Flexible string group photovoltaic cable and its preparation method

Abstract

The present invention discloses a flexible string group photovoltaic cable and a preparation method thereof, belonging to the technical field of cable preparation. The flexible string group photovoltaic cable includes an alloy inner conductor, a cross-linked polyolefin layer, a modified glass fiber layer, and a ceramized polyolefin layer which are arranged in sequence from inside to outside. The outside of the alloy inner conductor is tightly wrapped with a cross-linked polyolefin layer material, the outside of the cross-linked polyolefin layer material is wrapped with a layer of modified glass fiber layer material, and the outside of the modified glass fiber layer material is wrapped with a layer of ceramized polyolefin layer. The cable prepared by this method has excellent flame retardancy, low smoke property, abrasion resistance, and toughness.

Description

Technical Field

[0001] The present invention belongs to the technical field of cable preparation, and particularly relates to a flexible series-connected photovoltaic cable and a preparation method thereof. Background Art

[0002] As a core pillar of renewable energy, the system safety, power generation efficiency and full-life cycle cost optimization of photovoltaic power generation have become the key directions for technological breakthroughs in the industry. Traditional photovoltaic cables have bottlenecks in extreme environment adaptability, fire safety protection and power transmission performance. Especially in scenarios such as distributed optical cables, building integration and large-scale ground power stations, problems such as cable material aging, short-circuit explosion risk and insufficient current-carrying capacity are becoming increasingly prominent. Based on this, the research and development of a new generation of photovoltaic cables with low-smoke zero-halogen flame retardancy, non-flammability, high current density and flexibility has become the focus of the industry. Its technological breakthrough is of strategic significance for improving the reliability of photovoltaic systems, reducing operation and maintenance costs and promoting large-scale applications.

[0003] Patent CN112700919B discloses an anti-ultraviolet photovoltaic cable and an anti-ultraviolet method thereof. The cable includes a cable body. An insulating flexible column is arranged inside the cable body. A through-hole inner layer is arranged outside the insulating flexible column. A first insulating sleeve is arranged on the outer wall of the insulating flexible column. The first insulating sleeve is located inside the through-hole inner layer. A cable core is arranged inside the first insulating sleeve. By setting the anti-ultraviolet fiber layer, it is beneficial for the photovoltaic cable of the body to effectively prevent excessive ultraviolet radiation, and in cooperation with the provided reflective material, the body is in a sheet shape, which is beneficial for effectively reflecting ultraviolet rays and reducing the direct irradiation effect of ultraviolet rays on the photovoltaic cable of the body. By setting the heat insulation cavity, it is beneficial to present a heat insulation cavity inside the photovoltaic cable of the body, playing an effective heat insulation role when being heated by light radiation, and preventing the internal temperature from being too high and having a greater impact on the inside of the cable core. However, there is still room for improvement in the flame retardancy, low smoke property, wear resistance and toughness of the cable prepared by this method. Summary of the Invention

[0004] The purpose of the present invention is to provide a flexible series-connected photovoltaic cable and a preparation method thereof, which are used to solve the technical problems of poor flame retardancy, low smoke property, wear resistance and toughness of the cable in the prior art.

[0005] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0006] The present invention provides a flexible series-connected photovoltaic cable, including an alloy inner conductor, a cross-linked polyolefin layer, a modified glass fiber layer and a ceramized polyolefin layer which are arranged in sequence from inside to outside. The alloy inner conductor is tightly wrapped with the cross-linked polyolefin layer on the outside. A modified glass fiber layer is wrapped outside the cross-linked polyolefin layer. A ceramized polyolefin layer is wrapped outside the modified glass fiber layer.

[0007] Preferably, the preparation method of the crosslinked polyolefin layer material comprises the following steps:

[0008] S1: Add diethanolamine and paraformaldehyde into a reaction vessel, add ammonia water to adjust the pH during heating and stirring. After the stirring ends, add melamine and continue the reaction. After the reaction ends, perform high-temperature vacuum dehydration to obtain compound A; Add compound A and 2,5-furandicarboxylic acid into a container containing N,N-dimethylformamide, stir to dissolve, then add xylene and zinc acetate, raise the temperature for reflux reaction. After the reaction ends, spin-dry and dry to obtain compound B;

[0009] S2: Add compound B into N,N-dimethylformamide, then add epichlorohydrin and tetrabutylammonium bromide, heat for reflux reaction. After the reaction ends, perform rotary evaporation, add it into an aqueous sodium hydroxide solution, extract, separate the liquid, wash, and dry to obtain compound C;

[0010] S3: Add polyethylene and trimethylolpropane triacrylate into a mixer, mix, extrude, and granulate to obtain masterbatch one; Add compound C, zinc borate, compatibilizer, and mica powder into a mixer, mix, extrude, and granulate to obtain masterbatch two. Mix masterbatch one and masterbatch two evenly, extrude through a twin-screw extruder, cool with water, and pelletize to obtain the crosslinked polyolefin layer material.

[0011] In the above process, the synthesis reaction of compound C is as follows:

[0012]

[0013] The mass spectrometry analysis result of compound A is: m / z: 477.30 (100.0%), 478.31 (20.1%), 478.30(3.3%), 479.31 (3.2%).

[0014] Preferably, in S1, the dosage ratio of diethanolamine, paraformaldehyde, and melamine is (32 - 38) g : (8 - 12) g : (11 - 18) g, the heating and stirring temperature is 85 - 90 °C, the stirring time is 1 - 2 h, adjust the pH = 8 - 9, the continuous stirring time is 6 - 8 h, the high-temperature vacuum dehydration temperature is 120 - 130 °C, and the dehydration time is 2 - 3 h; The dosage ratio of compound A, 2,5-furandicarboxylic acid, N,N-dimethylformamide, xylene, and zinc acetate is (0.88 - 1.21) g : (1.87 - 3.12) g : (45 - 55) mL : (0.45 - 0.63) g : (0.12 - 0.31) g, the temperature for the reflux reaction is 200 - 220 °C, and the reflux reaction time is 20 - 40 h.

[0015] Preferably, in S2, the dosage ratio of compound B, N,N-dimethylformamide, epichlorohydrin and tetrabutylammonium bromide is (2 - 2.54) g : (20 - 25) mL : (14 - 17.78) g : (0.8 - 1.3) g, the heating reflux reaction temperature is 110 - 115 °C, the time is 7 - 9 h, and the mass fraction of the sodium hydroxide aqueous solution is 40 wt%.

[0016] Preferably, in S3, the dosage ratio of polyethylene and trimethylolpropane triacrylate is (8 - 12) g : (0.34 - 0.45) g, and the dosage ratio of compound C, zinc borate, compatibilizer and mica powder is (1 - 2) g : (0.8 - 0.85) g : (0.23 - 0.45) g : (0.15 - 0.25) g.

[0017] Preferably, the preparation method of the modified glass fiber layer material includes the following steps:

[0018] Q1: Add 1,2,4-benzenetricarboxylic anhydride, epichlorohydrin and tetrabutylammonium bromide into a container filled with tetrahydrofuran, introduce nitrogen, heat and stir for reaction. After the reaction ends, precipitate, separate the liquid, dissolve the precipitate, precipitate repeatedly, and vacuum dry to obtain intermediate a;

[0019] Q2: Add intermediate a into a container filled with an anhydrous potassium carbonate solution, heat and stir for reaction under a nitrogen atmosphere. After the reaction ends, precipitate, separate the liquid, dissolve the precipitate, precipitate repeatedly, and vacuum dry to obtain intermediate b;

[0020] Q3: Add intermediate b, triethoxysilylpropyl maleic acid and tetrabutylammonium bromide into a container filled with tetrahydrofuran, heat and stir for reaction under a nitrogen atmosphere, then add isobutyric anhydride and continue the reaction. After the reaction ends, dissolve, precipitate, precipitate repeatedly, and vacuum dry to obtain intermediate c;

[0021] Q4: Add glass fiber into hydrochloric acid, soak, wash, and dry to obtain pretreated glass fiber. Then add the pretreated glass fiber and intermediate c into distilled water, heat and stir for reaction. After the reaction ends, dry to obtain the modified glass fiber layer material.

[0022] In the above process, first, using 1,2,4-benzenetricarboxylic anhydride and epichlorohydrin as raw materials, through epoxy carboxylation reaction to form intermediate a with a hyperbranched structure, then through dehydrochlorination epoxidation reaction to form epoxy groups at the ends of intermediate a to obtain intermediate b, and finally reacting with triethoxysilylpropyl maleic acid and isobutyric anhydride through epoxy carboxylation reaction and nucleophilic addition reaction respectively to obtain intermediate c, and then mixing and reacting intermediate c with pretreated glass fiber to obtain the modified glass fiber layer material.

[0023] Preferably, in Q1, the dosage ratio of phthalic anhydride, epichlorohydrin, tetrabutylammonium bromide and tetrahydrofuran is (18.8 - 19.7) g : (27.12 - 28.56) g : (0.32 - 0.46) g : (40 - 50) mL. The heating and stirring reaction temperature is 68 - 74°C, the stirring speed is 240 - 260 rpm, the reaction time is 10 - 14 h. It is added to a mixed solution of distilled water and methanol with a mass ratio of 1:1 for precipitation. The precipitate is dissolved with tetrahydrofuran, and the precipitation is repeated 3 - 5 times. The vacuum drying temperature is 60 - 65°C, and the time is 12 - 16 h.

[0024] Preferably, in Q2, the dosage ratio of intermediate a and anhydrous potassium carbonate solution is (18.56 - 21.18) g : (50 - 75) mL. The concentration of the anhydrous potassium carbonate solution is 1 g / mL. The heating and stirring reaction temperature is 48 - 53°C, the stirring speed is 180 - 200 rpm, and the reaction time is 10 - 14 h.

[0025] Preferably, in Q3, the dosage ratio of intermediate b, triethoxysilylpropyl maleate, tetrabutylammonium bromide, tetrahydrofuran and isobutyric anhydride is (9.6 - 10.8) g : (8.68 - 9.52) g : (0.21 - 0.36) g : (18 - 24) mL : (5.4 - 6.5) g. The heating and stirring reaction temperature is 68 - 72°C, the reaction time is 8 - 10 h, the continued reaction temperature is 70 - 72°C, and the reaction time is 6 - 8 h. It is dissolved with tetrahydrofuran and added to methanol for precipitation, and the precipitation is repeated 3 - 5 times. In Q4, the concentration of hydrochloric acid is 0.1 mol / L, the soaking time is 3 - 5 h. The dosage ratio of pretreated glass fiber, intermediate c and distilled water is (1 - 1.5) g : (3.2 - 4.6) g : (80 - 100) mL. The heating and stirring reaction temperature is 75 - 80°C, the stirring speed is 1000 - 1500 rpm, and the reaction time is 2 - 4 h.

[0026] Preferably, the preparation method of the flexible string group photovoltaic cable includes the following steps:

[0027] Step 1: Anneal, multi-strand twist, and ultrasonically clean the highly conductive flexible alloy to obtain an alloy inner conductor;

[0028] Step 2: After melting and extruding the cross-linked polyolefin layer material, tightly wrap it on the surface of the alloy inner conductor, and then wrap the modified glass fiber layer material;

[0029] Step 3: Add mica and kaolin to ethylene-octene copolymer, stir, mix, and extrude to obtain a ceramized polyolefin layer material, and tightly wrap it on the surface of the modified glass fiber layer to obtain the flexible string group photovoltaic cable.

[0030] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are as follows:

[0031] 1. The crosslinked polyolefin layer material and the modified glass fiber layer material prepared in the present invention are used in the preparation process of cables, which can effectively improve their toughness, low smoke property, wear resistance and flame retardant and low smoke property.

[0032] 2. The crosslinked polyolefin layer material prepared in the present invention is applied to cables, which can effectively improve their flame retardancy and low smoke property. The triazine-based hyperbranched structure contained in the crosslinked polyolefin layer material has excellent flame retardant effect. The halogen-free flame retardant system contained avoids the toxic smoke released during the combustion of halogen flame retardants. The crosslinked structure contained can also inhibit the melting and dripping of the material and reduce the generation of soot particles during combustion.

[0033] 3. The modified glass fiber layer material prepared in the present invention is applied to cables, which can effectively improve the wear resistance and toughness of cables. The siloxane bonds contained in the modified glass fiber layer material form a dense hydrophobic layer on the surface of glass fibers. The low surface energy characteristic can reduce the friction coefficient, thereby reducing the friction loss of cables. The covalent bonds and hydrogen bond networks contained in the modified glass fiber layer material can strengthen the interfacial bonding force. The existence of the three-dimensional network can disperse the stress generated during the friction process, reduce wear, and the crosslinked network contained can also improve the crack propagation resistance of the material, avoid brittle fracture, and improve the toughness of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0035] Figure 1 is a cross-sectional schematic view of the flexible string photovoltaic cable prepared in the present invention;

[0036] Figure 2 is a structural schematic view of the flexible string photovoltaic cable prepared in the present invention.

[0037] BRIEF DESCRIPTION OF THE DRAWINGS: 1. Alloy inner conductor; 2. Crosslinked polyolefin layer; 3. Modified glass fiber layer; 4. Ceramicized polyolefin layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0039] The following are used in the embodiments of the present invention:

[0040] Diethanolamine was purchased from Shandong Mantanghong New Material Co., Ltd., CAS No.: 111-42-2;

[0041] Paraformaldehyde was purchased from Shandong Chuangli New Material Co., Ltd., CAS No.: 30525-89-4;

[0042] Ammonia water was purchased from Jinan Xinchen Chemical Co., Ltd., CAS No.: 1336-21-6;

[0043] Melamine was purchased from Jinan Rongguang Chemical Co., Ltd., CAS No.: 108-78-1;

[0044] 2,5-Furandicarboxylic acid was purchased from Wuhan Chengtian Fine Chemical Co., Ltd., CAS No.: 3238-40-2;

[0045] N,N-Dimethylformamide was purchased from Shanghai Denuo Chemical Co., Ltd., CAS No.: 68-12-2;

[0046] Xylene was purchased from Jinan Xinchen Chemical Co., Ltd., CAS No.: 95-47-6;

[0047] Zinc acetate was purchased from Langfang Qianyao Technology Co., Ltd., CAS No.: 557-34-6;

[0048] Epichlorohydrin was purchased from Shandong Chuangying Chemical Co., Ltd., CAS No.: 106-89-8;

[0049] Tetrabutylammonium bromide was purchased from Jinan Yuansu Chemical Co., Ltd., CAS No.: 1643-19-2;

[0050] Sodium hydroxide was purchased from Dezhou Lingwo Chemical Co., Ltd., CAS No.: 1310-73-2;

[0051] Polyethylene was purchased from Nanjing Milan Chemical Co., Ltd., CAS No.: 9002-88-4;

[0052] Trimethylolpropane triacrylate was purchased from Jiangsu Bost Chemical Technology Co., Ltd., CAS No.: 15625-89-5;

[0053] Zinc borate was purchased from Henan Xinyuanyuan Chemical Products Co., Ltd., CAS No.: 1332-07-6;

[0054] The compatibilizer was purchased from Nanjing Milan Chemical Co., Ltd.;

[0055] Mica powder was purchased from Hebei Huayuan Mining Co., Ltd.;

[0056] 1,2,4-Benzenetricarboxylic anhydride was purchased from Jiangsu Rayen Environmental Protection Technology Co., Ltd., CAS No.: 552-30-7;

[0057] Tetrahydrofuran was purchased from Jinan Xinchen Chemical Co., Ltd., CAS No.: 109-99-9;

[0058] Methanol was purchased from Wuxi Haomiao Chemical Technology Co., Ltd., CAS No.: 67-56-1;

[0059] Anhydrous potassium carbonate was purchased from Jinan Yuanfei Weiye Chemical Co., Ltd., CAS No.: 584-08-7;

[0060] Triethoxysilylpropyl maleic acid was purchased from Shandong Weiyuan Environmental Protection Technology Co., Ltd., CAS No.: 33525-68-7;

[0061] Isobutyric anhydride was purchased from Shandong Jinyufeng New Materials Co., Ltd., CAS No.: 97-72-3;

[0062] Glass fiber was purchased from Anhui Jiangzhen Geotechnical Materials Co., Ltd., CAS No.: 65997-17-3;

[0063] Mica was purchased from Hebei Zongrun Mineral Products Co., Ltd., CAS No.: 12001-26-2;

[0064] Kaolin was purchased from Hebei Leijiang New Materials Technology Co., Ltd., CAS No.: 1332-58-7;

[0065] Ethylene-octene copolymer was purchased from Dongguan Shangpin New Materials Technology Co., Ltd.

[0066] Example 1: Refer to Figure 1-2 As shown, a flexible string group photovoltaic cable in this example includes an alloy inner conductor 1, a cross-linked polyolefin layer 2, a modified glass fiber layer 3, and a ceramized polyolefin layer 4 arranged in sequence from inside to outside. The alloy inner conductor 1 is tightly wrapped with the cross-linked polyolefin layer 2 on the outside, the cross-linked polyolefin layer 2 is wrapped with a modified glass fiber layer 3 on the outside, and the modified glass fiber layer 3 is wrapped with a ceramized polyolefin layer 4 on the outside.

[0067] Example 2: This example discloses a preparation method of a cross-linked polyolefin layer material, including the following steps:

[0068] S1: Add 35 g of diethanolamine and 10 g of paraformaldehyde into a reaction vessel. During heating and stirring at 85 °C, add ammonia water to adjust the pH to 8. After stirring for 2 h, add 15 g of melamine and continue the reaction for 6 h. After the reaction is completed, perform high-temperature vacuum dehydration at 120 °C for 2 h to obtain compound A; Add 1.01 g of compound A and 2.45 g of 2,5-furandicarboxylic acid into a container containing 50 mL of N,N-dimethylformamide. After stirring and dissolving, add 0.54 g of xylene and 0.21 g of zinc acetate dihydrate, and raise the temperature to 200 °C for reflux reaction for 24 h. After the reaction is completed, spin-dry and dry to obtain compound B;

[0069] S2: Add 2.27 g of compound B into 22.5 mL of N,N-dimethylformamide, then add 15.89 g of epichlorohydrin and 1.05 g of tetrabutylammonium bromide, and heat under reflux at 115 °C for 8 h. After the reaction is completed, perform rotary evaporation, add it into an aqueous sodium hydroxide solution with a mass fraction of 40 wt%, extract, separate the liquid, wash, and dry to obtain compound C;

[0070] S3: Add 10 g of polyethylene and 0.39 g of trimethylolpropane triacrylate into a mixer, mix, extrude, and pelletize to obtain masterbatch one; Add 1.5 g of compound C, 0.82 g of zinc borate, 0.34 g of compatibilizer, and 0.2 g of mica powder into a mixer, mix, extrude, and pelletize to obtain masterbatch two. Mix masterbatch one and masterbatch two evenly, extrude through a twin-screw extruder, cool with water, and pelletize to obtain a crosslinked polyolefin layer material.

[0071] This example discloses a preparation method of a modified glass fiber layer material, including the following steps:

[0072] Q1: Add 19.3 g of 1,2,4-benzenetricarboxylic anhydride, 27.63 g of epichlorohydrin, and 0.39 g of tetrabutylammonium bromide into a container containing 45 mL of tetrahydrofuran, introduce nitrogen, and heat and stir at 70 °C and 260 rpm for 12 h. After the reaction is completed, add it into a mixed solution of distilled water and methanol with a mass ratio of 1:1 for precipitation, separate the liquid, dissolve the precipitate with tetrahydrofuran, and perform precipitation three times repeatedly. Vacuum dry at 65 °C for 12 h to obtain intermediate a;

[0073] Q2: Add 19.83 g of intermediate a into a container containing 62.5 mL of an anhydrous potassium carbonate solution with a concentration of 1 g / mL. Under a nitrogen atmosphere, heat and stir at 50 °C and 200 rpm for 14 h. After the reaction is completed, precipitate, separate the liquid, dissolve the precipitate, perform precipitation repeatedly, and vacuum dry to obtain intermediate b;

[0074] Q3: Add 10.1 g of intermediate b, 9.01 g of triethoxysilylpropyl maleate, and 0.27 g of tetrabutylammonium bromide into a container containing 21 mL of tetrahydrofuran. Under a nitrogen atmosphere, heat and stir the reaction at 70 °C for 10 h. Then add 5.9 g of isobutyric anhydride and continue the reaction at 70 °C for 8 h. After the reaction is completed, dissolve it with tetrahydrofuran, add it to methanol for precipitation, precipitate 3 times repeatedly, and dry it under vacuum to obtain intermediate c;

[0075] Q4: Add glass fibers into hydrochloric acid with a concentration of 0.1 mol / L, soak for 5 h, wash, and dry to obtain pretreated glass fibers. Then add 1.25 g of pretreated glass fibers and 3.9 g of intermediate c into 90 mL of distilled water, heat and stir the reaction at 80 °C and 1500 rpm for 4 h. After the reaction is completed, dry it to obtain a modified glass fiber layer material.

[0076] See Figure 1-2 As shown, this embodiment discloses a preparation method of a flexible string group photovoltaic cable, including the following steps:

[0077] Step 1: Anneal alloy conductor single wires with a diameter ≤ 0.28 mm at 300 °C under a nitrogen atmosphere, twist them with a 45 mm pitch push-twist method, and ultrasonically clean them at 20 kHz to obtain alloy inner conductor 1;

[0078] Step 2: After melting and extruding the cross-linked polyolefin layer 2 material at 210 °C, tightly wrap it on the surface of the alloy inner conductor 1, and then wrap the modified glass fiber layer 3 material. The thickness of the cross-linked polyolefin layer is 0.7 mm, and the thickness of the modified glass fiber layer ≤ 0.08 mm. Wind and wrap it with a 1 / 4 overlap rate;

[0079] Step 3: Add 1 part by weight of mica and 1 part by weight of kaolin into 8 parts by weight of ethylene-octene copolymer, stir, mix, and extrude to obtain a ceramized polyolefin layer 4 material, and tightly wrap it on the surface of the modified glass fiber layer material. The thickness of the ceramized polyolefin layer is 0.8 mm, bake it at 70 °C for 8 h, use a double-groove screw with a compression ratio of 1:1.65, and use a pressurized flow channel groove in the middle of the screw to obtain a flexible string group photovoltaic cable.

[0080] Example 3: This embodiment discloses a preparation method of a cross-linked polyolefin layer material, including the following steps:

[0081] S1: Add 32 g of diethanolamine and 12 g of paraformaldehyde into a reaction vessel. During heating and stirring at 85 °C, add ammonia water to adjust the pH to 8. After stirring for 2 h, add 11 g of melamine and continue the reaction for 6 h. After the reaction is completed, perform high-temperature vacuum dehydration at 120 °C for 2 h to obtain compound A; add 0.88 g of compound A and 1.87 g of 2,5-furandicarboxylic acid into a container containing 55 mL of N,N-dimethylformamide. After stirring and dissolving, add 0.45 g of xylene and 0.12 g of zinc acetate. Heat and reflux at 200 °C for 24 h. After the reaction is completed, spin-dry and dry to obtain compound B;

[0082] S2: Add 2.54 g of compound B into 25 mL of N,N-dimethylformamide, then add 14 g of epichlorohydrin and 0.8 g of tetrabutylammonium bromide. Heat and reflux at 115 °C for 8 h. After the reaction is completed, perform rotary evaporation, add it into an aqueous sodium hydroxide solution with a mass fraction of 40 wt%, extract, separate, wash, and dry to obtain compound C;

[0083] S3: Add 8 g of polyethylene and 0.34 g of trimethylolpropane triacrylate into a kneader, knead, extrude, and granulate to obtain masterbatch one; add 1 g of compound C, 0.8 g of zinc borate, 0.23 g of compatibilizer, and 0.15 g of mica powder into a kneader, knead, extrude, and granulate to obtain masterbatch two. Mix masterbatch one and masterbatch two evenly, extrude through a twin-screw extruder, cool with water, and pelletize to obtain a crosslinked polyolefin layer material.

[0084] This example discloses a preparation method of a modified glass fiber layer material, including the following steps:

[0085] Q1: Add 18.8 g of 1,2,4-benzenetricarboxylic anhydride, 27.12 g of epichlorohydrin, and 0.32 g of tetrabutylammonium bromide into a container containing 40 mL of tetrahydrofuran. Pass in nitrogen, heat and stir at 70 °C and 260 rpm for 12 h. After the reaction is completed, add it into a mixed solution of distilled water and methanol with a mass ratio of 1:1 for precipitation, separate, dissolve the precipitate with tetrahydrofuran, and precipitate repeatedly 3 times. Vacuum dry at 65 °C for 12 h to obtain intermediate a;

[0086] Q2: Add 18.56 g of intermediate a into a container containing 50 mL of an anhydrous potassium carbonate solution with a concentration of 1 g / mL. Under a nitrogen atmosphere, heat and stir at 50 °C and 200 rpm for 14 h. After the reaction is completed, precipitate, separate, dissolve the precipitate, precipitate repeatedly, and vacuum dry to obtain intermediate b;

[0087] Q3: 9.6 g of intermediate b, 8.68 g of triethoxysilylpropyl maleate and 0.21 g of tetrabutylammonium bromide were added to a container containing 18 mL of tetrahydrofuran. Under a nitrogen atmosphere, the mixture was heated and stirred at 70 °C for 10 h, and then 5.4 g of isobutyric anhydride was added. The reaction was continued at 70 °C for 8 h. After the reaction was completed, it was dissolved in tetrahydrofuran and added to methanol for precipitation. The precipitation was repeated 3 times, and then dried under vacuum to obtain intermediate c;

[0088] Q4: Glass fibers were added to hydrochloric acid with a concentration of 0.1 mol / L, soaked for 5 h, washed, and dried to obtain pretreated glass fibers. Then, 1.5 g of pretreated glass fibers and 3.2 g of intermediate c were added to 80 mL of distilled water, and the mixture was heated and stirred at 80 °C and 1500 rpm for 4 h. After the reaction was completed, it was dried to obtain a modified glass fiber layer material.

[0089] See Figure 1-2 As shown, this example discloses a preparation method of a flexible string group photovoltaic cable, including the following steps:

[0090] Step 1: The alloy conductor single wire with a diameter ≤ 0.28 mm was annealed at 300 °C under a nitrogen atmosphere, twisted by a 45 mm pitch push-twist method, and ultrasonically cleaned at 20 kHz to obtain an alloy inner conductor 1;

[0091] Step 2: After the cross-linked polyolefin layer 2 material was melt-extruded at 210 °C, it was tightly wrapped on the surface of the alloy inner conductor 1, and then the modified glass fiber layer 3 material was wrapped. The thickness of the cross-linked polyolefin layer was 0.7 mm, and the thickness of the modified glass fiber layer was ≤ 0.08 mm. It was wrapped around with a 1 / 4 overlap rate;

[0092] Step 3: 1 part by weight of mica and 1 part by weight of kaolin were added to 8 parts by weight of ethylene-octene copolymer, stirred, mixed, and extruded to obtain a ceramicized polyolefin layer 4 material, which was tightly wrapped on the surface of the modified glass fiber layer material. The thickness of the ceramicized polyolefin layer was 0.8 mm, baked at 70 °C for 8 h, and a double-groove screw with a compression ratio of 1:1.65 was used, and a pressurized flow channel groove was adopted in the middle of the screw to obtain a flexible string group photovoltaic cable.

[0093] Example 4: This example discloses a preparation method of a cross-linked polyolefin layer material, including the following steps:

[0094] S1: Add 38 g of diethanolamine and 8 g of paraformaldehyde into a reaction vessel. During heating and stirring at 85 °C, add ammonia water to adjust the pH to 8. After stirring for 2 h, add 18 g of melamine and continue the reaction for 6 h. After the reaction ends, perform high-temperature vacuum dehydration at 120 °C for 2 h to obtain compound A; Add 1.21 g of compound A and 3.12 g of 2,5-furandicarboxylic acid into a container containing 45 mL of N,N-dimethylformamide. After stirring and dissolving, add 0.63 g of xylene and 0.31 g of zinc acetate. Heat under reflux at 200 °C for 24 h. After the reaction ends, spin-dry and dry to obtain compound B;

[0095] S2: Add 2 g of compound B into 20 mL of N,N-dimethylformamide, then add 17.78 g of epichlorohydrin and 1.3 g of tetrabutylammonium bromide. Heat under reflux at 115 °C for 8 h. After the reaction ends, perform rotary evaporation, add it to an aqueous sodium hydroxide solution with a mass fraction of 40 wt%, extract, separate the liquid, wash, and dry to obtain compound C;

[0096] S3: Add 12 g of polyethylene and 0.45 g of trimethylolpropane triacrylate into a mixer, mix, extrude, and pelletize to obtain masterbatch one; Add 2 g of compound C, 0.85 g of zinc borate, 0.45 g of compatibilizer, and 0.25 g of mica powder into a mixer, mix, extrude, and pelletize to obtain masterbatch two. Mix masterbatch one and masterbatch two evenly, extrude through a twin-screw extruder, cool with water, and pelletize to obtain a crosslinked polyolefin layer material.

[0097] This example discloses a preparation method of a modified glass fiber layer material, including the following steps:

[0098] Q1: Add 19.7 g of 1,2,4-benzenetricarboxylic anhydride, 28.56 g of epichlorohydrin, and 0.46 g of tetrabutylammonium bromide into a container containing 50 mL of tetrahydrofuran. Pass in nitrogen, heat and stir at 70 °C and 260 rpm for 12 h. After the reaction ends, add it to a mixed solution of distilled water and methanol with a mass ratio of 1:1 for precipitation, separate the liquid, dissolve the precipitate with tetrahydrofuran, and precipitate repeatedly 3 times. Dry under vacuum at 65 °C for 12 h to obtain intermediate a;

[0099] Q2: Add 21.18 g of intermediate a into a container containing 75 mL of an anhydrous potassium carbonate solution with a concentration of 1 g / mL. Under a nitrogen atmosphere, heat and stir at 50 °C and 200 rpm for 14 h. After the reaction ends, precipitate, separate the liquid, dissolve the precipitate, precipitate repeatedly, and dry under vacuum to obtain intermediate b;

[0100] Q3: Add 10.8 g of intermediate b, 9.52 g of triethoxysilylpropyl maleate, and 0.36 g of tetrabutylammonium bromide into a container containing 24 mL of tetrahydrofuran. Under a nitrogen atmosphere, heat and stir the reaction at 70 °C for 10 h. Then add 6.5 g of isobutyric anhydride and continue the reaction at 70 °C for 8 h. After the reaction is completed, dissolve it with tetrahydrofuran, add it to methanol for precipitation, precipitate three times repeatedly, and dry it under vacuum to obtain intermediate c;

[0101] Q4: Add glass fiber into hydrochloric acid with a concentration of 0.1 mol / L, soak for 5 h, wash, and dry to obtain pretreated glass fiber. Then add 1 g of pretreated glass fiber and 4.6 g of intermediate c into 100 mL of distilled water, heat and stir the reaction at 80 °C and 1500 rpm for 4 h. After the reaction is completed, dry it to obtain a modified glass fiber layer material.

[0102] Refer to Figure 1-2 As shown, this example discloses a preparation method of a flexible string group photovoltaic cable, including the following steps:

[0103] Step 1: Anneal alloy conductor single wires with a diameter ≤ 0.28 mm at 300 °C under a nitrogen atmosphere, twist them with a 45 mm pitch push-twist method, and ultrasonically clean them at 20 kHz to obtain alloy inner conductor 1;

[0104] Step 2: After melting and extruding the cross-linked polyolefin layer 2 material at 210 °C, make it tightly wrap around the surface of the alloy inner conductor 1, and then wrap the modified glass fiber layer 3 material. The thickness of the cross-linked polyolefin layer is 0.7 mm, and the thickness of the modified glass fiber layer ≤ 0.08 mm. Wind and wrap it with a 1 / 4 overlap rate;

[0105] Step 3: Add 1 part by weight of mica and 1 part by weight of kaolin into 8 parts by weight of ethylene-octene copolymer, stir, mix, and extrude to obtain a ceramized polyolefin layer 4 material, make it tightly wrap around the surface of the modified glass fiber layer material. The thickness of the ceramized polyolefin layer is 0.8 mm, bake it at 70 °C for 8 h, use a double-groove screw with a compression ratio of 1:1.65, and use a pressurized flow channel groove in the middle of the screw to obtain a flexible string group photovoltaic cable.

[0106] Example 5: This example discloses a preparation method of a cross-linked polyolefin layer material, including the following steps:

[0107] S1: Add 34 g of diethanolamine and 9 g of paraformaldehyde into a reaction vessel. During heating and stirring at 85 °C, add ammonia water to adjust the pH to 8. After stirring for 2 h, add 12 g of melamine and continue the reaction for 6 h. After the reaction is completed, perform high-temperature vacuum dehydration at 120 °C for 2 h to obtain compound A; Add 0.95 g of compound A and 2.91 g of 2,5-furandicarboxylic acid into a container containing 48 mL of N,N-dimethylformamide. After stirring and dissolving, add 0.48 g of xylene and 0.18 g of zinc acetate. Heat under reflux at 200 °C for 24 h. After the reaction is completed, spin-dry and dry to obtain compound B;

[0108] S2: Add 2.12 g of compound B into 21 mL of N,N-dimethylformamide, then add 16.12 g of epichlorohydrin and 0.9 g of tetrabutylammonium bromide. Heat under reflux at 115 °C for 8 h. After the reaction is completed, perform rotary evaporation, add it to an aqueous sodium hydroxide solution with a mass fraction of 40 wt%, extract, separate the liquid, wash, and dry to obtain compound C;

[0109] S3: Add 9 g of polyethylene and 0.36 g of trimethylolpropane triacrylate into a mixer, mix, extrude, and pelletize to obtain masterbatch one; Add 1.2 g of compound C, 0.83 g of zinc borate, 0.28 g of compatibilizer, and 0.18 g of mica powder into a mixer, mix, extrude, and pelletize to obtain masterbatch two. Mix masterbatch one and masterbatch two evenly, extrude through a twin-screw extruder, cool with water, and pelletize to obtain a crosslinked polyolefin layer material.

[0110] This example discloses a preparation method of a modified glass fiber layer material, including the following steps:

[0111] Q1: Add 19.1 g of 1,2,4-benzenetricarboxylic anhydride, 27.38 g of epichlorohydrin, and 0.37 g of tetrabutylammonium bromide into a container containing 42 mL of tetrahydrofuran. Pass in nitrogen, heat and stir at 70 °C and 260 rpm for 12 h. After the reaction is completed, add it to a mixed solution of distilled water and methanol with a mass ratio of 1:1 for precipitation, separate the liquid, dissolve the precipitate with tetrahydrofuran, precipitate repeatedly 3 times, and perform vacuum drying at 65 °C for 12 h to obtain intermediate a;

[0112] Q2: Add 18.87 g of intermediate a into a container containing 60 mL of an anhydrous potassium carbonate solution with a concentration of 1 g / mL. Under a nitrogen atmosphere, heat and stir at 50 °C and 200 rpm for 14 h. After the reaction is completed, precipitate, separate the liquid, dissolve the precipitate, precipitate repeatedly, and perform vacuum drying to obtain intermediate b;

[0113] Q3: Add 9.8 g of intermediate b, 8.83 g of triethoxysilylpropyl maleate, and 0.24 g of tetrabutylammonium bromide into a container filled with 20 mL of tetrahydrofuran. Under a nitrogen atmosphere, heat and stir the reaction at 70 °C for 10 h, then add 5.7 g of isobutyric anhydride and continue the reaction at 70 °C for 8 h. After the reaction is completed, dissolve it with tetrahydrofuran, add it to methanol for precipitation, repeat the precipitation 3 times, and dry it under vacuum to obtain intermediate c;

[0114] Q4: Add glass fibers into hydrochloric acid with a concentration of 0.1 mol / L, soak for 5 h, wash, and dry to obtain pretreated glass fibers. Then add 1.1 g of pretreated glass fibers and 3.6 g of intermediate c into 85 mL of distilled water, heat and stir the reaction at 80 °C and 1500 rpm for 4 h. After the reaction is completed, dry to obtain the modified glass fiber layer material.

[0115] Refer to Figure 1-2 As shown, this embodiment discloses a preparation method of a flexible string group photovoltaic cable, including the following steps:

[0116] Step 1: Anneal the alloy conductor single wire with a diameter ≤ 0.28 mm at 300 °C under a nitrogen atmosphere, use a 45 mm pitch push-twist stranding, and perform 20 kHz ultrasonic cleaning to obtain alloy inner conductor 1;

[0117] Step 2: After melting and extruding the cross-linked polyolefin layer 2 material at 210 °C, make it tightly wrap around the surface of the alloy inner conductor 1, and then wrap the modified glass fiber layer 3 material. The thickness of the cross-linked polyolefin layer is 0.7 mm, and the thickness of the modified glass fiber layer ≤ 0.08 mm. Wind and wrap it with a 1 / 4 overlap rate;

[0118] Step 3: Add 1 part by weight of mica and 1 part by weight of kaolin into 8 parts by weight of ethylene-octene copolymer, stir, mix, and extrude to obtain the ceramicized polyolefin layer 4 material, make it tightly wrap around the surface of the modified glass fiber layer material. The thickness of the ceramicized polyolefin layer is 0.8 mm, bake at 70 °C for 8 h, use a double-groove screw with a compression ratio of 1:1.65, and a pressure flow channel in the middle of the screw to obtain the flexible string group photovoltaic cable.

[0119] Comparative Example 1: Compared with Example 1, in Comparative Example 1, during the preparation of the flexible string group photovoltaic cable, the modified glass fiber layer material directly uses glass fibers, and other conditions remain unchanged.

[0120] Comparative Example 2: Compared with Example 1, in Comparative Example 2, during the preparation of the flexible string group photovoltaic cable, compound C is not added to the cross-linked polyolefin layer material, and other conditions remain unchanged.

[0121] Experimental Example: The properties of the flexible string group photovoltaic cables prepared in Examples 2-5 and Comparative Examples 1-2 were tested. The flame retardancy of the samples was tested according to GB / T 18380.22-2008, the smoke density and minimum light transmittance of the samples were tested according to GB / T 17651.2-2021, the tensile strength of the samples was tested according to GB / T 2951.11-2008, and the abrasion resistance of the samples was tested according to GB / T 17737.324-2018. The test results are shown in Table 1.

[0122] Table 1:

[0123]

[0124] As can be seen from the test results in Table 1, the flexible string group photovoltaic cables prepared in Examples 2-5 of the present invention have excellent flame retardancy, low smoke property, toughness and abrasion resistance. By comparing Comparative Example 1 with Examples 2-5, it can be seen that the use of the modified glass fiber layer material can effectively improve the toughness and abrasion resistance of the flexible string group photovoltaic cable; by comparing Comparative Example 2 with Examples 2-5, it can be seen that the use of the crosslinked polyolefin layer material can improve the flame retardancy and low smoke property of the flexible string group photovoltaic cable.

[0125] As described above, the above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes, shall be covered by the protection scope of the present invention.

[0126] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the present invention to only the specific embodiments. Obviously, many modifications and changes can be made according to the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principle and practical application of the present invention, so that those skilled in the art in the relevant technical field can understand and utilize the present invention well. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. Flexible string group photovoltaic cable, characterized in that It includes an alloy inner conductor, a crosslinked polyolefin layer, a modified glass fiber layer, and a ceramized polyolefin layer arranged in sequence from the inside to the outside. The outside of the alloy inner conductor is tightly wrapped with the crosslinked polyolefin layer material. The outside of the crosslinked polyolefin layer material is wrapped with a layer of modified glass fiber layer material, and the outside of the modified glass fiber layer material is wrapped with a layer of ceramized polyolefin layer; The preparation method of the crosslinked polyolefin layer material includes the following steps: S1: Add diethanolamine and paraformaldehyde into a reaction vessel. During heating and stirring, add ammonia water to adjust the pH. After stirring ends, add melamine and continue the reaction. After the reaction ends, dehydrate under high temperature and vacuum to obtain compound A; Add compound A and 2,5-furandicarboxylic acid into a container containing N,N-dimethylformamide. After stirring and dissolving, add xylene and zinc acetate, heat under reflux for reaction. After the reaction ends, spin dry and dry to obtain compound B; S2: Add compound B into N,N-dimethylformamide, then add epichlorohydrin and tetrabutylammonium bromide, heat under reflux for reaction. After the reaction ends, perform rotary evaporation, add it into an aqueous sodium hydroxide solution, extract, separate the liquid, wash, and dry to obtain compound C; S3: Add polyethylene and trimethylolpropane triacrylate into a mixer, mix, extrude, and granulate to obtain masterbatch one; Add compound C, zinc borate, compatibilizer, and mica powder into a mixer, mix, extrude, and granulate to obtain masterbatch two. Mix masterbatch one and masterbatch two evenly, extrude, cool with water, and pelletize to obtain the crosslinked polyolefin layer material; The preparation method of the modified glass fiber layer material includes the following steps: Q1: Add 1,2,4-benzenetricarboxylic anhydride, epichlorohydrin, and tetrabutylammonium bromide into a container containing tetrahydrofuran, introduce nitrogen, heat and stir for reaction. After the reaction ends, precipitate, separate the liquid, dissolve the precipitate, precipitate repeatedly, and dry under vacuum to obtain intermediate a; Q2: Add intermediate a into a container containing an aqueous potassium carbonate solution, heat and stir for reaction under a nitrogen atmosphere. After the reaction ends, precipitate, separate the liquid, dissolve the precipitate, precipitate repeatedly, and dry under vacuum to obtain intermediate b; Q3: Add intermediate b, triethoxysilylpropyl maleate, and tetrabutylammonium bromide into a container containing tetrahydrofuran, heat and stir for reaction under a nitrogen atmosphere, then add isobutyric anhydride and continue the reaction. After the reaction ends, dissolve, precipitate, precipitate repeatedly, and dry under vacuum to obtain intermediate c; Q4: Add glass fiber into hydrochloric acid, soak, wash, and dry to obtain pretreated glass fiber. Then add the pretreated glass fiber and intermediate c into distilled water, heat and stir for reaction. After the reaction ends, dry to obtain the modified glass fiber layer material.

2. The flexible string group photovoltaic cable according to claim 1, wherein, In S1, the dosage ratio of diethanolamine, paraformaldehyde and melamine is (32 - 38) g : (8 - 12) g : (11 - 18) g; the dosage ratio of compound A, 2,5-furandicarboxylic acid, N,N-dimethylformamide, xylene and zinc acetate is (0.88 - 1.21) g : (1.87 - 3.12) g : (45 - 55) mL : (0.45 - 0.63) g : (0.12 - 0.31) g.

3. The flexible string group photovoltaic cable according to claim 1, wherein, In S2, the dosage ratio of compound B, N,N-dimethylformamide, epichlorohydrin and tetrabutylammonium bromide is (2 - 2.54) g : (20 - 25) mL : (14 - 17.78) g : (0.8 - 1.3) g.

4. The flexible string group photovoltaic cable according to claim 1, wherein In S3, the dosage ratio of polyethylene and trimethylolpropane triacrylate is (8 - 12) g : (0.34 - 0.45) g, and the dosage ratio of compound C, zinc borate, compatibilizer and mica powder is (1 - 2) g : (0.8 - 0.85) g : (0.23 - 0.45) g : (0.15 - 0.25) g.

5. The flexible string group photovoltaic cable according to claim 1, characterized in that, In Q1, the dosage ratio of phthalic anhydride, epichlorohydrin, tetrabutylammonium bromide and tetrahydrofuran is (18.8 - 19.7) g : (27.12 - 28.56) g : (0.32 - 0.46) g : (40 - 50) mL.

6. The flexible string group photovoltaic cable according to claim 1, wherein, In Q2, the dosage ratio of intermediate a and anhydrous potassium carbonate solution is (18.56 - 21.18) g : (50 - 75) mL.

7. The flexible string group photovoltaic cable according to claim 1, characterized in that, In Q3, the dosage ratio of intermediate b, triethoxysilylpropyl maleate, tetrabutylammonium bromide, tetrahydrofuran and isobutyric anhydride is (9.6 - 10.8) g : (8.68 - 9.52) g : (0.21 - 0.36) g : (18 - 24) mL : (5.4 - 6.5) g; in Q4, the dosage ratio of pretreated glass fiber, intermediate c and distilled water is (1 - 1.5) g : (3.2 - 4.6) g : (80 - 100) mL.

8. The preparation method of the flexible string group photovoltaic cable according to any one of claims 1-7, characterized in that, It includes the following steps: Step 1: Anneal, multi-strand twist and ultrasonically clean the highly conductive flexible alloy to obtain an alloy inner conductor; Step 2: After melt-extruding the cross-linked polyolefin layer material, tightly wrap it on the surface of the alloy inner conductor, and then wrap the modified glass fiber layer material; Step 3: Add mica and kaolin to ethylene-octene copolymer, stir, mix and extrude to obtain a ceramized polyolefin layer material, and tightly wrap it on the surface of the modified glass fiber layer to obtain a flexible string group photovoltaic cable.

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