Thermal insulation pipe with high compression resistance and tension resistance

Abstract

The invention relates to the technical field of pipe product manufacturing, in particular to a heat preservation pipe with high compression resistance and tensile resistance. The invention discloses a thermal insulation pipe with strong compression resistance and tension resistance, the thermal insulation pipe comprises an inner pipe and an outer pipe which are coaxial, a thermal insulation material is filled between the inner pipe and the outer pipe, and the thermal insulation material comprises the following raw materials in parts by mass: 60-70 parts of polyethylene, 20-30 parts of a reclaimed material, 5-10 parts of glass fiber, 2-4 parts of a coupling agent and 15-25 parts of a carbon nanotube / polyethylene composite material; wherein the carbon nanotube / polyethylene composite material comprises the following raw materials in parts by mass: 30-40 parts of polyethylene, 1-3 parts of carbon nanotubes, 1-3 parts of carbon black and 3-7 parts of maleic anhydride grafted polyethylene; according to the thermal insulation pipe with the high compression resistance and tensile resistance, the compression resistance and tensile resistance of the thermal insulation pipe are effectively improved, and meanwhile the good thermal insulation performance is kept.

Description

Technical Field

[0001] The present application relates to the technical field of pipe product manufacturing, and in particular to a thermal insulation pipe with strong compression and tensile resistance. Background Art

[0002] In the prior art, in order to solve the problem of insufficient compressive and tensile properties of insulation pipes, the industry has generally taken some measures; common means include increasing the wall thickness of the insulation pipe. Although this method can improve the compressive performance to a certain extent, it will significantly increase the manufacturing cost; another method is to add ordinary fillers, such as stone powder, talcum powder, etc. These fillers can improve the rigidity of the material to a certain extent, but the effect of improving the overall compressive and tensile properties is limited, and may cause the flexibility of the material to decrease.

[0003] However, the above method has obvious limitations. For example, increasing the wall thickness not only increases the manufacturing cost, but also makes the transportation and installation of the insulation pipe more difficult. Moreover, although adding ordinary fillers can partially improve the rigidity of the material, it cannot significantly improve its compressive and tensile properties. Especially under heavy loads, the insulation pipe is still prone to deformation or even rupture, resulting in a decrease in insulation performance, increased maintenance costs and safety hazards.

[0004] Therefore, how to effectively improve the compressive and tensile strength of the insulation pipe has become a problem that needs to be solved urgently. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present application provides a thermal insulation pipe with strong compression and tensile resistance.

[0006] In the first aspect, the present application provides a thermal insulation pipe with strong compression and tensile resistance, which adopts the following technical solution: A heat-insulating pipe with strong compression and tensile resistance, comprising a coaxial inner pipe and an outer pipe, wherein a heat-insulating material is filled between the inner pipe and the outer pipe, wherein the heat-insulating material comprises the following raw materials in parts by weight: 60-70 parts of polyethylene, 20-30 parts of recycled material, 5-10 parts of glass fiber, 2-4 parts of coupling agent, and 15-25 parts of nano carbon tube / polyethylene composite material; The carbon nanotube / polyethylene composite material comprises the following raw materials in parts by weight: 30-40 parts of polyethylene, 1-3 parts of carbon nanotubes, 1-3 parts of carbon black and 3-7 parts of maleic anhydride grafted polyethylene.

[0007] By adopting the above-mentioned technical scheme, in this application, the formula of the thermal insulation material is improved, and a nano-carbon tube / polyethylene composite material with compressive and tensile properties is added. The added nano-carbon tube / polyethylene composite material is mixed with polyethylene, recycled materials, and glass fibers under the action of a coupling agent to obtain a nano-carbon tube / polyethylene composite material with compressive and tensile properties, thereby further improving the compressive and tensile properties of the thermal insulation material.

[0008] In the present application, the components in the thermal insulation material and the proportion of each component are adjusted to effectively improve the compressive and tensile strengths and thermal insulation performance of the thermal insulation pipe.

[0009] Polyethylene (HDPE) has high mechanical strength and chemical corrosion resistance, and is suitable for making high-strength insulation pipes. In addition to HDPE, you can also choose low-density polyethylene or other types of polyethylene, but HDPE has better comprehensive performance.

[0010] Glass fiber has excellent mechanical properties and can significantly improve the tensile strength of the insulation pipe. In addition to glass fiber, you can also choose high-performance fibers such as carbon fiber and aramid fiber, which can improve the tensile strength while maintaining a certain degree of flexibility.

[0011] Coupling agents can promote bonding between different components and improve the consistency and durability of the overall structure.

[0012] The present application forms a thermal insulation pipe with good compression and tensile properties by reasonably proportioning polyethylene, recycled materials, glass fibers, and nano-carbon tube / polyethylene composite materials, and adding coupling agents. High-density polyethylene as a base material provides good mechanical strength and chemical corrosion resistance; the recycled materials are pre-treated to remove impurities, ensuring the uniform distribution of the material and improving the overall quality of the composite material; the addition of glass fibers significantly improves the tensile strength of the thermal insulation pipe, making it less likely to deform or break under heavy loads; the use of coupling agents enhances the bonding effect between different components, improves the consistency and durability of the overall structure, and the addition of nano-carbon tube / polyethylene composite materials improves the compression and tensile resistance of the thermal insulation pipe. The technical solution of the present application not only improves the mechanical properties of the thermal insulation pipe, but also reduces costs and simplifies the production process while ensuring the original thermal insulation performance, and has high practical value.

[0013] Preferably, the thermal insulation material further comprises 10-20 parts by weight of a phenolic resin / carbon nanoparticle composite material.

[0014] By adopting the above-mentioned technical scheme, in this application, the formula of the thermal insulation material is improved by adding a phenolic resin / carbon nanoparticle composite material with good thermal insulation performance. The added phenolic resin / carbon nanoparticle composite material is mixed with glass fiber and nanocarbon tube / polyethylene composite material under the action of a coupling agent, and then mixed with polyethylene and recycled materials to obtain a thermal insulation material with good thermal insulation performance, thereby further improving the thermal insulation performance of the insulation pipe.

[0015] Preferably, the phenolic resin / carbon nanoparticle composite material comprises the following raw materials in parts by weight: 60-90 parts of carbon nanoparticles, 50-150 parts of phenolic resin, 1-2 parts of polyurethane, 50-60 parts of anhydrous ethanol, 5-10 parts of gum arabic and 1-3 parts of coupling agent.

[0016] Preferably, the preparation method of the phenolic resin / carbon nanoparticle composite material comprises the following steps: Weigh each raw material according to the formula; Mixing phenolic resin and anhydrous ethanol, adding polyurethane and mixing, to obtain modified phenolic resin; The modified phenolic resin, carbon nanoparticles, gum arabic and a coupling agent are mixed to obtain a phenolic resin / carbon nanoparticle composite material.

[0017] By adopting the above technical scheme, since phenolic resin is a type of thermal insulation and fireproof material with low thermal conductivity and excellent chemical stability, but its mechanical properties are poor, which makes its construction difficult, in this application, the phenolic resin is modified and reacted with anhydrous ethanol and polyurethane to obtain a modified phenolic resin; the modified phenolic resin obtained is mixed with carbon nanoparticles, gum arabic and a coupling agent to obtain a phenolic resin / carbon nanoparticle composite material with thermal insulation performance, thereby further improving the thermal insulation performance of the insulated pipe.

[0018] Preferably, the steps for preparing the carbon nanotube / polyethylene composite material are as follows: Weigh each raw material according to the formula; adding the carbon nanotubes into aqua regia solution, mixing, and filtering to obtain modified carbon nanotubes; The modified carbon nanotubes are mixed with maleic anhydride grafted polyethylene, filtered, polyethylene and carbon black are added and mixed to obtain a carbon nanotube / polyethylene composite material.

[0019] By adopting the above technical scheme, the carbon nanotubes are modified in the present application to obtain modified carbon nanotubes; the modified carbon nanotubes are grafted with maleic anhydride-grafted polyethylene molecules, and the grafted modified carbon nanotubes are mixed with polyethylene and carbon black to obtain a carbon nanotube / polyethylene composite material with compression and tensile properties. At the same time, the prepared carbon nanotube / polyethylene composite material also has certain conductive properties.

[0020] Preferably, the glass fiber is modified by the following steps: After the coupling agent and ethanol are mixed, glass fibers are added and mixed, and the mixture is placed at 80-100° C. for 8-10 hours, and filtered to obtain modified glass fibers.

[0021] Preferably, the mass ratio of the coupling agent to ethanol is 1:(3-5); the mass ratio of the glass fiber to the coupling agent is (5-10):(1-2).

[0022] By adopting the above technical solution, in the present application, the glass fiber is modified, and the modified glass fiber has good compatibility, so that the modified glass fiber can be better mixed with other raw materials to obtain a thermal insulation material with compressive and tensile properties.

[0023] Preferably, the recycled material is waste plastic particles, and the waste plastic is at least one of high-density polyethylene, low-density polyethylene, polypropylene, and polystyrene.

[0024] By adopting the above technical solution, waste plastic particles are pre-treated to remove impurities, ensuring the uniform distribution of the material and improving the overall quality of the composite material; recycled materials can come from a variety of sources, such as waste plastic products, industrial waste, etc., and are processed through high-temperature disinfection and mechanical crushing to ensure their cleanliness and fineness.

[0025] In a second aspect, the present application provides a method for preparing a thermal insulation pipe with strong compression and tensile resistance, using the following technical solution: A method for preparing a thermal insulation pipe with strong compression and tensile resistance, the preparation method comprises the following steps: (1) Preparation of thermal insulation materials: Weigh each raw material according to the formula; The glass fiber, coupling agent, phenolic resin / carbon nanoparticle composite material are mixed, and the nano carbon tube / polyethylene composite material is added and mixed; polyethylene and recycled material are then added and mixed to obtain a thermal insulation material; (2) Preparation of insulation pipe; The heat-insulating material is pressed through a lamination process, and the pressed heat-insulating material is filled between the inner tube and the outer tube to obtain a heat-insulating tube.

[0026] Preferably, the reaction conditions of the lamination process are as follows: The reaction pressure is 5MPa; The reaction temperature is as follows: the initial temperature is 80°C, which is then increased to 145°C at a rate of 10°C / min and kept for 2 hours, then increased to 170°C at a rate of 5°C / min and kept for 1 hour, and then decreased to 20°C at a rate of 4°C / min.

[0027] By adopting the above technical solution, the present application prepares the thermal insulation material through lamination molding, and then fills the prepared thermal insulation material between the inner tube and the outer tube to obtain a thermal insulation tube with compressive and tensile properties.

[0028] In summary, the present application includes at least one of the following beneficial technical effects: The present application discloses a thermal insulation pipe with strong compression and tensile resistance. The thermal insulation pipe prepared by the present application effectively improves the compression and tensile resistance of the thermal insulation pipe while maintaining good thermal insulation performance. DETAILED DESCRIPTION

[0029] The technical solution of the present application is further illustrated by specific embodiments below. The specific embodiments do not limit the protection scope of the present application; some non-essential modifications and adjustments made by others based on the concept of the present application still fall within the protection scope of the present application.

[0030] The raw materials involved in this application are all commercially available products, among which: Raw materials involved in the preparation of carbon nanotube / polyethylene composite materials: Carbon nanotubes, diameter: 40-60nm, length: 5-15μm, molecular weight: 16.04246.

[0031] Maleic anhydride grafted polyethylene, grafting rate 1.5%, addition amount 3%-5%.

[0032] Carbon black, type JE-6900, radius 27nm.

[0033] Polyethylene, high-density polyethylene, density 0.955g / cm 3 , melt index is 5g / 10min, Shanghai Secco Petrochemical Co., Ltd.

[0034] Raw materials involved in the preparation of phenolic resin / carbon nanoparticle composite materials: Phenolic resin, thermosetting phenolic resin, solid content 70%, Xi'an Aerospace Composite Materials Research Institute.

[0035] Polyurethane, thermoplastic polyurethane, MW=15kg·mol -1 , dispersion index PDI=1, Jiangyin Ideal Rubber and Plastic Technology Co., Ltd.

[0036] Carbon nanoparticles, average particle size 40nm, specific surface area 500m 2 / g, Beijing Dekedaojin Technology Co., Ltd.

[0037] Raw materials involved in the preparation of insulation pipes: Polyethylene, choose high-density polyethylene, density greater than or equal to 0.94g / cm 3 , melt index MI is 0.2-0.6g / 10min; Glass fiber, length 0.1-1mm, diameter less than 0.01mm.

[0038] The present application is further described in detail below in conjunction with embodiments and comparative examples.

[0039] Source of raw materials: Preparation of recycled materials (waste plastic particles): The waste plastics are crushed into plastic particles of 60-100 meshes, and after being soaked in alkali solution, they are successively cleaned and removed by ultrasonic cleaning with a mixture of ethanol and acetone and deionized water, and then cleaned with acetone and deionized water, and dried for use to obtain waste plastic particles.

[0040] Among them, waste plastics are high-density polyethylene, low-density polyethylene, polypropylene and polystyrene mixed in a mass ratio of 1:1:1:1.

[0041] Preparation Example 1: Preparation of carbon nanotube / polyethylene composites: (1) mixing concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 1:3 to obtain an aqua regia solution; (2) adding 2 g of carbon nanotubes to 100 ml of aqua regia solution and mixing them evenly, mixing them at 140° C. for 40 minutes, filtering, washing with deionized water, and drying to obtain modified carbon nanotubes; (3) Add 5 g of maleic anhydride grafted polyethylene to 100 ml of decahydronaphthalene solution, mix at 145° C. for 30 minutes, add modified carbon nanotubes, react at 90° C. for 40 minutes, filter, and dry to obtain functionalized carbon nanotubes; (4) Place functionalized carbon nanotubes, 2 g of carbon black, and 35 g of polyethylene into an internal mixer, mix at 170°C and 100 rpm for 25 minutes, and cool to room temperature to obtain a carbon nanotube / polyethylene composite material.

[0042] Preparation Example 2: Preparation of carbon nanotube / polyethylene composites: (1) mixing concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 1:3 to obtain an aqua regia solution; (2) adding 1 g of carbon nanotubes to 100 ml of aqua regia solution and mixing well, mixing at 140° C. for 40 minutes, filtering, washing with deionized water, and drying to obtain modified carbon nanotubes; (3) Add 3 g of maleic anhydride grafted polyethylene to 100 ml of decahydronaphthalene solution, mix at 145° C. for 30 minutes, add modified carbon nanotubes, react at 90° C. for 40 minutes, filter, and dry to obtain functionalized carbon nanotubes; (4) Place functionalized carbon nanotubes, 1 g of carbon black, and 30 g of polyethylene into an internal mixer, mix at 170°C and 100 rpm for 25 minutes, and cool to room temperature to obtain a carbon nanotube / polyethylene composite material.

[0043] Preparation Example 3: Preparation of carbon nanotube / polyethylene composites: (1) mixing concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 1:3 to obtain an aqua regia solution; (2) adding 3 g of carbon nanotubes to 100 ml of aqua regia solution and mixing them evenly, mixing them at 140° C. for 40 minutes, filtering, washing with deionized water, and drying to obtain modified carbon nanotubes; (3) Add 7 g of maleic anhydride grafted polyethylene to 100 ml of decahydronaphthalene solution, mix at 145° C. for 30 minutes, add modified carbon nanotubes, react at 90° C. for 40 minutes, filter, and dry to obtain functionalized carbon nanotubes; (4) The functionalized carbon nanotubes, 3 g of carbon black, and 40 g of polyethylene were placed in an internal mixer, mixed at 170°C and 100 rpm for 25 minutes, and cooled to room temperature to obtain a carbon nanotube / polyethylene composite material.

[0044] Preparation Example 4: Preparation of phenolic resin / carbon nanoparticle composites: (1) 100 g of phenolic resin was dissolved in 55 g of anhydrous ethanol, and the mixture was mixed at 70° C. for 20 minutes. 1.5 g of polyurethane was added and mixed for 30 minutes to obtain a modified phenolic resin. (2) The modified phenolic resin, 75 g of carbon nanoparticles, 8 g of gum arabic, and 2 g of coupling agent KH560 were mixed uniformly, and the mixture was mixed at 80° C. for 4 hours, and then cooled to room temperature to obtain a phenolic resin / carbon nanoparticle composite material.

[0045] Preparation Example 5: Preparation of phenolic resin / carbon nanoparticle composites: (1) Dissolve 50 g of phenolic resin in 50 g of anhydrous ethanol, mix at 70° C. for 20 minutes, add 1 g of polyurethane and mix for 30 minutes to obtain a modified phenolic resin; (2) The modified phenolic resin, 60 g of carbon nanoparticles, 5 g of gum arabic, and 1 g of coupling agent KH560 were mixed uniformly, and the mixture was mixed at 80° C. for 4 hours, and then cooled to room temperature to obtain a phenolic resin / carbon nanoparticle composite material.

[0046] Preparation Example 6: Preparation of phenolic resin / carbon nanoparticle composites: (1) Dissolve 150 g of phenolic resin in 60 g of anhydrous ethanol, mix at 70° C. for 20 minutes, add 2 g of polyurethane and mix for 30 minutes to obtain a modified phenolic resin; (2) The modified phenolic resin, 90 g of carbon nanoparticles, 10 g of gum arabic, and 3 g of coupling agent KH560 were mixed uniformly, and the mixture was mixed at 80° C. for 4 hours, and then cooled to room temperature to obtain a phenolic resin / carbon nanoparticle composite material.

[0047] Embodiment 1: A method for preparing a thermal insulation pipe with strong compression and tensile resistance, the method for preparing the thermal insulation pipe comprises the following steps: Step 1: Preparation of thermal insulation materials; (1) Modification of glass fiber, After mixing 1 g of coupling agent KH560 and 4 g of ethanol for 30 minutes, 7 g of glass fiber was added and mixed, and the mixture was allowed to stand at 80° C. for 8 hours and filtered to obtain modified glass fiber.

[0048] (2) 7 g of modified glass fiber, 3 g of coupling agent KH560, 15 g of phenolic resin / carbon nanoparticle composite material, and 200 g of deionized water were mixed, and 20 g of carbon nanotube / polyethylene composite material was added and mixed; then 65 g of polyethylene and 25 g of recycled material were added and mixed to obtain a thermal insulation material; The carbon nanotube / polyethylene composite material was prepared by Preparation Example 1; The phenolic resin / carbon nanoparticle composite material was prepared by Preparation Example 4; Step 2: Preparation of insulation pipe; (1) Press the insulation material through a lamination process: After the thermal insulation material was allowed to stand at room temperature for 1 hour, a pressure of 5 MPa was applied to the upper surface, and the initial temperature was set to 80°C, and the temperature was increased to 145°C at a rate of 10°C / min and kept for 2 hours, and then the temperature was increased to 170°C at a rate of 5°C / min and kept for 1 hour, and the temperature was decreased to 20°C at a rate of 4°C / min to obtain a press-formed thermal insulation material; (2) Fill the compressed insulation material between the inner tube and the outer tube to obtain an insulation tube.

[0049] Embodiment 2: A method for preparing a thermal insulation pipe with strong compression and tensile resistance, the method for preparing the thermal insulation pipe comprises the following steps: Step 1: Preparation of thermal insulation materials; (1) Modification of glass fiber, After mixing 1 g of coupling agent KH560 and 3 g of ethanol for 30 minutes, 7 g of glass fiber was added and mixed, and the mixture was left at 80° C. for 8 hours and filtered to obtain modified glass fiber.

[0050] (2) 5 g of modified glass fiber, 2 g of coupling agent KH560, 10 g of phenolic resin / carbon nanoparticle composite material, and 200 g of deionized water were mixed, and 15 g of carbon nanotube / polyethylene composite material was added and mixed; then 60 g of polyethylene and 20 g of recycled material were added and mixed to obtain a thermal insulation material; The carbon nanotube / polyethylene composite material was prepared by Preparation Example 2; The phenolic resin / carbon nanoparticle composite material was prepared by Preparation Example 5; Step 2: Preparation of insulation pipe; (1) Press the insulation material through a lamination process: After the thermal insulation material was left at room temperature for 1 hour, a pressure of 5 MPa was applied to the upper surface, and the initial temperature was set to 80°C, and the temperature was increased to 145°C at a rate of 10°C / min and maintained for 2 hours, and then the temperature was increased to 170°C at a rate of 5°C / min and maintained for 1 hour, and the temperature was decreased to 20°C at a rate of 4°C / min to obtain a press-formed thermal insulation material; (2) Fill the compressed insulation material between the inner tube and the outer tube to obtain an insulation tube.

[0051] Embodiment 3: A method for preparing a thermal insulation pipe with strong compression and tensile resistance, the method for preparing the thermal insulation pipe comprises the following steps: Step 1: Preparation of thermal insulation materials; (1) Modification of glass fiber, After mixing 1 g of coupling agent KH560 and 5 g of ethanol for 30 minutes, 10 g of glass fiber was added and mixed, and the mixture was allowed to stand at 80° C. for 8 hours and filtered to obtain modified glass fiber.

[0052] (2) 10 g of modified glass fiber, 4 g of coupling agent KH560, 20 g of phenolic resin / carbon nanoparticle composite material, and 200 g of deionized water were mixed, and 25 g of carbon nanotube / polyethylene composite material was added and mixed; 70 g of polyethylene and 30 g of recycled material were added and mixed to obtain a thermal insulation material; The carbon nanotube / polyethylene composite material was prepared by Preparation Example 3; The phenolic resin / carbon nanoparticle composite material was prepared by Preparation Example 6; Step 2: Preparation of insulation pipe; (1) Press the insulation material through a lamination process: After the thermal insulation material was left at room temperature for 1 hour, a pressure of 5 MPa was applied to the upper surface, and the initial temperature was set to 80°C, and the temperature was increased to 145°C at a rate of 10°C / min and maintained for 2 hours, and then the temperature was increased to 170°C at a rate of 5°C / min and maintained for 1 hour, and the temperature was decreased to 20°C at a rate of 4°C / min to obtain a press-formed thermal insulation material; (2) Fill the compressed insulation material between the inner tube and the outer tube to obtain an insulation tube.

[0053] Embodiment 4: The difference from Example 1 is that the carbon nanotube / polyethylene composite material is prepared by Preparation Example 2; and the phenolic resin / carbon nanoparticle composite material is prepared by Preparation Example 5.

[0054] Embodiment 5: The difference from Example 1 is that the carbon nanotube / polyethylene composite material is prepared by Preparation Example 3; and the phenolic resin / carbon nanoparticle composite material is prepared by Preparation Example 6.

[0055] Embodiment 6: The difference from Example 1 is that the added amount of the carbon nanotube / polyethylene composite material is 15 g.

[0056] Embodiment 7: The difference from Example 1 is that the added amount of the carbon nanotube / polyethylene composite material is 25 g.

[0057] Embodiment 8: The difference from Example 1 is that the added amount of the phenolic resin / carbon nanoparticle composite material is 10 g.

[0058] Embodiment 9: The difference from Example 1 is that the added amount of the phenolic resin / carbon nanoparticle composite material is 20 g.

[0059] Comparative Example 1: The difference from Example 1 is that no phenolic resin / carbon nanoparticle composite material is added.

[0060] Comparative Example 2: The difference from Example 1 is that the glass fiber is not modified.

[0061] The preparation method of the thermal insulation pipe comprises the following steps: Step 1: Preparation of thermal insulation materials; 7 g of glass fiber, 3 g of coupling agent KH560, 15 g of phenolic resin / carbon nanoparticle composite material, and 200 g of deionized water were mixed, and 20 g of carbon nanotube / polyethylene composite material was added and mixed; 65 g of polyethylene and 25 g of recycled material were added and mixed to obtain a thermal insulation material; The carbon nanotube / polyethylene composite material was prepared by Preparation Example 1; The phenolic resin / carbon nanoparticle composite material was prepared by Preparation Example 4; Step 2: Preparation of insulation pipe; (1) Press the insulation material through a lamination process: After the thermal insulation material was left at room temperature for 1 hour, a pressure of 5 MPa was applied to the upper surface, and the initial temperature was set to 80°C, and the temperature was increased to 145°C at a rate of 10°C / min and maintained for 2 hours, and then the temperature was increased to 170°C at a rate of 5°C / min and maintained for 1 hour, and the temperature was decreased to 20°C at a rate of 4°C / min to obtain a press-formed thermal insulation material; (2) Fill the compressed insulation material between the inner tube and the outer tube to obtain an insulation tube.

[0062] Comparative Example 3: The difference from Example 1 is that the added amount of the phenolic resin / carbon nanoparticle composite material is 9 g.

[0063] Comparative Example 4: The difference from Example 1 is that the added amount of the phenolic resin / carbon nanoparticle composite material is 21 g.

[0064] Comparative Example 1: The difference from Example 1 is that no carbon nanotube / polyethylene composite material is added.

[0065] Comparative Example 2: The difference from Example 1 is that the added amount of the carbon nanotube / polyethylene composite material is 14 g.

[0066] Comparative Example 3: The difference from Example 1 is that the added amount of the carbon nanotube / polyethylene composite material is 26 g.

[0067] Performance testing: 1. Tensile strength, impact strength, bending strength, and longitudinal shrinkage rate testing: The performance of the thermal insulation pipes prepared in the above embodiments, comparative embodiments and comparative examples was tested according to the following test standards: (1) Longitudinal shrinkage rate: Tested in accordance with GB / T 6671-2001 "Determination of longitudinal shrinkage rate of thermoplastic plastic pipes"; (2) Tensile strength determination: Test according to GB / T 1447-2005 “Test method for tensile properties of fiber reinforced plastics”; (3) Impact strength test: Test according to GB / T 1843-2008 "Determination of cantilever beam impact strength of plastics"; (4) Bending strength determination: Test according to GB / T 9341-2008 “Test method for determination of plastic bending”.

[0068] The test results are shown in the table: Table 1 Insulation pipe performance test results

[0069] It can be seen from Table 1 that the insulation pipe prepared by the scheme of the present application (Examples 1-9) has significantly improved in longitudinal shrinkage rate, tensile strength, impact strength, bending strength, etc., indicating that the insulation pipe prepared by the present application has better comprehensive performance such as strength, impact resistance and toughness.

[0070] Combining Example 1 and Comparative Example 2, it can be seen that the longitudinal shrinkage rate, tensile strength, impact strength and bending strength of Example 1 are better than those of Comparative Example 2, which shows that when preparing the thermal insulation pipe, the glass fiber is modified, which effectively improves the compatibility of the glass fiber with other raw materials, allows the glass fiber to be better mixed with other raw materials, and further improves the strength, impact resistance and toughness of the thermal insulation pipe.

[0071] Combining Example 1 and Comparative Example 1, it can be seen that the longitudinal shrinkage rate, tensile strength, impact strength and bending strength of Example 1 are better than those of Comparative Example 1, indicating that the addition of nano-carbon tube / polyethylene composite materials effectively improves the strength, impact resistance and toughness of the insulation pipe.

[0072] In combination with Example 1, Example 6, Example 7, Comparative Example 2 and Comparative Example 3, it can be seen that the amount of carbon nanotube / polyethylene composite material added has a certain influence on the longitudinal shrinkage rate, tensile strength, impact strength and bending strength, and when the amount of carbon nanotube / polyethylene composite material added is 15-25g, the strength, impact resistance and toughness of the insulation pipe are optimal.

[0073] 2. Withstand voltage test The pressure resistance of the thermal insulation pipes prepared in the above embodiments, comparative embodiments and comparative examples was tested according to the testing standard "GB / T6111-2003 Test method for internal pressure resistance of thermoplastic plastic pipes for fluid transportation". The test results are shown in the following table: Table 2 Hipot test results

[0074] It can be seen from Table 2 that the insulation pipes prepared by the scheme of the present application (Examples 1-9) have significantly improved pressure resistance, indicating that the insulation pipes prepared by the present application have better pressure resistance.

[0075] Combining Example 1 and Comparative Example 2, it can be seen that the pressure resistance of Example 1 is better than that of Comparative Example 2, which shows that when preparing the insulation pipe, the glass fiber is modified, which effectively improves the compatibility of the glass fiber with other raw materials, allows the glass fiber to be better mixed with other raw materials, and further improves the pressure resistance of the insulation pipe.

[0076] Combining Example 1 and Comparative Example 1, it can be seen that the pressure resistance of Example 1 is better than that of Comparative Example 1, which indicates that the addition of the carbon nanotube / polyethylene composite material effectively improves the pressure resistance of the thermal insulation pipe.

[0077] In combination with Example 1, Example 6, Example 7, Comparative Example 2 and Comparative Example 3, it can be seen that the addition amount of the carbon nanotube / polyethylene composite material has a certain influence on the pressure resistance performance, and when the addition amount of the carbon nanotube / polyethylene composite material is 15-25g, the pressure resistance performance of the insulation pipe is the best.

[0078] 3. Thermal conductivity test: The insulation pipes prepared in the above-mentioned embodiments, comparative embodiments and comparative examples were cut into short pipes of 50 cm in length, and 100 pipes of each embodiment were selected for thermal conductivity testing. The average value was calculated, and the results are shown in the following table: Table 3 Thermal conductivity test results

[0079] It can be seen from Table 3 that the thermal insulation performance of the thermal insulation pipe prepared by the solution of the present application (Examples 1-9) has been significantly improved, indicating that the thermal insulation performance of the thermal insulation pipe prepared by the present application is better.

[0080] Combining Example 1 and Comparative Example 1, it can be seen that the thermal conductivity coefficient of Example 1 is better than that of Comparative Example 1, indicating that the addition of the phenolic resin / carbon nanoparticle composite material effectively improves the thermal insulation performance of the thermal insulation pipe.

[0081] Combining Example 1 and Comparative Example 2, it can be seen that the thermal conductivity coefficient of Example 1 is better than that of Comparative Example 2, which shows that when preparing the insulation pipe, the glass fiber is modified, which effectively improves the compatibility of the glass fiber with other raw materials, allows the glass fiber to be better mixed with other raw materials, and further improves the thermal insulation performance of the insulation pipe.

[0082] In combination with Example 1, Example 8, Example 9, Comparative Example 3 and Comparative Example 4, it can be seen that the amount of phenolic resin / carbon nanoparticle composite material added has an impact on the thermal insulation performance of the insulation pipe, and when the amount of phenolic resin / carbon nanoparticle composite material added is 10-20g, the thermal insulation performance of the insulation pipe is best.

[0083] The thermal insulation pipe prepared in the present application is particularly suitable for fluid transmission in high temperature environments in industries such as urban heating / cooling and industrial steam high-pressure transportation, ensuring effective heat transfer while reducing heat energy loss.

Claims

1. A thermal insulation pipe with strong compressive and tensile resistance, characterized in that: It comprises a coaxial inner tube and an outer tube, and a heat-insulating material is filled between the inner tube and the outer tube; The thermal insulation material comprises the following raw materials in parts by weight: 60-70 parts of polyethylene, 20-30 parts of recycled material, 5-10 parts of glass fiber, 2-4 parts of coupling agent and 15-25 parts of nano carbon tube / polyethylene composite material; The carbon nanotube / polyethylene composite material comprises the following raw materials in parts by weight: 30-40 parts of polyethylene, 1-3 parts of carbon nanotubes, 1-3 parts of carbon black and 3-7 parts of maleic anhydride grafted polyethylene.

2. The heat preservation pipe with strong compression and tensile resistance according to claim 1, characterized in that: The thermal insulation material also includes 10-20 parts by weight of a phenolic resin / carbon nanoparticle composite material.

3. The thermal insulation pipe with strong compressive and tensile resistance according to claim 2, characterized in that: The phenolic resin / carbon nanoparticle composite material comprises the following raw materials in parts by weight: 60-90 parts of carbon nanoparticles, 50-150 parts of phenolic resin, 1-2 parts of polyurethane, 50-60 parts of anhydrous ethanol, 5-10 parts of gum arabic and 1-3 parts of a coupling agent.

4. The thermal insulation pipe with strong compressive and tensile resistance according to claim 3, characterized in that: The preparation method of the phenolic resin / carbon nanoparticle composite material comprises the following steps: Weigh each raw material according to the formula; Mixing phenolic resin and anhydrous ethanol, adding polyurethane and mixing, to obtain modified phenolic resin; The modified phenolic resin, carbon nanoparticles, gum arabic and a coupling agent are mixed to obtain a phenolic resin / carbon nanoparticle composite material.

5. The thermal insulation pipe with strong compressive and tensile resistance according to claim 1, characterized in that: The preparation steps of the carbon nanotube / polyethylene composite material are as follows: Weigh each raw material according to the formula; adding the carbon nanotubes into aqua regia solution, mixing, and filtering to obtain modified carbon nanotubes; The modified nano carbon tubes are mixed with maleic anhydride grafted polyethylene, filtered, polyethylene and carbon black are added and mixed to obtain a nano carbon tube / polyethylene composite material.

6. The thermal insulation pipe with strong compressive and tensile resistance according to claim 1, characterized in that: The steps for modifying glass fiber are as follows: After the coupling agent and ethanol are mixed, glass fibers are added and mixed, and the mixture is placed at 80-100° C. for 8-10 hours, and filtered to obtain modified glass fibers.

7. The thermal insulation pipe with strong compression and tensile resistance according to claim 6, characterized in that: The mass ratio of the coupling agent to ethanol is 1:(3-5); the mass ratio of the glass fiber to the coupling agent is (5-10):(1-2).

8. The thermal insulation pipe with strong compression and tensile resistance according to claim 1, characterized in that: The recycled material is waste plastic particles, and the waste plastic is at least one of high-density polyethylene, low-density polyethylene, polypropylene, and polystyrene.

9. A method for preparing a thermal insulation pipe with strong compressive and tensile resistance, characterized in that: The preparation method comprises the following steps: (1) Preparation of thermal insulation materials: Weigh each raw material according to the formula; The glass fiber, coupling agent, phenolic resin / carbon nanoparticle composite material are mixed, and the nano carbon tube / polyethylene composite material is added and mixed; polyethylene and recycled material are then added and mixed to obtain a thermal insulation material; (2) Preparation of insulation pipe; The heat-insulating material is pressed through a lamination process, and the pressed heat-insulating material is filled between the inner tube and the outer tube to obtain a heat-insulating tube.

10. The method for preparing a thermal insulation pipe with strong compression and tensile strength according to claim 9, characterized in that: In the lamination process, the reaction pressure is 5MPa; The reaction temperature is as follows: the initial temperature is 80°C, which is then increased to 145°C at a rate of 10°C / min and kept for 2 hours, then increased to 170°C at a rate of 5°C / min and kept for 1 hour, and then decreased to 20°C at a rate of 4°C / min.

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