous earth, concentrated sulfuric acid and deionized water is 2-4g:2mL:8mL; in step C2, the weight ratio of activated kaolin, activated diatomaceous earth and polyacrylic acid is 2-4g:1-2g:0.5-1g.

8. A method for preparing a corrosion-resistant DC charging pile connection cable as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Mix the modified epoxy resin, composite modified filler, curing agent and auxiliary additives evenly, grind and sieve to obtain powder coating; S2. After the powder coating is applied to the outside of the cable substrate, it is heat-cured to obtain the connecting cable.

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