Heat-resistant high-strength MPP cable protection pipe and preparation method thereof

Abstract

The invention relates to the field of pipes, and discloses a heat-resistant high-strength MPP cable protection pipe and a preparation method thereof.The cable protection pipe comprises polypropylene resin, composite filler, modified layered lanthanum phenylphosphonate and auxiliaries; the composite filler is prepared by carrying out amino functional covalent modification on halloysite nanotubes by using a modified silane coupling agent, then carrying out protonation treatment and carrying out cation exchange on nano montmorillonite grafted with the modified silane coupling agent, and the modified silane coupling agent is prepared by reacting gamma-methacryloxypropyltrimethoxysilane with polyether amine; the modified layered lanthanum phenylphosphonate is prepared by grafting and modifying the surface of the layered lanthanum phenylphosphonate by using a cyclotriphosphazene substitute, the cyclotriphosphazene substitute is prepared by reacting 4-amino-1, 2, 4-triazole with p-hydroxybenzaldehyde and then substituting with phosphonitrilic chloride trimer, and the prepared MPP cable protection tube has the advantages of good tensile property, high impact resistance, high heat resistance, good flame retardancy, good flame retardancy and good flame retardancy. Meanwhile, excellent flame retardance and antibacterial effect are achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of pipe materials, and particularly relates to a heat-resistant high-strength MPP cable protection pipe and a preparation method thereof. BACKGROUND

[0002] The MPP cable protection pipe is a pipe material widely used in the fields of power and communication. It is mainly used for protecting cables and other facilities from damage caused by external environmental factors such as soil corrosion and mechanical damage. The MPP cable protection pipe uses modified polypropylene as the main raw material and has the characteristics of electrical insulation and resistance to external pressure. However, the flame retardance of the MPP cable protection pipe is poor, which may cause fire hazards. For example, in cable laying projects in the power and communication industries, the flame retardance of the MPP cable protection pipe is limited to a certain extent.

[0003] In order to improve the flame retardance of the pipe material, a large amount of inorganic flame retardant is often added in the prior art. However, the addition of the inorganic flame retardant may change the viscosity, compatibility and flexibility of the high molecular material. At the same time, these powders are prone to agglomeration, which directly affects the flame retardant effect of the inorganic flame retardant. Moreover, the agglomerated inorganic flame retardant may greatly cause internal void defects of the material, thereby leading to a decrease in the overall mechanical properties of the pipe material. In addition, the non-reactive cyclotriphosphazene derivative is introduced into the pipe material in a physical blending manner in the prior art, which may cause migration and leakage. The stability of the performance of the obtained product is generally poor.

[0004] In addition, the existing modified polypropylene has poor antibacterial performance, heat resistance and impact resistance, which limits its further application. For example, a high-wear-resistant impact-resistant MPP cable protection pipe and a production process thereof are disclosed in Chinese Patent No. CN 112745585A. Nano-silver is added as an antibacterial agent. However, since the antibacterial agent and the pipe material raw material are blended, the antibacterial performance is poor. At the same time, simple physical mixing may easily cause the antibacterial agent to precipitate. Therefore, it is difficult to ensure the long-lasting antibacterial effect of the pipe material, which is difficult to meet the high-end application requirements. SUMMARY

[0005] In order to solve the problems mentioned in the background, the purpose of the present application is to provide a heat-resistant high-strength MPP cable protection pipe and a preparation method thereof, so as to solve the problems of poor flame retardant effect, poor heat resistance, insufficient antibacterial performance and impact resistance of the existing MPP cable protection pipe.

[0006] The purpose of the present application can be achieved by the following technical solutions. A heat-resistant high-strength MPP cable protection pipe comprises the following components by weight: 100 parts of polypropylene resin, 2-7 parts of composite filler, 1-5 parts of modified layered lanthanum phenylphosphonate, 1-5 parts of high molecular compatibility agent and 1-3 parts of lubricant. The composite filler is modified nanometer montmorillonite prepared by grafting on the surface of nanometer montmorillonite with a modified silane coupling agent, and is covalently modified by using the modified silane coupling agent to amino-functionalize halloysite nanotubes, and is prepared by protonation treatment and cation exchange with the modified nanometer montmorillonite, wherein the modified silane coupling agent is prepared by Michael addition reaction of gamma-methacryloxypropyltrimethoxysilane and polyether amine; The modified layered lanthanum phenylphosphonate is prepared by grafting modification on the surface of layered lanthanum phenylphosphonate prepared by a reflux method by using gamma-aminopropyltriethoxysilane as a bridging agent and using a cyclotriphosphazene substituent, wherein the cyclotriphosphazene substituent is prepared by Schiff base reaction of 4-amino-1,2,4-triazole and p-hydroxybenzaldehyde, and then substitution reaction of the prepared Schiff base intermediate and hexachlorocyclotriphosphazene.

[0007] Preferably, the high molecular compatibilizer is one or more combinations of maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, glycidyl methacrylate grafted polyethylene, acrylic acid grafted polyethylene, silane grafted polyethylene, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-acrylate copolymer, and ethylene-acrylic acid copolymer; and the lubricant is one of polyethylene wax and oxidized polyethylene wax.

[0008] Preferably, the preparation method of the composite filler comprises the following steps: ①Polyether amine is taken in a reactor, heated to 50-55℃ to reduce the viscosity, then gamma-methacryloxypropyltrimethoxysilane is added dropwise, and after magnetic stirring for 30-40 min, the temperature is raised to 70-75℃ for reaction for 4-5 h to prepare the modified silane coupling agent; ②Nanometer montmorillonite is ultrasonically dispersed in a mixed solution of ethanol and deionized water, then the modified silane coupling agent is added, and the system is stirred and reacted at 70-75℃ for 6-6.5 h, after which it is washed, dried, and ground to prepare the modified nanometer montmorillonite; ③Halloysite nanotubes are ultrasonically dispersed in a mixed solution of ethanol and deionized water, then the modified silane coupling agent is added, the system is stirred and mixed, the pH value is adjusted to 3-4 with acetic acid, and the system is stirred and reacted at 70-75℃ for 6-6.5 h, after which it is washed, dried, and ground to prepare the modified halloysite nanotubes; ④The modified nanometer montmorillonite is ultrasonically dispersed in ethanol to obtain dispersion liquid one, the modified halloysite nanotubes are ultrasonically dispersed in ethanol to obtain dispersion liquid two, then the dispersion liquid two is slowly transferred into the reactor containing the dispersion liquid one by using a pipette, the temperature is raised to 70-80℃ and the system is stirred and reacted for 6-7 h, after which it is washed, dried, and ground to prepare the composite filler.

[0009] Preferably, the mass ratio of the polyether amine, the gamma-methacryloxypropyltrimethoxysilane, and the nanometer montmorillonite is 15-17:1:1.

[0010] Preferably, the mass ratio of the modified nanometer montmorillonite and the modified halloysite nanotube is 1:0.05-0.1.

[0011] Preferably, the preparation method of the modified layered lanthanum phenylphosphonate comprises the following steps: (1) 4-amino-1, 2, 4-triazole, p-hydroxybenzaldehyde, and ethanol are taken into a reactor, stirred and reacted at 75-80°C under a nitrogen atmosphere for 3-4h, and after the reaction is completed, filtration, rotary evaporation, ethanol recrystallization, and drying are performed to prepare a Schiff base intermediate; (2) a mixed solution of tetrahydrofuran and the Schiff base intermediate is added dropwise into a reactor containing potassium carbonate under ice bath and a nitrogen atmosphere, then a mixed solution of tetrahydrofuran and hexachlorocyclotriphosphazene is added dropwise, stirred and reacted at room temperature for 12-18h, and after the reaction is completed, centrifugation, reduced-pressure concentration, and column chromatography purification are performed to prepare a cyclotriphosphazene substituted body; (3) lanthanum chloride is dissolved in a mixed solution of deionized water and ethanol to obtain solution one, and lanthanum chloride is dissolved in deionized water to obtain solution two, solution one and solution two are mixed, the pH value of the system is adjusted to 2 by using 0.1 mol / L sodium hydroxide solution, and refluxing is performed at 75-85°C for 20-24h, and after the reaction is completed, precipitation, washing, and drying are performed to prepare layered lanthanum phenylphosphonate; (4) the layered lanthanum phenylphosphonate is dispersed in deionized water, gamma-aminopropyltriethoxysilane is added and stirred for 8-8.5h, the product is washed and dried, then dispersed in tetrahydrofuran, triethylamine is added, stirred for 1.5-2h, then the cyclotriphosphazene substituted body is added, refluxing is performed at 75-80°C for 5-8h, and after the reaction is completed, washing and drying are performed to prepare modified layered lanthanum phenylphosphonate.

[0012] Preferably, in step (1), the molar ratio of 4-amino-1, 2, 4-triazole and p-hydroxybenzaldehyde is 1:1; and in step (2), the molar ratio of the Schiff base intermediate and hexachlorocyclotriphosphazene is 3:1.

[0013] Preferably, in step (3), the addition ratio of lanthanum chloride, deionized water, and ethanol in solution one is 1.2-1.3g:50mL:50mL; and the addition ratio of lanthanum chloride and deionized water in solution two is 1.9-2g:75mL.

[0014] Preferably, in step (4), the mass ratio of the layered lanthanum phenylphosphonate, gamma-aminopropyltriethoxysilane, and the cyclotriphosphazene substituted body is 2.5-4:1:1.5-2.5.

[0015] The preparation method of the heat-resistant high-strength MPP cable protection pipe as described above comprises the following steps: S1, each raw material is weighed by weight parts, the polypropylene resin, the composite filler, the modified layered lanthanum phenylphosphonate, the polymer compatibilizer and the lubricant are uniformly mixed to obtain a pipe material composition; S2, the pipe material composition is melt-extruded into a mold by a double screw extruder to form and cool and shape, thereby preparing the heat-resistant high-strength MPP cable protection pipe.

[0016] The beneficial effects of the present application are: The present application utilizes Michael addition reaction to graft gamma-methyl acryloyl oxypropyl trimethoxysilane and polyether amine to prepare macromolecular modified silane coupling agent, then surface grafts nano montmorillonite with the modified silane coupling agent to prepare modified nano montmorillonite, which can increase the interlayer spacing of nano montmorillonite and produce mechanical locking effect between the nano montmorillonite and the matrix material, thereby forming good interface bonding, meanwhile, the modified silane coupling agent is used for amino functionalization covalent modification of halloysite nanotube, then through protonation treatment and cation exchange, the -NH3 + of the modified nano montmorillonite interlayer is exchanged, so that the two are combined in the form of ionic bond, resulting in that the modified halloysite nanotube is anchored in the modified nano montmorillonite interlayer, thereby preparing the composite filler. + The hybridization of the halloysite nanotube and the modified nano montmorillonite in the composite filler can promote the dispersion of each other in the matrix, has higher strength and modulus, the heat resistance and comprehensive mechanical properties of the pipe material are obviously improved, meanwhile, the halloysite nanotube anchored in the interlayer of the nano montmorillonite gives support to the interlayer space and helps to resist external stress, thereby producing synergistic effect to improve the impact stress buffering and energy absorption of the pipe material, and endowing the pipe material with excellent impact resistance.

[0017] The present application utilizes Schiff base reaction of 4-amino-1,2,4-triazole and p-hydroxybenzaldehyde to generate a Schiff base intermediate containing an antibacterial Schiff base group (-CH-N-), then utilizes the Schiff base intermediate to replace part of the chlorine atoms on hexachlorocyclotriphosphazene to prepare a cyclotriphosphazene substituent, meanwhile, the present application utilizes a reflux method to prepare layered lanthanum phenylphosphonate, and utilizes the cyclotriphosphazene substituent to perform surface grafting modification on the layered lanthanum phenylphosphonate by taking gamma-aminopropyl triethoxysilane as a bridging agent, the remaining P-Cl in the cyclotriphosphazene substituent is replaced, and a modified layered lanthanum phenylphosphonate is prepared, wherein the cyclotriphosphazene substituent contains abundant flame-retardant phosphorus-nitrogen elements and an antibacterial Schiff base group, can play a synergistic flame-retardant role with the phosphorus elements in the layered lanthanum phenylphosphonate, and the layered lanthanum phenylphosphonate has a catalytic effect of transition metal elements while blocking the layers, the grafting of the cyclotriphosphazene substituent in the layered lanthanum phenylphosphonate structure by a firm chemical bond can obviously improve the thermal stability and flame-retardant performance of the pipe material at a higher temperature, and can enhance the compatibility of the base material and the layered lanthanum phenylphosphonate, in addition, the triazole ring and the Schiff base group introduced in the layered lanthanum phenylphosphonate structure can endow the pipe material with excellent antibacterial effect. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0019] Embodiment 1: A preparation method of a composite filler comprises the following steps: ① 80g of polyetheramine D2000 is taken in a reactor, the temperature is raised to 50℃ to reduce the viscosity, then 5g of gamma-methacryloxypropyl trimethoxysilane is added dropwise, after magnetic stirring for 30min, the temperature is raised to 75℃ and reacted for 4h to prepare a modified silane coupling agent; ② 5g of nano-montmorillonite is ultrasonically dispersed in a mixed solution of 125mL of ethanol and 20mL of deionized water, then 5g of the modified silane coupling agent is added, and stirring reaction is carried out at 75℃ for 6h, after the reaction is completed, washing, drying and grinding are carried out to prepare a modified nano-montmorillonite; ③ 1g of halloysite nanotube is ultrasonically dispersed in a mixed solution of 150mL of ethanol and 25mL of deionized water, then 1.2g of the modified silane coupling agent is added, after stirring and mixing, acetic acid is used to adjust the pH value of the system to 3, stirring reaction is carried out at 75℃ for 6h, after the reaction is completed, washing, drying and grinding are carried out to prepare a modified halloysite nanotube; IV. 2 g of modified nanometer montmorillonite was ultrasonically dispersed in 50 mL of ethanol to obtain dispersion liquid one, 0.15 g of modified halloysite nanotube was ultrasonically dispersed in 100 mL of ethanol to obtain dispersion liquid two, then the dispersion liquid two was slowly transferred into the reactor containing the dispersion liquid one by using a pipette, after the addition was completed, the temperature was raised to 75℃ and stirring was carried out for 6 h, after the reaction was completed, washing, drying and grinding were carried out to prepare the composite filler.

[0020] Example 2: A preparation method of modified layered lanthanum phenylphosphonate comprises the following steps: (1) 4.20 g of 4-amino-1,2,4-triazole, 6.11 g of p-hydroxybenzaldehyde and 100 mL of ethanol were placed in a reactor, and stirring was carried out at 80℃ under a nitrogen atmosphere for 4 h, after the reaction was completed, filtration, rotary evaporation, ethanol recrystallization and drying were carried out to prepare a Schiff base intermediate; (2) under an ice bath and a nitrogen atmosphere, a mixed solution of 10 mL of tetrahydrofuran and 1.62 g of the Schiff base intermediate was added dropwise into a reactor containing 1.79 g of potassium carbonate, then a mixed solution of 20 mL of tetrahydrofuran and 1.00 g of hexachlorocyclotriphosphazene was added dropwise, stirring was carried out at room temperature for 16 h, after the reaction was completed, centrifugation, reduced pressure concentration and column chromatography (V petroleum ether / V ethyl acetate=15:1) were carried out to prepare a cyclotriphosphazene substituted body; (3) 1.26 g of lanthanum chloride was dissolved in a mixed solution of 50 mL of deionized water and 50 mL of ethanol to obtain solution one, 1.96 g of lanthanum chloride was dissolved in 75 mL of deionized water to obtain solution two, the solution one and the solution two were mixed, 0.1 mol / L sodium hydroxide solution was used to adjust the pH value of the system to 2, and refluxing was carried out at 80℃ for 24 h, after the reaction was completed, precipitation, washing and drying were carried out to prepare layered lanthanum phenylphosphonate; (4) 3 g of the layered lanthanum phenylphosphonate was dispersed in 100 mL of deionized water, 1 g of γ-aminopropyl triethoxysilane was added and stirring was carried out for 8 h, the product was washed and dried, then was dispersed in 70 mL of tetrahydrofuran, 3 mL of triethylamine was added, stirring was carried out for 2 h, then 2 g of the cyclotriphosphazene substituted body was added, refluxing was carried out at 80℃ for 6 h, after the reaction was completed, washing and drying were carried out to prepare modified layered lanthanum phenylphosphonate.

[0021] Example 3: A heat-resistant high-strength MPP cable protection pipe comprises the following components in parts by weight: polypropylene resin 100 parts, the composite filler prepared in example 1 2.2 parts, the modified layered lanthanum phenylphosphonate prepared in example 2 1.3 parts, maleic anhydride grafted polypropylene 1.2 parts, lubricant polyethylene wax 1.1 part.

[0022] The preparation method of the above heat-resistant high-strength MPP cable protection pipe comprises the following steps: S1, each raw material was weighed by parts by weight, the polypropylene resin, the composite filler, the modified layered lanthanum benzenephosphonate, the maleic anhydride grafted polypropylene and the lubricant were mixed uniformly to obtain a pipe composition; S2, the pipe composition was melt-extruded into a mold by a twin-screw extruder to form and cool to shape, thereby preparing a heat-resistant high-strength MPP cable protection pipe.

[0023] Example 4: A heat-resistant high-strength MPP cable protection pipe comprises the following components by parts by weight: polypropylene resin 100 parts, composite filler prepared in Example 1 4.6 parts, modified layered lanthanum benzenephosphonate prepared in Example 2 3.5 parts, maleic anhydride grafted polypropylene 2.7 parts, and lubricant oxidized polyethylene wax 1.7 parts.

[0024] The preparation method of the above heat-resistant high-strength MPP cable protection pipe is the same as that in Example 3.

[0025] Example 5: A heat-resistant high-strength MPP cable protection pipe comprises the following components by parts by weight: polypropylene resin 100 parts, composite filler prepared in Example 1 6.8 parts, modified layered lanthanum benzenephosphonate prepared in Example 2 4.6 parts, maleic anhydride grafted polypropylene 4.5 parts, and lubricant oxidized polyethylene wax 2.6 parts.

[0026] The preparation method of the above heat-resistant high-strength MPP cable protection pipe is the same as that in Example 3.

[0027] Comparative Example 1 A preparation method of a composite filler comprises the following steps: ① 5 g of nano-montmorillonite was ultrasonically dispersed in a mixed solution of 125 mL of ethanol and 20 mL of deionized water, then 5 g of γ-methacryloxypropyltrimethoxysilane was added, and the mixture was stirred at 75°C for 6 h. After the reaction was completed, the modified nano-montmorillonite was prepared by washing, drying and grinding. ② 1 g of halloysite nanotube was ultrasonically dispersed in a mixed solution of 150 mL of ethanol and 25 mL of deionized water, then 1.2 g of γ-methacryloxypropyltrimethoxysilane was added, and the mixture was stirred at 75°C for 6 h after the pH value of the system was adjusted to 3 with acetic acid. After the reaction was completed, the modified halloysite nanotube was prepared by washing, drying and grinding. ③ 2 g of modified nano-montmorillonite was ultrasonically dispersed in 50 mL of ethanol to obtain dispersion liquid one, and 0.15 g of modified halloysite nanotube was ultrasonically dispersed in 100 mL of ethanol to obtain dispersion liquid two. Then, the dispersion liquid two was slowly transferred into the reactor containing the dispersion liquid one using a pipette, and the temperature was raised to 75°C and stirred for 6 h after the addition was completed. After the reaction was completed, the composite filler was prepared by washing, drying and grinding.

[0028] Comparative Example 2 A preparation method of modified nanometer montmorillonite includes the following steps: ① 80 g of polyether amine D2000 was taken in a reactor, and the temperature was raised to 50°C to reduce the viscosity, then 5 g of γ-methacryloxypropyl trimethoxysilane was added dropwise, and after magnetic stirring for 30 min, the temperature was raised to 75°C for reaction for 4 h, to prepare a modified silane coupling agent; ② 5 g of nanometer montmorillonite was ultrasonically dispersed in a mixed solution of 125 mL of ethanol and 20 mL of deionized water, then 5 g of the modified silane coupling agent was added, and after stirring and mixing, acetic acid was used to adjust the pH value of the system to 3, and the system was stirred at 75°C for 6 h, and after the reaction was completed, the product was washed, dried and ground, to prepare the modified nanometer montmorillonite.

[0029] Comparative Example 3 A preparation method of modified layered lanthanum phenylphosphonate includes the following steps: (1) 1.26 g of lanthanum chloride was dissolved in a mixed solution of 50 mL of deionized water and 50 mL of ethanol to obtain solution one, and 1.96 g of lanthanum chloride was dissolved in 75 mL of deionized water to obtain solution two, the two solutions were mixed, and the pH value of the system was adjusted to 2 using a 0.1 mol / L sodium hydroxide solution, and the system was refluxed at 80°C for 24 h, and after the reaction was completed, the product was precipitated, washed and dried, to prepare the layered lanthanum phenylphosphonate; (2) 3 g of the layered lanthanum phenylphosphonate was dispersed in 100 mL of deionized water, 1 g of γ-aminopropyl triethoxysilane was added and stirred for 8 h, the product was washed, dried, then dispersed in 70 mL of tetrahydrofuran, 3 mL of triethylamine was added, stirred for 2 h, then 2 g of hexachlorotriphosphazene was added, and the system was refluxed at 80°C for 6 h, and after the reaction was completed, the product was washed and dried, to prepare the modified layered lanthanum phenylphosphonate.

[0030] Comparative Example 4 A heat-resistant and high-strength MPP cable protection pipe includes the following components by weight: 100 parts of polypropylene resin, 6.8 parts of the composite filler prepared in Comparative Example 1, 4.6 parts of the modified layered lanthanum phenylphosphonate prepared in Example 2, 4.5 parts of maleic anhydride grafted polypropylene, and 2.6 parts of lubricant oxidized polyethylene wax.

[0031] The preparation method of the heat-resistant and high-strength MPP cable protection pipe is the same as that in Example 3.

[0032] Comparative Example 5 A heat-resistant and high-strength MPP cable protection pipe includes the following components by weight: 100 parts of polypropylene resin, 6.8 parts of the modified nanometer montmorillonite prepared in Comparative Example 2, 4.6 parts of the modified layered lanthanum phenylphosphonate prepared in Example 2, 4.5 parts of maleic anhydride grafted polypropylene, and 2.6 parts of lubricant oxidized polyethylene wax.

[0033] The preparation method of the heat-resistant high-strength MPP cable protection pipe is the same as that of Example 3.

[0034] Comparative Example 6 A heat-resistant high-strength MPP cable protection pipe comprises the following components by weight: 100 parts of polypropylene resin, 6.8 parts of the composite filler prepared in Example 1, 4.6 parts of the modified layered lanthanum phenylphosphonate prepared in Comparative Example 3, 4.5 parts of maleic anhydride grafted polypropylene, and 2.6 parts of lubricant oxidized polyethylene wax.

[0035] The preparation method of the heat-resistant high-strength MPP cable protection pipe is the same as that of Example 3.

[0036] Comparative Example 7 A heat-resistant high-strength MPP cable protection pipe comprises the following components by weight: 100 parts of polypropylene resin, 6.8 parts of the composite filler prepared in Example 1, 4.6 parts of hexachlorocyclotriphosphazene, 4.5 parts of maleic anhydride grafted polypropylene, and 2.6 parts of lubricant oxidized polyethylene wax.

[0037] The preparation method of the heat-resistant high-strength MPP cable protection pipe is the same as that of Example 3.

[0038] Performance detection The MPP cable protection pipes prepared in Examples 3-5 and Comparative Examples 4-7 were subjected to performance detection: a. The pipes were injection molded into standard dumbbell-shaped samples with a thickness of 4 mm. Referring to GB / T 1042.2-2022, the tensile speed was set to 50 mm / min, and a BLD-1028A type tensile strength tester was used to test the tensile properties of the samples. The data results are shown in Table 1.

[0039] b. The pipes were injection molded into samples with a thickness of 4 mm, a width of 10 mm, and a length of 80 mm. Referring to GB / T 1843-2008, a CJ-120 type impact strength tester was used to test the impact strength of the samples. The data results are shown in Table 1.

[0040] c. The limiting oxygen index and vertical burning grade of the samples were tested according to GB / T 2408-2021 to evaluate the flame retardant performance of the samples. The data results are shown in Table 1.

[0041] d. The samples were placed in a TGA-103 type thermal gravimetric analyzer and heated from room temperature to 800℃ at a rate of 5℃ / min under nitrogen protection. The initial decomposition temperature of the material was recorded to evaluate the heat resistance of the sample. The data results are shown in Table 1.

[0042] e. The antibacterial rate test of the samples was carried out according to GB / T 21866-2008. The test bacteria were Staphylococcus aureus and Escherichia coli. The data results are shown in Table 1.

[0043] Table 1 Test sample performance test results

[0044] As can be seen from the data results in Table 1, the pipe prepared in Example 3-5 of the present application has good tensile properties, high impact resistance and heat resistance, and also has excellent flame retardant properties and antibacterial properties.

[0045] In Comparative Example 4, the composite filler added directly uses γ-methacryloxypropyl trimethoxysilane, and in Comparative Example 5, the composite filler is replaced with an equal amount of the modified nanometer montmorillonite prepared in Comparative Example 2. The tensile properties, impact resistance and heat resistance of Comparative Examples 4-5 are lower than those of Examples 3-5, because the amino functional modification, protonation treatment and cation exchange of the modified silane coupling agent enable the halloysite nanotubes to be anchored in the interlayer of the nanometer montmorillonite, which is beneficial to improving the heat resistance and tensile properties of the pipe. Meanwhile, the halloysite nanotubes anchored in the interlayer of the nanometer montmorillonite give support to the interlayer space and help resist external stress, greatly improving the impact resistance of the pipe. Moreover, the tensile properties, impact resistance and heat resistance of Comparative Example 5 are slightly lower than those of Comparative Example 4, indicating that the addition of the modified halloysite nanotubes can improve the comprehensive mechanical properties and heat resistance of the pipe to some extent.

[0046] In Comparative Example 6, the modified layered lanthanum phenylphosphonate component added has the cyclotriphosphazene substituent replaced with an equal amount of hexachlorocyclotriphosphazene, and in Comparative Example 7, the modified layered lanthanum phenylphosphonate is directly replaced with an equal amount of hexachlorocyclotriphosphazene. The measured E. coli and S. aureus inhibition rates of Comparative Examples 6-7 are significantly lower than those of Examples 3-5, because the introduction of the triazole ring and the Schiff base group is not introduced, resulting in a decrease in antibacterial properties. Moreover, the flame retardant properties, mechanical properties and heat resistance of Comparative Example 7 are lower than those of Examples 3-5, because the direct addition of hexachlorocyclotriphosphazene has poor compatibility with the matrix, and the introduction of the layered lanthanum phenylphosphonate improves the flame retardant properties, tensile properties and heat resistance of the pipe to some extent.

[0047] In the description of the present specification, the description referring to the terms “one embodiment”, “an example”, “a specific example” and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description 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.

[0048] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above-mentioned embodiments, and the above-mentioned embodiments and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application.

Claims

1. A heat-resistant high-strength MPP cable protection pipe, characterized in that, Comprise the following weight parts components: polypropylene resin 100 parts, composite filler 2~7 parts, modified layered lanthanum benzenephosphonate 1~5 parts, high polymer compatibility agent 1~5 parts, lubricant 1~3 parts; The composite filler is modified nanometer montmorillonite prepared by grafting a modified silane coupling agent on the surface of nanometer montmorillonite, and is covalently modified by amino functionalization of halloysite nanotubes by using the modified silane coupling agent, and is prepared by protonation treatment and cation exchange of the modified nanometer montmorillonite, wherein the modified silane coupling agent is prepared by Michael addition reaction of gamma-methacryloxypropyl trimethoxysilane and polyether amine; The modified layered lanthanum benzenephosphonate is prepared by surface grafting modification of layered lanthanum benzenephosphonate prepared by a reflux method by using gamma-aminopropyl triethoxysilane as a bridging agent and using a cyclotriphosphazene substituent, wherein the cyclotriphosphazene substituent is prepared by Schiff base reaction of 4-amino-1,2,4-triazole and p-hydroxybenzaldehyde, and then substitution reaction of the prepared Schiff base intermediate and hexachlorocyclotriphosphazene.

2. The heat-resistant high-strength MPP cable protection pipe according to claim 1, characterized in that, The high polymer compatibility agent is one or more combinations of maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, glycidyl methacrylate grafted polyethylene, acrylic acid grafted polyethylene, silane grafted polyethylene, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-acrylate copolymer, and ethylene-acrylic acid copolymer; and the lubricant is one of polyethylene wax and oxidized polyethylene wax.

3. The heat-resistant high-strength MPP cable protection pipe according to claim 1, characterized in that, The preparation method of the composite filler comprises the following steps: ① Put polyether amine in a reactor, heat to 50~55℃ to reduce viscosity, then add gamma-methacryloxypropyl trimethoxysilane drop by drop, stir magnetically for 30~40min, then heat to 70~75℃ and react for 4~5h to prepare a modified silane coupling agent; ② Take nanometer montmorillonite and disperse in a mixed solution of ethanol and deionized water by ultrasonic, then add the modified silane coupling agent, stir and react at 70~75℃ for 6~6.5h, then wash, dry and grind to prepare modified nanometer montmorillonite; ③ Take halloysite nanotubes and disperse in a mixed solution of ethanol and deionized water by ultrasonic, then add the modified silane coupling agent, adjust the pH value of the system to 3~4 by acetic acid after stirring and mixing, then stir and react at 70~75℃ for 6~6.5h, then wash, dry and grind to prepare modified halloysite nanotubes; ④ Take modified nanometer montmorillonite and disperse in ethanol to obtain dispersion liquid one, take modified halloysite nanotubes and disperse in ethanol to obtain dispersion liquid two, then slowly transfer dispersion liquid two to the reactor containing dispersion liquid one by using a pipette, heat to 70~80℃ and stir for 6~7h after adding, then wash, dry and grind to prepare the composite filler.

4. The heat-resistant high-strength MPP cable protection pipe according to claim 3, characterized in that, The mass ratio of the polyether amine, gamma-methacryloxypropyl trimethoxysilane and nanometer montmorillonite is 15~17:1:

1.

5. The heat-resistant high-strength MPP cable protection pipe according to claim 3, characterized in that, The mass ratio of the modified nanometer montmorillonite and the modified halloysite nanotubes is 1:0.05~0.

1.

6. The heat-resistant high-strength MPP cable protection pipe according to claim 1, characterized in that, The preparation method of the modified layered lanthanum benzenephosphonate comprises the following steps: (1) taking 4-amino-1,2,4-triazole, p-hydroxybenzaldehyde and ethanol in a reactor, stirring and reacting at 75-80℃ for 3-4h under nitrogen atmosphere, after the reaction is completed, filtering, rotary evaporation, ethanol recrystallization and drying to prepare a Schiff base intermediate; (2) under ice bath and nitrogen atmosphere, dropping a mixture of tetrahydrofuran and the Schiff base intermediate into a reactor containing potassium carbonate, then dropping a mixture of tetrahydrofuran and hexachlorocyclotriphosphazene, stirring and reacting at room temperature for 12-18h, after the reaction is completed, centrifuging, concentrating under reduced pressure and purifying by a chromatographic column to prepare a cyclotriphosphazene substituent; (3) taking lanthanum chloride to dissolve in a mixed solution of deionized water and ethanol to obtain solution one, taking lanthanum chloride to dissolve in deionized water to obtain solution two, mixing solution one and solution two, adjusting the pH value of the system to 2 by using 0.1mol / L sodium hydroxide solution, refluxing at 75-85℃ for 20-24h, after the reaction is completed, precipitating, washing and drying to prepare a layered lanthanum phenylphosphonate; (4) taking the layered lanthanum phenylphosphonate to disperse in deionized water, adding γ-aminopropyl triethoxysilane and stirring for 8-8.5h, washing and drying the product, then dispersing in tetrahydrofuran, adding triethylamine, stirring for 1.5-2h, then adding the cyclotriphosphazene substituent, refluxing at 75-80℃ for 5-8h, after the reaction is completed, washing and drying to prepare a modified layered lanthanum phenylphosphonate.

7. The heat-resistant high-strength MPP cable protection pipe according to claim 6, characterized in that, In step (1), the molar ratio of 4-amino-1,2,4-triazole to p-hydroxybenzaldehyde is 1:1; in step (2), the molar ratio of the Schiff base intermediate to hexachlorocyclotriphosphazene is 3:

1. 8.The heat-resistant high-strength MPP cable protection pipe according to claim 6, characterized in that, In step (3), the addition ratio of lanthanum chloride, deionized water and ethanol in solution one is 1.2-1.3g: 50mL: 50mL; the addition ratio of lanthanum chloride and deionized water in solution two is 1.9-2g: 75mL. 9.The heat-resistant high-strength MPP cable protection pipe according to claim 6, characterized in that, In step (4), the mass ratio of the layered lanthanum phenylphosphonate, γ-aminopropyl triethoxysilane and the cyclotriphosphazene substituent is 2.5-4: 1: 1.5-2.

5.

10. A method for preparing the heat-resistant high-strength MPP cable protection pipe according to any one of claims 1-9, characterized in that, The method comprises the following steps: S1, weighing each raw material according to weight parts, mixing polypropylene resin, composite filler, modified layered lanthanum phenylphosphonate, high molecular compatibility agent and lubricant uniformly to obtain a pipe material composition; S2, melt-extruding the pipe material composition through a double-screw extruder into a mold to form, cooling and shaping to prepare a heat-resistant high-strength MPP cable protection pipe.

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