Aging-resistant soft insulation pull rod and preparation method and application thereof

Abstract

This invention relates to the field of insulating rod technology, and discloses an aging-resistant soft insulating rod, its preparation method, and its application. The method includes the following steps: fluorinating aramid fibers to obtain fluorinated aramid fibers; immersing the fluorinated aramid fibers in an aminosilane composite solution, heating and stirring, then removing and washing to obtain modified aramid fibers; weaving the modified aramid fibers into a core rod, and weaving a modified aramid fiber outer sheath around the core rod; vacuuming the core rod, then injecting it into an aqueous polyurethane composite emulsion for impregnation, removing it, and heating to obtain an aging-resistant soft insulating rod. In this method, fluorination modification and aminosilane composite solution treatment improve the surface activity of the aramid fibers and enhance the interfacial bonding with the aqueous polyurethane composite emulsion, thereby improving the aging resistance of the soft insulating rod.

Description

Technical Field

[0001] This invention relates to the field of insulating rod technology, specifically to an aging-resistant soft insulating rod, its preparation method, and its application. Background Technology

[0002] With the deepening of the construction of new power systems, insulating rods, as key components of high-voltage switchgear and other power equipment, are widely used in high-voltage operation and equipment fixing scenarios. They must simultaneously possess excellent electrical insulation performance, mechanical flexibility, and weather resistance. Currently, insulating rods are prone to cracking, pulverization, and dielectric degradation in complex outdoor environments, shortening their service life and increasing maintenance costs.

[0003] Then, aramid fiber, with its excellent mechanical properties, has been studied by several units in the live-line working industry. State Grid Hubei Electric Power Company developed a soft insulating pull rod by modifying aramid fiber and compounding it with thermoplastic materials. However, the plastic recovery of the woven aramid fiber and thermoplastic material is inconsistent, making it prone to delamination. This results in a short service life for the pull rod, and it can only be customized according to the site conditions, lacking versatility.

[0004] In summary, the preparation of an aging-resistant soft insulating rod is of great significance. Summary of the Invention

[0005] The purpose of this invention is to provide an aging-resistant soft insulating rod, its preparation method, and its application, so as to solve the problems raised in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing an aging-resistant soft insulating rod includes the following steps: Step 1: (1) Fluoride-modify aramid fibers to obtain fluorinated aramid fibers; (2) Immerse the fluorinated aramid fibers in an aminosilane composite solution, heat and stir, then remove and wash to obtain modified aramid fibers; Step 2: (1) Mix the waterborne polyurethane urea emulsion, deionized water, emulsifier and initiator evenly, heat to 60~75℃ and keep warm for 30~40 minutes, cool to room temperature, add acrylate monomer pre-emulsion and stir evenly to obtain waterborne polyurethane composite emulsion. (2) Modified aramid fiber is woven into a core rod, and a modified aramid fiber outer sheath is woven on the outside of the core rod; after vacuuming, it is impregnated with water-based polyurethane composite emulsion, taken out and heated to obtain an aging-resistant soft insulating rod.

[0007] In a more optimized form, the raw materials for the aminosilane composite solution include the following components: by mass, 7-10 parts N-(2-aminoethyl)acrylamide, 3-6 parts fluorine-modified aminosiloxane, and 100 parts anhydrous ethanol. The raw materials of the waterborne polyurethane composite emulsion include the following components: by mass parts, 50-70 parts waterborne polyurethane urea emulsion, 30-50 parts acrylate monomer pre-emulsion, 30-60 parts deionized water, 0.1-0.4 parts emulsifier, and 0.3-0.6 parts initiator; The raw materials for the acrylate monomer preemulsion include the following components by mass: 10 parts octyl acrylate, 2-3 parts methyl methacrylate, 1-4 parts acrylic acid, 20-50 parts deionized water, 0.1-0.4 parts emulsifier, and 0.1-0.2 parts initiator.

[0008] A more optimized method for preparing the aqueous polyurethane urea emulsion is as follows: (1) Allyl polyethylene glycol ether and isophorone diisocyanate are added to acetone, stirred at room temperature for 20-40 minutes, heated and stirred for 1-2 hours, cooled to room temperature, diethanolamine is added and stirred at room temperature for 30-40 minutes, acetone is removed, and allyl polyurethane urea diol is obtained; (2) Polycarbonate diol and isophorone diisocyanate are added to acetone and mixed, heated to 50-60°C, and added Mix BMBA, heat to 60-70℃, stir for 4-5 hours, cool to room temperature, add 1,3-bis(3-aminopropyl)tetramethyldisiloxane and acetone, heat to 40-50℃ and stir for 1-2 hours, add allyl polyurethane urea glycol, heat to 70-80℃ and stir for 2-4 hours, cool to room temperature, add fluorinated modified aminosiloxane and stir, add triethylamine to neutralize, add deionized water and emulsifier, stir at high speed to remove acetone, and obtain an aqueous polyurethane urea emulsion.

[0009] In a more optimized configuration, the molar ratio of allyl polyethylene glycol ether, isophorone diisocyanate, and diethanolamine is 1:1:(1~2).

[0010] In a more optimized form, the raw materials of the waterborne polyurethane urea emulsion include the following components: by mass parts, 10-15 parts polycarbonate diol, 25 parts isophorone diisocyanate, 3-5 parts BMBA, 4-6 parts 1,3-bis(3-aminopropyl)tetramethyldisiloxane, 2-4 parts allyl polyurethane urea diol, 5-8 parts fluorinated modified aminosiloxane, 6-9 parts triethylamine, 200-400 parts deionized water, and 0.2-0.4 parts emulsifier.

[0011] A more optimized method for preparing the fluorinated modified aminosiloxane is as follows: under a nitrogen atmosphere, hexafluorobutanol is added to acetone and mixed evenly. The mixture is heated to 70-80°C, isophorone diisocyanate and catalyst are added, and the mixture is stirred for 2-3 hours. The temperature is then lowered to 40-50°C, 1,3-bis(3-aminopropyl)tetramethyldisiloxane is added, and the mixture is stirred for another 1-2 hours. The solvent is removed by rotary evaporation to obtain the fluorinated modified aminosiloxane.

[0012] In a more optimized manner, the molar ratio of hexafluorobutanol, isophorone diisocyanate, and 1,3-bis(3-aminopropyl)tetramethyldisiloxane is 1:1:(1~2).

[0013] A more optimized process condition for the fluorination modification is as follows: under a nitrogen atmosphere, an F2 / N2 mixed gas is introduced, with the volume fraction of F2 being 10%~20%, for 20~40 minutes, and the total pressure of the mixed gas being 10~50 kPa; The vacuum impregnation process conditions are as follows: under a vacuum degree ≤ -0.095MPa, the vacuum is maintained for 15~25 minutes, water-based polyurethane composite emulsion is injected, the vacuum is released, and the process is maintained for 30~40 minutes under a nitrogen pressure of 0.4~0.6MPa. The heat treatment process conditions are as follows: vertically suspended and allowed to drip dry naturally, under a nitrogen atmosphere, the temperature is increased to 60-70℃ at a rate of 1-2℃ / min for 1-2 hours, and then increased to 70-80℃ for 2-3 hours.

[0014] An aging-resistant soft insulating rod is prepared by a method.

[0015] An application of an aging-resistant soft insulating rod: The prepared aging-resistant soft insulating rod is used in the maintenance of ultra-high voltage AC / DC transmission lines.

[0016] In this design, an aging-resistant soft insulating rod is placed in a mold and combined with a thermoplastic elastomer material to obtain the product; its two ends are connected with titanium alloy fittings.

[0017] Compared with the prior art, the beneficial effects of the present invention are: The proposed solution addresses the shortcomings of aramid fibers, such as smooth surface and strong chemical inertness, by modifying them. The process involves first surface fluorination to introduce aromatic CF bonds into the aramid fiber surface, significantly enhancing surface energy. Then, APTES aminosilane is used to graft siloxane groups onto the fiber surface using active sites, effectively improving the interfacial bonding between the aramid fiber and the waterborne polyurethane urea emulsion. This enhances the aging resistance of the soft insulating rod and increases its application in the maintenance of ultra-high voltage AC / DC transmission lines.

[0018] In the proposed solution, the introduction of polycarbonate diol into the waterborne polyurethane urea emulsion has limited effect on reducing its rigidity. Therefore, allyl polyurethane urea diol is introduced to improve flexibility by utilizing its flexible polyether segments. When the waterborne polyurethane urea emulsion is applied, it can alleviate bending stress, improve adhesion, and prevent delamination and cracking after repeated bending, thereby significantly improving the fatigue resistance of the soft insulating rod.

[0019] In a further embodiment, an aqueous polyurethane urea emulsion is mixed with an acrylate monomer pre-emulsion to obtain an aqueous polyurethane composite emulsion. During this process, the double bonds of allyl polyurethane urea diol in the aqueous polyurethane urea emulsion participate in subsequent in-situ copolymerization with the acrylate monomer, leveraging the weather resistance of the polyacrylate to improve the system's aging resistance. It should be noted that the ratio of aqueous polyurethane urea emulsion to acrylate monomer pre-emulsion needs to be controlled during copolymerization. If the ratio is too high, the hydrophilicity of the aqueous polyurethane composite emulsion will increase, leading to poor interfacial compatibility when the aqueous polyurethane composite emulsion is combined with modified aramid fibers. This is because the modified aramid fibers use APTES aminosilane, which has poor interfacial compatibility with the acrylate monomer pre-emulsion but good interfacial compatibility with the aqueous polyurethane urea emulsion. If the proportion of the acrylate monomer pre-emulsion is too high, the interfacial compatibility with the aramid fibers will decrease, affecting the overall performance of the insulating rod.

[0020] In a further embodiment, 1,3-bis(3-aminopropyl)tetramethyldisiloxane and fluorinated modified aminosiloxane are further introduced into the aqueous polyurethane urea emulsion; wherein, the fluoroalkyl structure and siloxane segments provide excellent flexibility and weather resistance; significantly improving the aging resistance of the obtained soft insulating rod.

[0021] Meanwhile, APTES aminosilane is replaced with N-(2-aminoethyl)acrylamide, and together with fluorinated modified aminosiloxane, the wettability of aramid fiber and waterborne polyurethane composite emulsion is further enhanced, and the interfacial bonding is further optimized, thereby enhancing the performance of the insulating rod. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0023] The preparation method of waterborne polyurethane urea emulsion is as follows: (1) Allyl polyethylene glycol ether with a molecular weight of 600, isophorone diisocyanate, and diethanolamine are weighed in a molar ratio of 1:1:1; under a nitrogen atmosphere, allyl polyethylene glycol ether is added to acetone and mixed evenly, isophorone diisocyanate and catalyst are added, and the mixture is heated and stirred at 80°C for 1.5 hours. After cooling to room temperature, diethanolamine is added and stirred at room temperature for 40 minutes. Acetone is removed to obtain allyl polyurethane urea diol; the catalyst accounts for 0.08% of the total mass of the reactants; (2) 15 parts of polycarbonate diol with a molecular weight of 1000 and 25 parts of isophorone diisocyanate are added to the mixture. The ester was added to 70 parts of acetone and mixed. The mixture was heated to 60°C and stirred for 1 hour. Then, 5 parts of BMBA and 0.3 parts of catalyst were added and mixed. The mixture was heated to 80°C and stirred for 4 hours. After cooling to room temperature, 6 parts of 1,3-bis(3-aminopropyl)tetramethyldisiloxane and 20 parts of acetone were added. The mixture was heated to 40°C and stirred for 1 hour. Then, 3 parts of allyl polyurethane urea glycol were added and the mixture was heated to 80°C and stirred for 2 hours. After cooling to room temperature, 6 parts of fluorinated modified aminosiloxane were added and stirred. Then, 7 parts of triethylamine were added for neutralization. Finally, 200 parts of deionized water and 0.4 parts of emulsifier were added and stirred at high speed at 2000 rpm to remove acetone, thus obtaining an aqueous polyurethane urea emulsion.

[0024] Example 1

[0025] The preparation method of fluorinated modified aminosiloxane is as follows: hexafluorobutanol, isophorone diisocyanate, and 1,3-bis(3-aminopropyl)tetramethyldisiloxane are weighed in a molar ratio of 1:1:1; under a nitrogen atmosphere, hexafluorobutanol is added to acetone and mixed evenly, then isophorone diisocyanate and catalyst are added, the mixture is heated to 80°C and stirred for 2 hours, then cooled to 40°C and 1,3-bis(3-aminopropyl)tetramethyldisiloxane is added and stirring is continued for 40 minutes. The acetone is then removed to obtain fluorinated modified aminosiloxane; the catalyst accounts for 0.08% of the total mass of the reactants. Step 1: (1) In a nitrogen atmosphere, F2 / N2 mixed gas is introduced into the aramid fiber. The total pressure is 30 kPa and the volume fraction of F2 is 15%. The fluorination modification is carried out for 30 minutes to obtain fluorinated aramid fiber; (2) The fluorinated aramid fiber is immersed in an aminosilane composite solution, heated and stirred at 70°C for 2 hours, taken out, washed with ethanol to obtain modified aramid fiber; The aminosilane composite solution was obtained by uniformly mixing 10 parts of N-(2-aminoethyl)acrylamide, 6 parts of fluorine-modified aminosiloxane, and 100 parts of anhydrous ethanol. Step 2: By mass parts, (1) mix 70 parts of waterborne polyurethane urea emulsion, 30 parts of deionized water, 0.3 parts of emulsifier and 0.15 parts of initiator evenly, heat to 70°C and keep warm for 30 minutes, cool to room temperature, add 30 parts of acrylate monomer pre-emulsion and stir evenly to obtain waterborne polyurethane composite emulsion. In this process, 30 parts of deionized water, 0.2 parts of emulsifier, and 0.25 parts of initiator are mixed evenly, and then 10 parts of octyl acrylate, 3 parts of methyl methacrylate, and 4 parts of acrylic acid are added and stirred evenly to obtain an acrylate monomer preemulsion. (2) Modified aramid fiber is woven into a core rod, and a modified aramid fiber outer sheath is woven on the outside of the core rod; it is evacuated for 25 minutes under vacuum conditions ≤ -0.095MPa, water-based polyurethane composite emulsion is injected, the vacuum is released, and it is kept under nitrogen pressure of 0.6MPa for 40 minutes; it is taken out and hung vertically to drip dry naturally for 30 minutes, and then heated to 60℃ for 1 hour at a rate of 1~2℃ / min under nitrogen atmosphere, and then heated to 75℃ for 3 hours to obtain an aging-resistant soft insulating rod.

[0026] Example 2

[0027] The preparation method of fluorinated modified aminosiloxane is as follows: hexafluorobutanol, isophorone diisocyanate, and 1,3-bis(3-aminopropyl)tetramethyldisiloxane are weighed in a molar ratio of 1:1:1; under a nitrogen atmosphere, hexafluorobutanol is added to acetone and mixed evenly, then isophorone diisocyanate and catalyst are added, the mixture is heated to 80°C and stirred for 2 hours, then cooled to 40°C and 1,3-bis(3-aminopropyl)tetramethyldisiloxane is added and stirring is continued for 40 minutes. The acetone is then removed to obtain fluorinated modified aminosiloxane; the catalyst accounts for 0.08% of the total mass of the reactants. Step 1: (1) In a nitrogen atmosphere, F2 / N2 mixed gas is introduced into the aramid fiber. The total pressure is 30 kPa and the volume fraction of F2 is 15%. The fluorination modification is carried out for 30 minutes to obtain fluorinated aramid fiber; (2) The fluorinated aramid fiber is immersed in an aminosilane composite solution, heated and stirred at 70°C for 2 hours, taken out, washed with ethanol to obtain modified aramid fiber; The aminosilane composite solution was obtained by uniformly mixing 10 parts of N-(2-aminoethyl)acrylamide, 6 parts of fluorine-modified aminosiloxane, and 100 parts of anhydrous ethanol. Step 2: By mass, (1) mix 60 parts of waterborne polyurethane urea emulsion, 30 parts of deionized water, 0.3 parts of emulsifier and 0.15 parts of initiator evenly, heat to 70°C and keep warm for 30 minutes, cool to room temperature, add 40 parts of acrylate monomer pre-emulsion and stir evenly to obtain waterborne polyurethane composite emulsion. In this process, 50 parts of deionized water, 0.2 parts of emulsifier, and 0.25 parts of initiator are mixed evenly, and then 10 parts of octyl acrylate, 3 parts of methyl methacrylate, and 4 parts of acrylic acid are added and stirred evenly to obtain an acrylate monomer preemulsion. (2) Modified aramid fiber is woven into a core rod, and a modified aramid fiber outer sheath is woven on the outside of the core rod; it is evacuated for 25 minutes under vacuum conditions ≤ -0.095MPa, water-based polyurethane composite emulsion is injected, the vacuum is released, and it is kept under nitrogen pressure of 0.6MPa for 40 minutes; it is taken out and hung vertically to drip dry naturally for 30 minutes, and then heated to 60℃ for 1 hour at a rate of 1~2℃ / min under nitrogen atmosphere, and then heated to 75℃ for 3 hours to obtain an aging-resistant soft insulating rod.

[0028] Example 3

[0029] The preparation method of fluorinated modified aminosiloxane is as follows: hexafluorobutanol, isophorone diisocyanate, and 1,3-bis(3-aminopropyl)tetramethyldisiloxane are weighed in a molar ratio of 1:1:1; under a nitrogen atmosphere, hexafluorobutanol is added to acetone and mixed evenly, then isophorone diisocyanate and catalyst are added, the mixture is heated to 80°C and stirred for 2 hours, then cooled to 40°C and 1,3-bis(3-aminopropyl)tetramethyldisiloxane is added and stirring is continued for 40 minutes. The acetone is then removed to obtain fluorinated modified aminosiloxane; the catalyst accounts for 0.08% of the total mass of the reactants. Step 1: (1) In a nitrogen atmosphere, F2 / N2 mixed gas is introduced into the aramid fiber. The total pressure is 30 kPa and the volume fraction of F2 is 15%. The fluorination modification is carried out for 30 minutes to obtain fluorinated aramid fiber; (2) The fluorinated aramid fiber is immersed in an aminosilane composite solution, heated and stirred at 70°C for 2 hours, taken out, washed with ethanol to obtain modified aramid fiber; The aminosilane composite solution was obtained by uniformly mixing 10 parts of N-(2-aminoethyl)acrylamide, 6 parts of fluorine-modified aminosiloxane, and 100 parts of anhydrous ethanol. Step 2: By mass, (1) mix 50 parts of waterborne polyurethane urea emulsion, 30 parts of deionized water, 0.3 parts of emulsifier and 0.15 parts of initiator evenly, heat to 70°C and keep warm for 30 minutes, cool to room temperature, add 50 parts of acrylate monomer pre-emulsion and stir evenly to obtain waterborne polyurethane composite emulsion. In this process, 50 parts of deionized water, 0.2 parts of emulsifier, and 0.25 parts of initiator are mixed evenly, and then 10 parts of octyl acrylate, 3 parts of methyl methacrylate, and 4 parts of acrylic acid are added and stirred evenly to obtain an acrylate monomer preemulsion. (2) Modified aramid fiber is woven into a core rod, and a modified aramid fiber outer sheath is woven on the outside of the core rod; it is evacuated for 25 minutes under vacuum conditions ≤ -0.095MPa, water-based polyurethane composite emulsion is injected, the vacuum is released, and it is kept under nitrogen pressure of 0.6MPa for 40 minutes; it is taken out and hung vertically to drip dry naturally for 30 minutes, and then heated to 60℃ for 1 hour at a rate of 1~2℃ / min under nitrogen atmosphere, and then heated to 75℃ for 3 hours to obtain an aging-resistant soft insulating rod.

[0030] Comparative Example 1 is based on Example 1, but without the introduction of fluorinated modified aminosiloxanes; the remaining operating steps are the same. Step 1: (1) In a nitrogen atmosphere, F2 / N2 mixed gas is introduced into the aramid fiber. The total pressure is 30 kPa and the volume fraction of F2 is 15%. The fluorination modification is carried out for 30 minutes to obtain fluorinated aramid fiber; (2) The fluorinated aramid fiber is immersed in N-(2-aminoethyl)acrylamide solution, heated and stirred at 70°C for 2 hours, taken out, washed with ethanol to obtain modified aramid fiber; N-(2-aminoethyl)acrylamide is obtained by uniformly mixing 10 parts of N-(2-aminoethyl)acrylamide and 100 parts of anhydrous ethanol. Step 2: By mass parts, (1) mix 70 parts of waterborne polyurethane urea emulsion, 30 parts of deionized water, 0.3 parts of emulsifier and 0.15 parts of initiator evenly, heat to 70°C and keep warm for 30 minutes, cool to room temperature, add 30 parts of acrylate monomer pre-emulsion and stir evenly to obtain waterborne polyurethane composite emulsion. In this process, 30 parts of deionized water, 0.2 parts of emulsifier, and 0.25 parts of initiator are mixed evenly, and then 10 parts of octyl acrylate, 3 parts of methyl methacrylate, and 4 parts of acrylic acid are added and stirred evenly to obtain an acrylate monomer preemulsion. (2) Modified aramid fiber is woven into a core rod, and a modified aramid fiber outer sheath is woven on the outside of the core rod; it is evacuated for 25 minutes under vacuum conditions ≤ -0.095MPa, water-based polyurethane composite emulsion is injected, the vacuum is released, and it is kept under nitrogen pressure of 0.6MPa for 40 minutes; it is taken out and hung vertically to drip dry naturally for 30 minutes, and then heated to 60℃ for 1 hour at a rate of 1~2℃ / min under nitrogen atmosphere, and then heated to 75℃ for 3 hours to obtain an aging-resistant soft insulating rod.

[0031] Comparative Example 2 is based on Example 1, except that N-(2-aminoethyl)acrylamide is replaced with APTES; the operating steps are the same. The preparation method of fluorinated modified aminosiloxane is as follows: hexafluorobutanol, isophorone diisocyanate, and 1,3-bis(3-aminopropyl)tetramethyldisiloxane are weighed in a molar ratio of 1:1:1; under a nitrogen atmosphere, hexafluorobutanol is added to acetone and mixed evenly, then isophorone diisocyanate and catalyst are added, the mixture is heated to 80°C and stirred for 2 hours, then cooled to 40°C and 1,3-bis(3-aminopropyl)tetramethyldisiloxane is added and stirring is continued for 40 minutes. The acetone is then removed to obtain fluorinated modified aminosiloxane; the catalyst accounts for 0.08% of the total mass of the reactants. Step 1: (1) In a nitrogen atmosphere, F2 / N2 mixed gas is introduced into the aramid fiber. The total pressure is 30 kPa and the volume fraction of F2 is 15%. The fluorination modification is carried out for 30 minutes to obtain fluorinated aramid fiber; (2) The fluorinated aramid fiber is immersed in an aminosilane composite solution, heated and stirred at 70°C for 2 hours, taken out, washed with ethanol to obtain modified aramid fiber; The aminosilane composite solution was obtained by uniformly mixing 10 parts APTES, 6 parts fluorine-modified aminosiloxane, and 100 parts anhydrous ethanol. Step 2: By mass parts, (1) mix 70 parts of waterborne polyurethane urea emulsion, 30 parts of deionized water, 0.3 parts of emulsifier and 0.15 parts of initiator evenly, heat to 70°C and keep warm for 30 minutes, cool to room temperature, add 30 parts of acrylate monomer pre-emulsion and stir evenly to obtain waterborne polyurethane composite emulsion. In this process, 30 parts of deionized water, 0.25 parts of emulsifier, and 0.25 parts of initiator are mixed evenly, and then 10 parts of octyl acrylate, 3 parts of methyl methacrylate, and 4 parts of acrylic acid are added and stirred evenly to obtain an acrylate monomer pre-emulsion. (2) Modified aramid fiber is woven into a core rod, and a modified aramid fiber outer sheath is woven on the outside of the core rod; it is evacuated for 25 minutes under vacuum conditions ≤ -0.095MPa, water-based polyurethane composite emulsion is injected, the vacuum is released, and it is kept under nitrogen pressure of 0.6MPa for 40 minutes; it is taken out and hung vertically to drip dry naturally for 30 minutes, and then heated to 60℃ for 1 hour at a rate of 1~2℃ / min under nitrogen atmosphere, and then heated to 75℃ for 3 hours to obtain an aging-resistant soft insulating rod.

[0032] Comparative Example 3 is based on Example 1, except that allyl polyurethane urea glycol is replaced with hydroxyethyl acrylate; the remaining operating steps are the same. The preparation method of waterborne polyurethane urea emulsion is as follows: 15 parts of polycarbonate diol with a molecular weight of 1000 and 25 parts of isophorone diisocyanate are added to 70 parts of acetone and mixed. The mixture is heated to 60°C and stirred for 1 hour. 5 parts of BMBA and 0.3 parts of catalyst are added and mixed. The mixture is heated to 80°C and stirred for 4 hours. The mixture is cooled to room temperature and 6 parts of 1,3-bis(3-aminopropyl)tetramethyldisiloxane and 20 parts of acetone are added. The mixture is heated to 40°C and stirred for 1 hour. 3 parts of hydroxyethyl acrylate are added and the mixture is heated to 80°C and stirred for 2 hours. The mixture is cooled to room temperature and 6 parts of fluorinated modified aminosiloxane are added and stirred. 7 parts of triethylamine are added for neutralization. 300 parts of deionized water and 0.4 parts of emulsifier are added. The mixture is stirred at high speed at 2000 rpm to remove acetone and obtain waterborne polyurethane urea emulsion. Step 1: (1) In a nitrogen atmosphere, F2 / N2 mixed gas is introduced into the aramid fiber. The total pressure is 30 kPa and the volume fraction of F2 is 15%. The fluorination modification is carried out for 30 minutes to obtain fluorinated aramid fiber; (2) The fluorinated aramid fiber is immersed in an aminosilane composite solution, heated and stirred at 70°C for 2 hours, taken out, washed with ethanol to obtain modified aramid fiber; The aminosilane composite solution was obtained by uniformly mixing 10 parts of N-(2-aminoethyl)acrylamide, 6 parts of fluorine-modified aminosiloxane, and 100 parts of anhydrous ethanol. Step 2: By mass parts, (1) mix 70 parts of waterborne polyurethane urea emulsion, 30 parts of deionized water, 0.3 parts of emulsifier and 0.15 parts of initiator evenly, heat to 70°C and keep warm for 30 minutes, cool to room temperature, add 30 parts of acrylate monomer pre-emulsion and stir evenly to obtain waterborne polyurethane composite emulsion. In this process, 30 parts of deionized water, 0.2 parts of emulsifier, and 0.25 parts of initiator are mixed evenly, and then 10 parts of octyl acrylate, 3 parts of methyl methacrylate, and 4 parts of acrylic acid are added and stirred evenly to obtain an acrylate monomer preemulsion. (2) Modified aramid fiber is woven into a core rod, and a modified aramid fiber outer sheath is woven on the outside of the core rod; it is evacuated for 25 minutes under vacuum conditions ≤ -0.095MPa, water-based polyurethane composite emulsion is injected, the vacuum is released, and it is kept under nitrogen pressure of 0.6MPa for 40 minutes; it is taken out and hung vertically to drip dry naturally for 30 minutes, and then heated to 60℃ for 1 hour at a rate of 1~2℃ / min under nitrogen atmosphere, and then heated to 75℃ for 3 hours to obtain an aging-resistant soft insulating rod.

[0033] Comparative Example 4 is based on Example 1, in which waterborne polyurethane urea emulsion and acrylate monomer pre-emulsion are directly mixed to obtain waterborne polyurethane composite emulsion; the remaining operation steps are the same. Step 1: (1) In a nitrogen atmosphere, F2 / N2 mixed gas is introduced into the aramid fiber. The total pressure is 30 kPa and the volume fraction of F2 is 15%. The fluorination modification is carried out for 30 minutes to obtain fluorinated aramid fiber; (2) The fluorinated aramid fiber is immersed in an aminosilane composite solution, heated and stirred at 70°C for 2 hours, taken out, washed with ethanol to obtain modified aramid fiber; The aminosilane composite solution was obtained by uniformly mixing 10 parts of N-(2-aminoethyl)acrylamide, 6 parts of fluorine-modified aminosiloxane, and 100 parts of anhydrous ethanol. Step 2: By mass, (1) mix 70 parts of waterborne polyurethane urea emulsion, 0.2 parts of initiator and 30 parts of acrylate monomer pre-emulsion evenly to obtain waterborne polyurethane composite emulsion. In this process, 30 parts of deionized water, 0.2 parts of emulsifier, and 0.1 parts of initiator are mixed evenly, and then 10 parts of octyl acrylate, 3 parts of methyl methacrylate, and 4 parts of acrylic acid are added and stirred evenly to obtain an acrylate monomer preemulsion. (2) Modified aramid fiber is woven into a core rod, and a modified aramid fiber outer sheath is woven on the outside of the core rod; it is evacuated for 25 minutes under vacuum conditions ≤ -0.095MPa, water-based polyurethane composite emulsion is injected, the vacuum is released, and it is kept under nitrogen pressure of 0.6MPa for 40 minutes; it is taken out and hung vertically to drip dry naturally for 30 minutes, and then heated to 60℃ for 1 hour at a rate of 1~2℃ / min under nitrogen atmosphere, and then heated to 75℃ for 3 hours to obtain an aging-resistant soft insulating rod.

[0034] Comparative Example 5 is based on Example 1, but introduces fluorine groups onto the main chain of an aqueous polyurethane urea emulsion; the remaining steps are the same. The preparation method of waterborne polyurethane urea emulsion is as follows: (1) weigh hexafluorobutanol, isophorone diisocyanate and diethanolamine in a molar ratio of 1:1:1; under a nitrogen atmosphere, add hexafluorobutanol to acetone and mix evenly, add isophorone diisocyanate and catalyst, heat and stir at 80°C for 1.5 hours, cool to room temperature, add diethanolamine and stir at room temperature for 40 minutes, remove acetone, and obtain fluorinated polyurethane urea diol; the catalyst accounts for 0.08% of the total mass of the reactants; (2) weigh 15 parts of a molecular weight of 1 000 parts of polycarbonate diol and 25 parts of isophorone diisocyanate were added to 70 parts of acetone and mixed. The mixture was heated to 60°C and stirred for 1 hour. 5 parts of BMBA and 0.3 parts of catalyst were added and mixed. The mixture was heated to 80°C and stirred for 4 hours. The mixture was cooled to room temperature and 6 parts of fluorinated polyurethane urea diol and 20 parts of acetone were added. The mixture was heated to 80°C and stirred for 2 hours. 7 parts of triethylamine were added for neutralization. 300 parts of deionized water and 0.4 parts of emulsifier were added. The mixture was stirred at high speed at 2000 rpm to remove acetone and obtain an aqueous polyurethane urea emulsion. Step 1: (1) In a nitrogen atmosphere, F2 / N2 mixed gas is introduced into the aramid fiber. The total pressure is 30 kPa and the volume fraction of F2 is 15%. The fluorination modification is carried out for 30 minutes to obtain fluorinated aramid fiber; (2) The fluorinated aramid fiber is immersed in an aminosilane composite solution, heated and stirred at 70°C for 2 hours, taken out, washed with ethanol to obtain modified aramid fiber; The aminosilane composite solution was obtained by uniformly mixing 10 parts of N-(2-aminoethyl)acrylamide, 6 parts of fluorine-modified aminosiloxane, and 100 parts of anhydrous ethanol. Step 2: By mass parts, (1) mix 70 parts of waterborne polyurethane urea emulsion, 30 parts of deionized water, 0.3 parts of emulsifier and 0.15 parts of initiator evenly, heat to 70°C and keep warm for 30 minutes, cool to room temperature, add 30 parts of acrylate monomer pre-emulsion and stir evenly to obtain waterborne polyurethane composite emulsion. In this process, 30 parts of deionized water, 0.2 parts of emulsifier, and 0.25 parts of initiator are mixed evenly, and then 10 parts of octyl acrylate, 3 parts of methyl methacrylate, and 4 parts of acrylic acid are added and stirred evenly to obtain an acrylate monomer preemulsion. (2) Modified aramid fiber is woven into a core rod, and a modified aramid fiber outer sheath is woven on the outside of the core rod; it is evacuated for 25 minutes under vacuum conditions ≤ -0.095MPa, water-based polyurethane composite emulsion is injected, the vacuum is released, and it is kept under nitrogen pressure of 0.6MPa for 40 minutes; it is taken out and hung vertically to drip dry naturally for 30 minutes, and then heated to 60℃ for 1 hour at a rate of 1~2℃ / min under nitrogen atmosphere, and then heated to 75℃ for 3 hours to obtain an aging-resistant soft insulating rod.

[0035] Testing: The aging-resistant soft insulating rods prepared in Examples 1-3 and Comparative Examples 1-5 were placed in a mold and injected with molten thermoplastic elastomer for cooling and shaping. Titanium alloy connecting fittings were provided at both ends to obtain samples. The raw materials of the thermoplastic elastomer include the following components: by mass parts, 70 parts SEBS, 30 parts paraffin oil, 10 parts polypropylene, 15 parts maleic anhydride-grafted SEBS, 0.3 parts antioxidant 1010, 0.5 parts UV-531, and 0.5 parts sodium stearate. (1) The breakdown strength of the samples prepared in Examples 1-3 and Comparative Examples 1-5 was tested according to the standard GB / T1408.1-2006; (2) According to the testing standard of GB / T16422.2, the samples prepared in Examples 1-3 and Comparative Examples 1-5 were tested for 1000 hours of light irradiation for 102 min / spraying for 18 min at 65℃; according to the standard of GB / T35465.5-2020, the samples prepared in Examples 1 and Comparative Examples 1-5 after aging were subjected to 10,000 cyclic bending cycles, and the test was stopped after the number of cycles was reached; the delamination and cracking of the sample interface were observed. (3) Test the breakdown strength of the sample that was bent 1000 times in test (2) according to the standard GB / T1408.1-2006.

[0036] Table 1

[0037] Conclusions: Comparative Example 1, based on Example 1, did not introduce fluorinated modified aminosiloxane; the wettability and interfacial bonding strength of the modified aramid fiber and waterborne polyurethane composite emulsion decreased, and delamination occurred after multiple bends. Without fluorine and hydrophobic treatment, water and oxygen easily penetrated, and the insulation decreased significantly after aging. Comparative Example 2, based on Example 1, replaced N-(2-aminoethyl)acrylamide with APTES; this led to a decrease in the interfacial bonding between the modified aramid fiber and the waterborne polyurethane composite emulsion, and slight delamination after multiple bends, thus resulting in reduced performance. Comparative Example 3, based on Example 1, replaced allyl polyurethane urea glycol with hydroxyethyl acrylate; the introduction of hydroxyethyl acrylate resulted in fewer crosslinking points and an uneven network, thus leading to reduced performance.

[0038] Comparative Example 4, based on Example 1, involves directly mixing an aqueous polyurethane urea emulsion with an acrylate monomer pre-emulsion to obtain an aqueous polyurethane composite emulsion. This results in explosive polymerization during copolymerization, leading to flocculent formation in the aqueous polyurethane composite emulsion and uneven crosslinking, thus causing a performance degradation. Comparative Example 5, based on Example 1, involves introducing fluorine groups into the main chain of the aqueous polyurethane urea emulsion. After the fluorine groups are introduced into the main chain, the viscosity decreases, the binding with the thermoplastic elastomer is weak, and the fluorine groups cannot efficiently migrate to the surface for enrichment, thus causing a performance degradation.

[0039] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A method for preparing an aging-resistant soft insulating pull rod, characterized in that: The following steps are included: Step 1: (1) Fluoride-modify aramid fibers to obtain fluorinated aramid fibers; (2) Immerse the fluorinated aramid fibers in an aminosilane composite solution, heat and stir, then remove and wash to obtain modified aramid fibers; Step 2: (1) Mix the waterborne polyurethane urea emulsion, deionized water, emulsifier and initiator evenly, heat to 60~75℃ and keep warm for 30~40 minutes, cool to room temperature, add acrylate monomer pre-emulsion and stir evenly to obtain waterborne polyurethane composite emulsion. (2) Modified aramid fiber is woven into a core rod, and a modified aramid fiber outer sheath is woven on the outside of the core rod; after vacuuming, it is impregnated with water-based polyurethane composite emulsion, taken out and heated to obtain an aging-resistant soft insulating rod.

2. The method for preparing an aging-resistant soft insulating rod according to claim 1, characterized in that: The raw materials of the aminosilane composite solution include the following components: by mass, 7-10 parts of N-(2-aminoethyl)acrylamide, 3-6 parts of fluorine-modified aminosiloxane, and 100 parts of anhydrous ethanol. The raw materials of the waterborne polyurethane composite emulsion include the following components: by mass parts, 50-70 parts waterborne polyurethane urea emulsion, 30-50 parts acrylate monomer pre-emulsion, 30-60 parts deionized water, 0.1-0.4 parts emulsifier, and 0.3-0.6 parts initiator; The raw materials for the acrylate monomer preemulsion include the following components by mass: 10 parts octyl acrylate, 2-3 parts methyl methacrylate, 1-4 parts acrylic acid, 20-50 parts deionized water, 0.1-0.4 parts emulsifier, and 0.1-0.2 parts initiator.

3. The method for preparing an aging-resistant soft insulating rod according to claim 1, characterized in that: The method for preparing the aqueous polyurethane urea emulsion is as follows: (1) Allyl polyethylene glycol ether and isophorone diisocyanate are added to acetone, stirred at room temperature for 20-40 minutes, heated and stirred for 1-2 hours, cooled to room temperature, diethanolamine is added and stirred at room temperature for 30-40 minutes, acetone is removed, and allyl polyurethane urea diol is obtained; (2) Polycarbonate diol and isophorone diisocyanate are added to acetone and mixed, heated to 50-60°C, and BMB is added. Mix A, heat to 60-70℃, stir for 4-5 hours, cool to room temperature, add 1,3-bis(3-aminopropyl)tetramethyldisiloxane and acetone, heat to 40-50℃ and stir for 1-2 hours, add allyl polyurethane urea glycol, heat to 70-80℃ and stir for 2-4 hours, cool to room temperature, add fluorinated modified aminosiloxane and stir, add triethylamine to neutralize, add deionized water and emulsifier, stir at high speed to remove acetone, and obtain an aqueous polyurethane urea emulsion.

4. The method for preparing an aging-resistant soft insulating rod according to claim 3, characterized in that: The molar ratio of allyl polyethylene glycol ether, isophorone diisocyanate, and diethanolamine is 1:1:(1~2).

5. The method for preparing an aging-resistant soft insulating pull rod according to claim 3, characterized in that: The raw materials of the aqueous polyurethane urea emulsion include the following components by mass: 10-15 parts polycarbonate diol, 25 parts isophorone diisocyanate, 3-5 parts BMBA, 4-6 parts 1,3-bis(3-aminopropyl)tetramethyldisiloxane, 2-4 parts allyl polyurethane urea diol, 5-8 parts fluorinated modified aminosiloxane, 6-9 parts triethylamine, 200-400 parts deionized water, and 0.2-0.4 parts emulsifier.

6. The method for preparing an aging-resistant soft insulating rod according to claim 2, characterized in that: The preparation method of the fluorinated modified aminosiloxane is as follows: under a nitrogen atmosphere, hexafluorobutanol is added to acetone and mixed evenly. The mixture is heated to 70-80°C, isophorone diisocyanate and catalyst are added, and the mixture is stirred for 2-3 hours. The temperature is then lowered to 40-50°C, 1,3-bis(3-aminopropyl)tetramethyldisiloxane is added, and the mixture is stirred for another 1-2 hours. The solvent is removed by rotary evaporation to obtain the fluorinated modified aminosiloxane.

7. The method for preparing an aging-resistant soft insulating pull rod according to claim 6, characterized in that: The molar ratio of hexafluorobutanol, isophorone diisocyanate, and 1,3-bis(3-aminopropyl)tetramethyldisiloxane is 1:1:(1~2).

8. The method for preparing an aging-resistant soft insulating rod according to claim 1, characterized in that: The fluorination modification process conditions are as follows: under a nitrogen atmosphere, an F2 / N2 mixed gas is introduced, with the volume fraction of F2 being 10%~20%, for 20~40 minutes, and the total pressure of the mixed gas being 10~50 kPa; The vacuum impregnation process conditions are as follows: under a vacuum degree ≤ -0.095MPa, the vacuum is maintained for 15~25 minutes, water-based polyurethane composite emulsion is injected, the vacuum is released, and the process is maintained for 30~40 minutes under a nitrogen pressure of 0.4~0.6MPa. The heat treatment process conditions are as follows: vertically suspended and naturally drip-dried, under a nitrogen atmosphere, the temperature is increased to 60-70℃ at a rate of 1-2℃ / min for 1-2 hours, and then increased to 70-80℃ for 2-3 hours.

9. An aging-resistant soft insulating rod prepared by the method for preparing an aging-resistant soft insulating rod according to any one of claims 1 to 8.

10. An application of an aging-resistant soft insulating pull rod, characterized in that: The aging-resistant soft insulating rod prepared according to claim 9 is applied to the inspection of ultra-high voltage AC / DC transmission lines.

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