Heat-resistant modified MPP pipe and preparation method thereof

Abstract

The invention relates to the technical field of high polymer material pipes, and discloses a heat-resistant modified MPP pipe and a preparation method thereof.The heat-resistant modified MPP pipe is prepared from polypropylene resin, modified polypropylene resin, graphite powder, an antioxidant, a silane coupling agent, stearic acid, paraffin and heat-resistant filler; the preparation method of the modified polypropylene resin comprises the following steps: melting polypropylene resin to obtain melt liquid I; adding modified graphene into the melt I, and then increasing the temperature of the melt I to obtain melt II; adding focused piperazine phosphate and 1, 2-bis (diphenylphosphine) ethane into the molten liquid II, and uniformly stirring to obtain molten liquid III; a negative plate and a positive plate are inserted into the third molten liquid, and 0.1-0.5 A current is conducted for 40-60 min. The problems that when a high-power cable penetrates through an existing MPP pipe for use, due to the fact that the heat conduction performance of the MPP pipe is poor, heat in the MPP pipe is gathered and cannot be dissipated out of the MPP pipe in time, the performance and the service life of the cable are finally affected, and the service life of the MPP pipe is shortened are solved.

Description

Technical Field

[0001] The invention relates to the technical field of polymer material pipes, and in particular to a heat-resistant modified MPP pipe and a preparation method thereof. Background Art

[0002] MPP pipe is a new type of pipeline material with the characteristics of high strength, corrosion resistance and long life. It uses modified polypropylene as the main raw material and is processed through special production processes and technologies. This pipeline material has excellent physical and chemical properties and can operate stably for a long time in harsh environments such as high temperature, low temperature, high pressure and corrosion. In the future development, with the continuous advancement of technology and the continuous expansion of applications, MPP pipes will be more widely used and promoted. However, if the MPP pipe is under high temperature for a long time, the pipe body temperature may accumulate to exceed its allowable heat resistance temperature, resulting in thermal expansion and bending deformation, and reducing the service life; with the continuous development of the industry and the continuous advancement of science and technology, MPP pipes have gradually ushered in new challenges. Therefore, further improving the heat resistance of MPP pipes has become a research hotspot.

[0003] The patent with patent number CN202311675106.7 discloses a heat-resistant MPP pipe and its preparation process, including the following raw materials: polypropylene resin, talc, zinc oxide, antioxidant 1010, butyl stearate, heat-resistant filler, composite flame retardant. By grafting rigid groups onto the surface of nano-silicon carbide, the heat resistance of the MPP pipe is improved so that it will not deform or damage at high temperatures. By grafting guanylic acid onto the surface of basalt fiber, guanylic acid contains nitrogen heterocycles and phosphorus elements, and has excellent flame retardant properties. At the same time, it can improve the compatibility with polypropylene resin and improve the flame retardant properties of the MPP pipe.

[0004] Although the above-mentioned MPP pipe has improved heat resistance and flame retardancy, when the MPP pipe is used as an electric power pipe, if a high-power cable is passed through it, the cable will generate heat in the MPP pipe. Because the thermal conductivity of the current MPP pipe is generally poor, this will cause heat to accumulate inside the MPP pipe, which cannot be dissipated from the inside of the MPP pipe in time, and eventually the temperature of the inner wall of the MPP pipe will increase. If this continues for a long time, it will not only affect the performance and life of the cable, but the MPP pipe will be in a high temperature state for a long time, which will also reduce the life of the MPP pipe. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a heat-resistant modified MPP pipe and a preparation method thereof, so as to solve the problem that when the existing MPP pipe is used to pass high-power cables, the heat inside the MPP pipe is accumulated due to the poor thermal conductivity of the MPP pipe, and the heat cannot be dissipated from the inside of the MPP pipe in time, which ultimately affects the performance and life of the cable and reduces the life of the MPP pipe.

[0006] The present invention solves the above technical problems by the following technical means: In a first aspect, the present invention discloses a heat-resistant modified MPP pipe, comprising the following raw materials in parts by mass: 90-110 parts of polypropylene resin, 9-11 parts of modified polypropylene resin, 6-10 parts of graphite powder, 1-2 parts of antioxidant, 2-4 parts of silane coupling agent, 2-4 parts of stearic acid, 1-2 parts of paraffin, and 3-5 parts of heat-resistant filler; the modified polypropylene resin is a graphene-modified polypropylene resin.

[0007] Furthermore, the raw materials of the heat-resistant modified MPP pipe are as follows: 100 parts of polypropylene resin, 10 parts of modified polypropylene resin, 8 parts of graphite powder, 1.5 parts of antioxidant, 3 parts of silane coupling agent, 3 parts of stearic acid, 1.5 parts of paraffin wax, and 4 parts of heat-resistant filler; the particle size of the graphite powder is 10-30 μm.

[0008] Furthermore, the antioxidant is a combination of one or more of diphenylamine, p-phenylenediamine and antioxidant 1010.

[0009] Furthermore, the silane coupling agent is a combination of one or more of silane coupling agent KH550, silane coupling agent KH845, and silane coupling agent KH560.

[0010] Furthermore, the heat-resistant material is a combination of one or more of calcium carbonate, wood cellulose and magnesium silicide.

[0011] Furthermore, the preparation method of the modified polypropylene resin comprises the following steps: A1. Take 80-100 parts by mass of polypropylene resin and completely melt it to obtain a melt solution 1; A2, adding 4-5 parts of modified graphene to the melt 1 under stirring, then raising the temperature of the melt 1 by 8-12°C, stirring for 20-30 minutes, to obtain melt 2; A3, adding 3-5 parts of focused piperazine phosphate and 3-5 parts of 1,2-bis(diphenylphosphine)ethane to the molten solution 2, stirring evenly to obtain the molten solution 3; A4. Insert a cathode plate and an anode plate into the molten liquid 3, with the distance between the cathode plate and the anode plate being 0.4-1.0 m. Under stirring, pass a current of 0.1-0.5 A for 40-60 min to obtain modified polypropylene.

[0012] Furthermore, the preparation method of the modified graphene comprises the following steps: B1. Add 8-10 parts of graphene by mass to 300-500 parts of deionized water and perform ultrasonic treatment for 10-20 min. B2, add 3-5 parts of a mixture of phosphoric acid and sulfuric acid, and stir evenly to obtain a mixed solution; B3. Heat the mixed solution to 70-80°C and stir to react for 1-2h, then centrifuge. Wash the precipitate after centrifugation and freeze-dry it at -55 to -45°C to obtain modified graphene.

[0013] Furthermore, the power of the ultrasonic treatment in step B1 is 100-200 W and the frequency is 50-100 Hz; the concentration of phosphoric acid in step B2 is 75%-85%, and the concentration of sulfuric acid is 90%-98%.

[0014] In a second aspect, the present invention also discloses a method for preparing a heat-resistant modified MPP pipe, the steps comprising: uniformly stirring polypropylene resin, modified polypropylene resin, graphite powder, antioxidant, silane coupling agent, stearic acid, paraffin and heat-resistant filler in proportion, heating to 165-175°C for melting, and uniformly stirring to obtain a blended molten liquid; extruding and granulating the blended molten liquid through a twin-screw extruder, and obtaining a heat-resistant MPP pipe after thermoplastic molding through a mold.

[0015] Further, the parameters of the twin-screw extruder are set as follows: the temperature of zone 1 is 160-170°C, the temperature of zone 2 is 170-180°C, the temperature of zone 3 is 180-190°C, the temperature of zone 4 is 190-200°C, and the screw speed of the extruder is 80-120r / min.

[0016] In summary, this application has the following beneficial effects: 1. The present invention adds heat-resistant fillers such as calcium carbonate, cellulose or magnesium silicide to the MPP pipe, which can improve the overall heat resistance of the MPP pipe; and, part of the polypropylene resin raw materials in the present application are modified by modified graphene, so that a part of the modified graphene can be wrapped or adhered to the polypropylene resin, thereby improving the thermal conductivity of the polypropylene resin. In addition, graphite powder is added to the MPP pipe of the present invention, and the graphite powder also has strong thermal conductivity; thereby, the heat resistance and thermal conductivity of the MPP pipe of the present invention are better.

[0017] 2. When the high-power cable in the MPP pipe of the present invention is heated, the thermal expansion coefficient of the polypropylene resin modified with modified graphene in the MPP pipe will be increased, and it will have a certain range of moderate thermal expansion together with the graphite powder after being heated, and then further promote the gathering and aggregation of the graphene-modified polypropylene resin and the graphite powder on the wall of the MPP pipe, which will further improve the thermal conductivity of the MPP pipe, thereby further increasing the heat dissipation of the MPP pipe, and conducting and dissipating the heat generated by the cable inside the MPP pipe, reducing the heat accumulation inside the MPP pipe, and reducing the temperature of the cable and the MPP pipe itself, thereby extending the service life of the MPP pipe and the cable located therein. DETAILED DESCRIPTION

[0018] The following will be combined with 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 making creative work are within the scope of protection of the present invention. Example 1

[0019] This embodiment is a preparation method 1 of a heat-resistant modified MPP pipe, and the steps include: Preparation of modified graphene: 8 kg of three-dimensional network graphene is added to 300 liters of deionized water, and ultrasonic treatment is performed for 10 minutes, wherein the power during ultrasonic treatment is 100 W and the frequency is 50 Hz; then 3 kg of a mixture of phosphoric acid and sulfuric acid is added, and the volume ratio of phosphoric acid to sulfuric acid is 1:1, and the mixture is stirred evenly to obtain a mixed solution; wherein the concentration of phosphoric acid is 75%, and the concentration of sulfuric acid is 90%; the mixed solution is heated to 70°C and stirred for reaction for 1 hour, and then centrifuged at a rate of 8000 r / min, the precipitate after centrifugation is washed and freeze-dried at -55°C to obtain modified graphene.

[0020] Preparation of modified polypropylene resin: 80 kg of polypropylene resin is completely melted to obtain melt one; 4 kg of modified graphene is added to the melt one while stirring, and then the temperature of the melt one is increased by 8°C and stirred for 20 minutes to obtain melt two; 3 kg of focused piperazine phosphate and 3 kg of 1,2-bis(diphenylphosphine)ethane are added to the melt two, and the mixture is stirred evenly to obtain melt three; a cathode plate and an anode plate are inserted into the melt three, with a distance of 0.4 meters between the cathode plate and the anode plate, and a current of 0.1 A is passed for 40 minutes while stirring to obtain modified polypropylene.

[0021] Polypropylene resin, modified polypropylene resin, graphite powder, antioxidant, silane coupling agent, stearic acid, paraffin and heat-resistant filler are uniformly stirred in proportion, heated to 165°C for melting, and uniformly stirred to obtain a blended molten liquid; the blended molten liquid is extruded and granulated through a twin-screw extruder, and a heat-resistant MPP pipe is obtained after thermoplastic molding through a mold; the parameters of the twin-screw extruder are set as follows: the temperature of zone 1 is 160°C, the temperature of zone 2 is 170°C, the temperature of zone 3 is 180°C, the temperature of zone 4 is 190°C, and the screw speed of the extruder is 80r / min.

[0022] Among them, the heat-resistant modified MPP pipe in this embodiment includes the following raw materials: 90kg polypropylene resin, 9kg modified polypropylene resin, 6kg graphite powder, 1kg antioxidant, 2kg silane coupling agent, 2kg stearic acid, 1kg paraffin, and 3kg heat-resistant filler; the modified polypropylene resin is graphene-modified polypropylene resin, and the particle size of the graphite powder is 10μm.

[0023] The antioxidant is diphenylamine, the silane coupling agent is silane coupling agent KH550, and the heat-resistant material is calcium carbonate. Example 2

[0024] This embodiment is a preparation method 1 of a heat-resistant modified MPP pipe, and the steps include: Preparation of modified graphene: 9 kg of three-dimensional network graphene is added to 400 liters of deionized water, and ultrasonically treated for 15 min, wherein the power during ultrasonic treatment is 150 W and the frequency is 75 Hz; then 4 kg of a mixture of phosphoric acid and sulfuric acid is added, and the volume ratio of phosphoric acid to sulfuric acid is 1:1, and stirred evenly to obtain a mixed solution; wherein the concentration of phosphoric acid is 80%, and the concentration of sulfuric acid is 94%; the mixed solution is heated to 75°C and stirred for 1.5 hours, and then centrifuged at a rate of 9000 r / min, the precipitate after centrifugation is washed and freeze-dried at -50°C to obtain modified graphene.

[0025] Preparation of modified polypropylene resin: 90 kg of polypropylene resin is completely melted to obtain melt one; 4.5 kg of modified graphene is added to the melt one while stirring, and then the temperature of the melt one is increased by 10°C and stirred for 25 minutes to obtain melt two; 4 kg of focused piperazine phosphate and 4 kg of 1,2-bis(diphenylphosphine)ethane are added to the melt two, and the mixture is stirred evenly to obtain melt three; a cathode plate and an anode plate are inserted into the melt three, with a distance of 0.4 meters between the cathode plate and the anode plate, and a current of 0.3 A is passed for 50 minutes while stirring to obtain modified polypropylene.

[0026] Polypropylene resin, modified polypropylene resin, graphite powder, antioxidant, silane coupling agent, stearic acid, paraffin and heat-resistant filler are uniformly stirred in proportion, heated to 170°C for melting, and uniformly stirred to obtain a blended molten liquid; the blended molten liquid is extruded and granulated through a twin-screw extruder, and a heat-resistant MPP pipe is obtained after thermoplastic molding through a mold; the parameters of the twin-screw extruder are set as follows: the temperature of zone 1 is 165°C, the temperature of zone 2 is 175°C, the temperature of zone 3 is 185°C, the temperature of zone 4 is 195°C, and the screw speed of the extruder is 100r / min.

[0027] Among them, the heat-resistant modified MPP pipe in this embodiment includes the following raw materials: 100kg polypropylene resin, 10kg modified polypropylene resin, 8kg graphite powder, 1.5kg antioxidant, 3kg silane coupling agent, 3kg stearic acid, 1.5kg paraffin, and 4kg heat-resistant filler; the modified polypropylene resin is graphene-modified polypropylene resin, and the particle size of the graphite powder is 20μm.

[0028] The antioxidant is p-phenylenediamine, the silane coupling agent is silane coupling agent KH845, and the heat-resistant material is wood cellulose. Example 3

[0029] This embodiment is a preparation method 1 of a heat-resistant modified MPP pipe, and the steps include: Preparation of modified graphene: 10 kg of three-dimensional network graphene is added to 500 liters of deionized water, and ultrasonic treatment is performed for 20 min, wherein the power during ultrasonic treatment is 200 W and the frequency is 100 Hz; then 5 kg of a mixture of phosphoric acid and sulfuric acid is added, and the volume ratio of phosphoric acid to sulfuric acid is 1:1, and the mixture is stirred evenly to obtain a mixed solution; wherein the concentration of phosphoric acid is 85%, and the concentration of sulfuric acid is 98%; the mixed solution is heated to 80°C and stirred for 2 hours, and then centrifuged at a rate of 10,000 r / min, the precipitate after centrifugation is washed and freeze-dried at -45°C to obtain modified graphene.

[0030] Preparation of modified polypropylene resin: 100 kg of polypropylene resin is completely melted to obtain melt one; 5 kg of modified graphene is added to the melt one while stirring, and then the temperature of the melt one is increased by 12°C and stirred for 30 minutes to obtain melt two; 5 kg of focused piperazine phosphate and 5 kg of 1,2-bis(diphenylphosphine)ethane are added to the melt two, and the mixture is stirred evenly to obtain melt three; a cathode plate and an anode plate are inserted into the melt three, with a distance of 1.0 meter between the cathode plate and the anode plate, and a current of 0.5 A is passed for 60 minutes while stirring to obtain modified polypropylene.

[0031] Polypropylene resin, modified polypropylene resin, graphite powder, antioxidant, silane coupling agent, stearic acid, paraffin and heat-resistant filler are uniformly stirred in proportion, heated to 175°C for melting, and uniformly stirred to obtain a blended molten liquid; the blended molten liquid is extruded and granulated through a twin-screw extruder, and a heat-resistant MPP pipe is obtained after thermoplastic molding through a mold; the parameters of the twin-screw extruder are set as follows: the temperature of zone 1 is 170°C, the temperature of zone 2 is 180°C, the temperature of zone 3 is 190°C, the temperature of zone 4 is 200°C, and the screw speed of the extruder is 120r / min.

[0032] Among them, the heat-resistant modified MPP pipe in this embodiment includes the following raw materials: 110kg polypropylene resin, 11kg modified polypropylene resin, 10kg graphite powder, 2kg antioxidant, 4kg silane coupling agent, 4kg stearic acid, 2kg paraffin, and 5kg heat-resistant filler; the modified polypropylene resin is graphene-modified polypropylene resin, and the particle size of the graphite powder is 30μm.

[0033] The antioxidant is a combination of diphenylamine, p-phenylenediamine, and antioxidant 1010, with a mass ratio of 1:1:1. The silane coupling agent is a combination of silane coupling agent KH550, silane coupling agent KH845, and silane coupling agent KH560, with a mass ratio of 1:1:1. The heat-resistant material is a combination of calcium carbonate, wood cellulose, and magnesium silicide, with a mass ratio of 1:1:1. Example 4

[0034] This embodiment is compared with embodiment 2, and the difference is that in this embodiment, when preparing the heat-resistant modified MPP pipe, no modified polypropylene resin and graphite powder are added. Example 5

[0035] This embodiment is compared with embodiment 2, and the difference is that in this embodiment, when preparing the heat-resistant modified MPP pipe, no modified polypropylene resin is added. Example 6

[0036] This embodiment is compared with embodiment 2, and the difference is that in this embodiment, when preparing the heat-resistant modified MPP pipe, the added modified polypropylene resin is not inserted into the cathode plate and the anode plate in the molten liquid three during the preparation. Example 7

[0037] This embodiment is compared with embodiment 2, and the difference is that in this embodiment, when preparing the heat-resistant modified MPP pipe, the added modified polypropylene resin is not modified according to the method of embodiment 2 during preparation, and the added graphene is only commercially available conventional graphene.

[0038]

[0039] From the comparison of the above-mentioned Examples 1 to 7, we can see that the MPP pipes prepared in Examples 1 to 7 have little difference in tensile strength and impact strength, but the MPP pipes prepared in Examples 1 to 3 are much higher in thermal conductivity than the MPP pipes of Examples 4 to 7, especially higher than the MPP pipe in Example 4 to which no modified polypropylene resin and graphite powder are added; therefore, it can be seen that the MPP pipes prepared by the method of the present invention can greatly improve their thermal conductivity, thereby making the heat resistance and thermal conductivity of the MPP pipes of the present invention better.

[0040] From the comparison between Example 2 and Example 5, it can be seen that if the modified polypropylene resin is not added when preparing the heat-resistant modified MPP pipe, the thermal conductivity of the MPP pipe will also be reduced. From the comparison between Example 2 and Example 6, it can be seen that if the modified polypropylene resin added when preparing the heat-resistant modified MPP pipe is not inserted into the cathode plate and the anode plate in the melt three during the preparation, the thermal conductivity of the MPP pipe will be reduced. From the comparison between Example 2 and Example 7, it can be seen that if the modified polypropylene resin added is not modified according to the method of Example 2 during the preparation, and only the conventional commercially available graphene is used, the thermal conductivity of the MPP pipe will also be reduced.

[0041] From the comparison of the above embodiments, it can be seen that part of the polypropylene resin raw material of the present invention is modified by modified graphene, so that a part of the modified graphene can be wrapped or adhered to the polypropylene resin, thereby improving the thermal conductivity of the polypropylene resin. In addition, graphite powder is added to the MPP pipe of the present invention, and the graphite powder also has strong thermal conductivity; thereby, the heat resistance and thermal conductivity of the MPP pipe of the present invention are better. When the high-power cable in the MPP pipe of the present invention is heated, because the thermal expansion coefficient of the polypropylene resin modified by the modified graphene in the MPP pipe will be increased, it will have a certain range of moderate thermal expansion together with the graphite powder after being heated, and then further promote the gathering and aggregation of the graphene-modified polypropylene resin and the graphite powder on the wall of the MPP pipe, which will further improve the thermal conductivity of the MPP pipe, thereby further increasing the heat dissipation of the MPP pipe, and conducting and dissipating the heat generated by the cable inside the MPP pipe, reducing the heat accumulation inside the MPP pipe, and reducing the temperature of the cable and the MPP pipe itself, thereby extending the service life of the MPP pipe and the cable located therein.

[0042] It should be noted that, because the ratio of the modified polypropylene resin to the graphite powder in the present invention is not high, tests have shown that when heated, it will not cause expansion and bending deformation in appearance, nor will it reduce the service life of the MPP pipe.

[0043] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should be included in the scope of the claims of the present invention. The techniques, shapes, and structural parts not described in detail in the present invention are all known technologies.

Claims

1. A heat-resistant modified MPP pipe, characterized in that: The invention comprises the following raw materials in parts by weight: 90-110 parts of polypropylene resin, 9-11 parts of modified polypropylene resin, 6-10 parts of graphite powder, 1-2 parts of antioxidant, 2-4 parts of silane coupling agent, 2-4 parts of stearic acid, 1-2 parts of paraffin wax and 3-5 parts of heat-resistant filler; the modified polypropylene resin is graphene-modified polypropylene resin.

2. The heat-resistant modified MPP pipe according to claim 1, characterized in that: The raw materials of the heat-resistant modified MPP pipe are as follows: 100 parts of polypropylene resin, 10 parts of modified polypropylene resin, 8 parts of graphite powder, 1.5 parts of antioxidant, 3 parts of silane coupling agent, 3 parts of stearic acid, 1.5 parts of paraffin wax, and 4 parts of heat-resistant filler; the particle size of the graphite powder is 10-30 μm.

3. The heat-resistant modified MPP pipe according to claim 1, characterized in that: The antioxidant is a combination of one or more of diphenylamine, p-phenylenediamine and antioxidant 1010.

4. The heat-resistant modified MPP pipe according to claim 1, characterized in that: The silane coupling agent is a combination of one or more of silane coupling agent KH550, silane coupling agent KH845 and silane coupling agent KH560.

5. The heat-resistant modified MPP pipe according to claim 1, characterized in that: The heat-resistant material is a combination of one or more of calcium carbonate, wood cellulose and magnesium silicide.

6. A heat-resistant modified MPP pipe according to any one of claims 1 to 5, characterized in that: The preparation method of the modified polypropylene resin comprises the following steps: A1. Take 80-100 parts by mass of polypropylene resin and completely melt it to obtain a melt solution 1; A2, adding 4-5 parts of modified graphene to the melt 1 under stirring, then raising the temperature of the melt 1 by 8-12°C, stirring for 20-30 minutes, to obtain melt 2; A3, adding 3-5 parts of focused piperazine phosphate and 3-5 parts of 1,2-bis(diphenylphosphine)ethane to the molten solution 2, stirring evenly to obtain the molten solution 3; A4. Insert a cathode plate and an anode plate into the molten liquid 3, with the distance between the cathode plate and the anode plate being 0.4-1.0 m. Under stirring, pass a current of 0.1-0.5 A for 40-60 min to obtain modified polypropylene.

7. The heat-resistant modified MPP pipe according to claim 6, characterized in that: The preparation method of the modified graphene comprises the following steps: B1. Add 8-10 parts of graphene by mass to 300-500 parts of deionized water and perform ultrasonic treatment for 10-20 minutes; B2, add 3-5 parts of a mixture of phosphoric acid and sulfuric acid, and stir evenly to obtain a mixed solution; B3. Heat the mixed solution to 70-80°C and stir to react for 1-2h, then centrifuge. Wash the precipitate after centrifugation and freeze-dry it at -55 to -45°C to obtain modified graphene.

8. The heat-resistant modified MPP pipe according to claim 7, characterized in that: The power of the ultrasonic treatment in step B1 is 100-200 W and the frequency is 50-100 Hz; the concentration of phosphoric acid in step B2 is 75%-85%, and the concentration of sulfuric acid is 90%-98%.

9. A method for preparing a heat-resistant modified MPP pipe according to claim 1, characterized in that the steps include: Polypropylene resin, modified polypropylene resin, graphite powder, antioxidant, silane coupling agent, stearic acid, paraffin and heat-resistant filler are uniformly stirred in proportion, heated to 165-175°C for melting, and uniformly stirred to obtain a blended molten liquid; the blended molten liquid is extruded and granulated through a twin-screw extruder, and the heat-resistant MPP pipe is obtained after thermoplastic molding through a mold.

10. The method for preparing the heat-resistant modified MPP pipe according to claim 9, characterized in that: The parameters of the twin-screw extruder are set as follows: the temperature of zone 1 is 160-170°C, the temperature of zone 2 is 170-180°C, the temperature of zone 3 is 180-190°C, the temperature of zone 4 is 190-200°C, and the screw speed of the extruder is 80-120r / min.

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