High-impact-resistance PP (polypropylene) rectangular-opening drain pipe and preparation method thereof

Abstract

The invention belongs to the technical field of pipes, and particularly relates to a high-impact-resistance PP rectangular opening drainage pipe and a preparation method thereof. The drainage pipe is prepared from the following raw materials in parts by mass: 55 to 70 parts of polypropylene resin, 5 to 15 parts of polyolefin elastomer, 1 to 3 parts of ethylene-acrylic acid copolymer, 5 to 10 parts of modified talcum powder, 0.1 to 0.3 part of aromatic diamide beta nucleating agent, 0.5 to 1 part of polyester nucleating agent, 0.6 to 1 part of antioxidant and 1 to 1.5 parts of calcium stearate. The PP rectangular opening drain pipe prepared by the invention has excellent tensile strength, impact resistance, bending modulus, aging resistance and the like on the whole.

Description

Technical Field

[0001] The present invention belongs to the technical field of pipes, and in particular relates to a high-impact PP rectangular drainage pipe and a preparation method thereof. Background Art

[0002] Traditional drainage pipes, such as reinforced concrete and cast iron pipes, while strong, are heavy and difficult to transport. They also suffer from rough interior walls, creating significant flow resistance and prone to impurity adhesion and scaling. They also have poor corrosion resistance, particularly when transporting wastewater containing acidic and alkaline components, which can lead to corrosion and damage, shortening the pipe's service life. Polypropylene (PP) offers advantages such as ease of processing, light weight, wear resistance, and resistance to scaling. Currently, polypropylene pipes are gaining popularity and are being used in building drainage, municipal pipe networks, agricultural irrigation, industrial infusion, and other fields.

[0003] However, existing polypropylene drainage pipes still have some performance flaws. Some products experience rapid performance degradation in extreme temperatures or high-corrosion conditions, making them unable to meet drainage requirements. To overcome these flaws, polypropylene is often modified through filling, reinforcement, blending, copolymerization, and cross-linking. For example, materials such as calcium carbonate and glass fiber are added to enhance the tensile strength, impact resistance, and other related properties of polypropylene.

[0004] The Chinese patent application document with application publication number CN110105672A discloses an improved copolymer polypropylene injection molding tube, which includes the following raw materials: 70-80 parts of high-impact copolymer polypropylene resin, 10-16 parts of α-nucleating agent, 6-12 parts of barium sulfate, 6-12 parts of toughening agent, 0.2-0.8 parts of antioxidant, 0.1-0.5 parts of coupling agent, and 0.2-0.8 parts of processing aid. Although the use of α-nucleating agent TMA-3 in this technical solution can improve rigidity, ductility and heat resistance, The impact resistance of α-crystalline polypropylene itself, especially its impact resistance at low temperatures, is weaker than that of β-crystalline polypropylene. Although the lack of impact performance can be compensated by adding polyolefin elastomers, the toughening effect of polyolefin elastomers depends on the uniformity of dispersion. The inorganic filler barium sulfate used in this technical solution has a high density and high surface energy. If it is unevenly dispersed, it is easy to agglomerate, which can easily weaken the toughening effect of the polyolefin elastomer and may cause brittle fracture of the material in low temperature or high stress impact scenarios, making it difficult to meet the use requirements in extreme environments. Summary of the Invention

[0005] Existing polypropylene pipes have the problem of weak impact resistance at low temperatures. In order to solve this problem, the present invention provides a high-impact PP rectangular drainage pipe and a preparation method thereof.

[0006] In order to achieve the purpose of the present invention, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a high-impact PP rectangular drain pipe, which is made from the following raw materials in parts by weight: Polypropylene resin 55-70 parts, polyolefin elastomer 5-15 parts, ethylene-acrylic acid copolymer 1-3 parts, modified talc 5-10 parts, aromatic diamide β nucleating agent 0.1-0.3 parts, polyester nucleating agent 0.5-1 parts, antioxidant 0.6-1 parts, calcium stearate 1-1.5 parts; By adopting the above technical solution, with polypropylene resin as the matrix, polyolefin elastomer is dispersed in the PP matrix to absorb impact energy; ethylene-acrylic acid copolymer can be used as a compatibilizer to combine with the groups on the surface of polyolefin elastomer and modified talc powder to reduce interfacial tension, make the polyolefin elastomer more evenly dispersed, avoid performance fluctuations caused by phase separation, and ensure the toughening effect; aromatic diamide β nucleating agent and polyester nucleating agent work synergistically to increase the β crystal content, further improving the impact resistance of the pipe.

[0007] The preparation method of the polyester nucleating agent comprises the following steps: (1) drying biphenyl-2,5-dicarboxylic acid, 4,4'-dihydroxydiphenyl ether and the catalyst separately to obtain dried biphenyl-2,5-dicarboxylic acid, 4,4'-dihydroxydiphenyl ether and the catalyst; (2) Under nitrogen conditions, the dried biphenyl-2,5-dicarboxylic acid, 4,4'-dihydroxydiphenyl ether and catalyst are mixed evenly, the temperature is raised to carry out a prepolymerization reaction, the nitrogen is turned off, vacuum is drawn to carry out a secondary reaction, the reaction is cooled, and the reaction is dried to obtain a polyester nucleating agent.

[0008] By adopting the above technical solution, the polyester nucleating agent is formed by the condensation of biphenyl-2,5-dicarboxylic acid and 4,4'-dihydroxydiphenyl ether. The molecule contains a benzene ring and an ester group, which can provide nucleation sites for PP and induce β-crystal growth. The ester group can react with groups such as carboxyl groups in the ethylene-acrylic acid copolymer to improve its own dispersibility in PP.

[0009] Preferably, in step (2), the molar ratio of biphenyl-2,5-dicarboxylic acid to 4,4'-dihydroxydiphenyl ether is 1:(1-1.05).

[0010] By adopting the above technical solution, the reaction can be fully ensured under this ratio, which is conducive to the formation of a polyester nucleating agent with moderate molecular weight and uniform distribution: a slight excess of 4,4'-dihydroxydiphenyl ether can ensure that biphenyl-2,5-dicarboxylic acid as the acid component in the reaction can more fully participate in the polycondensation reaction, reduce the residual unreacted carboxylic acid groups, and improve the raw material conversion rate.

[0011] Preferably, in step (2), the catalyst is prepared by mixing zinc acetate, antimony trioxide and antimony acetate.

[0012] By adopting the above technical solution, zinc acetate has a strong ability to activate carboxyl groups, which can quickly promote the esterification reaction between carboxyl groups and hydroxyl groups and accelerate the formation of oligomers; antimony trioxide and antimony acetate work together to catalyze the ester exchange reaction in the high-temperature polycondensation stage, and the organic carboxylate groups of antimony acetate make it better dispersible and the catalysis more uniform; antimony trioxide is more stable under vacuum conditions and can continuously promote the removal of water; compared with a single catalyst, the combination of the two can make the catalytic active centers more evenly distributed and improve the reaction efficiency.

[0013] Preferably, the amount of zinc acetate is 0.1%-0.3% of the total mass of biphenyl-2,5-dicarboxylic acid and 4,4'-dihydroxydiphenyl ether, the amount of antimony trioxide is 0.2%-0.4% of the total mass of biphenyl-2,5-dicarboxylic acid and 4,4'-dihydroxydiphenyl ether, and the amount of antimony acetate is 0.1%-0.2% of the total mass of biphenyl-2,5-dicarboxylic acid and 4,4'-dihydroxydiphenyl ether.

[0014] By adopting the above technical solution and compounding the three in this ratio, it can be ensured that the entire reaction stage is fully carried out, avoiding the problem of insufficient activity of a single catalyst at a certain stage; too high a catalyst dosage can easily lead to an increase in the amount of residual metal ions, affecting the purity of the polyester nucleating agent and reducing the structural regularity of the nucleating agent; too low a catalyst dosage can easily lead to incomplete condensation reaction, small product molecular weight and irregular structure.

[0015] Preferably, in step (2), the prepolymerization temperature is 185-200° C., and the prepolymerization time is 2-3 h.

[0016] By adopting the above technical solution, the prepolymerization reaction at this temperature can form a step-by-step temperature control with the subsequent secondary reaction, avoiding problems such as local overheating caused by sudden temperature rise, and making the reaction smoothly transition from the "prepolymerization" stage to the "condensation" stage; the amount of oligomer generated can be guaranteed to be stable within this time range.

[0017] Preferably, in step (2), the temperature of the secondary reaction is 240-255° C., and the time of the secondary reaction is 4-6 hours.

[0018] By adopting the above technical solution, at this temperature, the mobility of the oligomer molecular chain segments is significantly enhanced, and the reactivity of the terminal hydroxyl group and the terminal ester group is greatly improved; within this time range, the oligomer can complete the process of connecting between oligomers and continuously removing trace water molecules, pushing the equilibrium towards the chain growth direction; and avoiding the generation of side reactions caused by excessive reaction.

[0019] Preferably, the preparation method of the modified talc powder comprises the following steps: The silane coupling agent and the ethanol aqueous solution are mixed evenly, and the pH is adjusted to 4-5 to obtain a silane coupling agent solution; the talc powder and the silane coupling agent solution are mixed evenly, and dried to obtain modified talc powder.

[0020] By adopting the above technical solution, the surface of talc powder is modified by using a silane coupling agent, and the organic functional groups of the silane coupling agent molecules extend outward, thereby improving its compatibility with materials such as polypropylene matrix.

[0021] Preferably, the amount of the silane coupling agent is 0.5%-2% of the mass of the talc powder; the mass fraction of the ethanol aqueous solution is 90%, and the amount ratio of the silane coupling agent to the ethanol aqueous solution is 1g: (7-8)mL.

[0022] By adopting the above technical solution, if the amount of silane coupling agent is too low, it is easy for talc powder to agglomerate in the polypropylene material; if the amount is too high, the excess silane coupling agent is prone to self-polymerization reaction. At the same time, the excess coupling agent is likely to remain in the composite material, becoming a stress concentration point, resulting in a decrease in impact resistance.

[0023] In a second aspect, the present invention provides a method for preparing the above-mentioned high-impact PP rectangular drainage pipe, comprising the following steps: S1: uniformly mixing polypropylene resin, polyolefin elastomer, ethylene-acrylic acid copolymer, modified talc, aromatic diamide β nucleating agent, polyester nucleating agent, antioxidant, and calcium stearate, kneading, extruding, and granulating to obtain granular material; S2: Extrude the granular material into a shape to obtain a high-impact PP rectangular drainage pipe.

[0024] By adopting the above technical solution, the preparation process is simple, the raw materials are evenly dispersed, and the prepared drainage pipe has properties such as high impact resistance.

[0025] Preferably, in step S2, the extrusion temperature is 175-220°C.

[0026] By adopting the above technical solution, this temperature can achieve stable production of high-impact PP rectangular drainage pipes.

[0027] The reaction formula of the above polyester nucleating agent is as follows:

[0028] In summary, the beneficial effects of the present invention are: (1) The present invention mainly strengthens polypropylene through the synergistic effect of "polyolefin elastomer and β crystal toughening, talc powder reinforcement", and compounding antioxidants and other additives, so that the prepared PP rectangular drainage pipe has excellent tensile strength, impact resistance, bending modulus and aging resistance. (2) The present invention prepares a β-type polyester nucleating agent through polycondensation reaction, which can generate β crystals and refine grains. The aromatic diamide β nucleating agent can efficiently induce the formation of β crystals. The two can synergistically increase the β crystal content and stability and enhance the toughening effect. The rigid main chain of the polyester nucleating agent can also form a π-π stacking effect with the amide group of the aromatic diamide β nucleating agent, thereby improving the compatibility of the nucleating agent with PP. (3) The present invention utilizes a silane coupling agent to form a uniform coating layer on the surface of talc powder, thereby improving the interfacial compatibility between talc powder and the PP matrix, making it easy to disperse evenly during the mixing process, and reducing the fluctuation of the mechanical properties of the material caused by particle agglomeration. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a morphology diagram of the isothermal crystallization of the pure polypropylene resin of the present invention at 130°C; Figure 2 This is a morphology diagram of the isothermal crystallization of the polypropylene resin to which only the polyester nucleating agent is added at 130°C; Figure 3 is the infrared spectrum of the polyester nucleating agent of the present invention; Figure 4 The WAXD spectra of the pure polypropylene resin of the present invention and the polypropylene resin with only a polyester nucleating agent added thereto after isothermal crystallization at 130°C are shown; wherein the m curve represents the polypropylene resin with only a polyester nucleating agent added thereto, and the n curve represents the pure polypropylene resin. DETAILED DESCRIPTION

[0030] The technical solution of the present invention is explained in detail below with reference to several representative embodiments of the present invention.

[0031] Unless otherwise specified, the experimental methods used in the following examples and comparative examples are all conventional methods. Unless otherwise specified, the materials, reagents, etc. used in the following examples and comparative examples are all commercially available.

[0032] The CAS number of biphenyl-2,5-dicarboxylic acid used in the following examples and comparative examples is 4445-51-6.

[0033] The TMB-5 used in the following examples and comparative examples is a polypropylene β-crystalline nucleating agent TMB-5.

[0034] Preparation Example 1 The preparation method of a modified talc powder in this preparation example comprises the following specific steps: Mix 2 g of silane coupling agent KH550 with 14 mL of 90% ethanol aqueous solution, stir for 30 min, and adjust the pH to 4 to obtain a silane coupling agent solution; add 100 g of dry talc powder into a reactor, heat to 65°C, add the silane coupling agent solution dropwise, continue stirring for 45 min, and transfer it to a vacuum drying oven and dry it at 80°C for 10 h to obtain modified talc powder.

[0035] Preparation Example 2 Mix 2 g of silane coupling agent KH550 with 16 mL of 90% ethanol aqueous solution, stir for 30 min, and adjust the pH to 5 to obtain a silane coupling agent solution; add 100 g of dry talc powder into a reactor, heat to 65°C, add the silane coupling agent solution dropwise, continue stirring for 45 min, and transfer it to a vacuum drying oven and dry it at 80°C for 10 h to obtain modified talc powder.

[0036] Example 1 The high-impact PP rectangular drain pipe of this embodiment is made of the following raw materials: 6.3 kg of polypropylene resin, 1.2 kg of polyolefin elastomer, 0.2 kg of ethylene-acrylic acid copolymer, 0.8 kg of modified talc, 0.02 kg of polypropylene β-crystal nucleating agent TMB-5 (TMB-5), 0.08 kg of polyester nucleating agent, 0.08 kg of antioxidant, and 0.15 kg of calcium stearate.

[0037] The method for preparing a high-impact PP rectangular drainage pipe in this embodiment comprises the following specific steps: S1: polypropylene resin, polyolefin elastomer, ethylene-acrylic acid copolymer, modified talc, TMB-5, polyester nucleating agent, antioxidant, and calcium stearate are uniformly mixed, kneaded, extruded, and granulated to obtain granular material; S2: Extruding the granular material into a high-impact PP rectangular drainage pipe; the extrusion temperature is 175-220℃.

[0038] The preparation method of a polyester nucleating agent of this embodiment comprises the following specific steps: (1) Biphenyl-2,5-dicarboxylic acid, 4,4'-dihydroxydiphenyl ether, zinc acetate, antimony trioxide and antimony acetate were placed in a vacuum drying oven at 80°C for 6 hours to obtain dried biphenyl-2,5-dicarboxylic acid, 4,4'-dihydroxydiphenyl ether, zinc acetate, antimony trioxide and antimony acetate; (2) Add 242.23g of biphenyl-2,5-dicarboxylic acid, 206.25g of 4,4'-dihydroxydiphenyl ether, 0.9g of zinc acetate, 1.35g of antimony trioxide and 0.45g of antimony acetate into a three-necked flask, introduce high-purity nitrogen to replace the air, continue stirring, and set the stirring speed at 150rpm. Start salt bath heating, raise the temperature to 190℃ and react for 3h. After the prepolymerization reaction is completed, turn off the nitrogen, start the oil pump to vacuum, raise the temperature to 255℃ and react for 5h, during which the stirring speed is maintained at 220rpm. After the reaction is completed, turn off the heating device, maintain the vacuum state and naturally cool to 150℃. Then introduce nitrogen to break the vacuum, naturally cool to room temperature, and place in a vacuum drying oven and dry at 120℃ for 8h to obtain a polyester nucleating agent.

[0039] Figure 3 This is the infrared spectrum of polyester nucleating agent; Figure 3 Medium, 3220cm -1 The stretching vibration peak of -OH is at 1709cm -1 The stretching vibration peak of C=O is 1594 cm -1 、1502cm -1 The stretching vibration peak of the benzene ring skeleton is near 1247cm -1 and 1050cm -1 The peaks at 837cm are the asymmetric stretching vibration peak and the symmetric stretching vibration peak of the ether bond; -1 The peak near the benzene ring hydrogen is the bending vibration peak; the above indicates that the polyester nucleating agent was successfully synthesized.

[0040] Example 2 The high-impact PP rectangular drain pipe of this embodiment is made of the following raw materials: 5.5 kg of polypropylene resin, 1 kg of polyolefin elastomer, 0.3 kg of ethylene-acrylic acid copolymer, 1 kg of modified talc, 0.03 kg of TMB-5, 0.05 kg of polyester nucleating agent, 0.06 kg of antioxidant, and 0.1 kg of calcium stearate.

[0041] The method for preparing a high-impact PP rectangular drainage pipe in this embodiment comprises the following specific steps: S1: polypropylene resin, polyolefin elastomer, ethylene-acrylic acid copolymer, modified talc, TMB-5, polyester nucleating agent, antioxidant, and calcium stearate are uniformly mixed, kneaded, extruded, and granulated to obtain granular material; S2: Extruding the granular material into a high-impact PP rectangular drainage pipe; the extrusion temperature is 175-220℃.

[0042] The preparation method of a polyester nucleating agent of this embodiment comprises the following specific steps: (1) Biphenyl-2,5-dicarboxylic acid, 4,4'-dihydroxydiphenyl ether, zinc acetate, antimony trioxide and antimony acetate were placed in a vacuum drying oven at 80°C for 6 hours to obtain dried biphenyl-2,5-dicarboxylic acid, 4,4'-dihydroxydiphenyl ether, zinc acetate, antimony trioxide and antimony acetate; (2) Add 242.23g of biphenyl-2,5-dicarboxylic acid, 202.21g of 4,4'-dihydroxydiphenyl ether, 0.45g of zinc acetate, 1.76g of antimony trioxide and 0.86g of antimony acetate into a three-necked flask, introduce high-purity nitrogen to replace the air, continue stirring, and set the stirring speed at 150rpm. Start the salt bath heating, raise the temperature to 200℃ and react for 2h. After the prepolymerization reaction is completed, turn off the nitrogen, start the oil pump to vacuum, raise the temperature to 240℃ and react for 5h, during which the stirring speed is maintained at 220rpm. After the reaction is completed, turn off the heating device, maintain the vacuum state and naturally cool to 150℃. Then introduce nitrogen to break the vacuum, cool naturally to room temperature, and place in a vacuum drying oven at 120℃ and dry for 8h to obtain a polyester nucleating agent.

[0043] Example 3 The high-impact PP rectangular drain pipe of this embodiment is made of the following raw materials: 7 kg of polypropylene resin, 1.05 kg of polyolefin elastomer, 0.3 kg of ethylene-acrylic acid copolymer, 1 kg of modified talc, 0.03 kg of TMB-5, 0.1 kg of polyester nucleating agent, 0.09 kg of antioxidant, and 0.12 kg of calcium stearate.

[0044] The method for preparing a high-impact PP rectangular drainage pipe in this embodiment comprises the following specific steps: S1: polypropylene resin, polyolefin elastomer, ethylene-acrylic acid copolymer, modified talc, TMB-5, polyester nucleating agent, antioxidant, and calcium stearate are uniformly mixed, kneaded, extruded, and granulated to obtain granular material; S2: Extruding the granular material into a high-impact PP rectangular drainage pipe; the extrusion temperature is 175-220℃.

[0045] The preparation method of a polyester nucleating agent of this embodiment comprises the following specific steps: (1) Biphenyl-2,5-dicarboxylic acid, 4,4'-dihydroxydiphenyl ether, zinc acetate, antimony trioxide and antimony acetate were placed in a vacuum drying oven at 80°C for 6 hours to obtain dried biphenyl-2,5-dicarboxylic acid, 4,4'-dihydroxydiphenyl ether, zinc acetate, antimony trioxide and antimony acetate; (2) Add 242.23g of dried biphenyl-2,5-dicarboxylic acid, 212.32g of 4,4'-dihydroxydiphenyl ether, 1.36g of zinc acetate, 1.14g of antimony trioxide and 0.69g of antimony acetate into a three-necked flask, introduce high-purity nitrogen to replace the air, continue stirring, and set the stirring speed at 150rpm. Start salt bath heating, raise the temperature to 185℃ and react for 3h. After the prepolymerization reaction is completed, turn off the nitrogen, start the oil pump to vacuum, raise the temperature to 245℃ and react for 6h, during which the stirring speed is maintained at 220rpm. After the reaction is completed, turn off the heating device, maintain the vacuum state and naturally cool to 150℃. Then introduce nitrogen to break the vacuum, cool naturally to room temperature, and place in a vacuum drying oven at 120℃ and dry for 8h to obtain a polyester nucleating agent.

[0046] Example 4 The high-impact PP rectangular drain pipe of this embodiment is made of the following raw materials: 6.8 kg of polypropylene resin, 1.5 kg of polyolefin elastomer, 0.1 kg of ethylene-acrylic acid copolymer, 0.5 kg of modified talc, 0.01 kg of TMB-5, 0.07 kg of polyester nucleating agent, 0.1 kg of antioxidant, and 0.15 kg of calcium stearate.

[0047] The method for preparing a high-impact PP rectangular drainage pipe in this embodiment comprises the following specific steps: S1: polypropylene resin, polyolefin elastomer, ethylene-acrylic acid copolymer, modified talc, TMB-5, polyester nucleating agent, antioxidant, and calcium stearate are uniformly mixed, kneaded, extruded, and granulated to obtain granular material; S2: Extruding the granular material into a high-impact PP rectangular drainage pipe; the extrusion temperature is 175-220℃.

[0048] The preparation method of a polyester nucleating agent of this embodiment comprises the following specific steps: (1) Biphenyl-2,5-dicarboxylic acid, 4,4'-dihydroxydiphenyl ether, zinc acetate, antimony trioxide and antimony acetate were placed in a vacuum drying oven at 80°C for 6 hours to obtain dried biphenyl-2,5-dicarboxylic acid, 4,4'-dihydroxydiphenyl ether, zinc acetate, antimony trioxide and antimony acetate; (2) Add 242.23g of dried biphenyl-2,5-dicarboxylic acid, 210.3g of 4,4'-dihydroxydiphenyl ether, 1.13g of zinc acetate, 0.91g of antimony trioxide and 0.46g of antimony acetate into a three-necked flask, introduce high-purity nitrogen to replace the air, continue stirring, and set the stirring speed at 150rpm. Start salt bath heating, raise the temperature to 190℃ and react for 3h. After the prepolymerization reaction is completed, turn off the nitrogen, start the oil pump to vacuum, raise the temperature to 255℃ and react for 5h, during which the stirring speed is maintained at 220rpm. After the reaction is completed, turn off the heating device, maintain the vacuum state and naturally cool to 150℃. Then introduce nitrogen to break the vacuum, cool naturally to room temperature, and place in a vacuum drying oven at 120℃ and dry for 8h to obtain a polyester nucleating agent.

[0049] Comparative Example 1 The difference from Example 1 is that TMB-5 and polyester nucleating agent are not added in this comparative example.

[0050] Comparative Example 2 The difference from Example 1 is that TMB-5 is not added in this comparative example.

[0051] Comparative Example 3 The difference from Example 1 is that no polyester nucleating agent is added in this comparative example.

[0052] Comparative Example 4 The difference from Example 1 is that no modified talc is added in this comparative example.

[0053] Comparative Example 5 The difference from Example 1 is that no polyolefin elastomer is added in this comparative example.

[0054] Related performance tests 1. Optical topography test The crystal morphology of the pure polypropylene resin and the polypropylene resin with only the polyester nucleating agent added (prepared by the same method as in Example 1) were observed using a hot stage polarizing microscope. Figure 1 This is the morphology of pure polypropylene resin isothermally crystallized at 130℃. Figure 2 This is the morphology of isothermal crystallization of polypropylene resin with only polyester nucleating agent added at 130℃.

[0055] Depend on Figure 1 and Figure 2 It can be seen that the pure polypropylene resin is α-crystal with large crystal size; while the sample with added polyester nucleating agent has smaller crystal size and more crystal number, indicating that the polyester nucleating agent prepared by the present invention has a significant nucleating effect on polypropylene.

[0056] 2. Wide-angle X-ray diffraction analysis The crystal forms of pure polypropylene resin and polypropylene resin with only polyester nucleating agent added were tested by wide-angle X-ray diffractometer. Figure 4 These are the WAXD spectra of pure polypropylene resin and polypropylene resin with only polyester nucleating agent added after isothermal crystallization at 130°C; among them, the m curve represents the polypropylene resin with only polyester nucleating agent added, and the n curve represents the pure polypropylene resin.

[0057] Depend on Figure 4 It can be seen that in the WAXD curve of pure polypropylene resin, there are five main diffraction peaks, with 2θ values ​​located at 14°, 16.8°, 18.4°, 21.1°, and 21.8°, respectively, representing the (110), (040), (130), (131), and (111) crystal plane diffraction peaks of α crystal, which are typical α crystal forms. The polypropylene resin with the addition of polyester nucleating agent has a large (300) crystal plane diffraction peak at 2θ value of 16°, which is typical of β crystal form, indicating that the polyester nucleating agent is a β-type nucleating agent.

[0058] 3. Mechanical properties test High-impact PP rectangular drain pipes prepared in Examples 1-4 and Comparative Examples 1-5 were subjected to relevant performance tests. Tensile yield strength was tested according to GB / T 1040.1-2018; bending performance was tested according to GB / T 9341-2008; and impact performance was tested according to GB / T 1043.1-2008. The test results are shown in Table 1.

[0059] Table 1 Test results

[0060] As can be seen from Table 1, the PP rectangular drainage pipe prepared in the present invention has excellent tensile strength, impact resistance and other properties.

[0061] The above is an exemplary description of the present invention. It should be noted that, without departing from the core of the present invention, any simple deformation, modification or other equivalent replacement that can be made by other skilled in the art without expending creative labor shall fall within the scope of protection of the present invention.

Claims

1. A high impact PP rectangular drain pipe, characterized in that: The high-impact PP rectangular drain pipe is made from the following raw materials in parts by mass: Polypropylene resin 55-70 parts, polyolefin elastomer 5-15 parts, ethylene-acrylic acid copolymer 1-3 parts, modified talc 5-10 parts, aromatic diamide β nucleating agent 0.1-0.3 parts, polyester nucleating agent 0.5-1 parts, antioxidant 0.6-1 parts, calcium stearate 1-1.5 parts; The preparation method of the polyester nucleating agent comprises the following steps: (1) drying biphenyl-2,5-dicarboxylic acid, 4,4'-dihydroxydiphenyl ether and the catalyst separately to obtain dried biphenyl-2,5-dicarboxylic acid, 4,4'-dihydroxydiphenyl ether and the catalyst; (2) Under nitrogen conditions, the dried biphenyl-2,5-dicarboxylic acid, 4,4'-dihydroxydiphenyl ether and catalyst are mixed evenly, the temperature is raised to carry out a prepolymerization reaction, the nitrogen is turned off, vacuum is drawn to carry out a secondary reaction, the reaction is cooled, and the reaction is dried to obtain a polyester nucleating agent.

2. A high impact PP rectangular drain pipe according to claim 1, characterized in that: In the step (2), the molar ratio of biphenyl-2,5-dicarboxylic acid to 4,4'-dihydroxydiphenyl ether is 1:(1-1.05).

3. The high-impact PP rectangular drain pipe according to claim 1, characterized in that: In the step (2), the catalyst is prepared by mixing zinc acetate, antimony trioxide and antimony acetate.

4. A high impact PP rectangular drain pipe according to claim 3, characterized in that: The amount of zinc acetate used is 0.1%-0.3% of the total mass of biphenyl-2,5-dicarboxylic acid and 4,4'-dihydroxydiphenyl ether, the amount of antimony trioxide used is 0.2%-0.4% of the total mass of biphenyl-2,5-dicarboxylic acid and 4,4'-dihydroxydiphenyl ether, and the amount of antimony acetate used is 0.1%-0.2% of the total mass of biphenyl-2,5-dicarboxylic acid and 4,4'-dihydroxydiphenyl ether.

5. The high-impact PP rectangular drain pipe according to claim 1, characterized in that: In the step (2), the temperature of the prepolymerization reaction is 185-200° C., and the time of the prepolymerization reaction is 2-3 hours.

6. The high-impact PP rectangular drain pipe according to claim 1, characterized in that: In the step (2), the temperature of the secondary reaction is 240-255° C., and the time of the secondary reaction is 4-6 hours.

7. The high-impact PP rectangular drain pipe according to claim 1, characterized in that: The preparation method of the modified talc powder comprises the following steps: The silane coupling agent and the ethanol aqueous solution are mixed evenly, and the pH is adjusted to 4-5 to obtain a silane coupling agent solution; the talc powder and the silane coupling agent solution are mixed evenly, and dried to obtain modified talc powder.

8. The high-impact PP rectangular drain pipe according to claim 7, characterized in that: The dosage of the silane coupling agent is 0.5%-2% of the mass of the talc powder; the mass fraction of the ethanol aqueous solution is 90%, and the dosage ratio of the silane coupling agent to the ethanol aqueous solution is 1g:(7-8)mL.

9. The method for preparing a high-impact PP rectangular drain pipe according to any one of claims 1 to 8, characterized in that: The steps include: S1: uniformly mixing polypropylene resin, polyolefin elastomer, ethylene-acrylic acid copolymer, modified talc, aromatic diamide β nucleating agent, polyester nucleating agent, antioxidant, and calcium stearate, kneading, extruding, and granulating to obtain granular material; S2: Extrude the granular material into a shape to obtain a high-impact PP rectangular drainage pipe.

10. The method for preparing a high-impact PP rectangular drain pipe according to claim 9, characterized in that: In step S2, the extrusion temperature is 175-220°C.

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