Outdoor anti-aging photovoltaic cable sheath material and preparation method thereof

Abstract

The invention discloses an outdoor anti-aging photovoltaic cable sheath material and a preparation method thereof. The outdoor anti-aging photovoltaic cable sheath material is prepared from the following raw materials in parts by mass: 100 parts of a polyurethane matrix, 25-30 parts of a plasticizer, 0.4-0.6 part of ferric acetylacetonate and 0.8-1.2 parts of a silane coupling agent. The polyurethane matrix is a polyurethane matrix, the silane coupling agent is a thiazolyl silane coupling agent, the difunctional nano whisker is 0.8-1.5 parts, the difunctional nano whisker is obtained by grafting a furan group and a catechol group on the surface of a cellulose whisker, and a locked quaternary synergistic infrastructure is formed by the polyurethane matrix, the thiazolyl silane coupling agent, ferric acetylacetonate and the difunctional whisker; the photovoltaic cable sheath material has excellent ultraviolet aging resistance, low-temperature toughness and basic self-repairing capability, and is suitable for being applied to outdoor environments with long-time illumination and large day and night temperature difference.

Description

TECHNICAL FIELD

[0001] The application relates to a photovoltaic cable, in particular to an outdoor anti-aging photovoltaic cable sheath material and a preparation method thereof. BACKGROUND

[0002] As a key component of a photovoltaic power generation system, the sheath material of a photovoltaic cable is exposed to the outdoor environment for a long time, especially in high-latitude areas, where the light time is long, the day-night temperature difference is large, and there is strong ultraviolet radiation and temperature change, so that the sheath of the photovoltaic cable is prone to aging failure.

[0003] At present, the anti-aging research on the sheath material of the photovoltaic cable mainly focuses on the following aspects: the use of ultraviolet absorbers and hindered amine light stabilizers in combination to slow down ultraviolet aging, however, such small molecule additives are prone to migration and precipitation during use, resulting in a sharp decline in the protection effect over time, and the addition of plasticizers to improve low-temperature toughness will reduce the mechanical strength of the material.

[0004] Therefore, it is urgent to develop an outdoor anti-aging photovoltaic cable sheath material to match the application requirements of the photovoltaic cable sheath material in the outdoor long-time light and large day-night temperature difference environment. SUMMARY

[0005] In order to solve the problem of fast aging and short service life of the sheath of the existing photovoltaic cable in the outdoor long-time light and large day-night temperature difference environment, an outdoor anti-aging photovoltaic cable sheath material and a preparation method thereof are provided.

[0006] The above first invention purpose of the application is realized by the following technical scheme: An outdoor anti-aging photovoltaic cable sheath material comprises the following raw materials by mass fraction: 100 parts of a polyurethane matrix; 25-30 parts of a plasticizer; 0.4-0.6 parts of iron acetylacetone; 0.8-1.2 parts of a silane coupling agent, the alkyl coupling agent being a thiazole-based silane coupling agent; 0.8-1.5 parts of a bifunctional nanowhisker, the bifunctional nanowhisker being obtained by grafting furan groups and catechol groups on the surface of cellulose whiskers.

[0007] By adopting the above technical scheme, a locked four-element synergistic basic framework is formed by the polyurethane matrix, the thiazole-based silane coupling agent, the iron acetylacetone and the bifunctional whisker in the application; The polyurethane matrix constitutes a continuous phase of the material: It provides basic mechanical properties and elasticity, on the other hand, it provides unreacted isocyanate groups (-NCO) and strong electronegative carbonyl (C=O) to provide chemical anchors for the construction of the entire synergistic network; Thiazole silane coupling agent is the molecular bridge and functional integration hub: Its thiol group (-SH) forms stable thiourethane bonds (-NH-C(O)-S-) with residual isocyanate groups (-NCO) in polyurethane segments, and forms hydrogen bonds with strong electronegative atoms (carbonyl oxygen-C=O) in TPU segments, firmly anchoring the coupling agent on the matrix network; Its sulfonic acid group (-SO3H) has strong electronegativity and can form strong ionic-dipole interactions with Fe 3+ released by acetylacetone iron, forming a stable coordination structure, thereby precisely and stably anchoring iron ions on the polymer network and effectively preventing migration and agglomeration; Its siloxane group (-Si(OCH3)3) reacts with the hydroxyl group (-OH) on the surface of the whisker to form a firm Si-O-C covalent bond, chemically "grafting" the whisker to the network; Acetylacetone iron as a dynamic repair and stability core: Acetylacetone iron as a Fe 3+ supply source, has two functions; First, the released Fe 3+ coordinates with the catechol group on the surface of the bifunctional whisker to form a reversible Fe 3 + -catechol coordination bond. This bond can reversibly break and recombine under thermal stimulation, realizing the self-repairing function of the material; Second, the redox cycle of Fe 3+ / Fe 2+ can efficiently quench free radicals generated during the ultraviolet aging process of the material, interrupting the degradation chain reaction; Bifunctional cellulose whiskers as reinforcement and repair execution units: Bifunctional cellulose whiskers form a three-dimensional network in the matrix, greatly improving the strength, modulus, and crack propagation resistance of the material through mechanical interlocking and stress transfer; The furan and catechol groups grafted on the surface of the bifunctional cellulose whisker make it a functional center, and the catechol group coordinates with Fe 3 + to participate in the construction of the above dynamic repair network; In summary, the four-component is bridged by the precise bridging of thiazole silane to form a stable and functionally integrated network architecture, which is anchored by the bonding and coordination of thiazole silane, and the hydrophilic cellulose whiskers and non-polar iron ions are stably and uniformly integrated into the hydrophobic polyurethane matrix, which fundamentally avoids phase separation and nanoparticle agglomeration, and ensures uniform and stable performance. The whiskers provide reinforcement while the functional groups (catechol) on their surface are the trigger points for repair, achieving a synergistic improvement in material strength and self-repairing ability without compromising performance. The thiazole silane chemically locks the components on the network, greatly inhibiting the migration, precipitation and failure of small molecule additives (such as iron ions), allowing the dynamic repair function and ultraviolet stability function to be maintained for a long time, laying the foundation for long-term stability, and is the key to achieving long service life of the material. Finally, the photovoltaic cable sheath material has excellent ultraviolet aging resistance, low-temperature toughness, and basic self-repairing ability, and is suitable for outdoor long-term light exposure and large diurnal temperature difference environments.

[0008] Optionally, the length-diameter ratio of the bifunctional nanowhisker is greater than 80.

[0009] Optionally, the length-diameter ratio of the bifunctional nanowhisker is 85-90.

[0010] By adopting the above technical solution, the nanowhisker with a length-diameter ratio greater than 80 has a larger specific surface area and a higher aspect ratio, and the furan groups and catechol groups grafted on its surface can significantly increase the number of chemical bonds formed with the polyurethane matrix and thiazole silane coupling agent, inhibit phase separation, and improve the mechanical strength and fatigue life of the material.

[0011] Optionally, the furan group grafting density on the surface of the bifunctional nanowhisker is 60-100 μmol / g, and the catechol group grafting density is 40-80 μmol / g.

[0012] By adopting the above technical solution, sufficient functional group density ensures the reaction probability of Fe 3+ and maleimide, ensuring repair efficiency, while avoiding excessive grafting that damages the crystal structure and mechanical strength of the cellulose whisker itself, optimizing the balance between reinforcement and repair.

[0013] Optionally, the plasticizer is epoxy acetylated cashew oil grafted with maleimide groups, with a grafting rate of 15-20%.

[0014] By adopting the above technical scheme, the epoxy acetylated cashew oil (EBE) itself is an excellent bio-based cold-resistant plasticizer due to its long fatty chain and epoxy group, the maleimide group grafted on the epoxy acetylated cashew oil serves as a dieneophile, and the furan group on the surface of the whisker undergoes a highly efficient cycloaddition reaction to form a reversible covalent crosslinking network, further improving the self-repairing performance, 15-20% grafting rate, ensuring reaction activity and retaining plasticizing effect, ensuring sufficient maleimide groups to match the density of furan groups on the surface of the whisker to meet the crosslinking requirement, while most of the EBE molecular chain segments are not modified, and the long fatty chain can effectively insert between polymer chains to weaken the intermolecular force, thereby significantly reducing the glass transition temperature of the material, realizing the unification of the plasticizing function and the repairing function, and the material obtains excellent low-temperature toughness without sacrificing the repairing ability at high temperature.

[0015] In addition, the polar epoxy group of EBE has good compatibility with the polyurethane matrix; the grafted maleimide group further locks the plasticizer on the polymer network through reaction with the furan group, inhibits migration and precipitation, and avoids problems such as surface tackiness and performance degradation caused by the precipitation of the plasticizer.

[0016] Optionally, the molar ratio of the maleimide group in the plasticizer to the furan group of the bifunctional nanowhisker is 1:1.1-1.3.

[0017] By adopting the above technical scheme, the slight excess of furan groups ensures the complete reaction of the maleimide groups, greatly improves the conversion rate of the Diels-Alder reaction, and the excess furan groups form a "dynamic bond reserve", which can quickly recombine with the exposed maleimide after damage, so as to improve the self-repairing effect of the material and make the repair response speed faster. The ratio is a relatively optimal ratio for maintaining the balance of the dynamic reversible crosslinking network, and after multiple damage-repair cycles, there are still sufficient free functional groups in the system to maintain the repair ability, so that the material can maintain a relatively optimal efficiency retention rate after more than 5 repair cycles. And the crosslinking network density is precisely controlled, avoiding the problems of excessive crosslinking (material becomes brittle) caused by excessive maleimide and the problem of reduced aging resistance caused by excessive furan, achieving a better balance between strength, toughness and repair ability without sacrificing flexibility.

[0018] Optionally, it also includes a hindered amine light stabilizer of 0.5-1.0 parts, and the hindered amine light stabilizer molecule contains a thiazole heterocycle.

[0019] By adopting the technical scheme, the specific hindered amine light stabilizer containing a thiazole heterocycle is introduced, the thiazole heterocycle in the HALS molecule and the thiazole silane coupling agent form a molecular level synergistic network through π-π stacking, the multifunctional synergy of "HALS-silane-acetylacetone iron" is realized, and the ultraviolet protection efficiency is improved.

[0020] The above second application purpose of the application is realized by the following technical scheme: A preparation method of an outdoor anti-aging photovoltaic cable sheath material, comprising the following steps: Disperse the bifunctional nanowhisker in anhydrous ethanol to obtain a suspension; Drop the silane coupling agent into the suspension, heat and stir to react; After the reaction is completed, centrifugal separation, washing and vacuum drying are performed to obtain the pretreated bifunctional nanowhisker; Select a double-screw extruder, add the polyurethane matrix and the plasticizer to the main feeding port, mix the pretreated bifunctional nanowhisker, acetylacetone iron and the silane coupling agent to obtain a premix, and uniformly add the premix to the molten polymer through the side feeding port; after extrusion, granulation storage or plastic packaging is performed according to production requirements to obtain the cable sheath layer; The silane coupling agent used for the pretreated bifunctional nanowhisker and the silane coupling agent used for the premix added through the side feeding port are the same silane coupling agent, and the total amount and the TPU mass ratio are 0.8-1.2:100.

[0021] When the raw material includes a hindered amine light stabilizer: A preparation method of an outdoor anti-aging photovoltaic cable sheath material, comprising the following steps: Disperse the bifunctional nanowhisker in anhydrous ethanol to obtain a suspension; Drop the silane coupling agent into the suspension, heat and stir to react; After the reaction is completed, centrifugal separation, washing and vacuum drying are performed to obtain the pretreated bifunctional nanowhisker; Select a double-screw extruder, add the polyurethane matrix and the plasticizer to the main feeding port, mix the pretreated bifunctional nanowhisker, acetylacetone iron and the silane coupling agent to obtain a premix, and uniformly add the premix to the molten polymer through the side feeding port; then the hindered amine light stabilizer is pumped into the molten polymer when the molten polymer is homogenized; After extrusion, granulation storage or plastic packaging is performed according to production requirements to obtain the cable sheath layer; The silane coupling agent used for the pretreated bifunctional nanowhisker and the silane coupling agent used for the premix added through the side feeding port are the same silane coupling agent, and the total amount and the TPU mass ratio are 0.8-1.2:100.

[0022] By adopting the technical scheme, the photovoltaic cable sheath material prepared has excellent ultraviolet aging resistance, low-temperature toughness, basic self-repairing capability, and is suitable for outdoor long-time light exposure and large diurnal temperature difference environment application.

[0023] In summary, the present application has at least the following beneficial effects: The polyurethane matrix, thiazole-based silane coupling agent, acetylacetone iron, and bifunctional whisker form a locking four-element synergistic basic framework, so that the photovoltaic cable sheath material has excellent ultraviolet aging resistance, low-temperature toughness, basic self-repairing capability, and is suitable for outdoor long-time light exposure and large diurnal temperature difference environment application. DETAILED DESCRIPTION

[0024] Raw materials The polyurethane matrix (TPU) is 1180A; The acetylacetone iron is Sigma-Aldrich product number: 520508, electronic grade, Fe content 11.2%, Cl-≤10ppm.

[0025] The thiazole-based silane coupling agent (HS-C4H3S-C(O)-NH-Si(OCH3)2-C3H6-SO3H) is custom-synthesized by Nanjing Shuguang Silane Chemical Co., Ltd., and is obtained by condensation reaction of 3-mercaptopropyl trimethoxysilane and 2-mercaptothiazole-5-carboxylic acid to form an amide bond.

[0026] The hindered amine light stabilizer containing a thiazole heterocycle (R1-N-(CH2)3-S-C4H3N2S-R2) is BASF's 460, R1 is C 12 H 25 , and R2 is H.

[0027] The cellulose nanocrystal whisker is NCC of CelluForce, USA TM , with a diameter of 15±1nm, and is divided into multiple specifications according to the aspect ratio, as shown below.

[0028] The epoxidized acetylated cashew nut oil (EBE) is BASF's TMMM, with an epoxy value of 5.1%, an acid value of ≤0.1mg KOH / g, and a viscosity (25°C) of 42.5mPa·s.

[0029] Preparation Example 1 The epoxidized acetylated cashew nut oil grafted with maleimide groups is obtained by grafting modification of epoxidized acetylated cashew nut oil (EBE), with a grafting rate of 18.2%.

[0030] The preparation process is as follows: Into a reactor were charged 28.0 kg of EBE and 2.5 kg of maleic anhydride, and the mixture was protected by nitrogen, heated to 110°C, and after the maleic anhydride completely melted, 0.15 kg of dimethylbenzylamine was added as a catalyst, and the mixture was reacted at 110°C for 3 h. After the reaction was completed, the unreacted maleic anhydride was removed by distillation under reduced pressure at -0.095 MPa and 120°C for 1 h, and thus grafted maleimide group-containing epoxy acetylated cashew oil was obtained.

[0031] The sample was titrated, and the maleimide grafting rate was determined to be 18.2%.

[0032] Preparation Example 2 Grafted maleimide group-containing epoxy acetylated cashew oil was obtained by grafting modification of epoxy acetylated cashew oil (EBE), and the grafting rate was 10.3%.

[0033] Into a reactor were charged 28.0 kg of EBE and 1.27 kg of maleic anhydride, and the mixture was protected by nitrogen, heated to 110°C, and after the maleic anhydride completely melted, 0.147 kg of dimethylbenzylamine was added as a catalyst, and the mixture was reacted at 110°C for 3 h. After the reaction was completed, the unreacted maleic anhydride was removed by distillation under reduced pressure at -0.095 MPa and 120°C for 1 h, and thus grafted maleimide group-containing epoxy acetylated cashew oil was obtained.

[0034] The sample was titrated, and the maleimide grafting rate was determined to be 10.3%.

[0035] Preparation Example 3 Grafted maleimide group-containing epoxy acetylated cashew oil was obtained by grafting modification of epoxy acetylated cashew oil (EBE), and the grafting rate was 15.0%.

[0036] The preparation process was as follows: Into a reactor were charged 28.0 kg of EBE and 1.90 kg of maleic anhydride, and the mixture was protected by nitrogen, heated to 110°C, and after the maleic anhydride completely melted, 0.149 kg of dimethylbenzylamine was added as a catalyst, and the mixture was reacted at 110°C for 3 h. After the reaction was completed, the unreacted maleic anhydride was removed by distillation under reduced pressure at -0.095 MPa and 120°C for 1 h, and thus grafted maleimide group-containing epoxy acetylated cashew oil was obtained.

[0037] The sample was titrated, and the maleimide grafting rate was determined to be 15.0%.

[0038] Preparation Example 4 Grafted maleimide group-containing epoxy acetylated cashew oil was obtained by grafting modification of epoxy acetylated cashew oil (EBE), and the grafting rate was 20.0%.

[0039] The preparation process was as follows: Into a reactor, 28.0 kg of EBE and 2.60 kg of maleic anhydride were added, and nitrogen was introduced for protection. The temperature was raised to 110°C, and after the maleic anhydride was completely melted, 0.153 kg of dimethylbenzylamine was added as a catalyst. The reaction was carried out at 110°C for 3 hours. After the reaction was completed, the unreacted maleic anhydride was removed by vacuum distillation at -0.095 MPa and 120°C for 1 hour, and epoxy acetylated cashew oil grafted with maleimide groups was obtained.

[0040] Sample titration showed that the grafting rate of maleimide was 20.0%.

[0041] Preparation Example 5 Epoxy acetylated cashew oil grafted with maleimide groups was obtained by grafting modification of epoxy acetylated cashew oil (EBE), and the grafting rate was 24.8%.

[0042] The preparation process was as follows: Into a reactor, 28.0 kg of EBE and 3.18 kg of maleic anhydride were added, and nitrogen was introduced for protection. The temperature was raised to 110°C, and after the maleic anhydride was completely melted, 0.156 kg of dimethylbenzylamine was added as a catalyst. The reaction was carried out at 110°C for 3 hours. After the reaction was completed, the unreacted maleic anhydride was removed by vacuum distillation at -0.095 MPa and 120°C for 1 hour, and epoxy acetylated cashew oil grafted with maleimide groups was obtained.

[0043] Sample titration showed that the grafting rate of maleimide was 24.8%.

[0044] Preparation Example 6 The bifunctional nanowhisker was obtained by grafting furan groups and pyrocatechol groups on the surface of cellulose nanowhisker, and had an aspect ratio of 85, a furan group grafting density of 80 μmol / g, and a pyrocatechol group grafting density of 60 μmol / g.

[0045] The preparation process was as follows: Into a reactor, 28.0 kg of EBE and 3.18 kg of maleic anhydride were added, and nitrogen was introduced for protection. The temperature was raised to 110°C, and after the maleic anhydride was completely melted, 0.156 kg of dimethylbenzylamine was added as a catalyst. The reaction was carried out at 110°C for 3 hours. After the reaction was completed, the unreacted maleic anhydride was removed by vacuum distillation at -0.095 MPa and 120°C for 1 hour, and epoxy acetylated cashew oil grafted with maleimide groups was obtained. Into the reaction kettle, 0.05 kg of ammonium persulfate was added, and stirred at 23°C for 30 minutes. Then, 0.30 kg of 2-furan acrylate was slowly added dropwise, and the dropwise addition of 2-furan acrylate was completed in 1.5 hours. The system was heated to 70°C, and continuously stirred at a speed of 200 rpm under nitrogen protection for 6 hours.

[0046] After the reaction was completed, the mixture was cooled to 23°C, and centrifuged at 8000 rpm. The supernatant was discarded, and the precipitate was washed with anhydrous ethanol and deionized water alternately until the washing liquid was detected to be free of SO4 2- ions; The washed product was re-dispersed in deionized water and vacuum freeze-dried (-50℃, 0.1 mBar, 48h) to obtain furan-functionalized cellulose nanowhiskers (F-CNC) 1.2 kg of F-CNC were dispersed in 60 L of 2-morpholinoethanesulfonic acid (MES) buffer solution (0.1 M, pH = 5.5) and sonicated for 1 h.

[0047] 0.38 kg of l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and 0.23 kg of N-hydroxysuccinimide (NHS) were added to the system and the carboxyl groups were activated by slow stirring at 23°C for 1 h.

[0048] 0.48 kg of dopamine hydrochloride was added and the pH of the system was adjusted to 5.5 with a dilute NaOH solution. The reaction was stirred at 23°C in the dark for 12 h.

[0049] After the reaction was completed, the product was separated by centrifugation and washed repeatedly with deionized water until the washing liquid was colorless and transparent. Vacuum freeze-drying was performed again to obtain the bifunctional nanowhiskers (DF-CNC).

[0050] The final product was confirmed to contain both furan and catechol functional groups by titration, and the grafting density of the furan groups was 80 μmol / g and the grafting density of the catechol groups was 60 μmol / g.

[0051] Preparation Examples 7-10 The bifunctional nanowhiskers were obtained by grafting furan groups and catechol groups onto the surface of cellulose nanowhiskers, and differed from Preparation Example 6 in that the raw materials were selected or used in different amounts during the preparation process, as shown in the following table.

[0052] Table 1. Differences in the preparation process of Preparation Examples 6-10 and the standard case Preparation Example 11 The bifunctional nanowhiskers differed from Preparation Example 6 in that the aspect ratio of the raw material cellulose nanowhiskers was 60.

[0053] Preparation Example 12 The bifunctional nanowhiskers differed from Preparation Example 6 in that the aspect ratio of the raw material cellulose nanowhiskers was 80.

[0054] Preparation Example 13 The bifunctional nanowhiskers differed from Preparation Example 6 in that the aspect ratio of the raw material cellulose nanowhiskers was 90.

[0055] Example 1 An outdoor aging-resistant photovoltaic cable sheath material, raw materials of which include the following mass fractions: Polyurethane matrix 100 parts, plasticizer 28 parts, acetylacetone iron 0.5 parts, silane coupling agent 1 part, bifunctional nanowhisker 1.2 parts, hindered amine light stabilizer 0.8 parts.

[0056] The plasticizer is grafted maleimide group epoxy acetylated cashew oil prepared in Preparation Example 1, and the grafting rate is 18.2%.

[0057] The silane coupling agent is a thiazole silane coupling agent, and the structural formula is: HS-C4H3S-C(O)-NH-Si(OCH3)2-C3H6-SO3H.

[0058] The bifunctional nanowhisker is prepared in Preparation Example 6, and the length-diameter ratio is 85, the furan group grafting density is 80 μmol / g, and the catechol group grafting density is 60 μmol / g.

[0059] The hindered amine light stabilizer is 460.

[0060] The specific preparation method is as follows: 1.2 kg of the bifunctional nanowhisker is dried at 105°C under a vacuum of-0.095 MPa for 4 h; The dried nanowhisker is dispersed in 150 L of anhydrous ethanol, and high-speed shearing dispersion (2000 rpm) is performed for 30 min to obtain a suspension; 0.24 kg of the silane coupling agent is slowly added dropwise into the suspension, the dropwise adding rate is controlled (30 min for dropwise adding), the system is warmed to 75°C, and the reaction is continuously performed at a rotation speed of 300 rpm for 2 h; after the reaction is completed, centrifugal separation is performed, fresh ethanol is used for washing 3 times, and 80°C vacuum drying is performed for 12 h to obtain the pretreated bifunctional nanowhisker, which is sealed for use; A co-rotating twin-screw extruder is selected, the screw diameter is 58 mm, the length-diameter ratio L / D is 40:1, the screw rotation speed is 300 rpm, a side feeder and a liquid injection pump are arranged, and the screw section and temperature control are as follows: the feeding section is 120°C, the melting section and the side feeding port are 165°C, the high-shear mixing section is 170°C, the homogenization section is 160°C, and the head and the die are 155°C; 100 kg of TPU and 28 kg of plasticizer are added to the main feeding port, The pretreated 1.2 kg of bifunctional nanowhisker, 0.5 kg of acetylacetone iron, and 0.76 kg of silane coupling agent are mixed in a small high-speed mixer for 60 s to obtain a premix, and the premix is uniformly added to the molten polymer through the side feeding port located in the melting section; 0.8 kg of the hindered amine light stabilizer is injected through a precision liquid injection pump before the front section of the homogenization section; After extrusion, granulation storage or plastic packaging is carried out according to production requirements to obtain a cable sheath layer.

[0061] The silane coupling agent used for the pretreated bifunctional nanowhisker and the silane coupling agent used for the side feeding port of the melting section of the premix are the same thiazole silane coupling agent, and the total amount is 1 kg.

[0062] The silane coupling agent used for the pretreated bifunctional nanowhisker is controlled to be 20 wt% of the mass of the bifunctional nanowhisker.

[0063] Comparative Example 1 An outdoor anti-aging photovoltaic cable sheath material, which is different from Example 1 in that the amount of acetylacetone iron is 0 kg, i.e. no acetylacetone iron is added in the raw materials, and the premix added to the side feeding port of the co-rotating twin-screw extruder is 1.2 kg of whisker and 0.76 kg of silane coupling agent mixed.

[0064] Comparative Example 2 An outdoor anti-aging photovoltaic cable sheath material, which is different from Example 1 in that 3-aminopropylmethyldiethoxysilane is used as the silane coupling agent, and the mass is replaced with the original thiazole silane coupling agent.

[0065] Comparative Example 3 An outdoor anti-aging photovoltaic cable sheath material, which is different from Example 1 in that the unmodified cellulose whisker is used to replace the bifunctional nanowhisker in the same mass, and the aspect ratio of the unmodified cellulose whisker is 85 and the diameter is 15 nm.

[0066] Example 2 An outdoor anti-aging photovoltaic cable sheath material, which is different from Example 1 in that the bifunctional nanowhisker is prepared in Preparation Example 7, and the aspect ratio is 60.

[0067] Example 3 An outdoor anti-aging photovoltaic cable sheath material, which is different from Example 1 in that the bifunctional nanowhisker is prepared in Preparation Example 8, and the aspect ratio is 80.

[0068] Example 4 An outdoor anti-aging photovoltaic cable sheath material, which is different from Example 1 in that the bifunctional nanowhisker is prepared in Preparation Example 9, and the aspect ratio is 90.

[0069] Example 5 An outdoor anti-aging photovoltaic cable sheath material, which is different from Example 1 in that the bifunctional nanowhisker is prepared in Preparation Example 10, and the surface furan group grafting density is 40 μmol / g, and the catechol group grafting density is 30 μmol / g.

[0070] Example 6 An outdoor weatherable photovoltaic cable jacket material differs from Example 1 in that the bifunctional nanowhisker is prepared as in Preparation Example 11 and has a furan group grafting density of 60 μmol / g and a catechol group grafting density of 40 μmol / g.

[0071] Example 7 An outdoor weatherable photovoltaic cable jacket material differs from Example 1 in that the bifunctional nanowhisker is prepared as in Preparation Example 12 and has a furan group grafting density of 100 μmol / g and a catechol group grafting density of 80 μmol / g.

[0072] Example 8 An outdoor weatherable photovoltaic cable jacket material differs from Example 1 in that the bifunctional nanowhisker is prepared as in Preparation Example 13 and has a furan group grafting density of 120 μmol / g and a catechol group grafting density of 95 μmol / g.

[0073] Example 9 An outdoor weatherable photovoltaic cable jacket material differs from Example 1 in that the epoxy acetylated cashew nut oil grafted with maleimide groups is replaced with epoxy acetylated cashew nut oil in an equal amount as a plasticizer.

[0074] Example 10 An outdoor weatherable photovoltaic cable jacket material differs from Example 1 in that the epoxy acetylated cashew nut oil grafted with maleimide groups is prepared as in Preparation Example 2 and has a grafting rate of 10%.

[0075] Example 11 An outdoor weatherable photovoltaic cable jacket material differs from Example 1 in that the epoxy acetylated cashew nut oil grafted with maleimide groups is prepared as in Preparation Example 3 and has a grafting rate of 15%.

[0076] Example 12 An outdoor weatherable photovoltaic cable jacket material differs from Example 1 in that the epoxy acetylated cashew nut oil grafted with maleimide groups is prepared as in Preparation Example 4 and has a grafting rate of 20%.

[0077] Example 13 An outdoor weatherable photovoltaic cable jacket material differs from Example 1 in that the epoxy acetylated cashew nut oil grafted with maleimide groups is prepared as in Preparation Example 5 and has a grafting rate of 25%.

[0078] Example 14 An outdoor weatherable photovoltaic cable jacketing material which differs from Example 1 in that the amount of bifunctional nanowhisker is 1.0 kg, the amount of epoxy acetylated cashew nut oil grafted with maleimide groups is 28 kg, and the molar ratio of maleimide groups to furan groups of the bifunctional nanowhisker in the plasticizer is 1 : 1.

[0079] Example 15 An outdoor weatherable photovoltaic cable jacketing material which differs from Example 1 in that the amount of bifunctional nanowhisker is 1.1 kg, the amount of epoxy acetylated cashew nut oil grafted with maleimide groups is 28 kg, and the molar ratio of maleimide groups to furan groups of the bifunctional nanowhisker in the plasticizer is 1 : 1.1.

[0080] Example 16 An outdoor weatherable photovoltaic cable jacketing material which differs from Example 1 in that the amount of bifunctional nanowhisker is 1.3 kg, the amount of epoxy acetylated cashew nut oil grafted with maleimide groups is 28 kg, and the molar ratio of maleimide groups to furan groups of the bifunctional nanowhisker in the plasticizer is 1 : 1.3.

[0081] Example 17 An outdoor weatherable photovoltaic cable jacketing material which differs from Example 1 in that the amount of bifunctional nanowhisker is 1.4 kg, the amount of epoxy acetylated cashew nut oil grafted with maleimide groups is 28 kg, and the molar ratio of maleimide groups to furan groups of the bifunctional nanowhisker in the plasticizer is 1 : 1.4.

[0082] Example 18 An outdoor weatherable photovoltaic cable jacketing material which differs from Example 1 in that the amount of bifunctional nanowhisker is 1.5 kg, the amount of epoxy acetylated cashew nut oil grafted with maleimide groups is 28 kg, and the molar ratio of maleimide groups to furan groups of the bifunctional nanowhisker in the plasticizer is 1 : 1.5. 770 (bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate) is used instead of 460 as the hindered amine light stabilizer.

[0083] Example 19 An outdoor weatherable photovoltaic cable jacketing material which differs from Example 1 in that the amounts of the raw materials are different, specifically: polyurethane matrix 100 kg, plasticizer 25 kg, acetylacetone iron 0.4 kg, silane coupling agent 0.8 kg, bifunctional nanowhisker 0.8 kg, hindered amine light stabilizer 0.5 kg.

[0084] The silane coupling agent is used in two parts; one, for pretreatment of the bifunctional nanowhisker, the amount of which is 20 wt% of the mass of the bifunctional nanowhisker, here 0.16 kg; the other, mixed into the premix, added to the molten polymer from the side feed port of the melt section, the amount of which is the remaining total amount, here 0.64 kg.

[0085] Example 20 An outdoor weatherable photovoltaic cable jacket material, which differs from Example 1 in the amount of raw materials used, specifically: polyurethane matrix 100 kg, plasticizer 30 kg, acetylacetone iron 0.6 kg, silane coupling agent 1.2 kg, bifunctional nanowhisker 1.5 kg, hindered amine light stabilizer 1 kg.

[0086] The silane coupling agent is used in two parts; one, for pretreatment of the bifunctional nanowhisker, amounting to 20 wt% of the mass of the bifunctional nanowhisker, here 0.3 kg; the other, mixed as a premix, added to the molten polymer from the side feed of the melt section, amounting to the remaining total amount, here 0.9 kg.

[0087] The cable jacket materials obtained in Examples 1-20 and Comparative Examples 1-3 were tested, and the test results are as follows.

[0088] Tensile strength test: according to ASTM D638.

[0089] Elongation at break test at -40°C: elongation at break test at -40°C according to ASTM D638, reflecting the low-temperature toughness of the material.

[0090] Ultraviolet aging 3000h: tensile strength test after 3000h of ultraviolet aging according to IEC 62788-7-2, and according to the initial tensile strength test results, the ultraviolet aging 3000h strength retention rate is calculated.

[0091] Repair efficiency at 80°C / 30min: The material was hot-pressed into a 1B type sample as specified in ISO 527-2; The sample was adjusted and stored in a standard laboratory environment (23±2°C, 50±10% RH) for 24h; A standard notch was introduced into the middle parallel section of the sample, perpendicular to the long axis of the sample, using a sharp blade. The standard notch depth was controlled at 50% of the sample thickness, and the standard notch length was 5mm; Immediately after the damaged sample was tested for tensile strength to obtain the baseline value before repair (control group), and the same size intact sample was tested for tensile strength as a blank control group; The sample with the same damage was placed in a blast drying oven and heated at 80°C for 30 minutes, and then taken out and cooled to room temperature in a standard laboratory environment; The tensile strength of the repaired sample was tested using a universal material testing machine, according to ISO 527 standard.

[0092] Repair efficiency (η) calculation formula η (%) = (A3-A2) ÷ (Al-A2) x 100%, Al, tensile strength of intact sample (blank control group); A2, tensile strength after damage and before repair (control group); A3, tensile strength after damage and repair (experimental group).

[0093] Efficiency after 5 repair cycles: Prepare the sample and damaged sample according to the above "Repair efficiency detection at 80℃ / 30min" method, define a complete "damage-repair" as a cycle, and repeat the cycle 5 times; First cycle, make a standard notch on the intact sample, repair at 80℃ for 30min, test its tensile strength after cooling, and calculate the first repair efficiency η1; Second cycle, introduce a new notch with the same depth and length as the first cycle at the same position and direction, repair at 80℃ for 30min, test and calculate the second repair efficiency η2 after cooling; Repeat the cycle to the fifth cycle, and calculate the second repair efficiency η5; Calculate the efficiency retention rate R after 5 cycles, R = η5 ÷ η1 x 100%.

[0094] The test results are shown in Tables 2 and 3 below.

[0095] Table 2. Test results of Examples 1-20 and Comparative Examples 1-3 Table 1 Tensile strength (MPa) Elongation at break at -40°C (%) Strength retention after UV aging for 3000h (%) Example 1 28.5 335 96.5 Example 2 24.1 310 95.8 Example 3 27.3 328 96.2 Example 4 28.8 338 96.7 Example 5 22.3 295 92.1 Example 6 26.7 320 95 Example 7 28 330 97 Example 8 27.9 305 93.5 Example 9 20.8 280 88.2 Example 10 23.5 290 90.5 Example 11 26.8 320 94.8 Example 12 28.2 332 96 Example 13 26.5 310 91 Example 14 26.1 322 95.2 Example 15 27.9 330 96 Example 16 28.3 333 96.3 Example 17 27.2 315 94.1 Example 18 27.8 332 90.1 Example 19 26.8 320 95.0 Example 20 29.0 350 97.5 Comparative Example 1 20.2 265 81.3 Comparative Example 2 22.7 285 86.5 Comparative Example 3 18.5 240 78.2 Table 3. Test results of Examples 1-20 and Comparative Examples 1-3 Table 2 Repair efficiency at 80°C / 30min (%) Efficiency retention after 5 repair cycles (%) Example 1 90.1 86.5 Example 2 88.5 85 Example 3 89.2 85.8 Example 4 89.7 86.2 Example 5 82.4 78.3 Example 6 87.6 84.1 Example 7 90.5 86.8 Example 8 85.2 79.6 Example 9 74.2 65.3 Example 10 76.3 70.1 Example 11 85.4 81.3 Example 12 88.9 85 Example 13 82.7 75.4 Example 14 83.5 76.8 Example 15 87.2 83.5 Example 16 88.1 84.8 Example 17 84.3 77.9 Example 18 88.9 85.1 Example 19 88.0 84.5 Example 20 90.5 85.0 Comparative Example 1 0 0 Comparative Example 2 45.3 38.1 Comparative Example 3 0 0 From Comparative Example 1 and Comparative Examples 1-3, The tensile strength of Example 1 is significantly better than that of Comparative Examples 1-3; The elongation at break at -40℃ of Example 1 is significantly greater than that of Comparative Examples 1-3, and the low temperature toughness of Example 1 is significantly better than that of Comparative Examples 1-3; The strength retention rate of Example 1 after UV aging for 3000h is significantly greater than that of Comparative Examples 1-3, and the UV aging resistance of Example 1 is significantly better than that of Comparative Examples 1-3; The repair efficiency of Comparative Example 1 and Comparative Example 3 at 80℃ / 30min and the efficiency retention rate after 5 repair cycles are both 0, and they do not have self-repairing performance; The repair efficiency of Example 1 at 80℃ / 30min and the efficiency retention rate after 5 repair cycles are significantly greater than those of Comparative Example 2, so the material of Example 1 has self-repairing performance and is significantly better than that of Comparative Example 2.

[0096] Therefore, it can be verified that the polyurethane matrix, thiazole silane coupling agent, acetylacetone iron and bifunctional whisker form a locking four-element synergistic framework in the application. In the locking four-element synergistic framework: The polyurethane matrix constitutes a continuous phase, provides basic mechanical properties and elasticity, and on the other hand, provides unreacted isocyanate groups (-NCO) and strong electronegative carbonyl groups (C=O) to provide chemical anchors for the construction of the entire synergistic network; the thiazole silane coupling agent is a molecular bridging and functional integration hub, the thiol group (-SH) thereof forms a stable thiourethane bond (-NH-C(O)-S-) with the residual isocyanate group (-NCO) in the polyurethane segment, and on the other hand, forms a hydrogen bond with the strong electronegative atom (such as carbonyl oxygen -C=O) in the TPU segment, firmly anchoring the coupling agent on the matrix network; the sulfonic acid group (-SO3H) has strong electronegativity and can form a stable coordination structure with the Fe 3+ released by the acetylacetone iron, thereby precisely and stably anchoring the iron ion on the polymer network and effectively preventing migration and agglomeration thereof; the siloxane group (-Si(OCH3)3) reacts with the hydroxyl group (-OH) on the surface of the whisker to form a firm Si-O-C covalent bond, and the whisker is "grafted" to the network in a chemical bond manner; Acetylacetone iron acts as a dynamic repair and stability core. Acetylacetone iron serves as a source of Fe 3+ , and has two functions; first, the released Fe 3+ forms a reversible Fe 3+ -catechol coordination bond with the catechol group on the surface of the bifunctional whisker. This bond can be reversibly broken and recombined under thermal stimulation (~ 80°C), realizing the self-repairing function of the material. Comparative Example 1 (without Fe 3+ ) and Comparative Example 3 (without bifunctional cellulose whisker) cannot form a repair network due to the lack of a dynamic coordination bond core component, and the repair efficiency is 0%; second, the redox cycle of Fe 3+ / Fe 2+ can efficiently quench free radicals generated during the ultraviolet aging process of the material, interrupting the degradation chain reaction; The bifunctional cellulose whisker is an enhancement and repair execution unit. The bifunctional cellulose whisker forms a three-dimensional network in the matrix, greatly improving the strength, modulus and crack propagation resistance of the material through mechanical interlocking and stress transfer; the furan group and catechol group grafted on the surface of the bifunctional cellulose whisker make it a functional center, and the catechol group coordinates with Fe 3+ to participate in the construction of the above dynamic repair network; In summary, the four-component is formed into a stable and functionally integrated network structure by the precise bridging of the thiazole silane, and the hydrophilic cellulose whisker and the nonpolar iron ion are stably and uniformly integrated into the hydrophobic polyurethane matrix through the bonding and coordination anchoring of the thiazole silane, which fundamentally avoids phase separation and nanoparticle agglomeration, ensures uniformity and stability of performance, and realizes synergistic improvement of material strength and self-repairing ability without performance compromise; the thiazole silane chemically locks each component on the network, greatly inhibits the migration, precipitation and failure of small molecule additives, and lays a foundation for long-term stability, which is the key to realizing long service life of the material.

[0097] Finally, the photovoltaic cable sheath material has excellent ultraviolet aging resistance, low-temperature toughness, and basic self-repairing ability, and is suitable for outdoor long-time light exposure and large diurnal temperature difference environment applications.

[0098] It can be seen from Comparative Examples 1-4 that: The tensile strength from high to low is in the order of Example 4, Example 1, Example 3, Example 2; The elongation at break at -40℃ from high to low is in the order of Example 4, Example 1, Example 3, Example 2; The strength retention rate after ultraviolet aging for 3000h from high to low is in the order of Example 4, Example 1, Example 3, Example 2, but the four are similar; The repair efficiency at 80℃ / 30min from high to low is in the order of Example 1, Example 4, Example 3, Example 2; The efficiency retention rate after 5 repair cycles from high to low is in the order of Example 1, Example 4, Example 3, Example 2; it can be seen that the performance of Examples 1 and 4 is better than that of Examples 2 and 3, and therefore the length-diameter ratio of the dual-functional nanowhisker in the application is greater than 80.

[0099] It can be seen from Comparative Example 1 and Examples 5-8 that: The tensile strength from high to low is in the order of Example 1, Example 7, Example 8, Example 6, Example 5; The elongation at break at -40℃ from high to low is in the order of Example 1, Example 7, Example 6, Example 8, Example 5; the strength retention rate after ultraviolet aging for 3000h from high to low is in the order of Example 7, Example 1, Example 6, Example 8, Example 5; The repair efficiency at 80℃ / 30min from high to low is in the order of Example 7, Example 1, Example 6, Example 8, Example 5; the efficiency retention rate after 5 repair cycles from high to low is in the order of Example 7, Example 1, Example 6, Example 8, Example 5; The performance of Example 1 and Example 7 is better than that of Example 5, 6 and 8, the performance of Example 6 and 8 is better than that of Example 5, the comprehensive performance of Example 6 is better than that of 8, therefore, in the present application, the grafting density of furan groups on the surface of the bifunctional nanowhisker is 60-100 μmol / g, and the grafting density of catechol groups is 40-80 μmol / g, which is relatively optimal, and the sufficient functional group density can ensure the reaction probability with Fe 3+ and maleimide, guarantee the repair efficiency, and avoid the destruction of the crystal structure and mechanical strength of the cellulose whisker due to excessive grafting, and optimize the balance between enhancement and repair.

[0100] As can be seen from Comparative Example 1 and Example 9, the tensile strength of Example 1 is greater than that of Example 9, the elongation at break at -40℃ of Example 1 is greater than that of Example 9, the strength retention rate after ultraviolet aging for 3000h of Example 1 is greater than that of Example 9, the repair efficiency of Example 1 after 80℃ / 30min is higher than that of Example 9, and the efficiency retention rate after 5 repair cycles of Example 1 is higher than that of Example 9, which is because the epoxy acetylated cashew oil of the injection agent in Example 1 is grafted with maleimide groups, the maleimide groups act as dienophiles, the furan groups on the surface of the whisker undergo efficient cycloaddition reaction to form a reversible covalent crosslinking network, which further improves the self-repairing performance, and the plasticizer can be further locked on the polymer network through reaction with the furan groups, migration and precipitation are inhibited, and problems such as surface tackiness and performance degradation caused by the precipitation of the plasticizer are avoided.

[0101] In combination with Example 1 and Examples 10-13, it can be seen that: The tensile strength from high to low is in the order of Example 1, Example 12, Example 11, Example 13, Example 10; The elongation at break at -40℃ from high to low is in the order of Example 1, Example 12, Example 11, Example 13, Example 10; the strength retention rate after ultraviolet aging for 3000h from high to low is in the order of Example 1, Example 12, Example 11, Example 13, Example 10; The repair efficiency after 80℃ / 30min from high to low is in the order of Example 1, Example 12, Example 11, Example 13, Example 10; The efficiency retention rate after 5 repair cycles from high to low is in the order of Example 1, Example 12, Example 11, Example 13, Example 10; Therefore, in this application, the grafting rate of the epoxy-acetylated cashew oil grafted with maleimide groups as a plasticizer is preferably controlled at 15-20%. This ensures reactivity and retains the plasticizing effect, while also ensuring a sufficient amount of maleimide groups to match the density of furan groups on the whisker surface and meet the crosslinking requirements. At the same time, most of the EBE molecular chain segments are not modified, and their long aliphatic chains can effectively insert into the polymer chains, weakening the intermolecular forces, thereby significantly reducing the glass transition temperature of the material. This achieves a unity of plasticizing and repairing functions, and the material obtains excellent low-temperature toughness without sacrificing its high-temperature repair capabilities.

[0102] Comparing Example 1 with Examples 14-17, we can see that: The tensile strengths of Examples 1 and Examples 14-17 are relatively close, and their order from high to low is Example 1, Example 16, Example 15, Example 17, and Example 14. The elongation at break at -40℃ from highest to lowest is Example 1, Example 16, Example 15, Example 14, and Example 17; the strength retention rates of Examples 1 and Examples 14-17 after 3000h of UV aging are relatively close, and the strength retention rates after 3000h of UV aging from highest to lowest are Example 1, Example 16, Example 15, Example 14, and Example 17. The repair efficiency at 80℃ / 30min, from highest to lowest, is as follows: Example 1, Example 16, Example 15, Example 17, and Example 14. The efficiency retention rates after 5 repair cycles, from highest to lowest, are Example 1, Example 16, Example 15, Example 17, and Example 14. Therefore, in this application, the molar ratio of maleimide groups to furan groups in the plasticizer is preferably 1:1.1-1.3. The slight excess of furan groups ensures the complete reaction of maleimide groups, greatly improving the Diels-Alder reaction conversion rate. The excess furan groups form a "dynamic bond reserve", which can quickly re-bond with the maleimide exposed after damage, thereby improving the self-healing effect of the material and the repair response speed. Furthermore, this ratio maintains a better balance of dynamic reversible cross-linking network. After multiple damage-repair cycles, there are still enough free functional groups in the system to maintain the repair capability, so that the efficiency retention rate of the material is still >85% after more than 5 repair cycles. Moreover, the cross-linking network density is precisely controlled, avoiding the problems of excessive cross-linking (material brittleness) caused by excessive maleimide or the decrease in aging resistance caused by excessive furan. Without sacrificing the flexibility of the material, the strength, toughness and repair capability are optimally balanced.

[0103] Comparative Example 1 and Example 18 can be known that the strength retention rate of Example 1 after ultraviolet aging for 3000h is significantly greater than that of Example 18, and the reason is that Example 18 uses 770, which does not contain a thiazole heterocycle in the molecule, cannot form a π-π stacking synergistic network with thiazole silane, resulting in reduced ultraviolet protection efficiency. The hindered amine light stabilizer molecule in Example 1 contains a thiazole heterocycle, and the thiazole heterocycle in the HALS molecule and the thiazole silane coupling agent form a molecular-level synergistic network through π-π stacking, realizing the multifunctional synergy of "HALS-silane-acetylacetone iron", and improving the ultraviolet protection efficiency.

[0104] It can be known from Examples 19-20 and Comparative Examples 1-3 that the tensile strength of Examples 19-20 is greater than that of Comparative Examples 1-3, the elongation at break at -40℃ of Examples 19-20 is greater than that of Comparative Examples 1-3, the strength retention rate of Examples 19-20 after ultraviolet aging for 3000h is greater than that of Comparative Examples 1-3, the repair efficiency of Examples 19-20 at 80℃ / 30min is higher than that of Comparative Examples 1-3, and the efficiency retention rate of Examples 19-20 after 5 repair cycles is higher than that of Comparative Examples 1-3. Therefore, the photovoltaic cable sheath material of the present application has a raw material quality fraction control of polyurethane matrix 100 parts, plasticizer 25-30 parts, acetylacetone iron 0.4-0.6 parts, silane coupling agent 0.8-1.2 parts, bifunctional nanowhisker 0.8-1.5 parts, and hindered amine light stabilizer 0.5-1.0 parts, which will have excellent ultraviolet aging resistance and basic self-repairing ability, and long service life.

[0105] The specific embodiments are only an explanation of the present application, and are not a limitation of the present application. Those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, and the modifications are protected by the patent law as long as they are within the scope of the present application.

Claims

1. An outdoor aging-resistant photovoltaic cable sheath material, characterized in that, It comprises the following parts by weight of raw materials: 100 parts of polyurethane matrix; Plasticizer 25-30 parts; Iron acetylacetone 0.4-0.6 parts; 0.8-1.2 parts of silane coupling agent, wherein the silane coupling agent is a thiazolylsilane coupling agent; 0.8-1.5 parts of bifunctional nanocrystals, which are obtained by grafting furan groups and catechol groups onto the surface of cellulose whiskers.

2. The outdoor aging-resistant photovoltaic cable sheath material according to claim 1, characterized in that, Bifunctional nanocrystals with an aspect ratio > 80.

3. The outdoor aging-resistant photovoltaic cable sheath material according to claim 1, characterized in that, The aspect ratio of the bifunctional nanocrystals is 85~90.

4. The outdoor aging-resistant photovoltaic cable sheath material according to claim 1, characterized in that, The surface of the bifunctional nanocrystals has a furan group grafting density of 60~100μmol / g and a catechol group grafting density of 40~80μmol / g.

5. The outdoor aging-resistant photovoltaic cable sheath material according to claim 1, characterized in that, The plasticizer is epoxy-acetylated cashew oil grafted with maleimide groups, with a grafting rate of 15-20%.

6. The outdoor aging-resistant photovoltaic cable sheath material according to claim 5, characterized in that, The molar ratio of maleimide groups to furan groups in bifunctional nanocrystals in the plasticizer is 1:1.1-1.

3.

7. The outdoor aging-resistant photovoltaic cable sheath material according to claim 1, characterized in that, It also includes 0.5-1.0 parts of hindered amine light stabilizer, the hindered amine light stabilizer molecule containing a thiazole heterocycle.

8. A method for preparing an outdoor aging-resistant photovoltaic cable sheath material according to any one of claims 1 to 6, characterized in that, Includes the following steps: Bifunctional nanocrystals were dispersed in anhydrous ethanol to obtain a suspension. The silane coupling agent was added dropwise to the suspension, and the mixture was heated and stirred to react. After the reaction was completed, the mixture was centrifuged, washed, and vacuum dried to obtain the pretreated bifunctional nanocrystals. A twin-screw extruder is selected. Polyurethane matrix and plasticizer are added to the main feed port. Pretreated bifunctional nanocrystals, iron acetylacetone and silane coupling agent are mixed to obtain a premix. The premix is ​​then uniformly added to the molten polymer through the side feed port. After extrusion, the material is granulated and stored or coated with plastic according to production needs to obtain the cable sheath layer. The silane coupling agent used in the pretreated bifunctional nanocrystals and the silane coupling agent used in the premix added through the side feed port are the same type of silane coupling agent, and the total amount used is 0.8~1.2:100 of the TPU mass.

9. A method for preparing an outdoor aging-resistant photovoltaic cable sheath material as described in claim 7, characterized in that, Includes the following steps: Bifunctional nanocrystals were dispersed in anhydrous ethanol to obtain a suspension. The silane coupling agent was added dropwise to the suspension, and the mixture was heated and stirred to react. After the reaction was completed, the mixture was centrifuged, washed, and vacuum dried to obtain the pretreated bifunctional nanocrystals. A twin-screw extruder is selected. Polyurethane matrix and plasticizer are added to the main feed port. Pretreated bifunctional nanocrystals, iron acetylacetone and silane coupling agent are mixed to obtain a premix. The premix is ​​uniformly added to the molten polymer through the side feed port. Then, the hindered amine light stabilizer is pumped into the medium molten polymer while the molten polymer is homogenized. After extrusion, the material is granulated and stored or coated with plastic according to production needs to obtain the cable sheath layer. The silane coupling agent used in the pretreated bifunctional nanocrystals and the silane coupling agent used in the premix added through the side feed port are the same type of silane coupling agent, and the total amount used is 0.8~1.2:100 of the TPU mass.

Images