Polyolefin pipeline material made of anhydrous calcium sulfate produced from phosphogypsum

Abstract

The present invention relates to a polyolefin pipeline material made of anhydrous calcium sulfate produced from phosphogypsum, belonging to the technical field of polyolefin composite materials. The polyolefin pipeline material comprises, by weight: 80-100 parts of PP masterbatch, 12-18 parts of LDPE masterbatch, 7-10 parts of recycled anhydrous calcium sulfate, 4-6 parts of compatibilizer, 3-5 parts of PE wax, and 0.2-0.3 parts of antioxidant; wherein, the recycled anhydrous calcium sulfate is made by an improved atmospheric pressure acidification method, and a templating agent is used in the recrystallization process of anhydrous calcium sulfate. The templating agent is a small molecule crosslinking substance containing nitrogen, sulfur and oxygen elements, which chelates and captures the released calcium ions as the initial crystallization template, and recrystallizes into anhydrous calcium sulfate with a spherical cluster structure, with more uniform particle size and being more easily dispersed in the polyolefin material. At the same time, the loaded templating agent contains a large number of amide structures, which have a strong induction effect on the β-phase crystallization of the polypropylene matrix, and can greatly improve the low-temperature toughness of the polypropylene matrix.

Description

Technical Field

[0001] The present invention belongs to the technical field of polyolefin composite materials, and specifically relates to a polyolefin pipeline material based on anhydrous calcium sulfate produced from phosphogypsum. Background Art

[0002] Phosphogypsum is a solid waste generated in the production process of wet-process phosphoric acid, and its main component is calcium sulfate dihydrate. It has a low decomposition temperature and unstable properties, and is generally difficult to be directly applied. After dehydration, anhydrous calcium sulfate has a dense crystal structure and excellent mechanical properties, and is a good filler for products such as rubber and plastics. Therefore, the resource utilization of phosphogypsum has good application prospects.

[0003] In the prior art, there are mainly two methods for preparing anhydrous calcium sulfate from phosphogypsum. One is to use the hydrothermal method to make phosphogypsum into hemihydrate calcium sulfate, and then decompose it by high-temperature roasting (above 600 °C) to form anhydrous calcium sulfate. This process has high energy consumption and high industrialization cost. The other is to use the atmospheric pressure acidification method to dissolve phosphogypsum and recrystallize it by controlling process conditions to form anhydrous calcium sulfate whiskers, which greatly reduces production energy consumption and cost. However, the crystal forms of anhydrous calcium sulfate prepared by the two methods are uneven and difficult to disperse in the polyolefin matrix, and usually need to be subjected to subsequent coupling treatment to be applied in polyolefin materials. Summary of the Invention

[0004] In order to solve the technical problems mentioned in the background art, the present invention provides a polyolefin pipeline material based on anhydrous calcium sulfate produced from phosphogypsum.

[0005] The object of the present invention can be achieved by the following technical solutions:

[0006] The polyolefin pipeline material based on anhydrous calcium sulfate produced from phosphogypsum includes the following raw materials in parts by weight:

[0007] 80 - 100 parts of PP masterbatch, 12 - 18 parts of LDPE masterbatch, 7 - 10 parts of recycled anhydrous calcium sulfate, 4 - 6 parts of compatibilizer, 3 - 5 parts of PE wax, and 0.2 - 0.3 parts of antioxidant.

[0008] The recycled anhydrous calcium sulfate is prepared by the following method:

[0009] Step A1: Mix triallylamine, dimethylphenylphosphine, and acetone, introduce nitrogen protection, keep the temperature constant in a water bath at 35 - 45 °C, assist with ultraviolet irradiation and mechanical stirring at 180 - 240 rpm, slowly add mercaptoacetic acid, control the total addition reaction time of mercaptoacetic acid to be 2.6 - 3.2 h, and after the reaction ends, rotary evaporate to remove acetone to obtain a carboxylated matrix;

[0010] Further, the dosage ratio of triallylamine, thioglycolic acid, dimethylphenylphosphine and acetone is 0.1 mol: 0.3 mol: 0.6 - 0.7 g: 40 - 50 mL. Dimethylphenylphosphine is used as a catalyst. Under ultraviolet irradiation, thioglycolic acid and triallylamine undergo click addition to form a compound modified with terminal branched carboxyl groups.

[0011] Step A2: Mix the carboxylated matrix, thionyl chloride and dioxane, heat to 60 - 70 °C and reflux with stirring for activation for 30 - 40 min. Rotary evaporate to remove thionyl chloride, then place it in an ice - water bath at 10 ± 2 °C for constant temperature, apply ultrasonic vibration, add diethylenetriamine and react under ultrasonic vibration for 20 - 30 min. Rotary evaporate under reduced pressure to remove dioxane to obtain the template agent.

[0012] Further, the dosage ratio of the carboxylated matrix, diethylenetriamine, thionyl chloride and dioxane is 0.1 mol: 0.16 - 0.17 mol: 0.2 - 0.22 mol: 120 - 160 mL. The carboxylated matrix is activated by thionyl chloride to improve its reactivity, and then undergoes a substitution reaction with diethylenetriamine to form a compound containing a large number of amide structures.

[0013] Step A3: Wet - grind phosphogypsum and add water to adjust the specific gravity to 2.2 - 2.5 g / cm 3 , add hydrochloric acid aqueous solution and the template agent, apply mechanical stirring at 120 - 180 rpm, heat to 85 - 92 °C, stir and mix for 2 - 2.5 h, filter, dry and disperse after cooling to obtain regenerated anhydrous calcium sulfate.

[0014] Further, the dosage ratio of phosphogypsum, hydrochloric acid aqueous solution and the template agent is 100 g: 1.2 - 1.4 L: 6 - 8 g. The mass fraction of the hydrochloric acid aqueous solution is 13 - 16%. After phosphogypsum is ground and refined and reacts with hydrochloric acid, the released calcium ions are chelated and captured by the template agent, causing the spatial structure of the template agent to bend. Along with the recrystallization of the captured calcium ions, primary spherical calcium sulfate particles are formed. Using it as the crystallization core, cluster - shaped anhydrous calcium sulfate is formed.

[0015] A preparation method of a polyolefin pipeline material made of anhydrous calcium sulfate produced from phosphogypsum includes the following steps:

[0016] Step S1: Mix and feed the PP masterbatch, LDPE masterbatch and antioxidant, melt - mix at 160 - 170 °C, then add the regenerated anhydrous calcium sulfate, compatibilizer and PE wax, continue to knead for 5 - 8 min, extrude and pelletize to obtain a kneaded masterbatch.

[0017] Step S2: Extrude the kneaded masterbatch through an extruder to form a pipe. Among them, the barrel temperature of the extruder is set as follows: the first section: 180 °C, the second section: 190 °C, the third section: 200 °C, the fourth section: 190 °C, and the die temperature is 210 °C.

[0018] Advantages of the present invention:

[0019] The present invention improves the existing atmospheric pressure acidification method, extracts anhydrous calcium sulfate from phosphogypsum waste, and effectively reuses the phosphogypsum waste, which is of great significance for promoting the resource utilization and green development of phosphogypsum; in the recrystallization process of anhydrous calcium sulfate, a self-made templating agent is used, with triallylamine as the matrix, and thioglycolic acid undergoes a click reaction under the catalysis of dimethylphenylphosphine and ultraviolet irradiation to modify the end of triallylamine with branched carboxyl groups, and at the same time introduce the coordination element sulfur. Then, the terminal carboxyl groups are activated by thionyl chloride, and diethylenetriamine is used as the linking material to form a small molecule crosslinking substance containing nitrogen, sulfur and oxygen elements through substitution reaction. During the recrystallization process, the released calcium ions are chelated and captured. As the chelated calcium ions increase, the spatial structure of the templating agent bends to form an arc-like structure, forming an initial crystallization template. At the same time, the calcium ions enriched in the near layer of the templating agent preferentially form calcium sulfate microcrystals, which serve as the crystallization core and continuously crystallize and grow to form a spherical cluster structure. Compared with the existing irregular anhydrous calcium sulfate whiskers, the particle size is more uniform, the cluster structure has a higher dispersion, and it is more conducive to uniformly dispersing in the polyolefin material to form a uniform strengthening effect; in addition, the present invention uses the atmospheric pressure acidification method to prepare anhydrous calcium sulfate, and the templating agent is loaded on the surface layer of anhydrous calcium sulfate. On the one hand, it forms an organic layer modification on the surface of anhydrous calcium sulfate to improve its compatibility with the polyolefin matrix. On the other hand, a large number of amide structures remain after the crosslinking of diethylenetriamine, which has a strong induction effect on the β-phase crystallization of the polypropylene (PP) matrix and can greatly improve the low-temperature toughness of the polypropylene matrix; after testing, applying the anhydrous calcium sulfate prepared by the present invention to the pipeline material with polypropylene as the main matrix, the notch impact strength reaches 20 KJ / m at -10°C 2 Above, far higher than the polypropylene material with traditional anhydrous calcium sulfate as the filler. Brief description of the drawings

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts.

[0021] Figure 1 Scanning electron micrograph of the regenerated anhydrous calcium sulfate prepared in Example 3 of the present invention. Detailed implementation manners

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0023] Example 1

[0024] In this embodiment, anhydrous calcium sulfate is prepared from phosphogypsum and applied in polyolefin materials to prepare pipeline materials. The specific implementation process is as follows:

[0025] 1) Preparation of regenerated anhydrous calcium sulfate

[0026] 1.1. Take triallylamine, dimethylphenylphosphine and acetone, feed and stir to mix evenly, introduce nitrogen protection, heat up to 35°C by water bath and keep constant temperature, apply 300W ultraviolet irradiation, and at the same time apply 180rpm mechanical stirring. Slowly add mercaptoacetic acid within 30 minutes. After complete addition, continue the reaction. Control the total addition reaction time of mercaptoacetic acid to be 3.2h. During the reaction, the dosage ratio of triallylamine, mercaptoacetic acid, dimethylphenylphosphine and acetone is 0.1mol:0.3mol:0.6g:40mL. After the reaction, rotary evaporate to remove acetone to obtain the carboxylated matrix.

[0027] 1.2. Take the carboxylated matrix, thionyl chloride and dioxane, feed and stir to mix evenly, apply 120rpm stirring, heat up to 60°C and reflux and stir for activation for 40 minutes. Then rotary evaporate to remove thionyl chloride, cool and place it in an ice-water bath at 10±2°C for constant temperature. Apply 28kHz ultrasonic oscillation, add diethylenetriamine, and keep ultrasonic oscillation reaction for 30 minutes. During the reaction, the dosage ratio of the carboxylated matrix, diethylenetriamine, thionyl chloride and dioxane is 0.1mol:0.16mol:0.2mol:120mL. After the reaction, rotary evaporate under reduced pressure to remove dioxane to obtain the template agent.

[0028] 1.3. Take phosphogypsum (waste from a certain phosphate fertilizer factory in Guizhou, the same batch of raw materials is used in the following examples) and wet grind it with water until the particle size reaches 6-8 microns. Adjust the specific gravity of the slurry to 2.2g / cm 3 , then add hydrochloric acid aqueous solution and the template agent, apply 120rpm mechanical stirring, heat up to 85°C, and stir and mix for 2.5h. During the reaction, the dosage ratio of phosphogypsum, hydrochloric acid aqueous solution and the template agent is 100g:1.2L:6g. The mass fraction of the hydrochloric acid aqueous solution is 13%. After the reaction, cool to room temperature, filter to obtain the filter cake, bake the filter cake at 80°C for 5h, and then use an air flow pulverizer to disperse it into uniform powder to obtain the regenerated anhydrous calcium sulfate.

[0029] 2) Preparation of polyolefin pipeline

[0030] 2.1. Weigh the following raw materials according to the weight ratio:

[0031] 90 parts of PP masterbatch, model T30S, provided by PetroChina Lanzhou Petrochemical Company;

[0032] 16 parts of LDPE masterbatch, model LD605, provided by Shanghai Suwan Industry & Plastic Co., Ltd.;

[0033] 7 parts of recycled anhydrous calcium sulfate, prepared in this example;

[0034] 5 parts of compatibilizer, selected from PP-g-MAH, with a melt flow rate of 40 g / 10 min, provided by Nanjing Sute Polymer Technology Co., Ltd.;

[0035] 4 parts of PE wax, model Buddy-655, provided by Shanghai Yiba Chemical Raw Materials Co., Ltd.;

[0036] 0.2 part of antioxidant, model XY-B215, provided by Jilin City Xingyun Chemical Co., Ltd.;

[0037] The following examples use raw materials of the same batch.

[0038] 2.2. Mix and feed the PP masterbatch, LDPE masterbatch and antioxidant, and melt and mix them at 160 °C through a torque rheometer. Then add the recycled anhydrous calcium sulfate, compatibilizer and PE wax, continue to knead for 8 min, extrude and draw to shape in a cooling tank, and pelletize to obtain the kneaded masterbatch.

[0039] 2.3. Extrude and form the kneaded masterbatch through an extruder. Among them, the barrel temperature of the extruder is set as follows: section 1: 180 °C, section 2: 190 °C, section 3: 200 °C, section 4: 190 °C, and the die temperature is 210 °C, and spray cooling is carried out to form a pipe.

[0040] Example 2

[0041] In this example, anhydrous calcium sulfate is prepared from phosphogypsum and applied in polyolefin materials to prepare pipe materials. The specific implementation process is as follows:

[0042] 1) Prepare recycled anhydrous calcium sulfate

[0043] 1.1. Take allylamine, dimethylphenylphosphine and acetone, put them into the reactor and stir to mix evenly. Introduce nitrogen for protection, heat up to 45 °C by water bath and keep it constant. Apply ultraviolet irradiation of 400 W and mechanical stirring of 240 rpm simultaneously. Slowly add mercaptoacetic acid within 20 min. After complete addition, continue the reaction. Control the total reaction time of mercaptoacetic acid addition to be 2.6 h. During the reaction, the dosage ratio of allylamine, mercaptoacetic acid, dimethylphenylphosphine and acetone is 0.1 mol: 0.3 mol: 0.7 g: 50 mL. After the reaction, rotary evaporation is used to remove acetone to obtain the carboxylated matrix.

[0044] 1.2. Take the carboxylated matrix, thionyl chloride and dioxane, put them into the reactor and stir to mix evenly. Apply stirring at 120 rpm, heat up to 70 °C and reflux and stir for activation for 30 min. Then rotary evaporation is used to remove thionyl chloride. Cool and keep it constant in an ice-water bath at 10 ± 2 °C. Apply ultrasonic oscillation at 28 kHz, add diethylenetriamine, and keep ultrasonic oscillation for reaction for 20 min. During the reaction, the dosage ratio of the carboxylated matrix, diethylenetriamine, thionyl chloride and dioxane is 0.1 mol: 0.17 mol: 0.22 mol: 160 mL. After the reaction, rotary evaporation under reduced pressure is used to remove dioxane to obtain the template agent.

[0045] 1.3. Wet-grind phosphogypsum and water until the particle size reaches 6 - 8 microns. Adjust the specific gravity of the slurry to 2.5 g / cm 3 , then add hydrochloric acid aqueous solution and the template agent, apply mechanical stirring at 180 rpm, heat up to 92 °C, and stir and mix for 2 h. During the reaction, the dosage ratio of phosphogypsum, hydrochloric acid aqueous solution and the template agent is 100 g: 1.4 L: 8 g. The mass fraction of the hydrochloric acid aqueous solution is 16%. After the reaction, cool to room temperature, filter to obtain the filter cake, bake the filter cake at 80 °C for 5 h, and then use an air-flow crusher to break it into uniform powder to obtain regenerated anhydrous calcium sulfate.

[0046] 2) Preparation of polyolefin pipes

[0047] 2.1. Take the following raw materials according to the weight ratio:

[0048] 100 parts of PP masterbatch, 18 parts of LDPE masterbatch, 10 parts of regenerated anhydrous calcium sulfate (prepared in this example), 6 parts of compatibilizer, 4 parts of PE wax and 0.3 part of antioxidant.

[0049] 2.2. Mix and feed the PP masterbatch, LDPE masterbatch and antioxidant, melt and mix them at 160 °C through a torque rheometer, then add the regenerated anhydrous calcium sulfate, compatibilizer and PE wax, continue to knead for 7 min, extrude and draw it into a cooling tank for shaping, and pelletize to obtain the kneaded masterbatch.

[0050] 2.3 Extrude the masterbatch through an extruder. The barrel temperature of the extruder is set as follows: Zone 1: 180°C, Zone 2: 190°C, Zone 3: 200°C, Zone 4: 190°C, and the die temperature is 210°C. Spray cooling is used to form the pipe.

[0051] Example 3

[0052] In this example, anhydrous calcium sulfate is prepared from phosphogypsum and applied in polyolefin materials to prepare pipe materials. The specific implementation process is as follows:

[0053] 1) Prepare regenerated anhydrous calcium sulfate

[0054] 1.1 Take triallylamine, dimethylphenylphosphine, and acetone, feed and stir them evenly, introduce nitrogen for protection, heat up to 42°C with a water bath and keep it constant temperature, apply 360W ultraviolet irradiation, and at the same time apply 240rpm mechanical stirring. Slowly add mercaptoacetic acid within 25 minutes. After complete addition, continue the reaction. Control the total addition reaction time of mercaptoacetic acid to be 3.0h. During the reaction, the dosage ratio of triallylamine, mercaptoacetic acid, dimethylphenylphosphine, and acetone is 0.1mol:0.3mol:0.6g:45mL. After the reaction, rotary evaporate to remove acetone to obtain the carboxylated matrix.

[0055] 1.2 Take the carboxylated matrix, thionyl chloride, and dioxane, feed and stir them evenly, apply 120rpm stirring, heat up to 65°C and reflux and stir for activation for 35 minutes. Then rotary evaporate to remove thionyl chloride, cool and place it in an ice-water bath at 10±2°C for constant temperature, apply 28kHz ultrasonic oscillation, add diethylenetriamine, and keep ultrasonic oscillation reaction for 28 minutes. During the reaction, the dosage ratio of the carboxylated matrix, diethylenetriamine, thionyl chloride, and dioxane is 0.1mol:0.16mol:0.21mol:140mL. After the reaction, rotary evaporate under reduced pressure to remove dioxane to obtain the template agent.

[0056] 1.3 Wet-grind phosphogypsum and water until the particle size reaches 6 - 8 microns, adjust the specific gravity of the slurry to 2.2 g / cm 3 , then add hydrochloric acid aqueous solution and the template agent, apply 180rpm mechanical stirring, heat up to 88°C, and stir and mix for 2.2h. During the reaction, the dosage ratio of phosphogypsum, hydrochloric acid aqueous solution, and the template agent is 100g:1.2L:7g. The mass fraction of the hydrochloric acid aqueous solution is 15%. After the reaction, cool to room temperature, filter to obtain the filter cake, bake the filter cake at 80°C for 5h, and then use an air flow pulverizer to break it into uniform powder to obtain the regenerated anhydrous calcium sulfate.

[0057] 2) Prepare polyolefin pipes

[0058] 2.1 Weigh the following raw materials according to the weight ratio:

[0059] 90 parts of PP masterbatch, 15 parts of LDPE masterbatch, 8 parts of recycled anhydrous calcium sulfate (prepared in this example), 5 parts of compatibilizer, 3 parts of PE wax, and 0.2 part of antioxidant.

[0060] 2.2. Mix and feed the PP masterbatch, LDPE masterbatch, and antioxidant, melt and mix them at 170 °C through a torque rheometer, then add the recycled anhydrous calcium sulfate, compatibilizer, and PE wax, continue to knead for 6 min, extrude and draw it into a cooling tank for shaping, and pelletize to obtain the kneaded masterbatch.

[0061] 2.3. Extrude and shape the kneaded masterbatch through an extruder. Among them, the barrel temperature of the extruder is set as follows: the first section: 180 °C, the second section: 190 °C, the third section: 200 °C, the fourth section: 190 °C, the die temperature is 210 °C, and spray cooling is carried out to form a pipe.

[0062] Example 4

[0063] In this example, anhydrous calcium sulfate is prepared from phosphogypsum and applied in polyolefin materials to prepare pipeline materials. The specific implementation process is as follows:

[0064] 1) Prepare recycled anhydrous calcium sulfate

[0065] 1.1. Take triallylamine, dimethylphenylphosphine, and acetone, feed and stir them evenly, introduce nitrogen for protection, heat them to 40 °C by water bath and keep them at a constant temperature, apply 340 W ultraviolet irradiation, and at the same time apply 240 rpm mechanical stirring. Slowly add mercaptoacetic acid within 28 min. After complete addition, continue the reaction. Control the total addition reaction time of mercaptoacetic acid to be 3.0 h. During the reaction, the dosage ratio of triallylamine, mercaptoacetic acid, dimethylphenylphosphine, and acetone is 0.1 mol: 0.3 mol: 0.7 g: 45 mL. After the reaction is completed, rotary evaporate to remove acetone to obtain the carboxylated matrix.

[0066] 1.2. Take the carboxylated matrix, thionyl chloride, and dioxane, feed and stir them evenly, apply 120 rpm stirring, heat to 65 °C and reflux and stir for activation for 40 min, then rotary evaporate to remove thionyl chloride, cool and place it in an ice-water bath at 10 ± 2 °C for constant temperature, apply 28 kHz ultrasonic oscillation, add diethylenetriamine, and keep ultrasonic oscillation reaction for 22 min. During the reaction, the dosage ratio of the carboxylated matrix, diethylenetriamine, thionyl chloride, and dioxane is 0.1 mol: 0.17 mol: 0.22 mol: 150 mL. After the reaction is completed, rotary evaporate under reduced pressure to remove dioxane to obtain the template agent.

[0067] 1.3. Wet-grind phosphogypsum and water until the particle size reaches 6 - 8 microns, and adjust the specific gravity of the slurry to 2.5 g / cm 3, add aqueous hydrochloric acid solution and template agent, apply mechanical stirring at 180 rpm, heat up to 90 °C, stir and mix for 2.3 h. During the reaction, the dosage ratio of phosphogypsum, aqueous hydrochloric acid solution and template agent is 100 g: 1.3 L: 7 g, the mass fraction of the aqueous hydrochloric acid solution is 15%, cool to room temperature after the reaction ends, filter to obtain the filter cake, bake the filter cake at 80 °C for 5 h, and then use an air flow pulverizer to break it into uniform powder to obtain regenerated anhydrous calcium sulfate.

[0068] 2) Preparation of polyolefin pipes

[0069] 2.1. Weigh the following raw materials according to the weight ratio:

[0070] 80 parts of PP masterbatch, 12 parts of LDPE masterbatch, 9 parts of regenerated anhydrous calcium sulfate (prepared in this example), 4 parts of compatibilizer, 5 parts of PE wax and 0.3 parts of antioxidant.

[0071] 2.2. Mix and feed the PP masterbatch, LDPE masterbatch and antioxidant, melt and mix them at 170 °C through a torque rheometer, then add the regenerated anhydrous calcium sulfate, compatibilizer and PE wax, continue to knead for 5 min, extrude and draw it into a cooling tank for shaping, and pelletize to obtain the kneaded masterbatch.

[0072] 2.3. Extrude and shape the kneaded masterbatch through an extruder. Among them, the barrel temperature of the extruder is set as follows: the first section: 180 °C, the second section: 190 °C, the third section: 200 °C, the fourth section: 190 °C, the die temperature is 210 °C, and spray cooling is carried out to form the pipe.

[0073] Comparative example

[0074] In this comparative example, a PP pipe is prepared, and its production process is exactly the same as that of Example 3. Replace the regenerated anhydrous calcium sulfate with the same amount of commercially available anhydrous calcium sulfate, model HS-410, provided by Shandong Haoshun Chemical Co., Ltd.

[0075] For the convenience of testing the mechanical properties of the pipes, during the process of extruding the molten material into pipes in Examples 1 - 4 and the comparative example, extrude the molten material into a mold with specifications of 200 × 200 × 5 mm, apply a pressure of 1.5 MPa for pressing, hold the pressure for cooling and shaping, and obtain a sheet after demolding. Take samples from the sheet for tensile and impact tests, specifically as follows:

[0076] Tensile property test: Refer to GB / T1040.1 - 2018 for testing, and select a tensile speed of 50 mm / min;

[0077] Flexural property test: Refer to GB / T9341 - 2008 for testing, and the test rate is 20 mm / min;

[0078] Impact performance test: The test was carried out with reference to GB / T1843-2008. A V-notch was used, and the test temperatures were -10°C and 25°C to simulate low-temperature and normal-temperature states;

[0079] The specific test data are shown in Table 1:

[0080] Table 1

[0081]

[0082] As can be seen from the data in Table 1, for the polyolefin material prepared by the present invention, at room temperature, the tensile strength is 28.2 - 30.4 MPa, the flexural strength is 18.7 - 21.4 MPa, and the impact strength is 26.2 - 29.6 KJ / m 2 , having good comprehensive mechanical properties. At room temperature, the polyolefin material prepared in the comparative example is similar to that in the example, but at -10°C, the impact strength of the comparative example drops significantly.

[0083] Take the pipes prepared in Examples 1 - 4 and the comparative example, and conduct the falling weight impact test with reference to the GB / T14152-2001 standard. The test temperature is 0 ± 1°C in an air bath and kept constant for 2 h; conduct the ring stiffness test with reference to the GB / T9647-2003 standard, and the test speed is 10 mm / min;

[0084] The specific test data are shown in Table 2:

[0085] Table 2

[0086]

[0087] As can be seen from the data in Table 2, the ring stiffness of the pipes prepared by the present invention is 12.5 - 13.6 kN / m 2 , and there is no cracking in 10 / 10 during the falling weight impact test. The ring stiffness of the comparative example is slightly lower than that of the example, and 2 / 10 is cracked and unqualified during the falling weight impact test, which may be related to the uneven distribution of anhydrous calcium sulfate.

[0088] Based on the above test data, the surface morphology of the regenerated anhydrous calcium sulfate prepared in Example 3 was observed by scanning electron microscopy, as specifically Figure 1 shown.

[0089] In the description of the specification, the description with reference to terms such as "one embodiment", "example", "specific example", etc. means 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 representation of the above terms does 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.

[0090] The above content is only an example and illustration of the concept of the present invention. Those skilled in the art of this technology can make various modifications, supplements, or use similar methods of substitution to the specific embodiments described. As long as they do not deviate from the concept of the invention or exceed the scope defined by this claim book, they shall fall within the protection scope of the present invention.

Claims

1. Polyolefin pipeline material made of anhydrous calcium sulfate produced from phosphogypsum, characterized in that, It includes the following raw materials by weight parts: 80 - 100 parts of PP masterbatch, 12 - 18 parts of LDPE masterbatch, 7 - 10 parts of recycled anhydrous calcium sulfate, 4 - 6 parts of compatibilizer, 3 - 5 parts of PE wax, and 0.2 - 0.3 parts of antioxidant; The recycled anhydrous calcium sulfate is prepared by the following method: Step A1: Mix triallylamine, dimethylphenylphosphine and acetone, introduce nitrogen protection, keep the temperature constant in a water bath at 35 - 45 °C, assist with ultraviolet irradiation and mechanical stirring, slowly add thioglycolic acid, control the total addition reaction time of thioglycolic acid to be 2.6 - 3.2 h, and rotary evaporate to remove acetone after the reaction to obtain a carboxylated matrix; Step A2: Mix the carboxylated matrix, thionyl chloride and dioxane, heat up to 60 - 70 °C and reflux with stirring for activation for 30 - 40 min, rotary evaporate to remove thionyl chloride, then keep the temperature constant in an ice - water bath at 10 ± 2 °C, apply ultrasonic oscillation, add diethylenetriamine and react under ultrasonic oscillation for 20 - 30 min, and rotary evaporate under reduced pressure to remove dioxane to obtain a template agent; Step A3: Wet - grind phosphogypsum and adjust the slurry specific gravity, add hydrochloric acid aqueous solution and the template agent, stir and heat up to 85 - 92 °C, mix for 2 - 2.5 h, cool, filter, dry and disperse to obtain recycled anhydrous calcium sulfate; The model of the PP masterbatch is T30S, and the model of the LDPE masterbatch is LD605.

2. The polyolefin pipeline material made of anhydrous calcium sulfate produced based on phosphogypsum according to claim 1, wherein The dosage ratio of triallylamine, thioglycolic acid, dimethylphenylphosphine and acetone is 0.1 mol: 0.3 mol: 0.6 - 0.7 g: 40 - 50 mL.

3. The polyolefin pipeline material made of anhydrous calcium sulfate produced based on phosphogypsum according to claim 2, characterized in that, The dosage ratio of the carboxylated matrix, diethylenetriamine, thionyl chloride and dioxane is 0.1 mol: 0.16 - 0.17 mol: 0.2 - 0.22 mol: 120 - 160 mL.

4. The polyolefin pipeline material made of anhydrous calcium sulfate produced based on phosphogypsum according to claim 3, characterized in that The dosage ratio of phosphogypsum, hydrochloric acid aqueous solution and the template agent is 100 g: 1.2 - 1.4 L: 6 - 8 g.

5. The polyolefin pipeline material made of anhydrous calcium sulfate produced based on phosphogypsum according to claim 4, characterized in that The specific gravity of the slurry after grinding phosphogypsum is 2.2 - 2.5 g / cm 3 .

6. The polyolefin pipeline material made of anhydrous calcium sulfate produced based on phosphogypsum according to claim 4, characterized in that, The mass fraction of the hydrochloric acid aqueous solution is 13 - 16%.

7. The polyolefin pipeline material made of anhydrous calcium sulfate produced from phosphogypsum according to claim 1, characterized in that, The polyolefin pipeline material is prepared by the following method: Step S1: Mix and feed the PP masterbatch, LDPE masterbatch and antioxidant, melt - mix at 160 - 170 °C, then add the recycled anhydrous calcium sulfate, compatibilizer and PE wax, continue to knead for 5 - 8 min, extrude and pelletize to obtain a kneaded masterbatch; Step S2: Extrude and form the kneaded masterbatch through an extruder to obtain a pipe.

8. The polyolefin pipeline material made of anhydrous calcium sulfate produced based on phosphogypsum according to claim 1, characterized in that, The barrel temperature of the extruder is set as follows: the first section: 180 °C, the second section: 190 °C, the third section: 200 °C, the fourth section: 190 °C, and the die temperature is 210 °C.

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