HPPM square electric power corrugated pipe using modified polypropylene

Abstract

The invention discloses an HPPM square electric power corrugated pipe using modified polypropylene, and belongs to the technical field of electric power pipe fittings. The HPPM square electric corrugated pipe sequentially comprises a circular inner cavity and a square annular wave from inside to outside, and is prepared from the following components in parts by weight: 50-70 parts of homo-polypropylene, 10-30 parts of modified insulating filler, 10-20 parts of modified glass fiber, 5-12.5 parts of a flame retardant, 1.5-4 parts of a toughening agent, 0.5-2 parts of bis (3, 4-difluorophenyl)-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, the invention relates to a high-temperature-resistant anti-static coating which is prepared from the following raw materials in parts by weight: 1-3 parts of 2, 5-di-tert-butyl-4-hydroxybenzyl monoethyl phosphate, 1-3 parts of a coupling agent, 1-2 parts of a lubricant, 0.5-1 part of an antistatic agent and 0.5-1 part of an ultraviolet absorbent. The HPPM square electric power corrugated pipe prepared by the invention has excellent mechanical property, high temperature resistance, electrical insulation property and flame retardant property.

Description

Technical Field

[0001] The invention belongs to the technical field of electric power pipe fittings, and in particular relates to an HPPM square electric power corrugated pipe using modified polypropylene. Background Art

[0002] As the world's third largest general-purpose resin, polypropylene has the advantages of low difficulty in processing and molding, non-toxic and transparent products, acid and alkali corrosion resistance, low production cost and good electrical insulation. Therefore, it has extremely wide applications in electronic appliances, film packaging, manufacturing industry and building materials. Polypropylene is formed by addition polymerization of propylene monomers. Its molecular structure is long-chain. It can be divided into isotactic polypropylene, syndiotactic polypropylene and atactic polypropylene according to stereoregularity. Among them, isotactic polypropylene is the main industrial product due to its high crystallinity, good mechanical properties and thermal stability. Polypropylene has a low density of about 0.90-0.91g / cm³, which makes it an ideal choice for lightweight applications. In terms of mechanical properties, polypropylene has moderate tensile strength and impact strength, as well as a high flexural modulus. In addition, polypropylene also has good electrical insulation properties and chemical stability.

[0003] High-strength polypropylene resin (HSPPR) is a modified or enhanced polypropylene material with higher mechanical properties than ordinary polypropylene, such as tensile strength, bending strength, impact strength, etc. Due to its advantages in light weight, corrosion resistance, low cost, etc., high-strength polypropylene resin has been widely used in many fields, especially in the automotive industry, packaging materials, electronic appliances, building materials and other fields. Therefore, the present invention develops and utilizes the HPPM square power corrugated pipe of modified polypropylene to solve the technical problem of poor electrical insulation performance and mechanical performance of the HPPM square power corrugated pipe in the prior art due to insufficient performance of insulating fillers and rigid materials. Summary of the invention

[0004] The purpose of the present invention is to provide a HPPM square power corrugated pipe using modified polypropylene, which is used to solve the technical problem that the insulation filler and rigid material performance of the HPPM square power corrugated pipe in the prior art are insufficient, resulting in poor electrical insulation performance and mechanical performance.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: The HPPM square power corrugated pipe using modified polypropylene comprises a circular inner cavity and a square ring wave from the inside to the outside in sequence; the HPPM square power corrugated pipe using modified polypropylene is composed of the following components in parts by weight: 50-70 parts of homopolypropylene, 10-30 parts of modified insulating filler, 10-20 parts of modified glass fiber, 5-12.5 parts of flame retardant, 1.5-4 parts of toughening agent, 0.5-2 parts of bis(3,5-di-tert-butyl-4-hydroxybenzyl phosphate monoethyl ester), 1-3 parts of coupling agent, 1-2 parts of lubricant, 0.5-1 parts of antistatic agent and 0.5-1 parts of ultraviolet absorber. The modified insulating filler is prepared by pre-treating, plasma-treating, intercalating and surface-modifying the insulating filler; the modified glass fiber is prepared by pre-treating and modifying the glass fiber; the flame retardant is a mixture of ammonium polyphosphate and red phosphorus, and the mass ratio of ammonium phosphate to red phosphorus is 4:1; the toughening agent is a mixture of ethylene propylene rubber and thermoplastic elastomer, and the mass ratio of ethylene propylene rubber to thermoplastic elastomer is 2-3:1; the coupling agent is an equal mixture of isopropyl titanate and KH550; the lubricant is an equal mixture of zinc stearate and erucic acid amide; the antistatic agent is an equal mixture of sodium stearate and diethyl methyl phosphate; and the ultraviolet absorber is an equal mixture of 2-hydroxy-4-methoxybenzophenone and 2-(2'-hydroxy-5'-methylphenyl)benzotriazole.

[0006] The preparation method of the modified insulating filler comprises the following steps: S1. Pretreatment: drying the insulating filler and then sieving it to obtain an insulating filler with uniform particle size; S2, plasma treatment: placing an insulating filler with uniform particle size into a plasma reaction chamber, distributing the filler evenly, introducing a reaction gas, and cooling the mixture to room temperature under nitrogen protection to obtain a plasma-treated insulating filler; S3, intercalation treatment: mixing the plasma-treated insulating filler with the intercalation agent, stirring and reacting in an aqueous solution, and after completion, centrifuging, washing, and drying to obtain the plasma- and intercalation-modified insulating filler; S4. Surface modification: mixing the plasma-intercalated modified insulating filler with a silane coupling agent, stirring and reacting in an ethanol solution, centrifugally separating and washing, and drying to obtain a modified insulating filler.

[0007] Furthermore, the insulating filler in S1 is a mixture of silicon dioxide, talc and montmorillonite, the mass ratio of silicon dioxide, talc and montmorillonite is 1-2:1-2:2, the drying temperature is 80-120°C, the drying time is 2-4 hours, and the sieve mesh is 300-400 mesh; the reaction gas in S2 is oxygen or air, the gas flow rate is 10-50sccm, the plasma power is 50-300W, and the treatment time is 5-30 minutes; the intercalating agent in S3 is hexadecyltrimethylammonium bromide and dimethyldiallyl An equal mixture of ammonium chloride, the mass ratio of the plasma-treated insulating filler to the intercalation agent is 1:1-3, the temperature of the aqueous solution is 60-80°C, the stirring reaction time is 2-4 hours, the silane coupling agent in S4 is a mixture of KH-550 and KH-570, the mass ratio of KH-550 to KH-570 is 1:2, the mass ratio of the plasma-modified intercalation insulating filler to the silane coupling agent is 1:0.1-0.5, the temperature of the ethanol solution is 60-80°C, and the stirring reaction time is 2-4 hours.

[0008] The preparation method of the modified glass fiber comprises the following steps: Q1. Preparation of bio-based solution: chitosan powder is added to acetic acid solution, stirred at room temperature until completely dissolved, and the pH value is adjusted to 7-7.5 with NaOH solution to obtain chitosan solution; lignin powder is added to ethanol solution, stirred until completely dissolved, to obtain lignin solution; Q2. Pretreatment of glass fiber: immerse the glass fiber in acetone or ethanol, clean it by ultrasonic, then wash it with deionized water and dry it to obtain clean glass fiber; Q3. Modification treatment: immerse the clean glass fiber into mixed liquid 1, then take it out, and immerse it into mixed liquid 2 again. After the end, take it out, dry it at room temperature, and solidify it to obtain modified glass fiber.

[0009] Furthermore, the mass concentration of the acetic acid solution in Q1 is 1-2wt%, the mass volume ratio of the chitosan powder to the acetic acid solution is 2-6:100, the concentration of the NaOH solution is 1M, the mass volume ratio of the lignin powder to the ethanol solution is 2-10:100, the volume concentration of the ethanol solution is 50-75vt%, and the stirring temperature is 60-80°C; Q2 is ultrasonically cleaned for 10-15 minutes, the drying temperature is 60-80°C, and the drying time is 12-16 hours; Q3, the first mixed solution is a mixed solution of chitosan solution and glutaraldehyde solution, the volume ratio of the chitosan solution and the glutaraldehyde solution is 1:1, the second mixed solution is a mixed solution of lignin solution and glutaraldehyde solution, the volume ratio of the chitosan solution and the glutaraldehyde solution is 1:1, the mass concentration of the glutaraldehyde solution is 2-4wt%, the immersion time is 30-60 minutes, the curing temperature is 80-120°C, and the curing time is 1-2 hours.

[0010] The preparation method of the HPPM square power corrugated pipe using modified polypropylene comprises the following steps: (1) Premixing: homopolypropylene, modified insulating filler, modified glass fiber and flame retardant are dried, and then homopolypropylene and modified insulating filler are added to a high-speed mixer first, and mixed evenly. Then, modified glass fiber, flame retardant, toughening agent, bis(3,5-di-tert-butyl-4-hydroxybenzyl phosphate monoethyl ester), antistatic agent and ultraviolet absorber are added in sequence, and stirred evenly. Finally, coupling agent and lubricant are added, and stirred thoroughly to obtain a premix. (2) Twin-screw extrusion: Use a twin-screw extruder to melt blend the premix, extrude, cool to room temperature, and pelletize to obtain a HPPM square power corrugated pipe mixture; (3) Molding: The HPPM square power corrugated pipe mixture is extruded and molded by a die, and cooled to room temperature to obtain the HPPM square power corrugated pipe using modified polypropylene.

[0011] Furthermore, in step (2), the screw temperature is 180-230°C, the screw speed is 100-200 rpm, the mixing time is 10-20 minutes, the extrusion feed zone temperature is 160-180°C, the melting zone temperature is 190-210°C, the homogenization zone temperature is 200-220°C, the die head temperature is 210-230°C, and the residence time is 5-8 minutes; in step (3), the molding temperature is 200-240°C, the extrusion speed is 2-5m / min, and the mold temperature is 30-50°C.

[0012] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. The present invention adopts a "square outside and round inside" structural design, that is, the outer wall is a square annular wave structure and the inner cavity is a circular structure, which not only improves the compressive strength and toughness of the pipe, but also makes the construction more convenient and has good anti-sedimentation performance; the tensile strength, bending strength and impact resistance of the material are enhanced by the addition of modified insulating fillers and modified glass fibers; the synergistic effect of ammonium polyphosphate and red phosphorus significantly improves the flame retardant grade of the pipe; through plasma treatment, intercalation treatment and surface modification, the dispersibility of the insulating filler and the bonding force with the matrix are optimized, and the insulation performance is improved; the addition of antioxidants and ultraviolet absorbers effectively inhibits the thermal oxidation aging and light aging of the material, improves the weather resistance of the pipe, and thus extends the service life; the addition of antistatic agents reduces static electricity accumulation and improves the electrical performance and safety of the pipe; in addition, the addition of lubricants reduces the friction coefficient of the material and improves the fluidity during melt blending and extrusion.

[0013] 2. The present invention modifies the insulating filler, performs plasma treatment, and uses oxygen or air as a reaction gas to generate oxygen plasma, effectively oxidize the filler surface, introduce oxygen-containing functional groups, and enhance the polarity and reactivity of the filler. In addition, the plasma treatment can also increase the roughness of the filler surface and enhance the interface bonding force with the matrix. The intercalation agents hexadecyltrimethylammonium bromide and dimethyldiallylammonium chloride can be inserted into the interlayer of the insulating filler, and through the action of ion exchange and van der Waals force, the interlayer spacing of the insulating filler is expanded, and its dispersibility in the polypropylene matrix is ​​improved, which is conducive to the insertion of the polypropylene molecular chain to form an intercalation composite material; the silane coupling agent can react with the hydroxyl group on the filler surface to form a chemical bond, and at the same time, the functional group at the other end can react or physically adsorb with the polypropylene matrix, thereby improving the compatibility and interface bonding force between the filler and the matrix.

[0014] 3. The present invention improves the tensile strength, impact resistance and toughness of the glass fiber by modifying the glass fiber, wherein two layers of coating are formed on the surface of the glass fiber by immersing it in a mixed solution twice, the amino groups in the chitosan solution react with the aldehyde groups in the glutaraldehyde solution to form a three-dimensional network structure, and the addition of glutaraldehyde as a cross-linking agent can improve the mechanical strength and stability of the chitosan, and the phenolic hydroxyl groups in the lignin react with the aldehyde groups in the glutaraldehyde to form a cross-linked structure, and the addition of glutaraldehyde further enhances the toughness, heat resistance and oxidation resistance of the lignin, thereby enhancing the mechanical properties, heat resistance and weather resistance of the glass fiber; in addition, both chitosan and lignin are bio-based materials, which meet the requirements of green environmental protection and reduce the cost of materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 A schematic cross-sectional view of the HPPM square power bellows of the present invention is shown; Wherein, the reference numerals are: 1: Circular inner cavity; 2: Square ring wave. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not 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. Example

[0018] See also Figure 1 As shown, this embodiment discloses a HPPM square power bellows using modified polypropylene, which includes a circular inner cavity 1 and a square annular wave 2 from the inside to the outside.

[0019] This embodiment discloses a method for preparing a modified insulating filler, comprising the following steps: S1, pretreatment: 1kg of silicon dioxide, 1kg of talc and 2kg of montmorillonite were dried at 80°C for 2 hours, and then sieved to a mesh size of 300 to obtain an insulating filler with uniform particle size; S2, plasma treatment: put the insulating filler with uniform particle size into the plasma reaction chamber, evenly distribute it, introduce oxygen or air, the gas flow rate is 10sccm, the plasma power is 50W, the treatment time is 5 minutes, and cool to room temperature under nitrogen protection to obtain the plasma-treated insulating filler; S3, intercalation treatment: 1 kg of plasma-treated insulating filler, 0.5 kg of hexadecyltrimethylammonium bromide and 0.5 kg of dimethyldiallylammonium chloride were mixed, stirred and reacted in a 60°C aqueous solution for 2 hours, centrifuged and washed, and dried to obtain a plasma-intercalated insulating filler; S4. Surface modification: 1 kg of plasma-intercalated modified insulating filler, 50 g of KH-550 and 50 g of KH-570 were mixed, and stirred in an ethanol solution at 60° C. for 2 hours. The mixture was centrifuged, washed and dried to obtain a modified insulating filler.

[0020] This embodiment discloses a method for preparing modified glass fiber, comprising the following steps: Q1. Preparation of bio-based solution: 2 g of chitosan powder was added to 100 mL of 1 wt% acetic acid solution, stirred at room temperature until completely dissolved, and the pH value was adjusted to 7 with 1 M NaOH solution to obtain a chitosan solution; 2 g of lignin powder was added to 100 mL of 50 wt% ethanol solution, stirred until completely dissolved, and the stirring temperature was 60°C to obtain a lignin solution; Q2. Pretreatment of glass fiber: immerse the glass fiber in acetone or ethanol, ultrasonically clean it for 10 minutes, then wash it with deionized water, and dry it at a temperature of 60°C for 12 hours to obtain clean glass fiber; Q3. Modification treatment: The clean glass fiber was immersed in a mixture of 100 mL 2wt% chitosan solution and 100 mL 2wt% glutaraldehyde solution, then taken out, and immersed in a mixture of 100 mL 2wt% lignin solution and 100 mL 2wt% glutaraldehyde solution for 30 minutes. The fiber was taken out, dried at room temperature, and cured at a curing temperature of 80°C for 1 hour to obtain a modified glass fiber.

[0021] The present embodiment discloses an HPPM square power corrugated pipe using modified polypropylene, which is composed of the following components in parts by weight: 50 parts of homopolymer polypropylene, 10 parts of modified insulating filler, 10 parts of modified glass fiber, 4 parts of ammonium polyphosphate, 1 part of red phosphorus, 1 part of ethylene propylene rubber, 0.5 parts of thermoplastic elastomer, 0.5 parts of bis(3,5-di-tert-butyl-4-hydroxybenzyl monoethyl phosphate), 0.5 parts of isopropyl titanate, 0.5 parts of KH550, 0.5 parts of zinc stearate, 0.5 parts of erucamide, 0.25 parts of sodium stearate, 0.25 parts of diethyl methyl phosphate, 0.25 parts of 2-hydroxy-4-methoxybenzophenone and 0.25 parts of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole.

[0022] The method for preparing the HPPM square power corrugated pipe using modified polypropylene comprises the following steps: (1) Premixing: homopolymer polypropylene, modified insulating filler, modified glass fiber and flame retardant are dried, and then homopolymer polypropylene and modified insulating filler are added to a high-speed mixer first, and mixed evenly, and then modified glass fiber, flame retardant, toughening agent, antioxidant, antistatic agent and ultraviolet absorber are added in sequence, and stirred evenly, and finally coupling agent and lubricant are added, and stirred thoroughly to obtain a premix; (2) Twin-screw extrusion: melt blend the premixed material using a twin-screw extruder, extrude the material, the screw temperature is 180°C, the screw speed is 100 rpm, the mixing time is 10 minutes, the extrusion feed zone temperature is 160°C, the melting zone temperature is 190°C, the homogenization zone temperature is 200°C, the die head temperature is 210°C, the residence time is 5 minutes, cool to room temperature, and pelletize to obtain a HPPM square power bellows mixture; (3) Molding: The HPPM square power corrugated pipe mixture is extruded through a mold at a molding temperature of 200°C, an extrusion speed of 2 m / min, and a mold temperature of 30°C. The mixture is cooled to room temperature to obtain an HPPM square power corrugated pipe made of modified polypropylene. Example

[0023] This embodiment discloses a method for preparing a modified insulating filler, comprising the following steps: S1, pretreatment: 1.5kg of silicon dioxide, 1.5kg of talc and 2kg of montmorillonite were dried at 100°C for 3 hours, and then sieved to a mesh size of 350 to obtain an insulating filler with uniform particle size; S2. Plasma treatment: placing an insulating filler with uniform particle size into a plasma reaction chamber, evenly distributing the filler, introducing oxygen or air, with a gas flow rate of 30 sccm, a plasma power of 200 W, a treatment time of 20 minutes, and cooling to room temperature under nitrogen protection to obtain a plasma-treated insulating filler; S3, intercalation treatment: 1 kg of plasma-treated insulating filler, 1 kg of hexadecyltrimethylammonium bromide and 1 kg of dimethyldiallylammonium chloride were mixed, stirred and reacted in a 70°C aqueous solution for 3 hours, centrifuged and washed, and dried to obtain a plasma- and intercalation-modified insulating filler; S4. Surface modification: 1 kg of plasma-intercalated modified insulating filler, 150 g of KH-550 and 150 g of KH-570 were mixed, stirred and reacted in an ethanol solution at 70° C. for 3 hours, centrifuged, washed, and dried to obtain a modified insulating filler.

[0024] This embodiment discloses a method for preparing modified glass fiber, comprising the following steps: Q1. Preparation of bio-based solution: 4 g of chitosan powder was added to 100 mL of 1.5 wt% acetic acid solution, stirred at room temperature until completely dissolved, and the pH value was adjusted to 7.2 with 1 M NaOH solution to obtain a chitosan solution; 4 g of lignin powder was added to 100 mL of 60 vt% ethanol solution, stirred until completely dissolved, and the stirring temperature was 80°C to obtain a lignin solution; Q2. Pretreatment of glass fiber: immerse the glass fiber in acetone or ethanol, ultrasonically clean it for 13 minutes, then wash it with deionized water, and dry it at a temperature of 70°C for 13 hours to obtain clean glass fiber; Q3. Modification treatment: The clean glass fiber was immersed in a mixture of 100 mL 4 wt% chitosan solution and 100 mL 3 wt% glutaraldehyde solution, then taken out, and immersed in a mixture of 100 mL 4 wt% lignin solution and 100 mL 3 wt% glutaraldehyde solution for 40 minutes. The fiber was taken out, dried at room temperature, and cured at a curing temperature of 100 ° C for 2 hours to obtain a modified glass fiber.

[0025] The present embodiment discloses an HPPM square power corrugated pipe using modified polypropylene, which is composed of the following components in parts by weight: 60 parts of homopolymer polypropylene, 20 parts of modified insulating filler, 15 parts of modified glass fiber, 8 parts of ammonium polyphosphate, 2 parts of red phosphorus, 2 parts of ethylene propylene rubber, 1 part of thermoplastic elastomer, 1 part of bis(3,5-di-tert-butyl-4-hydroxybenzyl monoethyl phosphate), 1 part of isopropyl titanate, 1 part of KH550, 1 part of zinc stearate, 1 part of erucamide, 0.3 parts of sodium stearate, 0.3 parts of diethyl methyl phosphate, 0.3 parts of 2-hydroxy-4-methoxybenzophenone and 0.3 parts of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole.

[0026] The method for preparing the HPPM square power corrugated pipe using modified polypropylene comprises the following steps: (1) Premixing: homopolymer polypropylene, modified insulating filler, modified glass fiber and flame retardant are dried, and then homopolymer polypropylene and modified insulating filler are added to a high-speed mixer first, and mixed evenly, and then modified glass fiber, flame retardant, toughening agent, antioxidant, antistatic agent and ultraviolet absorber are added in sequence, and stirred evenly, and finally coupling agent and lubricant are added, and stirred thoroughly to obtain a premix; (2) Twin-screw extrusion: melt blend the premixed material using a twin-screw extruder, extrude the material, the screw temperature is 200°C, the screw speed is 150 rpm, the mixing time is 15 minutes, the extrusion feed zone temperature is 170°C, the melting zone temperature is 200°C, the homogenization zone temperature is 210°C, the die head temperature is 220°C, the residence time is 7 minutes, cool to room temperature, and pelletize to obtain a HPPM square power bellows mixture; (3) Molding: The HPPM square power corrugated pipe mixture is extruded through a die at a molding temperature of 230°C, an extrusion speed of 4 m / min, and a die temperature of 40°C. The mixture is cooled to room temperature to obtain an HPPM square power corrugated pipe made of modified polypropylene. Example

[0027] This embodiment discloses a method for preparing a modified insulating filler, comprising the following steps: S1, pretreatment: 2kg of silicon dioxide, kg of talc and 2kg of montmorillonite were dried at 120°C for 4 hours, and then sieved to a mesh size of 400 to obtain an insulating filler with uniform particle size; S2. Plasma treatment: placing an insulating filler with uniform particle size into a plasma reaction chamber, evenly distributing the filler, introducing oxygen or air, with a gas flow rate of 50 sccm, a plasma power of 300 W, a treatment time of 30 minutes, and cooling to room temperature under nitrogen protection to obtain a plasma-treated insulating filler; S3, intercalation treatment: 1 kg of plasma-treated insulating filler, 1.5 kg of hexadecyltrimethylammonium bromide and 1.5 kg of dimethyldiallylammonium chloride were mixed, stirred and reacted in an aqueous solution at 80° C. for 4 hours, centrifuged, washed, and dried to obtain a plasma- and intercalation-modified insulating filler; S4, surface modification: 1 kg of plasma intercalation modified insulating filler, 250 g of KH-550 and 250 g of KH-570 were mixed, stirred and reacted in an ethanol solution at 80° C. for 4 hours, centrifuged and washed, and dried to obtain a modified insulating filler.

[0028] This embodiment discloses a method for preparing modified glass fiber, comprising the following steps: Q1. Preparation of bio-based solution: 6 g of chitosan powder was added to 100 mL of 2 wt% acetic acid solution, stirred at room temperature until completely dissolved, and the pH value was adjusted to 7.5 with 1 M NaOH solution to obtain a chitosan solution; 6 g of lignin powder was added to 100 mL of 75 wt% ethanol solution, stirred until completely dissolved, and the stirring temperature was 80°C to obtain a lignin solution; Q2. Pretreatment of glass fiber: immerse the glass fiber in acetone or ethanol, ultrasonically clean it for 15 minutes, then wash it with deionized water, and dry it at a temperature of 80°C for 16 hours to obtain clean glass fiber; Q3. Modification treatment: The clean glass fiber was immersed in a mixture of 100 mL 6 wt % chitosan solution and 100 mL 4 wt % glutaraldehyde solution, then taken out, and immersed in a mixture of 100 mL 6 wt % lignin solution and 100 mL 4 wt % glutaraldehyde solution for 60 minutes. The fiber was taken out, dried at room temperature, and cured at a curing temperature of 120 ° C for 2 hours to obtain a modified glass fiber.

[0029] The present embodiment discloses an HPPM square power corrugated pipe using modified polypropylene, which is composed of the following components in parts by weight: 70 parts of homopolymer polypropylene, 30 parts of modified insulating filler, 20 parts of modified glass fiber, 10 parts of ammonium polyphosphate, 2.5 parts of red phosphorus, 3 parts of ethylene propylene rubber, 1 part of thermoplastic elastomer, 2 parts of bis(3,5-di-tert-butyl-4-hydroxybenzyl monoethyl phosphate), 1.5 parts of isopropyl titanate, 1.5 parts of KH550, 1 part of zinc stearate, 1 part of erucamide, 0.5 part of sodium stearate, 0.5 part of diethyl methyl phosphate, 0.5 part of 2-hydroxy-4-methoxybenzophenone and 0.5 part of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole.

[0030] The method for preparing the HPPM square power corrugated pipe using modified polypropylene comprises the following steps: (1) Premixing: homopolymer polypropylene, modified insulating filler, modified glass fiber and flame retardant are dried, and then homopolymer polypropylene and modified insulating filler are added to a high-speed mixer first, and mixed evenly, and then modified glass fiber, flame retardant, toughening agent, antioxidant, antistatic agent and ultraviolet absorber are added in sequence, and stirred evenly, and finally coupling agent and lubricant are added, and stirred thoroughly to obtain a premix; (2) Twin-screw extrusion: melt blend the premixed material using a twin-screw extruder, extrude the material, the screw temperature is 230°C, the screw speed is 200 rpm, the mixing time is 20 minutes, the extrusion feed zone temperature is 180°C, the melting zone temperature is 210°C, the homogenization zone temperature is 220°C, the die head temperature is 230°C, the residence time is 8 minutes, cool to room temperature, and pelletize to obtain a HPPM square power bellows mixture; (3) Molding: The HPPM square power corrugated pipe mixture is extruded through a die at a molding temperature of 240°C, an extrusion speed of 5 m / min, and a die temperature of 50°C. The mixture is cooled to room temperature to obtain an HPPM square power corrugated pipe made of modified polypropylene.

[0031] Comparative Example 1: Comparative Example 1 Compared with Example 3, in the preparation process of the HPPM square power bellows in Comparative Example 1, the modified insulating filler is used instead of silica, and other conditions remain unchanged.

[0032] Comparative Example 2: Comparative Example 2 Compared with Example 3, in the preparation process of the HPPM square power corrugated pipe in Comparative Example 2, modified glass fiber is used instead of glass fiber, and other conditions remain unchanged.

[0033] Experimental example: The HPPM square power bellows samples prepared in Examples 1-3 and Comparative Examples 1-2 were subjected to the following performance tests: According to GB / T 9341-2008 "Test Method for Bending Properties of Plastics", GB / T 1040.1-2018 "Test Method for Tensile Properties of Plastics", GB / T 1043-2008 "Test Method for Impact Properties of Plastic Simply Supported Beams", GB / T 1634.1-2019 "Test Method for Deformation Temperature of Plastics under Load", GB / T 1410-2006 "Test Method for Volume Resistivity and Surface Resistivity of Solid Insulating Materials" and GB / T 2408-2008 "Test Method for Combustion Performance of Plastics", the mechanical properties, high temperature resistance, electrical insulation properties and flame retardant properties of the HPPM square power bellows were tested, and the test results are shown in Table 1: Table 1 Group Bending strength (MPa) Tensile strength (MPa) <![CDATA[Impact strength (kJ / m 2 )]]> Heat Deformation Temperature(°C) Insulation resistance(Ω) Flame retardant grade Example 1 1604 32 13.2 125 1.2×10¹² V-0 Example 2 1619 33 13.5 127 1.2×10¹² V-0 Example 3 1673 35 13.9 128 1.2×10¹² V-0 Comparative Example 1 1258 23 10.2 110 1.05×10¹² V-1 Comparative Example 2 1236 21 9.4 105 1.15×10¹² V-1 According to the test results in Table 1, the HPPM square power corrugated pipes prepared in Examples 1-3 of the present invention have excellent mechanical properties, high temperature resistance, electrical insulation and flame retardant properties. By comparing Comparative Examples 1-2 with Examples 1-3, it can be seen that adding modified insulating fillers and modified glass fibers can effectively improve the mechanical properties, high temperature resistance, electrical insulation and flame retardant properties of the HPPM square power corrugated pipes.

[0034] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0035] 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. HPPM square power bellows made of modified polypropylene, characterized in that: From the inside to the outside, it comprises a circular inner cavity (1) and a square annular wave (2); the HPPM square power corrugated pipe is prepared from the following components in parts by weight: 50-70 parts of homopolypropylene, 10-30 parts of modified insulating filler, 10-20 parts of modified glass fiber, 5-12.5 parts of flame retardant, 1.5-4 parts of toughening agent, 0.5-2 parts of bis(3,5-di-tert-butyl-4-hydroxybenzyl phosphate monoethyl ester), 1-3 parts of coupling agent, 1-2 parts of lubricant, 0.5-1 parts of antistatic agent and 0.5-1 parts of ultraviolet absorber; the modified insulating filler is prepared by pre-treating the insulating filler, plasma treating, intercalating and surface modifying the insulating filler; The modified glass fiber is prepared by pre-treating and modifying the glass fiber.

2. The HPPM square power bellows using modified polypropylene according to claim 1, characterized in that: The flame retardant is a mixture of ammonium polyphosphate and red phosphorus, and the mass ratio of ammonium phosphate to red phosphorus is 4:1; the toughening agent is a mixture of ethylene propylene rubber and thermoplastic elastomer, and the mass ratio of ethylene propylene rubber to thermoplastic elastomer is 2-3:1; the coupling agent is an equal mixture of isopropyl titanate and KH550; the lubricant is an equal mixture of zinc stearate and erucamide; the antistatic agent is an equal mixture of sodium stearate and diethyl methyl phosphate; and the ultraviolet absorber is an equal mixture of 2-hydroxy-4-methoxybenzophenone and 2-(2'-hydroxy-5'-methylphenyl)benzotriazole.

3. The HPPM square power bellows using modified polypropylene according to claim 1, characterized in that: The preparation method of the modified insulating filler comprises the following steps: S1. Pretreatment: drying the insulating filler and then sieving it to obtain an insulating filler with uniform particle size; S2, plasma treatment: placing an insulating filler with uniform particle size into a plasma reaction chamber, distributing the filler evenly, introducing a reaction gas, and cooling the mixture to room temperature under nitrogen protection to obtain a plasma-treated insulating filler; S3, intercalation treatment: mixing the plasma-treated insulating filler with the intercalation agent, stirring and reacting in an aqueous solution, and after completion, centrifuging, washing, and drying to obtain the plasma- and intercalation-modified insulating filler; S4. Surface modification: mixing the plasma-intercalated modified insulating filler with a silane coupling agent, stirring and reacting in an ethanol solution, centrifugally separating and washing, and drying to obtain a modified insulating filler.

4. The HPPM square power bellows using modified polypropylene according to claim 3, characterized in that: The insulating filler in S1 is a mixture of silicon dioxide, talc and montmorillonite, the mass ratio of silicon dioxide, talc and montmorillonite is 1-2:1-2:2, and the mesh size of the sieve is 300-400 mesh; the reaction gas in S2 is oxygen or air, the gas flow rate is 10-50sccm, the plasma power is 50-300W, and the treatment time is 5-30 minutes; the intercalation agent in S3 is an equal mixture of hexadecyltrimethylammonium bromide and dimethyldiallylammonium chloride, and the mass ratio of the plasma-treated insulating filler to the intercalation agent is 1:1-3; the silane coupling agent in S4 is a mixture of KH-550 and KH-570, the mass ratio of KH-550 to KH-570 is 1:2, and the mass ratio of the plasma-intercalated modified insulating filler to the silane coupling agent is 1:0.1-0.

5.

5. The HPPM square power corrugated pipe using modified polypropylene according to claim 1, characterized in that: The preparation method of the modified glass fiber comprises the following steps: Q1. Preparation of bio-based solution: chitosan powder is added to acetic acid solution, stirred at room temperature until completely dissolved, and the pH value is adjusted to 7-7.5 with NaOH solution to obtain chitosan solution; lignin powder is added to ethanol solution, stirred until completely dissolved, to obtain lignin solution; Q2. Pretreatment of glass fiber: immerse the glass fiber in acetone or ethanol, clean it by ultrasonic, then wash it with deionized water and dry it to obtain clean glass fiber; Q3. Modification treatment: immerse the clean glass fiber into mixed liquid 1, then take it out, and immerse it into mixed liquid 2 again. After the end, take it out, dry it at room temperature, and solidify it to obtain modified glass fiber.

6. The HPPM square power corrugated pipe using modified polypropylene according to claim 5, characterized in that: The mass concentration of the acetic acid solution in Q1 is 1-2wt%, the mass volume ratio of the chitosan powder to the acetic acid solution is 2-6:100, the concentration of the NaOH solution is 1M, the mass volume ratio of the lignin powder to the ethanol solution is 2-10:100, the volume concentration of the ethanol solution is 50-75vt%, and the stirring temperature is 60-80°C; Q2 is ultrasonically cleaned for 10-15 minutes; the mixed solution 1 in Q3 is a mixed solution of chitosan solution and glutaraldehyde solution, the volume ratio of the chitosan solution to the glutaraldehyde solution is 1:1, the mixed solution 2 is a mixed solution of lignin solution and glutaraldehyde solution, the volume ratio of the chitosan solution to the glutaraldehyde solution is 1:1, the mass concentration of the glutaraldehyde solution is 2-4wt%, the curing temperature is 80-120°C, and the curing time is 1-2 hours.

7. A method for preparing a HPPM square power corrugated pipe using modified polypropylene, characterized in that: The following steps are involved: (1) Premixing: homopolypropylene, modified insulating filler, modified glass fiber and flame retardant are dried, and then homopolypropylene and modified insulating filler are added to a high-speed mixer first, and mixed evenly. Then, modified glass fiber, flame retardant, toughening agent, bis(3,5-di-tert-butyl-4-hydroxybenzyl phosphate monoethyl ester), antistatic agent and ultraviolet absorber are added in sequence, and stirred evenly. Finally, coupling agent and lubricant are added, and stirred thoroughly to obtain a premix. (2) Twin-screw extrusion: Use a twin-screw extruder to melt blend the premix, extrude, cool to room temperature, and pelletize to obtain a HPPM square power corrugated pipe mixture; (3) Molding: The HPPM square power corrugated pipe mixture is extruded and molded by a die, and cooled to room temperature to obtain the HPPM square power corrugated pipe using modified polypropylene.

8. The method for preparing the HPPM square power corrugated pipe using modified polypropylene according to claim 7, characterized in that: In step (2), the screw temperature is 180-230°C, the screw speed is 100-200 rpm, the mixing time is 10-20 minutes, the extrusion feed zone temperature is 160-180°C, the melting zone temperature is 190-210°C, the homogenization zone temperature is 200-220°C, the die head temperature is 210-230°C, and the residence time is 5-8 minutes; in step (3), the molding temperature is 200-240°C, the extrusion speed is 2-5m / min, and the mold temperature is 30-50°C.

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