Anti-aging cable for photovoltaic power generation

Abstract

The invention discloses an anti-aging cable for photovoltaic power generation and a preparation method thereof, and relates to the technical field of cables. The anti-aging cable for photovoltaic power generation prepared by the invention comprises a conductor and a protective layer, the protective layer comprises modified polyethylene, modified silicon dioxide and phenylamino-terminated silicone oil, and the modified polyethylene is obtained by grafting polyethylene with N, N-dimethyl-3-buteneamine and then reacting with 3-(tert-butyl)-5-(chloromethyl)-2-hydroxybenzaldehyde; the modified silicon dioxide is obtained by grafting pretreated silicon dioxide with stilbene phosphine oxide and then carrying out formylation; and finally, uniformly mixing and extruding the modified polyethylene, the modified silicon dioxide and the phenylamino-terminated silicon oil to obtain the protective layer. The anti-aging cable for photovoltaic power generation prepared by the invention has good flame retardance, mechanical property and anti-aging property.

Description

Technical Field

[0001] The present invention relates to the technical field of cables, in particular to an aging-resistant cable for photovoltaic power generation. Background Art

[0002] Photovoltaic power cables are the key carriers connecting photovoltaic modules and power systems. Their performance is directly related to the long-term stable operation of the entire power station. Traditional cables have formed a mature structure in conventional power transmission scenarios and are generally composed of a conductor, a protective layer, and an optional shielding layer:

[0003] Although traditional materials for protective layers, such as polyvinyl chloride, are low-cost, they have the disadvantages of poor weather resistance and brittleness. Therefore, new cables often use thermoplastic polyurethane, chloroprene rubber or cross-linked polyolefins to enhance mechanical strength and environmental adaptability.

[0004] The protective layer must simultaneously perform multiple functions, including resisting mechanical stresses (such as stretching and extrusion) during installation and operation, blocking the penetration of moisture and chemically corrosive media, inhibiting material degradation caused by ultraviolet radiation, and reducing fire risks through flame-retardant design. However, photovoltaic cables are exposed to complex outdoor environments for long periods of time and face multiple severe challenges: First, in humid and rainy areas or when laid near soil, the surface of the protective layer is prone to the growth of microorganisms such as mold and algae, and their metabolites accelerate the decomposition of the material and reduce insulation performance. Second, the continuous strong ultraviolet radiation and extreme temperature cycles in the outdoor environment can cause the molecular chains of traditional sheath materials to break, causing powdering, cracking, and even insulation failure. In addition, rainwater penetration can easily cause conductor oxidation and short circuits. The high-voltage characteristics of photovoltaic systems require cables to have a high flame retardant rating, so the protective layer must be both waterproof and flame-retardant.

[0005] Therefore, developing a new protective layer material and preparation process that integrates multifunctional synergies such as anti-aging, antibacterial, flame retardant and waterproof has become a key technical direction to improve the durability and safety of photovoltaic cables. Summary of the Invention

[0006] The purpose of this section is to summarize some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of this application to avoid obscuring the purpose of this section, the abstract and the title of the invention, and such simplifications or omissions should not be used to limit the scope of the present invention.

[0007] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0008] Therefore, the purpose of the present invention is to overcome the deficiencies in the prior art and provide an aging-resistant photovoltaic power generation cable.

[0009] In order to solve the above technical problems, the present invention provides the following technical solutions: comprising:

[0010] An aging-resistant photovoltaic power generation cable, comprising a conductor and a protective layer from the inside out, wherein the protective layer is prepared as follows:

[0011] (1) Grafting N,N-dimethyl-3-buteneamine onto polyethylene to obtain pre-modified polyethylene; reacting the pre-modified polyethylene with 3-(tert-butyl)-5-(chloromethyl)-2-hydroxybenzaldehyde to obtain modified polyethylene;

[0012] (2) Octamethylcyclotetrasiloxane and bis(4-aminophenoxy)dimethylsilane are reacted to obtain terminal aminophenyl silicone oil;

[0013] (3) reacting pretreated silica and distyrylphosphine oxide to obtain pre-modified silica;

[0014] (4) Formaldehyde-forming the pre-modified silica to obtain modified silica;

[0015] (5) The modified polyethylene, modified silica, catalyst, plasticizer, and terminal amino silicone oil are mixed and extruded to obtain a protective layer.

[0016] Preferably, the preparation method of the modified polyethylene in step (1) is: dissolving polyethylene in xylene at 130-140°C, adding N,N-dimethyl-3-buteneamine and benzoyl peroxide-xylene solution at 110-120°C, and reacting for 90-120 minutes to obtain pre-modified polyethylene; preferably, the benzoyl peroxide-xylene solution is obtained by mixing benzoyl peroxide and xylene in a mass ratio of 1:10; the mass ratio of the polyethylene, xylene, N,N-dimethyl-3-buteneamine, and benzoyl peroxide-xylene solution is 1:(1 0-12):(0.2-0.3):(0.05-0.1); under nitrogen protection, the pre-modified polyethylene is dissolved in xylene at 130-140 ° C, and 3-(tert-butyl)-5-(chloromethyl)-2-hydroxybenzaldehyde and triethylamine are added at 110-120 ° C, and the reaction is carried out for 10-12 hours to obtain modified polyethylene; preferably, the mass ratio of the pre-modified polyethylene, xylene, 3-(tert-butyl)-5-(chloromethyl)-2-hydroxybenzaldehyde and triethylamine is 1:(10-12):(0.2-0.3):(0.3-0.5).

[0017] Preferably, the preparation method of the terminal amino silicone oil in step (2) is: under nitrogen protection, octamethylcyclotetrasiloxane, bis(4-aminophenoxy)dimethylsilane, tetramethylammonium hydroxide, and dimethyl sulfoxide are reacted at 80-90°C for 3-4 hours, and the temperature is raised to 140-150°C for reaction for 1-2 hours to obtain the terminal amino silicone oil.

[0018] Preferably, the molar ratio of octamethylcyclotetrasiloxane, bis(4-aminophenoxy)dimethylsilane, and tetramethylammonium hydroxide is 1:(0.8-1.0):(1.5-2.0); and the amount of dimethyl sulfoxide added is 0.5%-1% of the total mass of octamethylcyclotetrasiloxane and bis(4-aminophenoxy)dimethylsilane.

[0019] Preferably, the preparation method of the pre-modified silica in step (3) is as follows: nano-silica and anhydrous ethanol are ultrasonically mixed in a mass ratio of 1:(10-30) to obtain a dispersion, mercaptopropyltrimethoxysilane and pure water are mixed in a mass ratio of 1:(2-5) and then added to the dispersion, refluxed at 60-70°C for 3-5h, filtered, washed, and dried to obtain pre-treated silica; the mass ratio of nano-silica and mercaptopropyltrimethoxysilane is 1:(0.2-0.5); under nitrogen protection, the pre-treated silica, distyrylphosphine oxide, tetrahydrofuran, and a photoinitiator are mixed, irradiated under ultraviolet light for 1-2h, and filtered, washed, and dried to obtain pre-modified silica.

[0020] Preferably, the mass ratio of the pretreated silica, distyrylphosphine oxide, tetrahydrofuran, and photoinitiator is 1:(0.2-0.3):(50-60):(0.05-0.07); and the parameters of the ultraviolet lamp are 1000W, 365nm.

[0021] Preferably, the preparation method of the modified silica in step (4) is as follows: adding phosphorus oxychloride to N,N-dimethylformamide at 0-5°C and continuing the reaction for 30-40 minutes to obtain an activator; maintaining the temperature of the reaction system at 0-15°C; dispersing the pre-modified silica in N,N-dimethylformamide, adding the activator, heating to 60-70°C and reacting for 2-3 hours; after the reaction is completed, cooling to 0°C, adding an ice-water mixture, adjusting the pH to 6-7 with sodium hydroxide, continuing stirring for 1-2 hours, filtering, washing, and drying to obtain the modified silica.

[0022] Preferably, during the preparation of the activator, the mass ratio of N,N-dimethylformamide to phosphorus oxychloride is 5:1; the mass ratio of the pre-modified silica, N,N-dimethylformamide, activator, and ice-water mixture is 1:(20-30):(6-8):(30-50).

[0023] Preferably, in step (5), the mass ratio of the modified polyethylene, modified silica, catalyst, plasticizer, and terminal amino silicone oil is 1:(0.1-0.12):(0.01-0.02):(0.01-0.02):(0.01-0.02); the catalyst is zinc chloride; the extrusion instrument is a twin-screw extruder, the screw speed of the twin-screw extruder is 150r / min, and the heating temperatures of each section of the extruder are: 180℃, 190℃, 200℃, 200℃, 200℃, 200℃, 190℃.

[0024] The keto→enol tautomerism mechanism is shown below: .

[0025] Beneficial effects of the present invention:

[0026] The aging-resistant photovoltaic power generation cable prepared by the present invention comprises a conductor and a protective layer; the protective layer comprises modified polyethylene, modified silica, and terminal phenylamino silicone oil, wherein the modified polyethylene is obtained by grafting N,N-dimethyl-3-butenamine onto polyethylene and then reacting with 3-(tert-butyl)-5-(chloromethyl)-2-hydroxybenzaldehyde; the modified silica is obtained by grafting distyrylphosphine oxide onto pretreated silica and then aldehyde-forming; finally, the modified polyethylene, modified silica, and terminal phenylamino silicone oil are mixed and extruded to obtain the protective layer.

[0027] First, the protective sheath uses polyethylene as the base material. The polyethylene chain segment is grafted with N,N-dimethyl-3-buteneamine and then reacts with 3-(tert-butyl)-5-(chloromethyl)-2-hydroxybenzaldehyde to generate a quaternary ammonium salt structure with antibacterial properties, giving the material certain antibacterial properties; 3-(tert-butyl)-5-(chloromethyl)-2-hydroxybenzaldehyde has a hindered phenol structure with free radical capture ability, which can effectively inhibit the chain degradation reaction caused by thermal oxidative aging when the cable is exposed to high temperature environment for a long time.

[0028] Secondly, the uniform distribution of silica as a filler in the matrix also produces a significant reinforcement effect, which can enhance the mechanical properties of the protective cover; after the silica is pre-modified with mercaptopropyltrimethoxysilane, the abundant thiol groups on the surface provide active sites for subsequent click chemistry reactions. Under the initiation of ultraviolet light, distyrylphosphine oxide is precisely grafted to the silica surface through a thiol-ene reaction. In terms of flame retardancy, the phosphoric acid substances produced by the decomposition of this compound at high temperature can catalyze the formation of a carbon layer, giving the material excellent flame retardancy. Its rigid benzene ring structure produces physical entanglement with the polyethylene chain segment, significantly improving the interfacial bonding strength; making the dispersion uniformity of nano-silica in the matrix higher.

[0029] Finally, the modified polyethylene, modified silica, and end-phenylamino silicone oil are mixed and extruded to obtain a protective layer. The introduction of end-phenylamino silicone oil as a processing aid improves the processing fluidity of the nanocomposite by reducing the melt viscosity. The low surface energy siloxane chain segments can enhance the material's waterproof properties. The end-phenylamino groups of its molecular chain react with the aldehyde groups in the polyethylene side chains and the aldehyde-modified silica via Schiff base crosslinking to form a more complex crosslinked network, enhancing the material's mechanical properties. At the same time, the introduction of end-phenylamino silicone oil further strengthens the antioxidant defense system. The Schiff base formed by end-phenylamino silicone oil and 3-(tert-butyl)-5-(chloromethyl)-2-hydroxybenzaldehyde in the polyethylene side chain forms intramolecular hydrogen bonds through the benzene ring-imine (C=N) conjugated system and the hydroxyl group and imine group. After absorbing ultraviolet light, proton transfer occurs (keto-enol tautomerism), converting ultraviolet energy into heat or low-energy radiation, which can delay the photooxidation process of the material surface caused by ultraviolet light. This two-pronged antioxidant mechanism further enhances the material's anti-aging properties. DETAILED DESCRIPTION

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0031] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0032] In the following examples and comparative examples, the polyethylene model is HE3490-LS; the plasticizer is dioctyl adipate; the nano-silica particle size is 200 nm; the conductor is copper, and the remaining raw materials are all commercially available in the art unless otherwise specified.

[0033] Example 1:

[0034] An aging-resistant photovoltaic power generation cable, characterized in that the cable comprises a conductor and a protective layer from the inside to the outside, and the protective layer is prepared as follows:

[0035] (1) Polyethylene was dissolved in xylene at 140°C, N,N-dimethyl-3-butenylamine and benzoyl peroxide-xylene solution were added at 120°C, and the mixture was reacted for 120 minutes. The pre-modified polyethylene was obtained by precipitation with cold acetone, washing, and drying. The benzoyl peroxide-xylene solution was obtained by mixing benzoyl peroxide and xylene in a mass ratio of 1:10. The mass ratios of polyethylene, xylene, N,N-dimethyl-3-butenylamine, and benzoyl peroxide-xylene solution were: The ratio is 1:10:0.2:0.05; under nitrogen protection, the pre-modified polyethylene is dissolved in xylene at 140°C, 3-(tert-butyl)-5-(chloromethyl)-2-hydroxybenzaldehyde and triethylamine are added at 120°C, and the reaction is carried out for 12 hours. The modified polyethylene is precipitated with cold acetone, washed, and dried; the mass ratio of the pre-modified polyethylene, xylene, 3-(tert-butyl)-5-(chloromethyl)-2-hydroxybenzaldehyde, and triethylamine is 1:10:0.2:0.3;

[0036] (2) Under nitrogen protection, octamethylcyclotetrasiloxane, bis(4-aminophenoxy)dimethylsilane, tetramethylammonium hydroxide, and dimethyl sulfoxide were reacted at 90°C for 4 hours, then heated to 150°C for 2 hours, and distilled under reduced pressure to obtain terminal aminosilicone oil; the molar ratio of octamethylcyclotetrasiloxane, bis(4-aminophenoxy)dimethylsilane, and tetramethylammonium hydroxide was 1:0.8:1.5, and the amount of dimethyl sulfoxide added was 0.5% of the total mass of octamethylcyclotetrasiloxane and bis(4-aminophenoxy)dimethylsilane;

[0037] (3) Nano-silica and anhydrous ethanol were ultrasonically mixed in a mass ratio of 1:10 to obtain a dispersion, mercaptopropyl trimethoxysilane and pure water were mixed in a mass ratio of 1:2 and added to the dispersion, and refluxed at 70°C for 5 hours, and filtered, washed, and dried to obtain pretreated silica; the mass ratio of nano-silica and mercaptopropyl trimethoxysilane was 1:0.2; under nitrogen protection, pretreated silica, distyryl phosphine oxide, tetrahydrofuran, and photoinitiator 2,2-dimethoxy-2-phenylacetophenone were mixed in a mass ratio of 1:0.2:50:0.05, irradiated under 1000W, 365nm ultraviolet light for 2 hours, and filtered, washed, and dried to obtain pre-modified silica;

[0038] (4) In N,N-dimethylformamide at 0°C, phosphorus oxychloride was added at a rate of 0.5 mL / min, and the reaction was continued for 40 minutes after the addition was completed to obtain an activator, and the reaction system temperature was maintained at 15°C; the mass ratio of N,N-dimethylformamide to phosphorus oxychloride was 5:1; pre-modified silica was dispersed in N,N-dimethylformamide, a catalyst was added, and the temperature was raised to 70°C for reaction for 3 hours. After the reaction was completed, the temperature was lowered to 0°C, an ice-water mixture was added, and the pH was adjusted to 7 with sodium hydroxide, and the mixture was stirred for 2 hours. The mixture was filtered, washed, and dried to obtain modified silica; the mass ratio of pre-modified silica, N,N-dimethylformamide, activator, and ice-water mixture was 1:20:6:30;

[0039] (5) Add modified polyethylene, modified silica, catalyst zinc chloride, plasticizer, and terminal phenylamino silicone oil into a high-speed mixer in a mass ratio of 1:0.1:0.01:0.01:0.01 and mix well. Then transfer the mixture to a twin-screw extruder to extrude and obtain a protective layer. The screw speed of the twin-screw extruder is 150 r / min, and the heating temperatures of each section of the extruder are: 180°C, 190°C, 200°C, 200°C, 200°C, 200°C, 190°C.

[0040] Example 2:

[0041] An aging-resistant photovoltaic power generation cable, characterized in that the cable comprises a conductor and a protective layer from the inside to the outside, and the protective layer is prepared as follows:

[0042] (1) Polyethylene was dissolved in xylene at 135°C, N,N-dimethyl-3-buteneamine and benzoyl peroxide-xylene solution were added at 115°C, and the mixture was reacted for 105 minutes. The pre-modified polyethylene was obtained by precipitation with cold acetone, washing, and drying. The benzoyl peroxide-xylene solution was obtained by mixing benzoyl peroxide and xylene in a mass ratio of 1:10. The mass ratio of polyethylene, xylene, N,N-dimethyl-3-buteneamine, and benzoyl peroxide-xylene solution was 1:10. The weight ratio of the pre-modified polyethylene, xylene, 3-(tert-butyl)-5-(chloromethyl)-2-hydroxybenzaldehyde and triethylamine was 1:11:0.25:0.07; under nitrogen protection, the pre-modified polyethylene was dissolved in xylene at 135°C, 3-(tert-butyl)-5-(chloromethyl)-2-hydroxybenzaldehyde and triethylamine were added at 115°C, and the reaction was carried out for 11 hours. The modified polyethylene was precipitated with cold acetone, washed, and dried; the mass ratio of the pre-modified polyethylene, xylene, 3-(tert-butyl)-5-(chloromethyl)-2-hydroxybenzaldehyde, and triethylamine was 1:11:0.25:0.4;

[0043] (2) Under nitrogen protection, octamethylcyclotetrasiloxane, bis(4-aminophenoxy)dimethylsilane, tetramethylammonium hydroxide, and dimethyl sulfoxide were reacted at 85°C for 3.5 hours, then heated to 145°C for 1.5 hours, and distilled under reduced pressure to obtain terminal aminosilicone oil; the molar ratio of octamethylcyclotetrasiloxane, bis(4-aminophenoxy)dimethylsilane, and tetramethylammonium hydroxide was 1:0.9:1.7, and the amount of dimethyl sulfoxide added was 0.7% of the total mass of octamethylcyclotetrasiloxane and bis(4-aminophenoxy)dimethylsilane;

[0044] (3) Nano-silica and anhydrous ethanol were ultrasonically mixed in a mass ratio of 1:20 to obtain a dispersion, mercaptopropyl trimethoxysilane and pure water were mixed in a mass ratio of 1:4 and added to the dispersion, and refluxed at 65°C for 4 hours, and filtered, washed, and dried to obtain pretreated silica; the mass ratio of nano-silica and mercaptopropyl trimethoxysilane was 1:0.4; under nitrogen protection, pretreated silica, distyryl phosphine oxide, tetrahydrofuran, and photoinitiator 2,2-dimethoxy-2-phenylacetophenone were mixed in a mass ratio of 1:0.25:55:0.06, irradiated under 1000W, 365nm ultraviolet light for 1.5 hours, and filtered, washed, and dried to obtain pre-modified silica;

[0045] (4) In N,N-dimethylformamide at 3°C, phosphorus oxychloride was added at a rate of 0.5 mL / min, and the reaction was continued for 35 minutes after the addition was completed to obtain an activator, and the reaction system temperature was maintained at 7°C; the mass ratio of N,N-dimethylformamide to phosphorus oxychloride was 5:1; pre-modified silica was dispersed in N,N-dimethylformamide, a catalyst was added, and the temperature was raised to 65°C for reaction for 2.5 hours. After the reaction was completed, the temperature was lowered to 0°C, and an ice-water mixture was added. After adjusting the pH to 6.5 with sodium hydroxide, the mixture was stirred for 1.5 hours, filtered, washed, and dried to obtain modified silica; the mass ratio of pre-modified silica, N,N-dimethylformamide, activator, and ice-water mixture was 1:25:7:40;

[0046] (5) Modified polyethylene, modified silica, catalyst zinc chloride, plasticizer, and terminal phenylamino silicone oil are added into a high-speed mixer in a mass ratio of 1:0.11:0.015:0.017:0.013 and mixed evenly, and then transferred to a twin-screw extruder to extrude to obtain a protective layer; the screw speed of the twin-screw extruder is 150r / min, and the heating temperatures of each section of the extruder are: 180℃, 190℃, 200℃, 200℃, 200℃, 200℃, 200℃, 190℃.

[0047] Example 3:

[0048] An aging-resistant photovoltaic power generation cable, characterized in that the cable comprises a conductor and a protective layer from the inside to the outside, and the protective layer is prepared as follows:

[0049] (1) Polyethylene was dissolved in xylene at 130°C, N,N-dimethyl-3-buteneamine and benzoyl peroxide-xylene solution were added at 110°C, and the mixture was reacted for 90 minutes. The pre-modified polyethylene was obtained by precipitation with cold acetone, washing, and drying. The benzoyl peroxide-xylene solution was obtained by mixing benzoyl peroxide and xylene in a mass ratio of 1:10. The mass ratios of polyethylene, xylene, N,N-dimethyl-3-buteneamine, and benzoyl peroxide-xylene solution were: The ratio is 1:12:0.3:0.1; under nitrogen protection, the pre-modified polyethylene is dissolved in xylene at 130°C, 3-(tert-butyl)-5-(chloromethyl)-2-hydroxybenzaldehyde and triethylamine are added at 110°C, and the reaction is carried out for 10 hours. The modified polyethylene is precipitated with cold acetone, washed, and dried to obtain the modified polyethylene; the mass ratio of the pre-modified polyethylene, xylene, 3-(tert-butyl)-5-(chloromethyl)-2-hydroxybenzaldehyde, and triethylamine is 1:12:0.3:0.5;

[0050] (2) Under nitrogen protection, octamethylcyclotetrasiloxane, bis(4-aminophenoxy)dimethylsilane, tetramethylammonium hydroxide, and dimethyl sulfoxide were reacted at 80°C for 3 h, then heated to 140°C for 1 h, and distilled under reduced pressure to obtain terminal aminosilicone oil; the molar ratio of octamethylcyclotetrasiloxane, bis(4-aminophenoxy)dimethylsilane, and tetramethylammonium hydroxide was 1:1.0:2.0, and the amount of dimethyl sulfoxide added was 1% of the total mass of octamethylcyclotetrasiloxane and bis(4-aminophenoxy)dimethylsilane;

[0051] (3) Nano-silica and anhydrous ethanol were ultrasonically mixed in a mass ratio of 1:3 to obtain a dispersion, mercaptopropyl trimethoxysilane and pure water were mixed in a mass ratio of 1:5 and added to the dispersion, and refluxed at 60°C for 3 hours, and filtered, washed, and dried to obtain pretreated silica; the mass ratio of nano-silica and mercaptopropyl trimethoxysilane was 1:0.5; under nitrogen protection, pretreated silica, distyryl phosphine oxide, tetrahydrofuran, and photoinitiator 2,2-dimethoxy-2-phenylacetophenone were mixed in a mass ratio of 1:0.3:60:0.07, irradiated under 1000W, 365nm ultraviolet light for 1 hour, and filtered, washed, and dried to obtain pre-modified silica;

[0052] (4) In N,N-dimethylformamide at 5°C, phosphorus oxychloride was added at a rate of 0.5 mL / min, and the reaction was continued for 30 min after the addition was completed to obtain an activator, and the reaction system temperature was maintained at 0°C; the mass ratio of N,N-dimethylformamide to phosphorus oxychloride was 5:1; pre-modified silica was dispersed in N,N-dimethylformamide, a catalyst was added, and the temperature was raised to 60°C for reaction for 2 h. After the reaction was completed, the temperature was lowered to 0°C, an ice-water mixture was added, and the pH was adjusted to 6 with sodium hydroxide. The mixture was stirred for 1 h, filtered, washed, and dried to obtain modified silica; the mass ratio of pre-modified silica, N,N-dimethylformamide, activator, and ice-water mixture was 1:30:8:50;

[0053] (5) Modified polyethylene, modified silica, catalyst zinc chloride, plasticizer, and terminal phenylamino silicone oil are added into a high-speed mixer in a mass ratio of 1:0.12:0.02:0.02:0.02 and mixed evenly, and then transferred to a twin-screw extruder to extrude to obtain a protective layer; the screw speed of the twin-screw extruder is 150r / min, and the heating temperatures of each section of the extruder are: 180℃, 190℃, 200℃, 200℃, 200℃, 200℃, 200℃, 190℃.

[0054] Comparative Example 1:

[0055] The aging-resistant photovoltaic power generation cable of Comparative Example 1 differs from that of Example 2 in that polyethylene is not modified, specifically, step (1) is not included, and step (5) is modified as follows: polyethylene, modified silica, catalyst zinc chloride, plasticizer, and terminal amino silicone oil are added into a high-speed mixer in a mass ratio of 1:0.11:0.015:0.017:0.013 and mixed uniformly, and then transferred to a twin-screw extruder for extrusion to obtain a protective layer; the screw speed of the twin-screw extruder is 150 r / min, and the heating temperatures of the various sections of the extruder are: 180°C, 190°C, 200°C, 200°C, 200°C, 200°C, 200°C, and 190°C. The remaining steps are the same as those of Example 2.

[0056] Comparative Example 2:

[0057] The preparation method of the aging-resistant photovoltaic power generation cable of Comparative Example 2 differs from that of Example 2 in that the nano-silica is not modified, specifically, steps (3) to (4) are not included, and step (5) is modified as follows: modified polyethylene, nano-silica, catalyst zinc chloride, plasticizer, and terminal amino silicone oil are added into a high-speed mixer in a mass ratio of 1:0.11:0.015:0.017:0.013 and mixed uniformly, and then transferred to a twin-screw extruder for extrusion to obtain a protective layer; the screw speed of the twin-screw extruder is 150 r / min, and the heating temperatures of the various sections of the extruder are: 180°C, 190°C, 200°C, 200°C, 200°C, 200°C, 200°C, and 190°C. The remaining steps are the same as those of Example 2.

[0058] Comparative Example 3:

[0059] The preparation method of the aging-resistant photovoltaic power generation cable of Comparative Example 3 differs from that of Example 2 in that no terminal aminophenyl silicone oil is added, specifically, step (2) is not included, and step (5) is modified as follows: modified polyethylene, modified silicon dioxide, catalyst zinc chloride, and plasticizer are added to a high-speed mixer in a mass ratio of 1:0.11:0.015:0.017 and mixed uniformly, and then transferred to a twin-screw extruder for extrusion to obtain a protective layer; the screw speed of the twin-screw extruder is 150 r / min, and the heating temperatures of the various sections of the extruder are: 180°C, 190°C, 200°C, 200°C, 200°C, 200°C, 200°C, and 190°C. The remaining steps are the same as those of Example 2.

[0060] The following performance tests were performed on the protective layer materials prepared in the examples and comparative examples:

[0061] Test Example 1:

[0062] Mechanical properties test: The tensile strength of the material was tested according to the standard GB / T2951.11-2008 "General test methods for insulation and sheathing materials of electric and optical cables Part 11: General test methods - Thickness and dimensional measurement - Mechanical properties test". Type 1 dumbbell specimens were prepared with a tensile rate of 500 mm / min.

[0063] Anti-aging performance test:

[0064] Test Method: Aging was performed for 720 hours at 80°C in accordance with the standard GB / T 2951.12-2008, "General Test Methods for Insulation and Sheathing Materials of Electrical and Optical Cables - Part 12: General Test Methods - Thermal Aging Test Method." The tensile strength after aging was measured according to the mechanical properties test method, and the tensile strength retention rate was calculated: tensile strength retention rate = (tensile strength before aging / tensile strength after aging) × 100%. The results are shown in Table 1.

[0065] Table 1 Test results of anti-aging performance

[0066] Tensile strength (MPa) Tensile strength retention rate (%) Example 1 23.33 Example 1 88.24 Example 2 23.76 Example 2 89.37 Example 3 24.02 Example 3 89.42 Comparative Example 1 17.24 Comparative Example 1 53.24 Comparative Example 2 19.36 Comparative Example 2 83.77 Comparative Example 3 15.21 Comparative Example 3 72.69

[0067] From the comparison of the experimental data of Examples 1-3 and Comparative Examples 1-3 in Table 1, it can be found that the materials prepared by the present invention have good mechanical properties and anti-aging properties.

[0068] The mechanical and anti-aging properties of Examples 1-3 are better than those of Comparative Examples 1-3, which shows that, first, the protective sheath uses polyethylene as the base material, and the polyethylene segment is grafted with N,N-dimethyl-3-butenamine and then reacted with 3-(tert-butyl)-5-(chloromethyl)-2-hydroxybenzaldehyde; 3-(tert-butyl)-5-(chloromethyl)-2-hydroxybenzaldehyde has a hindered phenol structure with free radical capture ability, so that when the cable is exposed to a high temperature environment for a long time, it can effectively inhibit the chain degradation reaction caused by thermal oxidative aging; the modified polyethylene, modified silica, and terminal phenylamino silicone oil are mixed and extruded to obtain a protective layer; the phenylamino group at the end of the terminal phenylamino silicone oil molecular chain is cross-linked with the aldehyde group in the polyethylene side chain and the aldehyde-modified silica through Schiff base to form a more complex cross-linked network, thereby enhancing the mechanical properties of the material.

[0069] Test Example 2:

[0070] Flame retardant performance test:

[0071] Test method: Oxygen index was tested according to ISO 4589-2. The sample size was 150 mm long and 10 mm wide. The results are shown in Table 2.

[0072] Table 2 Test results of flame retardant properties

[0073] Oxygen index (%) Oxygen index (%) Example 1 34 Comparative Example 1 32 Example 2 35 Comparative Example 2 27 Example 3 35 Comparative Example 3 30

[0074] From the comparison of the experimental data of Examples 1-3 and Comparative Examples 1-3 in Table 2, it can be found that the material prepared by the present invention has good flame retardant properties.

[0075] The flame retardant properties of Examples 1-3 are better than those of Comparative Example 2, indicating that after the silica is pre-modified with mercaptopropyltrimethoxysilane, the abundant thiol groups on the surface provide active sites for the subsequent click chemistry reaction. Under the initiation of ultraviolet light, distyrylphosphine oxide is precisely grafted to the silica surface through the thiol-ene reaction. In terms of flame retardant properties, the phosphoric acid substances produced by the decomposition of this compound at high temperature can catalyze the formation of a carbon layer, giving the material excellent flame retardant properties.

[0076] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. An aging-resistant photovoltaic power generation cable, characterized in that: The cable comprises a conductor and a protective layer from the inside to the outside, and the protective layer is prepared as follows: (1) Grafting N,N-dimethyl-3-buteneamine onto polyethylene to obtain pre-modified polyethylene; reacting the pre-modified polyethylene with 3-(tert-butyl)-5-(chloromethyl)-2-hydroxybenzaldehyde to obtain modified polyethylene; (2) Octamethylcyclotetrasiloxane and bis(4-aminophenoxy)dimethylsilane are reacted to obtain terminal aminophenyl silicone oil; (3) reacting pretreated silica and distyrylphosphine oxide to obtain pre-modified silica; (4) Formaldehyde-forming the pre-modified silica to obtain modified silica; (5) The modified polyethylene, modified silica, catalyst, plasticizer, and terminal amino silicone oil are mixed and extruded to obtain a protective layer.

2. The aging-resistant photovoltaic power generation cable according to claim 1, characterized in that: The preparation method of the modified polyethylene in step (1) is as follows: dissolving polyethylene in xylene at 130-140° C., adding N,N-dimethyl-3-buteneamine and benzoyl peroxide-xylene solution at 110-120° C., and reacting for 90-120 minutes to obtain pre-modified polyethylene; Under nitrogen protection, the pre-modified polyethylene was dissolved in xylene at 130-140° C., and 3-(tert-butyl)-5-(chloromethyl)-2-hydroxybenzaldehyde and triethylamine were added at 110-120° C. and the reaction was carried out for 10-12 hours to obtain the modified polyethylene.

3. The aging-resistant photovoltaic power generation cable according to claim 2, characterized in that: The benzoyl peroxide-xylene solution is obtained by mixing benzoyl peroxide and xylene in a mass ratio of 1:10; the mass ratio of the polyethylene, N,N-dimethyl-3-buteneamine, and the benzoyl peroxide-xylene solution is 1:(0.2-0.3):(0.05-0.1); the mass ratio of the pre-modified polyethylene, 3-(tert-butyl)-5-(chloromethyl)-2-hydroxybenzaldehyde, and triethylamine is 1:(0.2-0.3):(0.3-0.5).

4. The aging-resistant photovoltaic power generation cable according to claim 1, characterized in that: The preparation method of the terminal amino silicone oil in step (2) is as follows: under nitrogen protection, octamethylcyclotetrasiloxane, bis(4-aminophenoxy)dimethylsilane, tetramethylammonium hydroxide, and dimethyl sulfoxide are reacted at 80-90° C. for 3-4 hours, and the temperature is raised to 140-150° C. and reacted for 1-2 hours to obtain the terminal amino silicone oil.

5. The aging-resistant photovoltaic power generation cable according to claim 4, characterized in that: The molar ratio of octamethylcyclotetrasiloxane, bis(4-aminophenoxy)dimethylsilane and tetramethylammonium hydroxide is 1:(0.8-1.0):(1.5-2.0); the added amount of dimethyl sulfoxide is 0.5%-1% of the total mass of octamethylcyclotetrasiloxane and bis(4-aminophenoxy)dimethylsilane.

6. The aging-resistant photovoltaic power generation cable according to claim 1, characterized in that: The preparation method of the pre-modified silica in step (3) is as follows: nano-silica and anhydrous ethanol are mixed in a mass ratio of 1:(10-30) to obtain a dispersion, mercaptopropyltrimethoxysilane and pure water are mixed in a mass ratio of 1:(2-5) and then added to the dispersion, and refluxed at 60-70°C for 3-5h to obtain pre-treated silica; the mass ratio of nano-silica and mercaptopropyltrimethoxysilane is 1:(0.2-0.5); under nitrogen protection, the pre-treated silica, distyrylphosphine oxide, tetrahydrofuran, and a photoinitiator are mixed, and irradiated under ultraviolet light for 1-2h to obtain pre-modified silica.

7. The aging-resistant photovoltaic power generation cable according to claim 6, characterized in that: The mass ratio of the pretreated silica, distyrylphosphine oxide, tetrahydrofuran and photoinitiator is 1:(0.2-0.3):(50-60):(0.05-0.07); the parameters of the ultraviolet lamp are 1000W, 365nm.

8. The aging-resistant photovoltaic power generation cable according to claim 1, characterized in that: The preparation method of the modified silica in step (4) is as follows: adding phosphorus oxychloride to N,N-dimethylformamide at 0-5°C and continuing the reaction for 30-40 minutes to obtain an activator; maintaining the temperature of the reaction system at 0-15°C; dispersing the pre-modified silica in N,N-dimethylformamide, adding the activator, heating to 60-70°C and reacting for 2-3 hours; after the reaction is completed, cooling to 0°C, adding an ice-water mixture, adjusting the pH to 6-7 with sodium hydroxide, continuing stirring for 1-2 hours, filtering, washing, and drying to obtain the modified silica.

9. The aging-resistant photovoltaic power generation cable according to claim 8, characterized in that: During the preparation of the activator, the mass ratio of N,N-dimethylformamide to phosphorus oxychloride is 5:1; the mass ratio of the pre-modified silica, N,N-dimethylformamide, activator, and ice-water mixture is 1:(20-30):(6-8):(30-50).

10. The aging-resistant photovoltaic power generation cable according to claim 1, characterized in that: In the step (5), the mass ratio of the modified polyethylene, modified silica, catalyst, plasticizer, and terminal amino silicone oil is 1:(0.1-0.12):(0.01-0.02):(0.01-0.02):(0.01-0.02); the catalyst is zinc chloride; the extrusion instrument is a twin-screw extruder, the screw speed of the twin-screw extruder is 150r / min, and the heating temperatures of each section of the extruder are: 180℃, 190℃, 200℃, 200℃, 200℃, 200℃, 190℃.