Stretch-resistant and fracture-resistant cable protection tube and preparation method thereof

Abstract

The invention discloses a stretch-resistant and fracture-resistant cable protection tube and a preparation method thereof, and belongs to the technical field of cable protection tube materials, and the stretch-resistant and fracture-resistant cable protection tube specifically comprises low-density polyethylene, polymer-coated inorganic mixed filler, modified PBAT, kaolin, glass beads and bisphenol A type polysulfone. The low-density polyethylene and the modified PBAT are used as main base materials, so that the tensile property of the prepared cable protection pipe is improved; and the anti-fracture performance of the cable protection pipe is improved by the inorganic mixed filler coated with the polymer. The problems that in the prior art, low-density polyethylene for cable protection pipes is poor in mechanical property, and the tensile property of the cable protection pipes is reduced when inorganic materials are adopted for improving the strength and fracture performance of the low-density polyethylene are solved. In addition, the cable protection pipe prepared by the invention is excellent in weather resistance and thermal extensibility, and the application scene of the cable protection pipe is expanded.

Description

Technical Field

[0001] The invention relates to the technical field of cable protection tube materials, and in particular to a tensile and fracture-resistant cable protection tube and a preparation method thereof. Background Art

[0002] In the construction and practical application of power cable projects, the selection of cable protection materials is a key link to ensure the safety of power transmission. The main function of the cable protection tube is to prevent the power cable from being damaged, and it plays an important role as a bridge, support, tunnel, etc. in the transmission and distribution lines. Low-density polyethylene, as the base material of the cable protection tube, has good softness and extensibility, which can improve the tensile strength of the cable protection tube and make it easy to process. However, low-density polyethylene has low mechanical strength and poor anti-fracture performance, which shortens its service life.

[0003] Patent application CN116333404A discloses a high-strength, impact-resistant HDPE cable protection tube and its preparation method. Fischer-Tropsch wax is added in the process of preparing the HDPE cable protection tube. The Fischer-Tropsch wax is easily filled into the gaps between the fibers and the matrix during the blending process, so that the interface between the HDPE molecular chain and the carbon fiber has a larger van der Waals force and mechanical interlocking force. However, the boiling point of Fischer-Tropsch wax is only 60-70°C, and it is easy to melt under high temperature irradiation, which limits the application field of preparing cable protection tubes.

[0004] Patent application CN110194879A discloses a high-strength MPP material, a preparation method thereof, and a cable protection tube obtained therefrom. The high-strength MPP material includes a modified acrylic resin, etc., and a few-layer graphene oxide is connected to the acrylic resin to improve its own impact resistance. However, the acrylic resin is used as a substrate and modified with a large amount of inorganic materials, which will reduce the tensile properties of the prepared MPP material and is not conducive to extending the service life of the MPP material.

[0005] In view of the technical defects in this aspect, a solution is now proposed. Summary of the invention

[0006] In order to solve the problems raised in the background technology, the present invention provides a tensile and fracture-resistant cable protection tube and a preparation method thereof. A tensile and fracture-resistant cable protection tube comprises low-density polyethylene, a polymer-coated inorganic mixed filler, modified PBAT, kaolin, glass microspheres and bisphenol A type polysulfone. Low-density polyethylene and modified PBAT are used as the main substrates to improve the tensile properties of the cable protection tube; the polymer-coated inorganic mixed filler is filled to improve the fracture resistance of the cable protection tube.

[0007] The purpose of the present invention can be achieved through the following technical solutions: A tensile and fracture-resistant cable protection tube comprises, by weight, 60-70 parts of low-density polyethylene, 10-20 parts of polymer-coated inorganic mixed fillers, 5-10 parts of modified PBAT, 1-3 parts of kaolin, 2-3 parts of glass microspheres and 3-5 parts of bisphenol A polysulfone.

[0008] Furthermore, the preparation method of the polymer-coated inorganic mixed filler comprises the following steps: A1, polyvinyl alcohol, saturated solution of sodium chloride and distilled water are mixed evenly, and then heated to 45-55°C to obtain a transparent liquid; the inorganic mixed filler is added to the above transparent liquid, mixed evenly, and an aqueous phase is obtained; Polyvinyl alcohol is used as a dispersant to obtain a water phase monomer; an inorganic mixed filler of a substance to be coated is pre-added into the water phase monomer to obtain a water phase.

[0009] A2, ethylene glycol dimethacrylate, N,N'-methylenebisacrylamide, initiator and composite stabilizer are uniformly mixed to obtain an oil phase monomer; The oil phase is prepared by using ethylene glycol dimethacrylate as an oil phase monomer and N,N'-methylenebisacrylamide as a crosslinking agent.

[0010] A3, adding the oil phase to the water phase, stirring, so that the oil phase monomers are dispersed into droplets suspended in the water phase, to obtain a mixed system; the mixed system is reacted at 50-60° C. for 1-2 hours, then heated to 70-80° C. for 1-2 hours, and then heated to 80-90° C. for 4-5 hours, the polymerization reaction is completed, and a reaction liquid is obtained; the reaction liquid is filtered and resin beads are collected; The oil phase monomer is suspended in an immiscible water phase monomer medium, and the oil phase monomer is dispersed into liquid droplets of appropriate size by stirring, and polymerized into spheres with relatively uniform particle size to obtain resin beads; the inner layer of the resin beads is coated with inorganic mixed fillers.

[0011] A4. Add the resin beads into ethanol and mix evenly; then add bisphenol A epoxy resin and react at 70-80° C. for 2-3 hours to obtain polymer spheres; the polymer spheres are post-processed to obtain polymer-coated inorganic fillers with a diameter of 3-4 mm.

[0012] In the above reaction process, the imino functional groups contained in the resin beads can react with the epoxy groups in the bisphenol A epoxy resin, and through secondary crosslinking, the coating diameter is expanded to obtain a polymer-coated inorganic filler.

[0013] The invention adopts suspension polymerization to prepare spherical polymer, and then uses organic spherical polymer to cover inorganic mixed filler, and performs secondary crosslinking to obtain polymer-covered inorganic filler.

[0014] Furthermore, in step A1, the amount ratio of polyvinyl alcohol, saturated solution of sodium chloride, distilled water and inorganic mixed filler is 2.2-4.4g:10mL:200mL:50-60g, and the inorganic mixed filler is obtained by mixing talcum powder and wollastonite in a mass ratio of 1:2-3.

[0015] Furthermore, in step A2, the initiator is lauroyl peroxide, and the composite stabilizer is obtained by mixing polyvinyl alcohol and gelatin in a mass ratio of 3:2; the amount ratio of ethylene glycol dimethacrylate, N,N'-methylenebisacrylamide, initiator and composite stabilizer is 50-60g:15-30g:0.1-0.3g:30g; in step A4, the amount ratio of resin beads, ethanol and bisphenol A epoxy resin is 20-30g:300mL:3-5g; the post-processing step includes: placing the polymerized spheres in a Soxhlet extractor and performing an extraction operation with petroleum ether; then washing with ethanol and deionized water in turn, and vacuum drying to constant weight.

[0016] Furthermore, the preparation method of the modified PBAT comprises the following steps: B1. In a nitrogen atmosphere, chlorobenzene and methyldichlorosilane are mixed and preheated to 600-620° C. to obtain a heated mixed gas; the heated mixed gas enters a tubular reactor, the temperature of the tubular reactor is set to 650-700° C., and is in contact with the reactor at this temperature for 20-30 seconds to generate a polychlorosilane mixed gas; Chlorobenzene and methyldichlorosilane undergo condensation reaction at a temperature of 650-700°C. The main products are phenyltrichlorosilane and methyltrichlorosilane. Since the separation and purification of various main and side products are relatively difficult, all of them are collected as a polychlorosilane mixed gas.

[0017] B2, passing the polychlorosilane mixed gas into a 5%wt hydrochloric acid aqueous solution for hydrolysis, and separating the organic gel polymer to obtain a polychlorosilane alcohol mixture; B3, the polychlorosilanol mixture and the dried PBAT are melt-blended at a temperature of 130-140° C. for 10-15 min to obtain a modified PBAT.

[0018] The alkoxy groups in polysiloxanes undergo hydrolysis under acidic conditions to generate corresponding silanol groups, which further undergo polycondensation to form an organic gel polymer, namely a polychlorosilanol mixture. PBAT undergoes partial degradation under high-temperature melting conditions, and the polychlorosilanol mixture can undergo partial ester exchange reaction with PBAT to obtain modified PBAT.

[0019] Furthermore, in step B1, the molar ratio of chlorobenzene to methyldichlorosilane is 2-3:1; in step B2, the amount ratio of hydrochloric acid aqueous solution to polychlorosilane is 50mL:20-30mL; the hydrolysis temperature is 40-50°C, and the hydrolysis time is 20-30min; in step B3, the amount ratio of polychlorosilanol mixture to PBAT is 50:50 in parts by weight.

[0020] A method for preparing a tensile and fracture-resistant cable protection tube comprises the following steps: Low-density polyethylene, polymer-coated inorganic mixed filler, modified PBAT, kaolin, glass microspheres and bisphenol A polysulfone are added into a twin-screw extruder for extrusion granulation to obtain a tensile and fracture-resistant cable protection tube.

[0021] Furthermore, the rotation speed of the screw extruder is 200-220 r / min, and the extrusion temperature is 130-140°C.

[0022] Low-density polyethylene, polymer-coated inorganic mixed filler, modified PBAT and related additives are mixed and added into a twin-screw extruder for extrusion granulation to obtain a tensile and fracture-resistant cable protection tube.

[0023] The present invention has the following beneficial effects: The present invention uses low-density polyethylene as a base material for preparing a cable protection tube, and the prepared cable protection tube has good tensile resistance. In order to further improve the anti-fracture property of the cable protection tube, the present invention adds a certain amount of polymer-coated inorganic mixed filler to the prepared cable protection tube material. Talc and wollastonite are mixed as inorganic mixed fillers to improve the tensile strength and mechanical properties of the prepared cable protection tube. However, the inorganic mixed filler has poor compatibility with the organic substrate; the present invention uses ethylene glycol dimethacrylate and N,N'-methylenebisacrylamide to prepare the spherical resin, and in the process of suspension polymerization, the spherical resin coats the inorganic mixed filler, thereby improving the compatibility of the inorganic mixed filler with the organic substrate. The resin beads are then continued to react with bisphenol A epoxy resin and undergo secondary crosslinking. More crosslinking bridges are generated by further crosslinking, thereby reducing the pore size of the prepared spherical resin and increasing its own coating density, thereby improving the stability of the polymer-coated inorganic mixed filler.

[0024] As a biodegradable polyester, PBAT itself is composed of rigid butylene terephthalate segments and flexible butylene adipate segments, and has impact resistance and thermal stability. Methyldichlorosilane and chlorobenzene undergo a gas phase condensation reaction to generate a polychlorosilane mixed gas; the polychlorosilane mixed gas undergoes a hydrolysis reaction and polycondensation to obtain a polymerized silanol gel, which will further undergo a dehydration condensation reaction to generate a siloxane group to obtain an incompletely dissolved multi-molecular polymer, namely a polychlorosilanol mixture. By adopting a high-temperature melt blending method, PBAT is slightly degraded, and then an ester exchange occurs with the polychlorosilanol mixture to obtain a modified PBAT. PBAT modified by the polychlorosilanol mixture can improve its own heat oxidation resistance and aging resistance, thereby expanding the application temperature range of the cable protection tube.

[0025] The anti-fracture performance of low-density polyethylene and PBAT is relatively poor. Kaolin is used to replace the nucleating agent; glass microspheres are spherical, so they have good fluidity during plasticization. The present invention uses glass microspheres to replace lubricants; the sulfur atoms on the main chain of bisphenol A polysulfone are in the highest oxidation state, and the oxygen atoms on the sulfone group of diphenylene are symmetrical, so that bisphenol A polysulfone has excellent antioxidant ability and can replace antioxidants. All of the above-mentioned substitutes have excellent mechanical strength and mechanical properties, and can improve the anti-fracture performance of the cable protection tube. The cable protection tube prepared by the present invention does not use relevant additives, and has excellent tensile resistance and anti-fracture performance. DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] The polyvinyl alcohol used in Examples 1-3 was purchased from Shanghai Yingjia Industrial Development Co., Ltd., with a polymerization degree of 1000-2000 and an alcoholysis degree of 80-90%; the wollastonite used in Examples 1-3 was purchased from Yunnan Superfine New Materials Co., Ltd., with an aspect ratio of 20-28:1 and a whiteness of 85-90%; The glass microspheres used in Examples 7-9 were from Lingshou County Jieling Mineral Products Trading Co., Ltd., and had a particle size of 120-200 mesh; The kaolin used in Examples 7-9 was purchased from Guangzhou Zhanfei Chemical Technology Co., Ltd., with a mesh size of 3000 and a Mohs hardness of 6-7.

[0028] Example 1 This embodiment provides a method for preparing a polymer-coated inorganic mixed filler for a tensile and fracture-resistant cable protection tube, comprising the following steps: A1. Equip a 500mL three-necked flask with a reflux condenser, a stirring device and a thermometer. At room temperature, add 2.2g of polyvinyl alcohol (polyvinyl alcohol has a degree of polymerization of 1000 and a degree of alcoholysis of 80%), 10mL of a saturated solution of sodium chloride and 200mL of distilled water to the three-necked flask, mix well, and then heat to 55°C to obtain a transparent liquid. Mix talcum powder and wollastonite in a mass ratio of 1:2 and ball-mill to 200 mesh to obtain an inorganic mixed filler. Add 50g of the inorganic mixed filler to the above transparent liquid and stir well to obtain an aqueous phase monomer.

[0029] A2, polyvinyl alcohol and gelatin were mixed in a mass ratio of 3:2 to obtain a composite stabilizer. 50 g of ethylene glycol dimethacrylate and 15 g of N,N'-methylenebisacrylamide were added to a 500 mL beaker, followed by 0.1 g of initiator lauroyl peroxide and 30 g of the composite stabilizer, and stirred until the initiator was completely dissolved and the components were evenly mixed to obtain an oil phase monomer.

[0030] A3. Add the above oil phase monomer to the above water phase monomer, mix and stir, so that the oil phase monomer is dispersed into droplets suspended in the water phase monomer to obtain a mixed system. The mixed system is reacted at 50°C for 1 hour, then heated to 70°C for 1 hour, and then heated to 80°C for 4 hours. The polymerization reaction is completed to obtain a reaction solution. Filter the reaction solution and collect the resin beads.

[0031] A4. Add 20g of resin beads to 300mL of ethanol and mix well; then add 3g of bisphenol A epoxy resin and react at 70°C for 2h to obtain polymer spheres. The polymer spheres are placed in a Soxhlet extractor and extracted with petroleum ether; then washed three times with ethanol to remove the residual petroleum ether in the polymer spheres, then washed three times with deionized water, and then placed in a vacuum drying oven to dry to constant weight to obtain a polymer-coated inorganic filler, the average diameter of the polymer-coated inorganic filler is 3mm.

[0032] Example 2 This embodiment provides a method for preparing a polymer-coated inorganic mixed filler for a tensile and fracture-resistant cable protection tube, comprising the following steps: A1. Equip a 500mL three-necked flask with a reflux condenser, a stirring device and a thermometer. Add 3.3g of polyvinyl alcohol (polyvinyl alcohol has a degree of polymerization of 2000 and a degree of alcoholysis of 85%), 10mL of a saturated solution of sodium chloride and 200mL of distilled water to the three-necked flask, mix well, and then heat to 45°C to obtain a transparent liquid. Mix talcum powder and wollastonite in a mass ratio of 1:3 and ball-mill to 300 mesh to obtain an inorganic mixed filler. Add 55g of the inorganic mixed filler to the above transparent liquid and stir well to obtain an aqueous phase monomer.

[0033] A2, polyvinyl alcohol and gelatin were mixed in a mass ratio of 3:2 to obtain a composite stabilizer. 55 g of ethylene glycol dimethacrylate and 20 g of N,N'-methylenebisacrylamide were added to a 500 mL beaker, followed by 0.2 g of initiator lauroyl peroxide and 30 g of the composite stabilizer, and stirred until the initiator was completely dissolved and the components were evenly mixed to obtain an oil phase monomer.

[0034] A3. Add the above oil phase monomer to the above water phase monomer, mix and stir, so that the oil phase monomer is dispersed into droplets suspended in the water phase monomer to obtain a mixed system. The mixed system is reacted at 55°C for 1.5h, then heated to 75°C for 1.6h, and then heated to 86°C for 4.3h. The polymerization reaction is completed to obtain a reaction solution. Filter the reaction solution and collect the resin beads.

[0035] A4. Add 25g of resin beads to 300mL of ethanol and mix well; then add 3-5g of bisphenol A epoxy resin and react at 77°C for 2.5h to obtain polymer spheres. The polymer spheres are placed in a Soxhlet extractor and extracted with petroleum ether; then washed three times with ethanol to remove the residual petroleum ether in the polymer spheres, then washed three times with deionized water, and then placed in a vacuum drying oven to dry to constant weight to obtain a polymer-coated inorganic filler, the average diameter of the polymer-coated inorganic filler is 3.4mm.

[0036] Example 3 This embodiment provides a method for preparing a polymer-coated inorganic mixed filler for a tensile and fracture-resistant cable protection tube, comprising the following steps: A1. Equip a 500mL three-necked flask with a reflux condenser, a stirring device and a thermometer. Add 4.4g of polyvinyl alcohol (polyvinyl alcohol has a degree of polymerization of 1500 and a degree of alcoholysis of 90%), 10mL of a saturated solution of sodium chloride and 200mL of distilled water into the three-necked flask, mix well, and then heat to 50°C to obtain a transparent liquid. Mix talcum powder and wollastonite in a mass ratio of 1:3 and ball-mill to 220 mesh to obtain an inorganic mixed filler. Add 60g of the inorganic mixed filler to the above transparent liquid and stir well to obtain an aqueous phase monomer.

[0037] A2, polyvinyl alcohol and gelatin were mixed in a mass ratio of 3:2 to obtain a composite stabilizer. 60 g of ethylene glycol dimethacrylate and 30 g of N,N'-methylenebisacrylamide were added to a 500 mL beaker, followed by 0.3 g of initiator lauroyl peroxide and 30 g of the composite stabilizer, and stirred until the initiator was completely dissolved and the components were evenly mixed to obtain an oil phase monomer.

[0038] A3. Add the above oil phase monomer to the above water phase monomer, mix and stir, so that the oil phase monomer is dispersed into droplets suspended in the water phase monomer to obtain a mixed system. The mixed system is reacted at 60°C for 2h, then heated to 80°C for 2h, and then heated to 90°C for 5h. The polymerization reaction is completed to obtain a reaction solution. Filter the reaction solution and collect the resin beads.

[0039] A4. Add 30 g of resin beads to 300 mL of ethanol and mix well; then add 5 g of bisphenol A epoxy resin and react at 80° C. for 3 h to obtain polymer spheres. The polymer spheres are placed in a Soxhlet extractor and extracted with petroleum ether; then washed three times with ethanol to remove the residual petroleum ether in the polymer spheres, then washed three times with deionized water, and then placed in a vacuum drying oven to dry to constant weight to obtain a polymer-coated inorganic filler, the average diameter of the polymer-coated inorganic filler is 4 mm.

[0040] Example 4 This embodiment provides a method for preparing a modified PBAT for a tensile and fracture-resistant cable protection tube, comprising the following steps: B1. Dry nitrogen is passed into a tubular reactor for gas replacement, so that the tubular reactor is placed in a nitrogen atmosphere. According to the molar ratio, 2 parts of chlorobenzene and 1 part of methyldichlorosilane are added from the feed port to the preheating device of the tubular reactor, and the temperature of the preheating device reaches 600°C to obtain a heated mixed gas. The heated mixed gas enters the tubular reactor, and the temperature of the tubular reactor is set to 650°C. At this temperature, the mixed gas is contacted for 20 seconds. Through a gas phase condensation reaction, chlorobenzene and methyldichlorosilane react to generate a polychlorosilane mixed gas.

[0041] B2. Add 50 mL of 5% wt hydrochloric acid aqueous solution into a 250 mL three-necked flask, then add 20 mL of polychlorosilane mixed gas into the three-necked flask through a connecting tube, transfer the three-necked flask to a water bath, start magnetic stirring at 300 r / min, hydrolyze the polychlorosilane mixed gas, the hydrolysis temperature is 40°C, the hydrolysis time is 20 min, and separate the organic gel polymer, which is a polychlorosilanol mixture.

[0042] B3. The PBAT was placed in a vacuum dryer at 60° C. for 24 hours to obtain a dried PBAT; 50 parts of the polysiloxane silanol mixture and 50 parts of the dried PBAT were placed in an internal mixer for melt blending according to weight parts; wherein the speed of the internal mixer was set to 100 rpm, the melt blending temperature was 130° C., and the melt blending time was 10 minutes to obtain a modified PBAT.

[0043] Example 5 This embodiment provides a method for preparing a modified PBAT for a tensile and fracture-resistant cable protection tube, comprising the following steps: B1. Dry nitrogen is passed into a tubular reactor for gas replacement, so that the tubular reactor is placed in a nitrogen atmosphere. According to the molar ratio, 3 parts of chlorobenzene and 1 part of methyldichlorosilane are added to the preheating device of the tubular reactor from the feed port, and the temperature of the preheating device reaches 620°C to obtain a heated mixed gas. The heated mixed gas enters the reactor, and the temperature of the reactor is set to 660°C. At this temperature, the mixed gas is contacted for 25 seconds, and through a gas phase condensation reaction, chlorobenzene and methyldichlorosilane react to generate a polychlorosilane mixed gas.

[0044] B2. Add 50 mL of 5% wt hydrochloric acid aqueous solution into a 250 mL three-necked flask, then add 25 mL of polychlorosilane mixed gas into the three-necked flask through a connecting tube, transfer the three-necked flask to a water bath, start magnetic stirring at 200 r / min, and hydrolyze the polychlorosilane mixed gas at a temperature of 45°C for 22 minutes. Separate the organic gel polymer, which is a polychlorosilanol mixture.

[0045] B3. The PBAT was placed in a vacuum dryer at 60° C. for 24 hours to obtain a dried PBAT; 50 parts of the polysiloxane silanol mixture and 50 parts of the dried PBAT were placed in an internal mixer for melt blending according to weight; wherein the speed of the internal mixer was set to 80 rpm, the melt blending temperature was 135° C., and the melt blending time was 12 minutes to obtain a modified PBAT.

[0046] Example 6 This embodiment provides a method for preparing a modified PBAT for a tensile and fracture-resistant cable protection tube, comprising the following steps: B1. Dry nitrogen is passed into a tubular reactor for gas replacement, so that the tubular reactor is placed in a nitrogen atmosphere. According to the molar ratio, 3 parts of chlorobenzene and 1 part of methyldichlorosilane are added to the preheating device of the tubular reactor from the feed port, and the temperature of the preheating device reaches 620°C to obtain a heated mixed gas. The heated mixed gas enters the reactor, and the temperature of the reactor is set to 700°C. At this temperature, the mixed gas is contacted for 30 seconds. Through a gas phase condensation reaction, chlorobenzene and methyldichlorosilane react to generate a polychlorosilane mixed gas.

[0047] B2. Add 50 mL of 5% wt hydrochloric acid aqueous solution into a 250 mL three-necked flask, then add 30 mL of polychlorosilane mixed gas into the three-necked flask through a connecting tube, transfer the three-necked flask to a water bath, start magnetic stirring at 300 r / min, and hydrolyze the polychlorosilane mixed gas at a temperature of 50°C for 30 minutes, and separate the organic gel polymer, which is a polychlorosilanol mixture.

[0048] B3. The PBAT was placed in a vacuum dryer at 60° C. for 24 hours to obtain a dried PBAT; 50 parts of the polysiloxane silanol mixture and 50 parts of the dried PBAT were placed in an internal mixer for melt blending according to weight; wherein the speed of the internal mixer was set to 100 rpm, the melt blending temperature was 140° C., and the melt blending time was 15 minutes to obtain a modified PBAT.

[0049] Example 7 This embodiment provides a method for preparing a tensile and fracture-resistant cable protection tube, comprising the following steps: According to weight parts, 60 parts of low-density polyethylene, 10 parts of the polymer-coated inorganic mixed filler prepared in Example 3, 5 parts of the modified PBAT prepared in Example 6, 1 part of kaolin, 2 parts of glass microspheres (the selected glass microspheres have a particle size of 120 mesh) and 3 parts of bisphenol A type polysulfone are added to a twin-screw extruder for extrusion granulation. The speed of the twin-screw extruder is 200r / min and the extrusion temperature is 130°C to obtain a tensile and anti-fracture cable protection tube.

[0050] Example 8 This embodiment provides a method for preparing a tensile and fracture-resistant cable protection tube, comprising the following steps: According to weight parts, 68 parts of low-density polyethylene, 13 parts of the polymer-coated inorganic mixed filler prepared in Example 3, 7 parts of the modified PBAT prepared in Example 6, 2 parts of kaolin, 3 parts of glass microspheres (the selected glass microspheres have a particle size of 150 mesh) and 4 parts of bisphenol A type polysulfone are added to a twin-screw extruder for extrusion granulation. The speed of the twin-screw extruder is 210r / min and the extrusion temperature is 135°C to obtain a tensile and fracture-resistant cable protection tube.

[0051] Example 9 This embodiment provides a method for preparing a tensile and fracture-resistant cable protection tube, comprising the following steps: According to weight parts, 70 parts of low-density polyethylene, 20 parts of the polymer-coated inorganic mixed filler prepared in Example 3, 10 parts of the modified PBAT prepared in Example 6, 3 parts of kaolin, 3 parts of glass microspheres (the selected glass microspheres have a particle size of 200 mesh) and 5 parts of bisphenol A type polysulfone are added to a twin-screw extruder for extrusion granulation. The speed of the twin-screw extruder is 220r / min and the extrusion temperature is 140°C to obtain a tensile and fracture-resistant cable protection tube.

[0052] Comparative Example 1 The difference between this comparative example and Example 9 is that the inorganic mixed filler is used instead of the polymer-coated inorganic mixed filler.

[0053] Comparative Example 2 The difference between this comparative example and Example 9 is that when preparing the polymer-coated inorganic hybrid filler, step A4 is omitted and the polymer-coated inorganic hybrid filler is replaced by resin beads.

[0054] Comparative Example 3 The difference between this comparative example and Example 9 is that PBAT of equal mass is used to replace the modified PBAT.

[0055] Performance Test: 1. According to GB / T1040.1-2006 "Determination of tensile properties of plastics", the tensile and fracture-resistant cable protection tubes prepared in Examples 7-9 and Comparative Examples 1-3 were cut into dumbbell-shaped specimens, and then the dumbbell-shaped specimens were placed on a CMT6104 universal material testing machine, and tensile strength and nominal strain at break tests were performed in sequence. The test tensile speed was set to 50 mm / min, and the tensile strength and elongation at break were calculated.

[0056] 2. According to GB / T1843-2008 "Determination of cantilever beam impact strength", the tensile and anti-fracture cable protection tubes prepared in Examples 7-9 and Comparative Examples 1-3 were cut into strips of 80 mm × 10 mm × 4 mm, and then placed on a 2BC1400 pendulum impact tester to perform an impact strength test at room temperature.

[0057] 3. According to GB / T2951.5-1997, the thermal extension properties of the tensile and fracture-resistant cable protection tubes prepared in Examples 7-9 and Comparative Examples 1-3 were measured, the permanent deformation rate was calculated, and the average value was obtained by three measurements. The specific test results are shown in the following table: Table 1. Sample performance test data

[0058] Data analysis: Comparative analysis of the data in Table 1 shows that the cable protection tubes prepared in Examples 7-9 of the present invention all have excellent tensile strength and anti-fracture properties. In addition, the cable protection tubes have good toughness and heat resistance, as shown by high impact strength values ​​and low permanent deformation rates.

[0059] However, in Comparative Example 1, the inorganic hybrid filler was substituted for the polymer-coated inorganic hybrid filler; due to the poor compatibility of the inorganic hybrid filler with the organic substrate low-density polyethylene and PBAT, the tensile strength and elongation at break values ​​were reduced. In Comparative Example 2, the polymer-coated inorganic hybrid filler was substituted for the resin pellet; the coating density of the resin pellet itself without secondary crosslinking was reduced, resulting in a reduction in its thermal stability, which was manifested as a reduction in the permanent deformation rate value.

[0060] In Comparative Example 3, PBAT was used to replace the modified PBAT, and the thermal oxidation resistance of the PBAT itself that was not modified with the polychlorosilanol mixture was reduced, which was manifested in an increase in the value of its permanent deformation rate after thermal stretching.

[0061] The above contents are merely examples and explanations of the structure of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

[0062] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0063] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A tensile and fracture-resistant cable protection tube, characterized in that: In parts by weight, it includes 60-70 parts of low-density polyethylene, 10-20 parts of polymer-coated inorganic mixed filler, 5-10 parts of modified PBAT, 1-3 parts of kaolin, 2-3 parts of glass microspheres and 3-5 parts of bisphenol A polysulfone.

2. The tensile and fracture-resistant cable protection tube according to claim 1, characterized in that: The preparation method of the polymer-coated inorganic mixed filler comprises the following steps: A1, polyvinyl alcohol, saturated solution of sodium chloride and distilled water are mixed evenly, and then heated to 45-55°C to obtain a transparent liquid; the inorganic mixed filler is added to the above transparent liquid, mixed evenly, and an aqueous phase is obtained; A2, ethylene glycol dimethacrylate, N,N'-methylenebisacrylamide, initiator and composite stabilizer are uniformly mixed to obtain an oil phase monomer; A3, adding the above oil phase monomer to the above water phase, mixing, so that the oil phase monomer is dispersed into droplets suspended in the water phase, to obtain a mixed system; the mixed system is reacted at 50-60° C. for 1-2 hours, then heated to 70-80° C. for 1-2 hours, and then heated to 80-90° C. for 4-5 hours to obtain a reaction solution; filtering the reaction solution and collecting resin beads; A4. Add the resin beads into ethanol and mix evenly; then add bisphenol A epoxy resin and react at 70-80° C. for 2-3 hours to obtain polymer spheres; the polymer spheres are post-processed to obtain polymer-coated inorganic fillers.

3. The tensile and fracture-resistant cable protection tube according to claim 1, characterized in that: In step A1, the amount ratio of polyvinyl alcohol, saturated solution of sodium chloride, distilled water and inorganic mixed filler is 2.2-4.4g:10mL:200mL:50-60g, and the inorganic mixed filler is obtained by mixing talcum powder and wollastonite in a mass ratio of 1:2-3.

4. The tensile and fracture-resistant cable protection tube according to claim 1, characterized in that: In step A2, the initiator is lauroyl peroxide, and the composite stabilizer is obtained by mixing polyvinyl alcohol and gelatin in a mass ratio of 3:2; the dosage ratio of ethylene glycol dimethacrylate, N,N'-methylenebisacrylamide, initiator and composite stabilizer is 50-60g:15-30g:0.1-0.3g:30g; in step A4, the dosage ratio of resin beads, ethanol and bisphenol A epoxy resin is 20-30g:300mL:3-5g; the post-processing step comprises: placing the polymerized spheres in a Soxhlet extractor and performing an extraction operation with petroleum ether; then washing with ethanol and deionized water in sequence, and vacuum drying to constant weight.

5. The tensile and fracture-resistant cable protection tube according to claim 1, characterized in that: The preparation method of the modified PBAT comprises the following steps: B1. In a nitrogen atmosphere, chlorobenzene and methyldichlorosilane are mixed and preheated to 600-620° C. to obtain a heated mixed gas; the heated mixed gas enters a tubular reactor, the temperature of the tubular reactor is set to 650-700° C., and is in contact with the reactor at this temperature for 20-30 seconds to generate a polychlorosilane mixed gas; B2, passing the polychlorosilane mixed gas into a 5%wt hydrochloric acid aqueous solution for hydrolysis, and separating the organic gel polymer to obtain a polychlorosilane alcohol mixture; B3, the polychlorosilanol mixture and the dried PBAT are melt-blended at a temperature of 190-200° C. for 10-15 min to obtain a modified PBAT.

6. The tensile and fracture-resistant cable protection tube according to claim 5, characterized in that: In step B1, the molar ratio of chlorobenzene to methyldichlorosilane is 2-3:1; in step B2, the amount ratio of hydrochloric acid aqueous solution to polychlorosilane is 50mL:20-30mL; the hydrolysis temperature is 40-50°C, and the hydrolysis time is 20-30min; in step B3, the amount ratio of polychlorosilanol mixture to PBAT is 50:50 in parts by weight.

7. A method for preparing a tensile and fracture-resistant cable protection tube according to any one of claims 1 to 6, characterized in that: The following steps are involved: A polymer-coated inorganic mixed filler, modified PBAT, kaolin, glass microspheres and bisphenol A polysulfone are added into a twin-screw extruder for extrusion granulation to obtain a tensile and fracture-resistant cable protection tube.

8. A method for preparing a tensile and fracture-resistant cable protection tube according to any one of claim 7, characterized in that: The speed of the screw extruder is 200-220r / min, and the extrusion temperature is 130-140°C.

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