HPPM double-wall corrugated pipe with round inside and square outside and made of nano-modified polypropylene

Abstract

The invention discloses an HPPM double-wall corrugated pipe with a round inner part and a square outer part and made of nano-modified polypropylene, and belongs to the technical field of electrical accessories. The corrugated pipe sequentially comprises a first square outer wall, a second square outer wall, a third square outer wall, a fourth square outer wall, a fifth square outer wall, first concave corrugations, second concave corrugations, third concave corrugations, fourth concave corrugations and a circular inner wall from outside to inside. The material is prepared from components in parts by weight as follows: 70-90 parts of homo-polypropylene, 9-20 parts of insulating filler, 5-15 parts of a modified nano-composite, 5-10 parts of modified temperature control capsules, 4-8 parts of a flame retardant, 0-10 parts of color master batches, 2-5 parts of carbon nanotubes, 2-4 parts of a flexibilizer, 1-3 parts of a coupling agent, 1-2 parts of calcium stearate and 1-2 parts of a stabilizer. The 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 electrical accessories, and in particular relates to an HPPM inner-circle and outer-square double-wall corrugated pipe made of nano-modified polypropylene. Background Art

[0002] As a general-purpose plastic, polypropylene (PP) has been widely used in many industries such as chemical, electrical, automotive, and packaging due to its excellent physical properties, easy molding and processing, and low density. Polypropylene has the characteristics of high yield strength and tensile strength, and is inexpensive and good quality, and occupies an increasingly important position in the plastics industry. However, polypropylene also has some inherent weaknesses, such as large molding shrinkage, high brittleness, low notched impact strength, poor UV resistance, and poor compatibility with non-polar polymers and inorganic fillers or metals. These weaknesses limit the application of polypropylene in some high-end fields. In order to broaden its scope of application, modification of polypropylene has always been one of the important contents of the development of the plastics industry.

[0003] Traditional corrugated pipes have certain limitations in performance and cannot fully meet the increasing requirements of modern electrical wiring and other application scenarios. In electrical systems, the protection of cables and other lines is crucial, and corrugated pipes are commonly used line protection pipes. Their mechanical properties and environmental resistance directly affect the safety and stable operation of electrical lines. Corrugated pipes made of traditional materials also have defects in chemical corrosion resistance. In some environments with the risk of corrosion by chemical substances such as acids and alkalis, their service life will be greatly shortened.

[0004] Therefore, the purpose of the present invention is to provide an HPPM inner circle and outer square double-wall corrugated pipe using nano-modified polypropylene, which is used to solve the technical problems of poor mechanical properties and insufficient service life caused by insufficient strength and weather resistance of the corrugated pipe in the prior art. Summary of the invention

[0005] The object of the present invention is to provide an HPPM inner circle and outer square double-wall corrugated pipe using nano-modified polypropylene, which is used to solve the technical problems of poor mechanical properties and insufficient service life caused by insufficient strength and weather resistance of the corrugated pipe in the prior art.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The HPPM inner circle outer square double-wall corrugated pipe using nano-modified polypropylene comprises, from outside to inside, a first square outer wall, a second square outer wall, a third square outer wall, a fourth square outer wall, a fifth square outer wall, a first concave corrugation, a second concave corrugation, a third concave corrugation, a fourth concave corrugation and a circular inner wall; the HPPM inner circle outer square double-wall corrugated pipe using nano-modified polypropylene is composed of the following components in parts by weight: 70-90 parts of homopolymer polypropylene, 9-20 parts of insulating filler, 5-15 parts of modified nanocomposite, 5-10 parts of modified temperature control capsule, 4-8 parts of flame retardant, 0-10 parts of masterbatch, 2-5 parts of carbon nanotubes, 2-4 parts of toughening agent, 1-3 parts of coupling agent, 1-2 parts of calcium stearate and 1-2 parts of stabilizer. The modified nanocomposite is obtained by modifying nano titanium dioxide and nano cellulose and compounding them; the modified temperature control capsule is prepared by wrapping a composite core material with a wall material and performing surface modification.

[0007] Furthermore, the insulating filler is a mixture of talcum powder, mica powder and kaolin, and the mass ratio of talcum powder, mica powder and kaolin is 1:1-2:1-2; the flame retardant is an equal mixture of aluminum hydroxide and magnesium hydroxide; the toughening agent is a polyolefin elastomer purchased from Shanghai Ruihongzhe New Materials Technology Co., Ltd.; the coupling agent is a mixture of aluminate coupling agent DL-411-A and γ-aminopropyltriethoxysilane, and the mass ratio of aluminate coupling agent DL-411-A and γ-aminopropyltriethoxysilane is 1:1-2; the stabilizer is an equal mixture of antioxidant 1010 and light stabilizer 944.

[0008] Furthermore, the preparation method of the modified nanocomposite comprises the following steps: (1) dispersing nano titanium dioxide in water, adjusting the pH, adding sodium silicate solution, stirring, and continuing to stir after the addition is complete, and drying to obtain modified nano titanium dioxide; dispersing the modified nano titanium dioxide in anhydrous ethanol, adding a silane coupling agent, stirring, centrifuging, washing, and drying to obtain composite modified nano titanium dioxide; (2) dispersing nanocellulose in pyridine, adding acetic anhydride, stirring, filtering, washing, and freeze-drying to obtain modified nanocellulose; adding the modified nanocellulose to a mixture of sodium hydroxide solution and chloroacetic acid solution, stirring, adjusting the pH value, filtering, washing, and freeze-drying to obtain positively charged modified nanocellulose; (3) The composite modified nano-titanium dioxide and the positively charged modified nano-cellulose are dispersed in acetone, ultrasonically stirred, vacuum distilled, and vacuum dried to obtain a modified nano-composite.

[0009] Furthermore, in step (1), the nano titanium dioxide is purchased from Hubei Huifu Nanomaterial Co., Ltd., the mass volume ratio of nano titanium dioxide to water is 10-15:100 g / mL, the pH is adjusted to 8-10 with 1-2 mol / L sodium hydroxide solution, the concentration of the sodium silicate solution is 0.1-0.5 mol / L, the volume ratio of the sodium silicate solution to water is 0.2-0.5:1, the dripping speed is 1-2 mL / min, the stirring speed is 120-180 r / min, the stirring time is 2-4 h, the stirring time is continued for 1-2 h, and the drying temperature is 80-120 ° C , the drying time is 12-24h, the mass volume ratio of modified nano-titanium dioxide to anhydrous ethanol is 10-20:100g / mL, the silane coupling agent is an equal mixture of KH-550 and KH-792, the mass ratio of silane coupling agent to modified nano-titanium dioxide is 0.02-0.05:1, the stirring reaction temperature is 60-80℃, the stirring reaction time is 2-4h, the centrifugal speed is 2000-3000rpm, the centrifugal time is 10-15min, washed with anhydrous ethanol 4-8 times, the drying temperature is 80-120℃, and the drying time is 12-24h.

[0010] Furthermore, in step (2), pyridine is analytically pure and purchased from Beijing Jingtu Hengsheng Trading Co., Ltd., nanocellulose is purchased from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd., the mass volume ratio of nanocellulose to pyridine is 1:10-100 g / mL, the mass ratio of nanocellulose to acetic anhydride is 1:2-5, washed with water 2-3 times, the stirring reaction temperature is 50-60°C, the stirring reaction time is 3-4h, the mixed solution is prepared by sodium hydroxide solution and chloroacetic acid solution in a volume ratio of 4:3, the sodium hydroxide solution The concentration of the liquid is 1-5 mol / L, the concentration of the chloroacetic acid solution is 0.5-3 mol / L, the pH value is adjusted to 3-4 with hydrochloric acid, the pre-freezing temperature of freeze drying is -40°C to -80°C, the pre-freezing time is 2-4 hours, the vacuum degree is 1-10 Pa, and the drying time is 24-72 hours; in step (3), the mass ratio of the composite modified nano-titanium dioxide and the positively charged modified nano-cellulose is 1-3:1, the ultrasonic stirring time is 1-2h, the drying temperature is 60-80°C, and the drying time is 4-48h.

[0011] Furthermore, the preparation method of the modified temperature-control capsule comprises the following steps: Q1. Add the composite core material into a reaction kettle, heat, stir, then add into an emulsifier aqueous solution, stir, and obtain a core material emulsion; Q2. Add the core material emulsion to the wall material monomer solution, stir to react, cool, centrifuge, wash, and dry to obtain a temperature-controlled capsule; soak the temperature-controlled capsule in the modified solution, stir, filter, and dry to obtain a modified temperature-controlled capsule.

[0012] Furthermore, the composite core material in Q1 is obtained by mixing paraffin and stearic acid in a mass ratio of 3:2, heated to 80-90°C, stirring at a speed of 300-500r / min, and stirring for 30-45min. The emulsifier aqueous solution is prepared by dissolving Span-20 and Tween-80 in water in a mass ratio of 2:1. The mass concentration of the emulsifier aqueous solution is 1-3wt%, the mass volume ratio of the composite core material to the emulsifier aqueous solution is 1:5-10, the stirring speed is 500-700r / min, and the stirring time is 20-35min.

[0013] Furthermore, the wall material monomer solution in Q2 is prepared by dissolving 3,3'-diaminobenzidine and isophthalic acid in polyphosphoric acid in an equimolar ratio, the mass concentration of the wall material monomer solution is 10-20wt%, the volume ratio of the core material emulsion to the wall material monomer solution is 0.2-0.5:1, cooled to 20-25°C, the centrifugal speed is 2000-3000r / min, the centrifugal time is 10-15min, washed with ethanol 3-5 times, the drying temperature is 60-80°C, the drying time is 12-24h, and the modified solution is prepared by dissolving KH560 in ethanol, the concentration of the modified solution is 1-3wt%, and the stirring time is 30-60min.

[0014] The preparation method of the HPPM inner circle and outer square double-wall corrugated pipe using nano-modified polypropylene comprises the following steps: M1. After diluting the coupling agent with ethanol, preliminarily mix it with the insulating filler in a high-speed mixer, then sequentially add homopolymer polypropylene, modified nanocomposite, modified temperature control capsule, flame retardant, masterbatch, carbon nanotube, toughening agent and stabilizer, stir, and finally add calcium stearate, stir to obtain a premix; M2. Use a twin-screw extruder to melt-blend the premixed material, extrude it, cool it, cut it into pellets, and then extrude it into shape with a mold, cool it, and obtain a corrugated tube.

[0015] Furthermore, the mass volume ratio of the coupling agent to ethanol in M1 is 1-3:7 g / mL, the initial mixing temperature is 60-80°C, the initial mixing time is 10-20 min, the screw temperature in M2 is 180-230°C, the screw speed is 100-200 r / min, the mixing time is 10-20 min, 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 head temperature is 210-230°C, the residence time is 5-8 min, the molding temperature is 200-240°C, the extrusion speed is 2-5 m / min, and the mold temperature is 30-50°C.

[0016] 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 double-wall structure design of "inner circle and outer square", which is composed of a square outer wall, a concave corrugation and a circular inner wall. The square outer wall increases the installation stability and space utilization of the pipe, and the circular inner wall ensures the smooth transportation of the fluid. In addition, the modified nano-composite material, modified temperature control material and other functional additives are added to the polypropylene matrix to synergistically improve the mechanical properties, high temperature resistance, electrical insulation properties and flame retardant properties of the corrugated pipe as a whole.

[0017] 2. The present invention prepares a modified nano-composite by modifying nano-titanium dioxide and nano-cellulose and then compounding the two. Sodium silicate is used as a silicon source to coat a layer of nano-silicon dioxide on the surface of nano-titanium dioxide to improve the chemical stability and weather resistance of nano-titanium dioxide. Silane coupling agent and acetylation and positive charge modification of nano-cellulose are added to improve the composite strength and efficiency with nano-titanium dioxide, thereby improving the strength and interfacial bonding force of the modified nano-composite. Wall material monomers are polymerized on the surface of core material oil droplets to form polybenzimidazole wall materials to wrap the core material, thereby achieving the purpose of effectively controlling the temperature of the temperature control capsule in a wider temperature range and improving the mechanical strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] 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.

[0019] Figure 1 A partial schematic diagram of the HPPM inner circle outer square double-wall corrugated pipe using nano-modified polypropylene of the present invention is shown; Reference numerals: 1: first square outer wall; 2: second square outer wall; 3: third square outer wall; 4: fourth square outer wall; 5: fifth square outer wall; 6: first concave corrugation; 7: second concave corrugation; 8: third concave corrugation; 9: fourth concave corrugation; 10: circular inner wall. DETAILED DESCRIPTION

[0020] 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. Embodiment 1:

[0021] See also Figure 1 As shown, this embodiment discloses an HPPM inner circular outer square double-wall corrugated pipe using nano-modified polypropylene, which includes, from outside to inside, a first square outer wall 1, a second square outer wall 2, a third square outer wall 3, a fourth square outer wall 4, a fifth square outer wall 5, a first concave corrugation 6, a second concave corrugation 7, a third concave corrugation 8, a fourth concave corrugation 9, and a circular inner wall 10.

[0022] This embodiment discloses a method for preparing a modified nanocomposite, comprising the following steps: (1) Disperse 20g of nano titanium dioxide in 200mL of water, adjust the pH to 8 with 1mol / L sodium hydroxide solution, add 40mL of 0.1mol / L sodium silicate solution, stir, the dropping speed is 1mL / min, the stirring speed is 120r / min, and the stirring time is 2h. After the dropping is completed, continue to stir for 1h, dry, the drying temperature is 80℃, and the drying time is 12h to obtain modified nano titanium dioxide; disperse 10g of modified nano titanium dioxide in 100mL of anhydrous ethanol, add 0.1 KH-550 and 0.1g KH-792, stir, the stirring reaction temperature is 60℃, the stirring reaction time is 2h, centrifuge, the centrifugal speed is 2000rpm, the centrifugal time is 10min, wash with anhydrous ethanol 4 times, dry, the drying temperature is 80℃, and the drying time is 12h to obtain composite modified nano titanium dioxide; (2) Disperse 10 g of nanocellulose in 100 mL of pyridine, add 20 g of acetic anhydride, stir, filter, wash twice with water, and freeze-dry to obtain modified nanocellulose; add the modified nanocellulose to a mixed solution, the mixed solution is prepared by a sodium hydroxide solution and a chloroacetic acid solution in a volume ratio of 4:3, the concentration of the sodium hydroxide solution is 1 mol / L, and the concentration of the chloroacetic acid solution is 0.5 mol / L, stir, the stirring reaction temperature is 50°C, the stirring reaction time is 3 hours, adjust the pH value to 3 with hydrochloric acid, filter, wash, freeze-dry, the pre-freezing temperature of freeze-drying is -40°C, the pre-freezing time is 2 hours, the vacuum degree is 1 Pa, and the drying time is 24 hours to obtain positively charged modified nanocellulose; (3) The composite modified nano-titanium dioxide and positively charged modified nano-cellulose were dispersed in acetone, ultrasonically stirred for 1 hour, distilled under reduced pressure, and vacuum dried at a temperature of 60°C for 4 hours to obtain a modified nano-composite.

[0023] This embodiment discloses a method for preparing a modified temperature-control capsule, comprising the following steps: Q1. Add 6 g of paraffin and 4 g of stearic acid into a reactor, heat to 80°C, stir at a speed of 300 r / min, and stir for 30 min, then add into 50 mL of an emulsifier aqueous solution, wherein the emulsifier aqueous solution is prepared by dissolving Span-20 and Tween-80 in water at a mass ratio of 2:1, and the mass concentration of the emulsifier aqueous solution is 1 wt %, and stir at a speed of 500 r / min for 20 min to obtain a core material emulsion; Q2. Add 20 mL of the core material emulsion into 100 mL of the wall material monomer solution. The wall material monomer solution is prepared by dissolving 3,3'-diaminobenzidine and isophthalic acid in polyphosphoric acid in an equimolar ratio. The mass concentration of the wall material monomer solution is 10 wt%. Stir the reaction, cool to 20°C, centrifuge at a speed of 2000 r / min, and for 10 min. Wash with ethanol three times, dry at 60°C, and dry for 12 h to obtain a temperature-controlled capsule. Immerse the temperature-controlled capsule in a 1 wt% KH560 ethanol solution, stir for 30 min, filter, and dry to obtain a modified temperature-controlled capsule.

[0024] The present embodiment discloses an HPPM inner circle and outer square double-wall corrugated pipe using nano-modified polypropylene, which is composed of the following components by weight: 70kg homopolymer polypropylene, 3kg talc, 3kg mica powder, 3kg kaolin, 5kg modified nanocomposite, 5kg modified temperature control capsule, 2kg aluminum hydroxide, 2kg magnesium hydroxide, 2kg carbon nanotubes, 2kg polyolefin elastomer, 0.5kg aluminate coupling agent DL-411-A, 0.5kg γ-aminopropyltriethoxysilane, 1kg calcium stearate, 0.5kg antioxidant 1010 and 0.5kg light stabilizer 944.

[0025] The preparation method of the HPPM inner circle and outer square double-wall corrugated pipe using nano-modified polypropylene comprises the following steps: M1. Dilute 1 kg of coupling agent with 7 L of ethanol, and initially mix it with insulating filler in a high-speed mixer. The initial mixing temperature is 60° C., and the initial mixing time is 10 min. Then, homopolymerized polypropylene, modified nanocomposite, modified temperature control capsule, flame retardant, masterbatch, carbon nanotube, toughening agent and stabilizer are added in sequence, and stirred. Finally, calcium stearate is added and stirred to obtain a premix. M2, use twin-screw extruder that premix is ​​carried out melt blending, extrude, cool, pelletize, screw temperature is 180 ℃, screw speed is 100r / min, mixing time is 10min, the feed zone temperature of extrusion is 160 ℃, melting zone temperature is 190 ℃, homogenizing zone temperature is 200 ℃, head temperature is 210 ℃, residence time is 5min, then use die extrusion molding, molding temperature is 200 ℃, extrusion speed is 2m / min, die temperature is 30 ℃, cool, obtain corrugated pipe. Embodiment 2:

[0026] This embodiment discloses a method for preparing a modified nanocomposite, comprising the following steps: (1) Disperse 25g of nano titanium dioxide in 200mL of water, adjust the pH to 9 with 1.5mol / L sodium hydroxide solution, add 80mL of 0.3mol / L sodium silicate solution, stir, the dropping speed is 1.5mL / min, the stirring speed is 160r / min, and the stirring time is 3h. After the dropping is completed, continue to stir for 1.5h, dry, the drying temperature is 100℃, and the drying time is 18h to obtain modified nano titanium dioxide; disperse 15g of modified nano titanium dioxide in 100mL of anhydrous ethanol, add 0.3g of KH-550 and 0.3g of KH-792, stir, the stirring reaction temperature is 70℃, the stirring reaction time is 3h, centrifuge, the centrifugal speed is 2500rpm, the centrifugal time is 13min, wash with anhydrous ethanol 6 times, dry, the drying temperature is 100℃, and the drying time is 18h to obtain composite modified nano titanium dioxide; (2) Disperse 10 g of nanocellulose in 500 mL of pyridine, add 40 g of acetic anhydride, stir, filter, wash with water three times, and freeze-dry to obtain modified nanocellulose; add the modified nanocellulose to a mixed solution, the mixed solution is prepared by sodium hydroxide solution and chloroacetic acid solution in a volume ratio of 4:3, the concentration of the sodium hydroxide solution is 4 mol / L, the concentration of the chloroacetic acid solution is 2 mol / L, stir, the stirring reaction temperature is 55 ° C, the stirring reaction time is 3.5 h, adjust the pH value to 3.5 with hydrochloric acid, filter, wash, freeze-dry, the pre-freezing temperature of freeze-drying is -60 ° C, the pre-freezing time is 3 hours, the vacuum degree is 5 Pa, and the drying time is 48 hours to obtain positively charged modified nanocellulose; (3) The composite modified nano-titanium dioxide and positively charged modified nano-cellulose were dispersed in acetone, ultrasonically stirred for 1.5 h, distilled under reduced pressure, and vacuum dried at a temperature of 70 °C for 28 h to obtain a modified nano-composite.

[0027] This embodiment discloses a method for preparing a modified temperature-control capsule, comprising the following steps: Q1. Add 6 g of paraffin and 4 g of stearic acid into a reactor, heat to 85°C, stir at a speed of 400 r / min, and stir for 40 min, then add into 80 mL of an emulsifier aqueous solution, wherein the emulsifier aqueous solution is prepared by dissolving Span-20 and Tween-80 in water at a mass ratio of 2:1, and the mass concentration of the emulsifier aqueous solution is 2 wt %. Stir at a speed of 600 r / min and stir for 25 min to obtain a core material emulsion; Q2. Add 40 mL of the core material emulsion into 100 mL of the wall material monomer solution. The wall material monomer solution is prepared by dissolving 3,3'-diaminobenzidine and isophthalic acid in polyphosphoric acid in an equimolar ratio. The mass concentration of the wall material monomer solution is 15 wt%. Stir the reaction, cool to 23°C, centrifuge at a speed of 2500 r / min, and for 13 min. Wash with ethanol 4 times, dry at 70°C, and dry for 18 h to obtain a temperature-controlled capsule. Immerse the temperature-controlled capsule in a 2 wt% KH560 ethanol solution, stir for 50 min, filter, and dry to obtain a modified temperature-controlled capsule.

[0028] The present embodiment discloses an HPPM inner circle and outer square double-wall corrugated pipe using nano-modified polypropylene, which is composed of the following components by weight: 80kg homopolymer polypropylene, 4kg talc, 8kg mica powder, 8kg kaolin, 10kg modified nanocomposite, 8kg modified temperature control capsule, 3kg aluminum hydroxide, 3kg magnesium hydroxide, 5kg masterbatch, 3kg carbon nanotubes, 3kg polyolefin elastomer, 1kg aluminate coupling agent DL-411-A, 2kg γ-aminopropyltriethoxysilane, 1.5kg calcium stearate, 0.8kg antioxidant 1010 and 0.8kg light stabilizer 944.

[0029] The preparation method of the HPPM inner circle and outer square double-wall corrugated pipe using nano-modified polypropylene comprises the following steps: M1. After diluting 3 kg of coupling agent with 7 L of ethanol, initially mix it with insulating filler in a high-speed mixer at an initial mixing temperature of 70° C. for 15 min. Then, homopolymerized polypropylene, modified nanocomposite, modified temperature control capsule, flame retardant, masterbatch, carbon nanotube, toughening agent and stabilizer are added in sequence and stirred. Finally, calcium stearate is added and stirred to obtain a premix. M2, use twin-screw extruder that premix is ​​carried out melt blending, extrude, cool, pelletize, screw temperature is 200 ℃, screw speed is 160r / min, mixing time is 160min, the feed zone temperature of extrusion is 170 ℃, melting zone temperature is 200 ℃, homogenizing zone temperature is 210 ℃, head temperature is 220 ℃, residence time is 7min, then use die extrusion molding, molding temperature is 230 ℃, extrusion speed is 4m / min, die temperature is 40 ℃, cool, obtain corrugated pipe. Embodiment 3:

[0030] This embodiment discloses a method for preparing a modified nanocomposite, comprising the following steps: (1) Disperse 30g of nano titanium dioxide in 200mL of water, adjust the pH to 10 with 2mol / L sodium hydroxide solution, add 100mL of 0.5mol / L sodium silicate solution, stir, the dropping speed is 2mL / min, the stirring speed is 180r / min, and the stirring time is 4h. After the dropping is completed, continue to stir for 2h, dry, the drying temperature is 120℃, and the drying time is 24h to obtain modified nano titanium dioxide; disperse 20g of modified nano titanium dioxide in 100mL of anhydrous ethanol, add 0.5g of KH-550 and 0.5g of KH-792, stir, the stirring reaction temperature is 80℃, the stirring reaction time is 4h, centrifuge, the centrifugal speed is 3000rpm, the centrifugal time is 15min, wash with anhydrous ethanol 8 times, dry, the drying temperature is 120℃, and the drying time is 24h to obtain composite modified nano titanium dioxide; (2) Disperse 10 g of nanocellulose in 100 mL of pyridine, add 50 g of acetic anhydride, stir, filter, wash with water three times, and freeze-dry to obtain modified nanocellulose; add the modified nanocellulose to a mixed solution, the mixed solution is prepared by a sodium hydroxide solution and a chloroacetic acid solution in a volume ratio of 4:3, the concentration of the sodium hydroxide solution is 5 mol / L, and the concentration of the chloroacetic acid solution is 3 mol / L, stir, the stirring reaction temperature is -60 ° C, the stirring reaction time is 4 hours, adjust the pH value to 4 with hydrochloric acid, filter, wash, freeze-dry, the pre-freezing temperature of freeze-drying is -80 ° C, the pre-freezing time is 4 hours, the vacuum degree is 10 Pa, and the drying time is 72 hours to obtain positively charged modified nanocellulose; (3) The composite modified nano-titanium dioxide and positively charged modified nano-cellulose were dispersed in acetone, ultrasonically stirred for 2 h, distilled under reduced pressure, and vacuum dried at a temperature of 80 °C for 48 h to obtain a modified nano-composite.

[0031] This embodiment discloses a method for preparing a modified temperature-control capsule, comprising the following steps: Q1. Add 6 g of paraffin and 4 g of stearic acid into a reactor, heat to 90°C, stir at a speed of 500 r / min, and stir for 45 min, then add into 100 mL of an emulsifier aqueous solution, wherein the emulsifier aqueous solution is prepared by dissolving Span-20 and Tween-80 in water at a mass ratio of 2:1, and the mass concentration of the emulsifier aqueous solution is 3 wt %. Stir at a speed of 700 r / min and stir for 35 min to obtain a core material emulsion; Q2. Add 50 mL of the core material emulsion into 100 mL of the wall material monomer solution. The wall material monomer solution is prepared by dissolving 3,3'-diaminobenzidine and isophthalic acid in polyphosphoric acid in an equimolar ratio. The mass concentration of the wall material monomer solution is 20 wt%. Stir the reaction, cool to 25°C, centrifuge at a speed of 3000 r / min, and for 15 min. Wash with ethanol 5 times, dry at 80°C, and dry for -24 h to obtain a temperature-controlled capsule. Immerse the temperature-controlled capsule in a 3 wt% KH560 ethanol solution, stir for 60 min, filter, and dry to obtain a modified temperature-controlled capsule.

[0032] The present embodiment discloses an HPPM inner circle and outer square double-wall corrugated pipe using nano-modified polypropylene, which is composed of the following components by weight: 90kg homopolymer polypropylene, 4kg talc, 8kg mica powder, 8kg kaolin, 15kg modified nanocomposite, 10kg modified temperature control capsule, 4kg aluminum hydroxide, 4kg magnesium hydroxide, 10kg masterbatch, 5kg carbon nanotubes, 4kg polyolefin elastomer, 1.5kg aluminate coupling agent DL-411-A, 1.5kg γ-aminopropyltriethoxysilane, 1kg calcium stearate, 1kg antioxidant 1010 and 1kg light stabilizer 944.

[0033] The preparation method of the HPPM inner circle and outer square double-wall corrugated pipe using nano-modified polypropylene comprises the following steps: M1. Dilute 3 kg of coupling agent with 7 L of ethanol, and initially mix it with insulating filler in a high-speed mixer. The initial mixing temperature is 80 ° C. The initial mixing time is 20 min. Then, homopolymerized polypropylene, modified nanocomposite, modified temperature control capsule, flame retardant, masterbatch, carbon nanotube, toughening agent and stabilizer are added in sequence, and stirred. Finally, calcium stearate is added and stirred to obtain a premix. M2, use twin screw extruder that premix is ​​carried out melt blending, extrude, cool, pelletize, screw temperature is 230 ℃, screw speed is 200r / min, mixing time is 20min, the feed zone temperature of extrusion is 180 ℃, melting zone temperature is 210 ℃, homogenizing zone temperature is 220 ℃, head temperature is 230 ℃, residence time is 8min, then use die extrusion molding, molding temperature is 240 ℃, extrusion speed is 5m / min, die temperature is 50 ℃, cool, obtain corrugated pipe.

[0034] Comparative Example 1: Comparative Example 1 Compared with Example 2, in the preparation process of the HPPM inner circle and outer square double-wall corrugated pipe, nano titanium dioxide is used instead of the modified nano composite material, and other conditions remain unchanged.

[0035] Comparative Example 2: Comparative Example 2 Compared with Example 2, in the preparation process of the HPPM inner circle and outer square double-wall corrugated pipe, nanocellulose is used instead of the modified nanocomposite, and other conditions remain unchanged.

[0036] Comparative Example 3: Comparative Example 3 Compared with Example 2, in the preparation process of the HPPM inner circle and outer square double-wall corrugated pipe in Comparative Example 3, no modified temperature control capsule is added, and other conditions remain unchanged.

[0037] Experimental example: The following performance measurements were performed on the HPPM inner circle and outer square double-wall corrugated pipe samples prepared in Examples 1-3 and Comparative Examples 1-3: 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 Simply Supported Beams of Plastics", 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 corrugated pipe 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 1590 34 14.1 128 1.2×10¹² V-0 Example 2 1687 39 14.8 135 1.2×10¹² V-0 Example 3 1635 37 14.2 130 1.2×10¹² V-0 Comparative Example 1 1058 20 9.2 110 1.1×10¹² V-1 Comparative Example 2 1001 19 9.0 104 1.1×10¹² V-1 Comparative Example 3 1416 24 9.5 101 1.05×10¹² V-1 According to the test results in Table 1, the HPPM inner circle outer square double-wall 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 1-3 with Examples 1-3, it can be seen that adding modified nanocomposites and modified temperature control capsules can effectively improve the mechanical properties, high temperature resistance, electrical insulation and flame retardant properties of the HPPM inner circle outer square double-wall corrugated pipes.

[0038] 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.

[0039] 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 inner circle outer square double wall corrugated pipe using nano-modified polypropylene, characterized in that: The invention comprises, from the outside to the inside, a first square outer wall (1), a second square outer wall (2), a third square outer wall (3), a fourth square outer wall (4), a fifth square outer wall (5), a first concave corrugation (6), a second concave corrugation (7), a third concave corrugation (8), a fourth concave corrugation (9) and a circular inner wall (10); the corrugated tube is composed of the following components in parts by weight: 70-90 parts of homopolymer polypropylene, 9-20 parts of insulating filler, 5-15 parts of modified nanocomposite, 5-10 parts of modified temperature control capsule, 4-8 parts of flame retardant, 0-10 parts of masterbatch, 2-5 parts of carbon nanotube, 2-4 parts of toughening agent, 1-3 parts of coupling agent, 1-2 parts of calcium stearate and 1-2 parts of stabilizer; the modified nanocomposite is obtained by modifying and compounding nano titanium dioxide and nano cellulose; the modified temperature control capsule is prepared by wrapping a composite core material with a wall material and modifying the composite core material.

2. The HPPM inner circle and outer square double-wall corrugated pipe using nano-modified polypropylene according to claim 1, characterized in that: The insulating filler is a mixture of talcum powder, mica powder and kaolin, and the mass ratio of talcum powder, mica powder and kaolin is 1:1-2:1-2; the flame retardant is an equal mixture of aluminum hydroxide and magnesium hydroxide; the toughening agent is a polyolefin elastomer; the coupling agent is a mixture of aluminate coupling agent DL-411-A and γ-aminopropyltriethoxysilane, and the mass ratio of aluminate coupling agent DL-411-A and γ-aminopropyltriethoxysilane is 1:1-2; the stabilizer is an equal mixture of antioxidant 1010 and light stabilizer 944.

3. The HPPM inner circle and outer square double-wall corrugated pipe using nano-modified polypropylene according to claim 1, characterized in that: The preparation method of the modified nanocomposite comprises the following steps: (1) dispersing nano titanium dioxide in water, adjusting the pH, adding sodium silicate solution dropwise, stirring, and continuing to stir after the addition is complete, and drying to obtain modified nano titanium dioxide; Dispersing the modified nano titanium dioxide in anhydrous ethanol, adding a silane coupling agent, stirring, centrifuging, washing, and drying to obtain composite modified nano titanium dioxide; (2) dispersing nanocellulose in pyridine, adding acetic anhydride, stirring, filtering, washing, and freeze-drying to obtain modified nanocellulose; The modified nanocellulose is added to a mixture of a sodium hydroxide solution and a chloroacetic acid solution, stirred, the pH value is adjusted, filtered, washed, and freeze-dried to obtain positively charged modified nanocellulose; (3) The composite modified nano-titanium dioxide and the positively charged modified nano-cellulose are dispersed in acetone, ultrasonically stirred, vacuum distilled, and vacuum dried to obtain a modified nano-composite.

4. The HPPM inner circle and outer square double-wall corrugated pipe using nano-modified polypropylene according to claim 3, characterized in that: In step (1), the mass volume ratio of nano titanium dioxide to water is 10-15:100 g / mL, the pH is adjusted to 8-10 with 1-2 mol / L sodium hydroxide solution, the concentration of the sodium silicate solution is 0.1-0.5 mol / L, the volume ratio of the sodium silicate solution to water is 0.2-0.5:1, the dropping speed is 1-2 mL / min, the mass volume ratio of the modified nano titanium dioxide to anhydrous ethanol is 10-20:100 g / mL, the silane coupling agent is an equal mixture of KH-550 and KH-792, and the mass ratio of the silane coupling agent to the modified nano titanium dioxide is 0.02-0.05:

1.

5. The HPPM inner circle and outer square double-wall corrugated pipe using nano-modified polypropylene according to claim 3, characterized in that: In step (2), the mass volume ratio of nanocellulose to pyridine is 1:10-100 g / mL, the mass volume ratio of nanocellulose to acetic anhydride is 1:2-5, the mixed solution is prepared by mixing sodium hydroxide solution and chloroacetic acid solution in a volume ratio of 4:3, the concentration of the sodium hydroxide solution is 1-5 mol / L, the concentration of the chloroacetic acid solution is 0.5-3 mol / L, and the pH value is adjusted to 3-4 with hydrochloric acid.

6. The HPPM inner circle and outer square double-wall corrugated pipe using nano-modified polypropylene according to claim 3, characterized in that: In step (3), the mass ratio of the composite modified nano-titanium dioxide and the positively charged modified nano-cellulose is 1-3:

1.

7. The HPPM inner circle and outer square double-wall corrugated pipe using nano-modified polypropylene according to claim 1, characterized in that: The preparation method of the modified temperature-control capsule comprises the following steps: Q1. Add the composite core material into a reaction kettle, heat, stir, then add into an emulsifier aqueous solution, stir, and obtain a core material emulsion; Q2. Add the core material emulsion to the wall material monomer solution, stir to react, cool, centrifuge, wash, and dry to obtain a temperature-controlled capsule; soak the temperature-controlled capsule in the modified solution, stir, filter, and dry to obtain a modified temperature-controlled capsule.

8. The HPPM inner circle and outer square double-wall corrugated pipe using nano-modified polypropylene according to claim 6, characterized in that: The composite core material in Q1 is obtained by mixing paraffin and stearic acid in a mass ratio of 3:2, and the emulsifier aqueous solution is prepared by dissolving Span-20 and Tween-80 in water in a mass ratio of 2:1, and the mass concentration of the emulsifier aqueous solution is 1-3wt%; the wall material monomer solution in Q2 is prepared by dissolving 3,3'-diaminobenzidine and isophthalic acid in polyphosphoric acid in an equimolar ratio, and the mass concentration of the wall material monomer solution is 10-20wt%, and the volume ratio of the core material emulsion to the wall material monomer solution is 0.2-0.5:1, and the modified solution is prepared by dissolving KH560 in ethanol, and the concentration of the modified solution is 1-3wt%.

9. A method for preparing a HPPM inner circle and outer square double-wall corrugated pipe using nano-modified polypropylene, characterized in that: The steps include: M1. After diluting the coupling agent with ethanol, preliminarily mix it with the insulating filler in a high-speed mixer, then sequentially add homopolymer polypropylene, modified nanocomposite, modified temperature control capsule, flame retardant, masterbatch, carbon nanotube, toughening agent and stabilizer, stir, and finally add calcium stearate, stir to obtain a premix; M2. Use a twin-screw extruder to melt-blend the premixed material, extrude it, cool it, cut it into pellets, and then extrude it into shape with a mold, cool it, and obtain a corrugated tube.

10. The method for preparing the HPPM inner circle and outer square double-wall corrugated pipe using nano-modified polypropylene according to claim 9, characterized in that: The mass volume ratio of coupling agent to ethanol in M1 is 1-3:7 g / mL; in M2, the screw temperature is 180-230°C, the screw speed is 100-200 r / min, the mixing time is 10-20 min, 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, the residence time is 5-8 min, the molding temperature is 200-240°C, the extrusion speed is 2-5 m / min, and the mold temperature is 30-50°C.

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