A modified polypropylene HPPM square power corrugated pipe

Abstract

The present invention discloses a modified polypropylene HPPM square power corrugated pipe, belonging to the technical field of corrugated pipes, and is used to solve the technical problems that when preparing polypropylene square power corrugated pipes in the prior art, it is impossible to make them have both toughness and excellent mechanical properties. In order to improve the mechanical properties of polypropylene, the nucleating agents used have low nucleating efficiency and complex preparation processes; the present invention includes block copolymerized polypropylene, modified nucleating agent, alkaline glass fiber and related additives. Using maleimide, propylene and allyl cinnamate as monomers, block copolymerized polypropylene with both high mechanical properties and high toughness is prepared. Ethylenediamine and hexachlorocyclotriphosphazene undergo a nucleophilic substitution reaction to prepare a polyamine phosphazene containing multiple diamino groups. The polyamine phosphazene reacts with phthalic anhydride to obtain a modified nucleating agent with multiple amide carboxylic acid nucleation centers, which has the advantages of high nucleating efficiency and simplified preparation process.

Description

Technical Field

[0001] The present invention relates to the technical field of corrugated pipes, and particularly to a modified polypropylene HPPM square power corrugated pipe. Background Art

[0002] The power corrugated pipe adopts a "square outside and round inside" structural design, with a square annular corrugated structure on the outer wall and a circular flat wall structure on the inner wall, which improves the compressive strength and ring stiffness of the pipe and is widely used in high-voltage DC cables.

[0003] Among them, cross-linked polyethylene has good physical and chemical properties and dielectric properties and has become the main insulating material for square power corrugated pipes. However, the cross-linking agent used for cross-linking and the cross-linking by-products generated during the cross-linking process may remain inside the cable insulation, causing space charge accumulation problems and affecting the service life of the cable. The polypropylene corrugated pipe made mainly of polypropylene resin has excellent flexibility while having sufficient mechanical strength and rigidity, and also has the advantages of strong chemical corrosion resistance, convenient installation and good sealing performance.

[0004] In the preparation of polypropylene HPPM square power corrugated pipes, a certain amount of nucleating agent can be appropriately added. The nucleating agent can be divided into β-nucleating agent and α-nucleating agent. The β-nucleating agent can crystallize due to the interaction energy with the surface of the block copolymerized polypropylene matrix and can induce polypropylene to form β-crystalline form. Compared with polypropylene in α-crystalline form, polypropylene in β-crystalline form has more stable elongation at break, impact strength and heat distortion temperature. The polypropylene β-nucleating agent can be divided into amide nucleating agent and carboxylate nucleating agent. Compared with the carboxylate nucleating agent, the amide β-nucleating agent has the advantage of good thermal stability. However, in the synthesis process of the amide nucleating agent, environmentally unfriendly chemical reagents such as acyl chloride and thionyl chloride are used. In addition, how to improve the nucleation efficiency of the prepared amide β-nucleating agent and simplify the process flow is also a technical problem that needs to be solved urgently.

[0005] In view of the technical defects in this regard, a solution is proposed now. Summary of the Invention

[0006] The purpose of the present invention is to provide a modified polypropylene HPPM square power corrugated pipe, which is used to solve the technical problems that when preparing polypropylene square power corrugated pipes in the prior art, it is impossible to make them have both toughness and excellent mechanical properties, and that for improving the mechanical properties of polypropylene, the nucleating agent used has low nucleation efficiency and complex preparation process.

[0007] The object of the present invention can be achieved by the following technical solutions: A modified polypropylene HPPM square power bellows, calculated by weight, comprises 60-70 parts of block copolymerized polypropylene, 0.2-0.5 parts of modified nucleating agent, 5-10 parts of alkaline glass fiber, 0.5-1 part of heat stabilizer, 1-2 parts of plasticizer, 0.5-1 part of antioxidant, 0.1-0.5 part of light stabilizer and 1-1.5 parts of lubricant;

[0008] The preparation method of the modified nucleating agent comprises the following steps:

[0009] A1. Ethylenediamine and 1,4-dioxane are mixed evenly to obtain an ethylenediamine solution; hexachlorocyclotriphosphazene and 1,4-dioxane are mixed evenly to obtain a hexachlorocyclotriphosphazene solution; the hexachlorocyclotriphosphazene solution is added dropwise to the ethylenediamine solution drop by drop. After the addition is completed, the mixture is kept at a constant temperature of 40-50 °C for 2 h to obtain a product; the product is subjected to vacuum distillation to obtain a white solid polyamine phosphazene;

[0010] The reaction formula for preparing polyamine phosphazene by the nucleophilic substitution of ethylenediamine and hexachlorocyclotriphosphazene is as follows:

[0011] A2. Phthalic anhydride is dissolved in tetrahydrofuran to obtain a phthalic anhydride solution; polyamine phosphazene and tetrahydrofuran are mixed and stirred at 50-60 °C until completely dissolved to obtain a polyamine phosphazene solution; the polyamine phosphazene solution is added dropwise to the phthalic anhydride solution drop by drop. After the addition is completed, the reaction is continued at room temperature for 24 h to obtain a reaction system; the reaction system is centrifuged, washed with deionized water, and vacuum dried at 60 °C to constant weight to obtain the modified nucleating agent.

[0012] When phthalic anhydride reacts with the amino group of polyamine phosphazene, the amino group attacks the carbonyl group of phthalic anhydride as a nucleophilic group, generating an amide group and a carboxylic acid group.

[0013] The reaction formula of phthalic anhydride and polyamine phosphazene is as follows:

[0014]

[0015] Further, in step A1, the dosage ratio of ethylenediamine to 1,4-dioxane is 5-10 g:25 mL, the dosage ratio of hexachlorocyclotriphosphazene to 1,4-dioxane is 15-20 g:100 mL; the dosage ratio of the ethylenediamine solution to the hexachlorocyclotriphosphazene solution is 30 mL:120 mL; in step A2, the dosage ratio of phthalic anhydride to tetrahydrofuran is 15 g:100 mL; the dosage ratio of polyamine phosphazene to tetrahydrofuran is 20-30 g:100 mL; the dosage ratio of the polyamine phosphazene solution to the phthalic anhydride solution is 115-120 mL:120 mL.

[0016] Furthermore, the preparation method of the block copolymer polypropylene includes the following steps:

[0017] S1. The co-emulsifier isooctadecane is dissolved in benzyl benzoate to obtain a co-emulsifier solution; the main emulsifier sodium dodecyl sulfate is dissolved in deionized water to obtain a main emulsifier solution; the co-emulsifier solution and the main emulsifier solution are mixed evenly to obtain an emulsifier solution.

[0018] S2. An iodine transfer agent CHI3 and the emulsifier solution are added to the reaction kettle, and the reaction kettle is purged with propylene three times; the reaction kettle reacts at 35 - 40 °C for 100 - 120 min to obtain copolymer emulsion I.

[0019] S3. The maleimide powder is transferred to the reaction kettle, and the copolymer emulsion reacts at 50 - 60 °C for 100 - 120 min to obtain copolymer emulsion I; allyl cinnamate is added to the reaction kettle and reacts at 50 - 60 °C for 130 - 150 min to obtain copolymer emulsion II; then a 0.5 - 1%wt hydroquinone ethanol solution is added to the reaction kettle to terminate the reaction, and then the reaction kettle is cooled to room temperature and discharged to obtain a copolymer emulsion; the copolymer emulsion is subjected to post-process treatment to obtain block copolymer polypropylene.

[0020] Maleimide, propylene and allyl cinnamate undergo an addition reaction of olefins to prepare block copolymer polypropylene.

[0021] Furthermore, in step S1, the dosage ratio of the co-emulsifier to benzyl benzoate is 25 - 30 mL:100 mL; the dosage ratio of sodium dodecyl sulfate to deionized water is 25 g:100 mL; the dosage ratio of the co-emulsifier solution to the main emulsifier solution is 100 - 120 mL:120 mL.

[0022] Furthermore, in step S2, the dosage ratio of the iodine transfer agent to the emulsifier solution is 0.3 - 0.5 g:100 - 150 mL; the dosage of the maleimide powder is 10 - 20 g, the dosage of allyl cinnamate is 15 - 20 mL, and the dosage of the hydroquinone ethanol solution is 5 mL.

[0023] Furthermore, in step S3, the post-process treatment includes: 30 - 50 mL of the copolymer emulsion is added to acidified ethanol and stirred for sedimentation, and then the solvent is removed with a Buchner funnel to obtain a polymer; the polymer is placed in a vacuum oven at 60 °C and dried to a constant weight to obtain block copolymer polypropylene.

[0024] Furthermore, the heat stabilizer is tribasic lead sulfate, the plasticizer is dibutyl sebacate, the antioxidant is antioxidant 330, the light stabilizer is 2,4-dihydroxybenzophenone, and the lubricant is paraffin.

[0025] As another aspect of the present invention, a method for preparing a modified polypropylene HPPM square power corrugated pipe is characterized by comprising the following steps:

[0026] B1. Mix block copolymerized polypropylene, a modified nucleating agent, alkaline glass fiber, a heat stabilizer, a plasticizer, an antioxidant, a light stabilizer, and a lubricant evenly, and add them into a twin-screw extruder for melt extrusion. The temperature of melt extrusion is 200 - 210 °C, and the screw speed is 100 r / min to obtain a composite material;

[0027] B2. Inject the mixed masterbatch into a spline through an injection molding machine. The injection temperature is 225 - 240 °C, the injection pressure is 30 MPa, the injection holding pressure and the holding time are 30 s, and the cooling time is 20 - 30 s to obtain a modified polypropylene HPPM square power corrugated pipe.

[0028] The present invention has the following beneficial effects:

[0029] 1. The modified polypropylene HPPM square power corrugated pipe prepared by the present invention comprises block copolymerized polypropylene, a modified nucleating agent, alkaline glass fiber, and related additives. Among them, maleimide, propylene, and allyl cinnamate are used as monomers for copolymerization to prepare a triblock block copolymerized polypropylene. Polypropylene itself has the drawbacks of high low-temperature brittleness, poor toughness, and poor impact resistance; when maleimide and propylene are copolymerized, due to the presence of a maleimide ring five-membered ring structure in the molecular main chain, the rotation movement of the imide group around the macromolecular main chain is restricted, thereby increasing its glass transition temperature and further improving the rigidity of the block copolymerized polypropylene. Propylene is pre-homopolymerized, and then maleimide and allyl cinnamate monomers are added for copolymerization; on the one hand, a small amount of allyl cinnamate is dispersed and interspersed as a copolymer monomer unit on the isotactic molecular chain, which to a certain extent destroys the regularity of polypropylene, thereby improving the toughness of polypropylene; while in the regular regions without embedded monomers, the block copolymerized polypropylene still maintains a relatively high crystallinity, making it have relatively high rigidity. In addition, when alkaline glass fiber is added to the mixed masterbatch, it can not only significantly improve the mechanical strength of the prepared product but also make it have a low water absorption rate.

[0030] 2. The molecular chains of block copolymer polypropylene are closely arranged in the crystal region. In order to induce the formation of β-crystal form of polypropylene in the crystal region, a certain amount of modified nucleating agent is added during the preparation of the power bellows pipe in the present invention. The modified nucleating agent adopted in the present invention is essentially an amide carboxylate β-nucleating agent. Ethylenediamine and hexachlorocyclotriphosphazene undergo a nucleophilic substitution reaction to prepare a polyamine phosphazene containing multiple diamino groups; the anhydride in phthalic anhydride has a high reaction activity with the diamino group of the amine phosphazene and can react even at room temperature, thus a modified nucleating agent with a polyamide carboxylic acid and cyclic structure can be constructed; the modified nucleating agent generated in the present invention has a large number of amide carboxylic acid nucleation centers, thereby improving the nucleation efficiency of the modified nucleating agent. In addition, the modified nucleating agent designed in the present invention improves its own molecular weight through active group grafting, thereby improving the compatibility between the nucleating agent and the polypropylene matrix. Detailed implementation mode

[0031] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention. Embodiment 1

[0032] This embodiment provides a preparation method of a modified nucleating agent for modified polypropylene HPPM square power bellows pipes, including the following steps:

[0033] A1. 5 g of ethylenediamine and 25 mL of 1,4-dioxane are mixed evenly to obtain an ethylenediamine solution; 15 g of hexachlorocyclotriphosphazene and 100 mL of 1,4-dioxane are mixed evenly to obtain a hexachlorocyclotriphosphazene solution. Transfer 30 mL of the ethylenediamine solution to a 250 mL round-bottom three-necked flask. A thermometer is set at one port of the round-bottom three-necked flask, and a constant pressure dropping funnel is set at one end. 120 mL of the hexachlorocyclotriphosphazene solution is added dropwise to the round-bottom three-necked flask through the constant pressure dropping funnel. After the addition is completed, an electric heating mantle is set outside the round-bottom three-necked flask, and the temperature is set at 50 °C for a constant temperature reaction for 2 h to obtain a reaction product. The reaction product is subjected to vacuum distillation to obtain a white solid, which is polyamine phosphazene.

[0034] A2. 15 g of phthalic anhydride and 100 mL of tetrahydrofuran were mixed and stirred at 100 r / min at room temperature until the white crystalline powder was completely dissolved to obtain a phthalic anhydride solution; 30 g of polyamine phosphazene and 100 mL of tetrahydrofuran were mixed and stirred at 60 °C until completely dissolved to obtain a polyamine phosphazene solution. A 500 mL round-bottom flask was equipped with a magnetic stirrer and a dropping funnel. Then, 110 mL of the phthalic anhydride solution was transferred to the round-bottom flask, and 120 mL of the polyamine phosphazene solution was added dropwise to the round-bottom flask through the dropping funnel. White precipitate would be produced during the dropping process. After the dropping was completed, the reaction was continued at 200 r / min at room temperature for 24 h to obtain a reaction system. The reaction system was centrifuged to obtain a white precipitate. The white precipitate was washed three times with deionized water and then placed in a vacuum oven at 60 °C and dried to a constant weight to obtain the modified nucleating agent. Example 2

[0035] This example provides a preparation method of a modified nucleating agent for modified polypropylene HPPM square power corrugated pipes, including the following steps:

[0036] A1. 6 g of ethylenediamine and 25 mL of 1,4-dioxane were mixed evenly to obtain an ethylenediamine solution; 18 g of hexachlorocyclotriphosphazene and 100 mL of 1,4-dioxane were mixed evenly to obtain a hexachlorocyclotriphosphazene solution. 30 mL of the ethylenediamine solution was transferred to a 250 mL three-necked round-bottom flask. A thermometer was set at one port of the three-necked round-bottom flask, and a constant pressure dropping funnel was set at one end. 120 mL of the hexachlorocyclotriphosphazene solution was added dropwise to the three-necked round-bottom flask through the constant pressure dropping funnel. After the dropping was completed, an electric heating mantle was set outside the three-necked round-bottom flask, and the temperature was set at 45 °C for a constant temperature reaction for 2 h to obtain a product. The product was subjected to vacuum distillation to obtain a white solid, which was polyamine phosphazene.

[0037] A2. 15 g of phthalic anhydride and 100 mL of tetrahydrofuran were mixed and stirred at 100 r / min at room temperature until the white crystalline powder was completely dissolved to obtain a phthalic anhydride solution; 25 g of polyamine phosphazene and 100 mL of tetrahydrofuran were mixed and stirred at 55 °C until completely dissolved to obtain a polyamine phosphazene solution. A 500 mL round-bottom flask was equipped with a magnetic stirrer and a dropping funnel. Then, 118 mL of the phthalic anhydride solution was transferred to the round-bottom flask, and 120 mL of the polyamine phosphazene solution was added dropwise to the round-bottom flask through the dropping funnel. White precipitate would be produced during the dropping process. After the dropping was completed, the reaction was continued at 150 r / min at room temperature for 24 h to obtain a reaction system. The reaction system was centrifuged to obtain a white precipitate. The white precipitate was washed three times with deionized water and then placed in a vacuum oven at 60 °C and dried to a constant weight to obtain the modified nucleating agent. Example 3

[0038] This embodiment provides a preparation method of a modified nucleating agent for modified polypropylene HPPM square power corrugated pipes, comprising the following steps:

[0039] A1. Mix 10 g of ethylenediamine and 25 mL of 1,4-dioxane evenly to obtain an ethylenediamine solution; mix 20 g of hexachlorocyclotriphosphazene and 100 mL of 1,4-dioxane evenly to obtain a hexachlorocyclotriphosphazene solution. Transfer 30 mL of the ethylenediamine solution to a 250 mL round-bottomed three-necked flask. Set a thermometer at one port of the round-bottomed three-necked flask and a constant-pressure dropping funnel at one end. Gradually drop 120 mL of the hexachlorocyclotriphosphazene solution into the round-bottomed three-necked flask through the constant-pressure dropping funnel. After the dropping is completed, set an electric heating mantle outside the round-bottomed three-necked flask, set the temperature to 50 °C, and react at a constant temperature for 2 h to obtain a product. Subject the product to vacuum distillation to obtain a white solid, which is polyamine phosphazene.

[0040] A2. Mix 15 g of phthalic anhydride and 100 mL of tetrahydrofuran, and stir at 100 r / min at room temperature until the white crystalline powder is completely dissolved to obtain a phthalic anhydride solution; mix 30 g of polyamine phosphazene and 100 mL of tetrahydrofuran, and stir at 60 °C until completely dissolved to obtain a polyamine phosphazene solution. A 500 mL round-bottomed flask is equipped with a magnetic stirrer and a dropping funnel. Then transfer 120 mL of the phthalic anhydride solution to the round-bottomed flask, and then gradually drop 120 mL of the polyamine phosphazene solution into the round-bottomed flask through the dropping funnel. White precipitate will be generated during the dropping process; after the dropping is completed, continue to react at -200 r / min at room temperature for 24 h to obtain a reaction system; centrifuge the reaction system to obtain a white precipitate. Wash the white precipitate three times with deionized water, and then place it in a vacuum oven at 60 °C to dry to constant weight to obtain the modified nucleating agent. Example 4

[0041] This embodiment provides a preparation method of block copolymer polypropylene for modified polypropylene HPPM square power corrugated pipes, comprising the following steps:

[0042] S1. Dissolve 25 mL of co-emulsifier isoparaffin in 100 mL of benzyl benzoate to obtain a co-emulsifier solution; dissolve 25 g of main emulsifier sodium dodecyl sulfate in 50 mL of deionized water to obtain a main emulsifier solution; mix 100 mL of the co-emulsifier solution and 50 mL of the main emulsifier solution evenly and add them to a beaker, and stir at 200 r / min for 30 min to obtain an emulsifier solution.

[0043] S2. Inside a 200 mL double-jacketed reactor, a four-blade helical agitator is installed. Add 0.3 g of iodine transfer agent CHI3 and 100 mL of emulsifier solution to the reactor. The reactor is purged with propylene three times, and then the temperature of the reactor is raised to 35 °C, and the mixture is reacted at 100 r / min for 100 min to obtain copolymer emulsion I.

[0044] S3. The temperature of the reactor is raised to 40 °C, and then 10 g of maleimide powder is transferred to the reactor through a three-way conduit, and the reaction is carried out at 100 r / min for 100 min to obtain copolymer emulsion I. The temperature of the reactor is further raised to 50 °C, and then 15 mL of allyl cinnamate is transferred to the reactor through a three-way conduit, and the reaction is continued for 130 min to obtain copolymer emulsion II. Then, 5 mL of 0.5%wt hydroquinone ethanol solution is added to the reactor to terminate the polymerization; the temperature of the reactor is cooled to room temperature, and the product is discharged to obtain copolymer emulsion; the copolymer emulsion is added to 500 mL of acidified ethanol for stirring and sedimentation, and the solvent is removed with a Buchner funnel to obtain a polymer; the polymer is placed in a vacuum oven at 60 °C and dried until a constant weight is obtained to obtain block copolymerized polypropylene. Example 5

[0045] This example provides a method for preparing block copolymerized polypropylene for modified polypropylene HPPM square power corrugated pipes, including the following steps:

[0046] S1. 26 mL of co-emulsifier isooctadecane is dissolved in 100 mL of benzyl benzoate to obtain a co-emulsifier solution; 25 g of main emulsifier sodium dodecyl sulfate is dissolved in 50 mL of deionized water to obtain a main emulsifier solution; 110 mL of co-emulsifier solution and 50 mL of main emulsifier solution are mixed evenly and added to a beaker, and the mixture is stirred at 150 r / min for 30 min to obtain an emulsifier solution.

[0047] S2. Inside a 200 mL double-jacketed reactor, a four-blade helical agitator is installed. Add 0.4 g of iodine transfer agent CHI3 and 120 mL of emulsifier solution to the reactor. The reactor is purged with propylene three times, and then the temperature of the reactor is raised to 36 °C, and the mixture is reacted at 150 r / min for 105 min to obtain copolymer emulsion I.

[0048] S3. The reactor is heated to 450 °C, and then 15 g of maleimide powder is transferred into the reactor through a three-way conduit. The reaction is carried out at 110 r / min for 115 min to obtain copolymer emulsion I. The reactor is further heated to 55 °C, and then 16 mL of allyl cinnamate is transferred into the reactor through the three-way conduit, and the reaction is continued for 140 min to obtain copolymer emulsion II. Then, 5 mL of 0.6%wt hydroquinone ethanol solution is added to the reactor to terminate the polymerization; the reactor is cooled to room temperature, and the product is discharged to obtain the copolymer emulsion; the copolymer emulsion is added to 500 mL of acidified ethanol for stirring and sedimentation, and the solvent is removed with a Buchner funnel to obtain the polymer; the polymer is placed in a vacuum oven at 60 °C and dried until constant weight to obtain block copolymerized polypropylene. Example 6

[0049] This example provides a preparation method of block copolymerized polypropylene for modified polypropylene HPPM square power corrugated pipes, including the following steps:

[0050] S1. 30 mL of co-emulsifier isooctadecane is dissolved in 100 mL of benzyl benzoate to obtain a co-emulsifier solution; 25 g of main emulsifier sodium dodecyl sulfate is dissolved in 50 mL of deionized water to obtain a main emulsifier solution; 120 mL of the co-emulsifier solution and 50 mL of the main emulsifier solution are mixed evenly and added to a beaker, and mixed and stirred at 200 r / min for 30 min to obtain an emulsifier solution.

[0051] S2. A four-blade helical stirrer is arranged inside a 200 mL double-jacket reactor. 0.5 g of iodine transfer agent CHI3 and 150 mL of the emulsifier solution are added to the reactor. The reactor is purged with propylene three times, and then the reactor is heated to 40 °C and mixed and reacted at 200 r / min for 120 min to obtain copolymer emulsion I.

[0052] S3. The reactor is heated to 50 °C, and then 20 g of maleimide powder is transferred into the reactor through a three-way conduit. The reaction is carried out at 200 r / min for 120 min to obtain copolymer emulsion I. The reactor is further heated to 60 °C, and then 20 mL of allyl cinnamate is transferred into the reactor through the three-way conduit, and the reaction is continued for 150 min to obtain copolymer emulsion II. Then, 5 mL of 1%wt hydroquinone ethanol solution is added to the reactor to terminate the polymerization; the reactor is cooled to room temperature, and the product is discharged to obtain the copolymer emulsion; the copolymer emulsion is added to 500 mL of acidified ethanol for stirring and sedimentation, and the solvent is removed with a Buchner funnel to obtain the polymer; the polymer is placed in a vacuum oven at 60 °C and dried until constant weight to obtain block copolymerized polypropylene. Example 7

[0053] This example provides a preparation process of modified polypropylene HPPM square power corrugated pipes, including the following steps:

[0054] B1. By weight, mix 60 parts of the block copolymer polypropylene prepared in Example 4, 0.2 part of the modified nucleating agent prepared in Example 1, 5 parts of alkaline glass fiber, 0.5 part of tribasic lead sulfate, 1 part of dibutyl sebacate, 0.5 part of antioxidant 330, 0.1 part of 2,4-dihydroxybenzophenone and 1 part of paraffin wax evenly, and then add them into a twin-screw extruder for extrusion granulation. Among them, the extrusion temperature is 200 °C, and the screw speed of the twin-screw extruder is 100 r / min to obtain a mixed masterbatch.

[0055] B2. Inject the mixed masterbatch into a spline by an injection molding machine to obtain the prepared modified polypropylene HPPM square power corrugated pipe; among them, the injection temperature is 225 °C, and the injection pressure is 30 MPa; among them, the injection holding pressure and the holding pressure time are 30 s, and the cooling time is 20 s. Example 8

[0056] This example provides a preparation process for a modified polypropylene HPPM square power corrugated pipe, including the following steps:

[0057] B1. By weight, mix 63 parts of the block copolymer polypropylene prepared in Example 4, 0.3 part of the modified nucleating agent prepared in Example 1, 6 parts of alkaline glass fiber, 0.6 part of tribasic lead sulfate, 1.5 parts of dibutyl sebacate, 0.6 part of antioxidant 330, 0.2 part of 2,4-dihydroxybenzophenone and 1.2 parts of paraffin wax evenly, and then add them into a twin-screw extruder for extrusion granulation. Among them, the extrusion temperature is 205 °C, and the screw speed of the twin-screw extruder is 100 r / min to obtain a mixed masterbatch.

[0058] B2. Inject the mixed masterbatch into a spline by an injection molding machine to obtain the prepared modified polypropylene HPPM square power corrugated pipe; among them, the injection temperature is 230 °C, and the injection pressure is 30 MPa; among them, the injection holding pressure and the holding pressure time are 30 s, and the cooling time is 22 s. Example 9

[0059] This example provides a preparation process for a modified polypropylene HPPM square power corrugated pipe, including the following steps:

[0060] B1. By weight, mix 70 parts of the block copolymer polypropylene prepared in Example 4, 0.5 part of the modified nucleating agent prepared in Example 1, 10 parts of alkaline glass fiber, 1 part of tribasic lead sulfate, 2 parts of dibutyl sebacate, 1 part of antioxidant 330, 0.5 part of 2,4-dihydroxybenzophenone and 1.5 parts of paraffin wax evenly, and then add them into a twin-screw extruder for extrusion granulation. Among them, the extrusion temperature is 210 °C, and the screw speed of the twin-screw extruder is 100 r / min to obtain a mixed masterbatch.

[0061] B2. The masterbatch is injected into a spline by an injection molding machine to obtain the prepared modified polypropylene HPPM square power bellows. Among them, the injection temperature is 240 °C and the injection pressure is 30 MPa. Among them, the injection holding pressure and the holding pressure time are 30 s, and the cooling time is 30 s.

[0062] Comparative Example 1

[0063] Compared with Example 9 of the present invention, when preparing the masterbatch, polypropylene of the same quality is used to replace block copolymer polypropylene.

[0064] Comparative Example 2

[0065] Compared with Example 9 of the present invention, when preparing the masterbatch, the modified nucleating agent is not added.

[0066] Comparative Example 3

[0067] Compared with Example 9 of the present invention, when preparing the masterbatch, alkaline glass fiber is not added.

[0068] Performance test:

[0069] 1. According to GB / T1040-2006 "Determination of Tensile Properties of Plastics", the tensile strength of the modified polypropylene HPPM square power bellows prepared in Examples 7-9 and Comparative Examples 1-3 is tested, and the tensile rate is 50 mm / min.

[0070] 2. According to GB / T1043.1-2008 "Determination of Charpy Impact Properties", the impact properties of the modified polypropylene HPPM square power bellows prepared in Examples 7-9 and Comparative Examples 1-3 are tested. Among them, a 4J pendulum is selected, and the test temperatures are 23 °C and -20 °C respectively.

[0071] 3. According to GB / T9341-2008 "Determination of Bending Properties of Plastics", the bending properties of the modified polypropylene HPPM square power bellows prepared in Examples 7-9 and Comparative Examples 1-3 are tested. Among them, the bending rate is 2 mm / min. The specific test results are shown in Table 1:

[0072]

[0073] Data analysis:

[0074] By comparing and analyzing the data in Table 1 above, the mechanical properties and toughness of the modified polypropylene HPPM square power bellows prepared in Examples 7-9 of the present invention are excellent, which is manifested by higher values of tensile strength, impact strength and bending strength. However, in Comparative Example 1, when preparing the masterbatch, polypropylene is used to replace block copolymer polypropylene, reducing its own toughness and mechanical properties, which is manifested by the reduction of the values of tensile strength, bending strength and impact strength at high and low temperatures.

[0075] In Comparative Example 2, no modified nucleating agent was added during the preparation of the masterbatch. The modified nucleating agent helps to induce the formation of β-crystalline form in the crystalline region of polypropylene. The mechanical properties of polypropylene with β-crystalline form are better. Therefore, the strength value of the modified polypropylene HPPM square power corrugated pipe prepared in Comparative Example 2 decreased. In Comparative Example 3, no alkaline glass fiber was added during the preparation of the masterbatch, which reduced the impact strength value of the modified polypropylene HPPM square power corrugated pipe, but its toughness did not decrease, as shown by the unchanged tensile strength value and flexural strength value.

[0076] The above content is only an example and illustration of the structure of the present invention. Those skilled in the art of the present technology can make various modifications or supplements to the described specific embodiments or use similar ways to replace them. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims of the present invention, they should fall within the protection scope of the present invention.

[0077] In the description of this specification, the descriptions referring to terms such as "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0078] 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 the specific implementation manners. Obviously, many modifications and variations can be made according to the content of this specification. The present specification selects and specifically describes these embodiments to better explain the principle and practical application of the present invention, so that those skilled in the art can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A modified polypropylene HPPM square power corrugated pipe, characterized in that: According to weight parts, it includes 60-70 parts of block copolymer polypropylene, 0.2-0.5 parts of modified nucleating agent, 5-10 parts of alkaline glass fiber, 0.5-1 parts of heat stabilizer, 1-2 parts of plasticizer, 0.5-1 parts of antioxidant, 0.1-0.5 parts of light stabilizer and 1-1.5 parts of lubricant; The preparation method of the modified nucleating agent comprises the following steps: A1, ethylenediamine and 1,4-dioxane are mixed evenly to obtain an ethylenediamine solution; hexachlorocyclotriphosphazene and 1,4-dioxane are mixed evenly to obtain a hexachlorocyclotriphosphazene solution; the hexachlorocyclotriphosphazene solution is added dropwise to the ethylenediamine solution, and after the addition is completed, the reaction is carried out at a constant temperature of 40-50° C. for 2 hours to obtain a product; the product is distilled under reduced pressure to obtain a white solid polyamine phosphazene; A2, dissolving phthalic anhydride in tetrahydrofuran to obtain a phthalic anhydride solution; mixing polyamine phosphazene and tetrahydrofuran, stirring at 50-60° C. until completely dissolved, to obtain a polyamine phosphazene solution; dropping the polyamine phosphazene solution dropwise into the phthalic anhydride solution, and after the dropwise addition is completed, continuing the reaction at room temperature for 24 hours to obtain a reaction system; centrifuging the reaction system, washing with deionized water, and vacuum drying at 60° C. to constant weight to obtain a modified nucleating agent; The method for preparing the block copolymer polypropylene comprises the following steps: S1, dissolving an auxiliary emulsifier, isohexadecane, in benzyl benzoate to obtain an auxiliary emulsifier solution; dissolving a primary emulsifier, sodium dodecyl sulfate, in deionized water to obtain a primary emulsifier solution; and uniformly mixing the auxiliary emulsifier solution and the primary emulsifier solution to obtain an emulsifier solution; S2, add iodine transfer agent CHI3 and emulsifier solution into the reactor, and ventilate the reactor with propylene three times; react the reactor at 35-40°C for 100-120min to obtain copolymer emulsion I; S3. The maleimide powder is transferred to a reactor, and the copolymer emulsion is reacted at 50-60°C for 100-120min to obtain copolymer emulsion I; allyl cinnamate is added to the reactor, and the copolymer emulsion is reacted at 50-60°C for 130-150min to obtain copolymer emulsion II; 0.5-1%wt of hydroquinone ethanol solution is added to the reactor to terminate the reaction, and the reactor is cooled to room temperature, and the material is discharged to obtain the copolymer emulsion; the copolymer emulsion is subjected to post-processing to obtain block copolymer polypropylene.

2. A modified polypropylene HPPM square power corrugated pipe according to claim 1, characterized in that: In step A1, the usage ratio of ethylenediamine and 1,4-dioxane is 5-10g:25mL, the usage ratio of hexachlorocyclotriphosphazene and 1,4-dioxane is 15-20g:100mL; the usage ratio of ethylenediamine solution and hexachlorocyclotriphosphazene solution is 30mL:120mL; in step A2, the usage ratio of phthalic anhydride and tetrahydrofuran is 15g:100mL; the usage ratio of polyamine phosphazene and tetrahydrofuran is 20-30g:100mL; the usage ratio of polyamine phosphazene solution and phthalic anhydride solution is 115-120mL:120mL.

3. A modified polypropylene HPPM square power corrugated pipe according to claim 1, characterized in that: In step S1, the dosage ratio of the auxiliary emulsifier to benzyl benzoate is 25-30 mL:100 mL; the dosage ratio of sodium dodecyl sulfate to deionized water is 25 g:100 mL; and the dosage ratio of the auxiliary emulsifier solution to the primary emulsifier solution is 100-120 mL:120 mL.

4. A modified polypropylene HPPM square power corrugated pipe according to claim 1, characterized in that: In step S2, the dosage ratio of the iodine transfer agent and the emulsifier solution is 0.3-0.5 g:100-150 mL; the dosage of the maleimide powder is 10-20 g, the dosage of allyl cinnamate is 15-20 mL, and the dosage of the hydroquinone ethanol solution is 5 mL.

5. A modified polypropylene HPPM square power corrugated pipe according to claim 1, characterized in that: In step S3, the post-process treatment includes: adding 30-50 mL of the copolymer emulsion into acidified ethanol, stirring and settling, and then removing the solvent with a Buchner funnel to obtain a polymer; the polymer is placed in a vacuum oven at 60° C. and dried to constant weight to obtain block copolymer polypropylene.

6. A modified polypropylene HPPM square power corrugated pipe according to claim 1, characterized in that: The heat stabilizer is tribasic lead sulfate, the plasticizer is butylene sebacate, the antioxidant is antioxidant 330, the light stabilizer is 2,4-dihydroxybenzophenone, and the lubricant is paraffin.

7. A method for preparing a modified polypropylene HPPM square power corrugated pipe according to any one of claims 1 to 6, characterized in that: The following steps are involved: B1. Mix block copolymer polypropylene, modified nucleating agent, alkaline glass fiber, heat stabilizer, plasticizer, antioxidant, light stabilizer and lubricant evenly, add them into a twin-screw extruder for melt extrusion, the melt extrusion temperature is 200-210° C., and the screw speed is 100 r / min to obtain a composite material; B2. The mixed masterbatch is injected into a strip by an injection molding machine. The injection temperature is 225-240° C., the injection pressure is 30 MPa, the injection pressure holding time is 30 s, and the cooling time is 20-30 s; a modified polypropylene HPPM square power corrugated pipe is obtained.

Images