Environment-friendly water-permeable T-shaped filter brick and preparation process thereof

Abstract

This invention discloses an environmentally friendly permeable T-shaped filter brick and its preparation process, relating to the technical field of T-shaped filter bricks. The process includes the following steps: Step 1: High-density polyethylene, recycled polyethylene, modified filler, maleic anhydride-grafted polyethylene, vinyl silane coupling agent, antioxidant, lubricant, and initiator are added to a mixer and mixed evenly to obtain a mixture; Step 2: The mixture is added to a twin-screw extruder, melt-blended, extruded, and granulated to obtain T-shaped filter brick outer shell granules; Step 3: The T-shaped filter brick outer shell granules are added to an injection molding machine, heated and melted, injection molded, and cooled to obtain the T-shaped filter brick outer shell; Step 4: Concrete is injected into the T-shaped filter brick outer shell, and after the concrete solidifies, the environmentally friendly permeable T-shaped filter brick is obtained.

Description

Technical Field

[0001] This invention relates to the field of T-type filter brick technology, specifically an environmentally friendly permeable T-type filter brick and its preparation process. Background Technology

[0002] With accelerated urbanization and frequent extreme weather events, urban flooding and water shortages are becoming increasingly severe. Permeable pavement systems, as a core component of "sponge city" construction, play a crucial role in enabling rapid rainwater infiltration, retention, and purification. Filter bricks, serving as the underlying support and water-conducting structure of permeable pavement systems, directly affect the permeability, load-bearing capacity, and service life of the entire system. T-shaped filter bricks, characterized by high hardness, good permeability, strong erosion resistance, and ease of installation, are widely used. However, existing T-shaped filter bricks are primarily made from virgin materials such as high-density polyethylene for their outer shell, resulting in higher costs.

[0003] In response to the environmental protection concept advocated by society today, this invention effectively utilizes waste polyethylene plastic, and through modification treatment, processes it into T-shaped filter brick shells, which can both meet the needs of environmental protection and reduce costs.

[0004] Based on this, the present invention proposes an environmentally friendly permeable T-shaped filter brick and its preparation process, which is of great significance. Summary of the Invention

[0005] The purpose of this invention is to provide an environmentally friendly permeable T-type filter brick and its preparation process to solve the problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] An environmentally friendly permeable T-shaped filter brick includes a T-shaped filter brick shell and concrete filling the interior therein.

[0008] Furthermore, the outer shell of the T-type filter brick comprises the following raw material components: by weight, 70 parts of high-density polyethylene, 30-40 parts of recycled polyethylene, 20-30 parts of modified filler, 15-25 parts of maleic anhydride-grafted polyethylene, 1-2 parts of vinyl silane coupling agent, 0.5-1.5 parts of antioxidant, 1-3 parts of lubricant, and 0.5-1 part of initiator.

[0009] Furthermore, the method for preparing the recycled polyethylene material is as follows:

[0010] (1) After crushing the waste polyethylene into fragments of 5-10cm, wash it with clean water, dry it in an environment of 60-80℃ until the moisture content is ≤0.3%, and finally crush it into particles of 1-5mm to obtain pretreated waste polyethylene.

[0011] (2) Add pretreated waste polyethylene, modified lignin, fluorinated acrylate, initiator and antioxidant into a twin-screw extruder, melt graft, extrude and pelletize to obtain recycled polyethylene material.

[0012] Furthermore, the raw materials required for the preparation of the polyethylene recycled material include the following components: by weight, 40 parts of pretreated waste polyethylene, 4-8 parts of modified lignin, 2-4 parts of fluorinated acrylate, 0.05-0.07 parts of initiator, and 0.1-0.3 parts of antioxidant.

[0013] Furthermore, the fluorinated acrylates include, but are not limited to, one or a combination of several of the following: hexafluorobutyl acrylate, hexafluorobutyl methacrylate, trifluoroethyl methacrylate, dodecafluoroheptyl methacrylate, dodecafluoroheptyl acrylate, nonadecafluoro acrylate, and perfluorobutyl ethyl methacrylate.

[0014] Furthermore, the twin-screw extruder is divided into seven heating zones, with a temperature range of 130~200℃; specifically, the temperature of the first heating zone is 130~150℃, the temperature of the second heating zone is 150~170℃, the temperature of the third heating zone is 150~170℃, the temperature of the fourth heating zone is 180~200℃, the temperature of the fifth heating zone is 180~190℃, the temperature of the sixth heating zone is 170~180℃, and the temperature of the seventh heating zone is 160~170℃.

[0015] The extrusion temperature is 160~170℃ and the screw speed is 200~300rpm.

[0016] Furthermore, the method for preparing the modified lignin is as follows:

[0017] (1) Add lignin to a 0.1~0.2mol / L sodium hydroxide solution and stir and mix at 120~140℃ for 1~4h to obtain activated lignin;

[0018] (2) Under nitrogen protection, maleic anhydride and activated lignin were added to acetic acid and stirred at 30-40°C for 1-4 hours. The mixture was then filtered, washed, and dried to obtain modified lignin.

[0019] Furthermore, the ratio of lignin to sodium hydroxide solution is 1g:5mL.

[0020] Furthermore, the lignin is G-type lignin;

[0021] The G-type lignin is specifically coniferous lignin.

[0022] Furthermore, the mass ratio of maleic anhydride, activated lignin, and acetic acid is (0.1~0.2):1:10.

[0023] Furthermore, the method for preparing the modified filler is as follows:

[0024] (1) Add bamboo fiber, p-toluenesulfonic acid and acetic anhydride to acetic acid, stir and react at 70~75℃ for 20~60min, filter, wash with 5wt% sodium bicarbonate solution, wash with deionized water, and dry to obtain acetylated bamboo fiber.

[0025] (2) Add the vinylsilane coupling agent to a 75wt% ethanol aqueous solution, add acetic acid to adjust the pH to 4-6, stir and mix for 20-60 min to obtain silane hydrolysate;

[0026] (3) Immerse acetylated bamboo fiber and silicon dioxide in silane hydrolysate for 0.5-1.5 h, remove and dry to obtain modified filler.

[0027] Furthermore, the mass ratio of bamboo fiber, p-toluenesulfonic acid, acetic anhydride, and acetic acid is 1:(0.04~0.08):(10~16):(10~16).

[0028] Furthermore, the bamboo fiber has an aspect ratio of 40 to 50 and a length of 3 to 6 mm.

[0029] Furthermore, the volume ratio of the vinylsilane coupling agent to the ethanol aqueous solution is (0.04~0.08):1.

[0030] Furthermore, the ratio of the acetylated bamboo fiber, silicon dioxide, and silane hydrolysate is 1g:1g:5mL.

[0031] Furthermore, the average particle size of the silicon dioxide is 50~200nm.

[0032] Furthermore, the vinyl silane coupling agent includes, but is not limited to, one or a combination of several of vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri(2-methoxyethoxy)silane, vinyldimethylethoxysilane, vinylmethyldiethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane.

[0033] Furthermore, in this invention, the antioxidant is antioxidant 1076.

[0034] Furthermore, the lubricant is polyethylene wax.

[0035] Furthermore, in this invention, the initiator is dicumyl peroxide.

[0036] Furthermore, the preparation process of the environmentally friendly permeable T-shaped filter brick includes the following steps:

[0037] Step 1: Add high-density polyethylene, recycled polyethylene, modified filler, maleic anhydride grafted polyethylene, vinyl silane coupling agent, antioxidant, lubricant, and initiator into a mixer and mix them evenly to obtain a mixture.

[0038] Step 2: Add the mixture into a twin-screw extruder, melt-mix, extrude and granulate to obtain T-shaped filter brick shell granules;

[0039] Step 3: Add the T-shaped filter brick shell granules into the injection molding machine, heat and melt them, injection mold them, and cool them to obtain the T-shaped filter brick shell;

[0040] Step 4: Inject concrete into the shell of the T-shaped filter brick and wait for the concrete to solidify to obtain the environmentally friendly permeable T-shaped filter brick.

[0041] Further, in step 2, the twin-screw extruder is divided into seven heating zones, with a temperature range of 150~200℃; specifically, the temperature of the first heating zone is 150~170℃, the temperature of the second heating zone is 170~185℃, the temperature of the third heating zone is 185~195℃, the temperature of the fourth heating zone is 190~200℃, the temperature of the fifth heating zone is 190~200℃, the temperature of the sixth heating zone is 180~190℃, and the temperature of the seventh heating zone is 175~185℃; the extrusion temperature is 175~185℃, and the screw speed is 200~300 rpm.

[0042] Furthermore, in step 3, the relevant parameters of the injection molding machine are: the heating and melting temperature is 175~185℃, the injection molding pressure is 80~100MPa, and the injection molding time is 5~15s.

[0043] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0044] (1) This invention uses waste polyethylene as raw material to achieve the purpose of environmental protection and recycling. Considering that waste polyethylene is inferior to new polyethylene in terms of mechanical properties, thermal stability, and antioxidant properties, this invention uses modified lignin and fluorinated acrylate for melt grafting to enhance its related properties. Since G-type lignin contains abundant guaiac wood matrix structure, it has high thermal stability. Therefore, modified lignin is prepared by activating G-type lignin with alkaline solution and then reacting it with maleic anhydride through esterification. When G-type lignin is activated, the number of phenolic hydroxyl groups on its surface increases, which significantly increases its reactivity and reduces the amount of maleic anhydride used. The activated G-type lignin also contains a large number of unreacted phenolic hydroxyl groups, which have a significant effect on the thermal stability and antioxidant properties of waste polyethylene and greatly inhibit its thermal decomposition during the melting process. After processing and molding, modified lignin also acts as a filler, which has an effect on the mechanical properties, wear resistance, and corrosion resistance of the T-type filter brick shell. The role of fluorinated acrylates is to introduce fluorinated segments, which synergistically modify lignin to enhance the thermal stability and antioxidant properties of waste polyethylene, while also helping to improve the corrosion resistance of the processed T-shaped filter brick shell. Finally, this invention further incorporates antioxidants to synergistically modify lignin and fluorinated acrylates, ultimately producing a recycled polyethylene material with excellent thermal stability, antioxidant properties, and improved wear and corrosion resistance of the T-shaped filter brick shell. The amount of modified lignin incorporated needs to be controlled; too little will result in low modification levels, while too much will lead to an excessive number of phenolic hydroxyl groups in the modified lignin, reducing its compatibility and deteriorating the performance of the recycled polyethylene material.

[0045] (2) In this invention, bamboo fiber is further used as an environmentally friendly reinforcing filler. However, bamboo fiber absorbs water and swells, and direct modification and addition will affect the performance of the final product. Therefore, the bamboo fiber is first acetylated to reduce its water absorption, then combined with silica, and modified with a vinyl silane coupling agent to finally prepare the modified filler. The modified filler has good dispersibility and is tightly bonded to the resin matrix. The fiber part mainly acts as a skeleton network to enhance the mechanical properties of the T-shaped filter brick shell, while silica mainly improves the wear resistance and corrosion resistance of the T-shaped filter brick shell. The two work together to obtain a T-shaped filter brick shell with better performance. Among them, the acetylation treatment of bamboo fiber requires strict control of the acetylation time to avoid excessive acetylation, which increases the difficulty of subsequent modification.

[0046] (3) In this invention, maleic anhydride-grafted polyethylene is further added as a compatibilizer, which can effectively enhance the compatibility between the raw material components and improve the overall performance of the T-type filter brick shell.

[0047] (4) In this invention, a vinyl silane coupling agent is further added, which can be further hydrolyzed and crosslinked in the subsequent concrete hydration environment to form a dense Si-O-Si network, which can enhance the water resistance of the T-type filter brick shell and provide secondary protection against the potential water absorption and swelling of bamboo fiber.

[0048] (5) This invention makes full use of waste polyethylene, significantly reducing the consumption of virgin plastics, and further modifies and utilizes biomass resources (lignin, bamboo fiber), indicating that this invention has great environmental value.

[0049] In summary, this invention uses high-density polyethylene as the main material, supplemented by recycled polyethylene and modified fillers, and works in conjunction with maleic anhydride-grafted polyethylene and vinyl silane coupling agent to comprehensively consider performance, cost, and environmental friendliness. This results in the preparation of an environmentally friendly permeable T-shaped filter brick shell with high wear resistance and corrosion resistance, which is of great significance. Detailed Implementation

[0050] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] It should be noted that the following quantities are by weight, and there are no special restrictions on the suppliers of all raw materials involved in this invention. Exemplary examples include:

[0052] In the following examples, high-density polyethylene (H790495) with a melt flow index of 12 g / 10 min at 190°C and a load of 2.16 kg; hexafluorobutyl acrylate with a purity of 99%; maleic anhydride-grafted polyethylene with a grafting rate of 1-1.3% and an average molecular weight of 10,000; antioxidant 1076 with a purity of 98%; maleic anhydride with a purity of 98%; p-toluenesulfonic acid with a purity of 99%; acetic acid with a purity of 99.5%; vinyltriethoxysilane with a purity of 99%; silica with an average particle size of 100 nm; polyethylene wax with an average molecular weight of 3,000-4,000; and dicumyl peroxide with a purity of 99% were all purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0053] Bamboo fiber with an aspect ratio of 50 and a length of 5mm; lignin from both coniferous and broadleaf trees was extracted in the laboratory using conventional alkaline extraction methods, with an average molecular weight of 4000; other raw materials were commercially available.

[0054] The dimensions of the T-type filter brick shell are the standard dimensions, specifically 543.5mm × 202.5mm × 187mm.

[0055] Example 1: A preparation process for an environmentally friendly permeable T-shaped filter brick:

[0056] Step 1: S11: Preparation of modified lignin: (1) Add coniferous lignin to 0.15 mol / L sodium hydroxide solution (the ratio of the two is 1 g: 5 mL), stir and mix at 130 °C for 2 h to obtain activated lignin; (2) Under nitrogen protection, add 0.9 parts maleic anhydride and 6 parts activated lignin to 60 parts acetic acid, stir and react at 35 °C for 2 h, filter, wash, dry to obtain modified lignin;

[0057] S12: Preparation of recycled polyethylene: (1) After crushing waste polyethylene into fragments of 5-10cm, wash it with clean water, dry it at 70℃ until the moisture content is ≤0.3%, and finally crush it into particles of 1-5mm to obtain pretreated waste polyethylene; (2) Add 40 parts of pretreated waste polyethylene, 6 parts of modified lignin, 3 parts of hexafluorobutyl acrylate, 0.06 parts of diisopropylbenzene peroxide, and 0.2 parts of antioxidant 1076 into a twin-screw extruder, melt graft, extrude and pelletize to obtain recycled polyethylene;

[0058] The twin-screw extruder is divided into seven heating zones. The temperature of the first heating zone is 140±1℃, the temperature of the second heating zone is 160±1℃, the temperature of the third heating zone is 165±1℃, the temperature of the fourth heating zone is 190±1℃, the temperature of the fifth heating zone is 185±1℃, the temperature of the sixth heating zone is 175±1℃, and the temperature of the seventh heating zone is 165±1℃. The extrusion temperature is 165±1℃, and the screw speed is 250 rpm.

[0059] S13: Preparation of modified filler: (1) Add 15 parts of bamboo fiber (length-to-diameter ratio 50, length 5mm), 0.9 parts of p-toluenesulfonic acid, and 195 parts of acetic anhydride to 195 parts of acetic acid, stir and react at 72℃ for 40min, filter, wash with 5wt% sodium bicarbonate solution, wash with deionized water, and dry to obtain acetylated bamboo fiber; (2) Add vinyltriethoxysilane to 75wt% ethanol aqueous solution (volume ratio of the two is 0.06:1), add acetic acid to adjust pH to 5, stir and mix for 40min to obtain silane hydrolysate; (3) Immerse acetylated bamboo fiber and silicon dioxide (average particle size 100nm) in silane hydrolysate (the ratio of the three is 1g:1g:5mL), soak for 1h, take out, dry to obtain modified filler;

[0060] S14: Add 70 parts high-density polyethylene, 35 parts recycled polyethylene, 25 parts modified filler, 20 parts maleic anhydride grafted polyethylene, 1.5 parts vinyltriethoxysilane, 1 part antioxidant 1076, 2 parts polyethylene wax, and 1 part dicumyl peroxide into a mixer and mix them evenly to obtain a mixture.

[0061] Step 2: Add the mixture into a twin-screw extruder, melt-mix, extrude and granulate to obtain T-shaped filter brick shell granules;

[0062] The twin-screw extruder is divided into seven heating zones. The temperature of the first heating zone is 160±1℃, the temperature of the second heating zone is 175±1℃, the temperature of the third heating zone is 190±1℃, the temperature of the fourth heating zone is 195±1℃, the temperature of the fifth heating zone is 195±1℃, the temperature of the sixth heating zone is 185±1℃, and the temperature of the seventh heating zone is 180±1℃. The extrusion temperature is 180±1℃, and the screw speed is 250 rpm.

[0063] Step 3: Add the T-shaped filter brick shell granules into the injection molding machine, heat and melt them, injection mold them, and cool them to obtain the T-shaped filter brick shell;

[0064] The heating and melting temperature is 180±2℃, the injection molding pressure is 90MPa, and the injection molding time is 10s;

[0065] Step 4: Inject C30 concrete into the shell of the T-shaped filter brick, and wait for the concrete to solidify and form to obtain the environmentally friendly permeable T-shaped filter brick.

[0066] Example 2: A preparation process for an environmentally friendly permeable T-shaped filter brick:

[0067] Step 1: S11: Preparation of modified lignin: (1) Add coniferous lignin to 0.15 mol / L sodium hydroxide solution (the ratio of the two is 1 g: 5 mL), stir and mix at 130 °C for 2 h to obtain activated lignin; (2) Under nitrogen protection, add 0.9 parts maleic anhydride and 6 parts activated lignin to 60 parts acetic acid, stir and react at 35 °C for 2 h, filter, wash, dry to obtain modified lignin;

[0068] S12: Preparation of recycled polyethylene: (1) After crushing waste polyethylene into fragments of 5-10cm, wash it with clean water, dry it at 70℃ until the moisture content is ≤0.3%, and finally crush it into particles of 1-5mm to obtain pretreated waste polyethylene; (2) Add 40 parts of pretreated waste polyethylene, 4 parts of modified lignin, 3 parts of hexafluorobutyl acrylate, 0.06 parts of diisopropylbenzene peroxide, and 0.2 parts of antioxidant 1076 into a twin-screw extruder, melt graft, extrude and pelletize to obtain recycled polyethylene;

[0069] The twin-screw extruder is divided into seven heating zones. The temperature of the first heating zone is 140±1℃, the temperature of the second heating zone is 160±1℃, the temperature of the third heating zone is 165±1℃, the temperature of the fourth heating zone is 190±1℃, the temperature of the fifth heating zone is 185±1℃, the temperature of the sixth heating zone is 175±1℃, and the temperature of the seventh heating zone is 165±1℃. The extrusion temperature is 165±1℃, and the screw speed is 250 rpm.

[0070] S13: Preparation of modified filler: (1) Add 15 parts of bamboo fiber (length-to-diameter ratio 50, length 5mm), 0.9 parts of p-toluenesulfonic acid, and 195 parts of acetic anhydride to 195 parts of acetic acid, stir and react at 72℃ for 40min, filter, wash with 5wt% sodium bicarbonate solution, wash with deionized water, and dry to obtain acetylated bamboo fiber; (2) Add vinyltriethoxysilane to 75wt% ethanol aqueous solution (volume ratio of the two is 0.06:1), add acetic acid to adjust pH to 5, stir and mix for 40min to obtain silane hydrolysate; (3) Immerse acetylated bamboo fiber and silicon dioxide (average particle size 100nm) in silane hydrolysate (the ratio of the three is 1g:1g:5mL), soak for 1h, take out, dry to obtain modified filler;

[0071] S14: Add 70 parts high-density polyethylene, 35 parts recycled polyethylene, 25 parts modified filler, 20 parts maleic anhydride grafted polyethylene, 1.5 parts vinyltriethoxysilane, 1 part antioxidant 1076, 2 parts polyethylene wax, and 1 part dicumyl peroxide into a mixer and mix them evenly to obtain a mixture.

[0072] Step 2: Add the mixture into a twin-screw extruder, melt-mix, extrude and granulate to obtain T-shaped filter brick shell granules;

[0073] The twin-screw extruder is divided into seven heating zones. The temperature of the first heating zone is 160±1℃, the temperature of the second heating zone is 175±1℃, the temperature of the third heating zone is 190±1℃, the temperature of the fourth heating zone is 195±1℃, the temperature of the fifth heating zone is 195±1℃, the temperature of the sixth heating zone is 185±1℃, and the temperature of the seventh heating zone is 180±1℃. The extrusion temperature is 180±1℃, and the screw speed is 250 rpm.

[0074] Step 3: Add the T-shaped filter brick shell granules into the injection molding machine, heat and melt them, injection mold them, and cool them to obtain the T-shaped filter brick shell;

[0075] The heating and melting temperature is 180±2℃, the injection molding pressure is 90MPa, and the injection molding time is 10s;

[0076] Step 4: Inject C30 concrete into the shell of the T-shaped filter brick, and wait for the concrete to solidify and form to obtain the environmentally friendly permeable T-shaped filter brick.

[0077] Example 3: A preparation process for an environmentally friendly permeable T-shaped filter brick:

[0078] Step 1: S11: Preparation of modified lignin: (1) Add coniferous lignin to 0.15 mol / L sodium hydroxide solution (the ratio of the two is 1 g: 5 mL), stir and mix at 130 °C for 2 h to obtain activated lignin; (2) Under nitrogen protection, add 0.9 parts maleic anhydride and 6 parts activated lignin to 60 parts acetic acid, stir and react at 35 °C for 2 h, filter, wash, dry to obtain modified lignin;

[0079] S12: Preparation of recycled polyethylene: (1) After crushing waste polyethylene into fragments of 5-10cm, wash it with clean water, dry it at 70℃ until the moisture content is ≤0.3%, and finally crush it into particles of 1-5mm to obtain pretreated waste polyethylene; (2) Add 40 parts of pretreated waste polyethylene, 8 parts of modified lignin, 3 parts of hexafluorobutyl acrylate, 0.06 parts of diisopropylbenzene peroxide, and 0.2 parts of antioxidant 1076 into a twin-screw extruder, melt graft, extrude and pelletize to obtain recycled polyethylene;

[0080] The twin-screw extruder is divided into seven heating zones. The temperature of the first heating zone is 140±1℃, the temperature of the second heating zone is 160±1℃, the temperature of the third heating zone is 165±1℃, the temperature of the fourth heating zone is 190±1℃, the temperature of the fifth heating zone is 185±1℃, the temperature of the sixth heating zone is 175±1℃, and the temperature of the seventh heating zone is 165±1℃. The extrusion temperature is 165±1℃, and the screw speed is 250 rpm.

[0081] S13: Preparation of modified filler: (1) Add 15 parts of bamboo fiber (length-to-diameter ratio 50, length 5mm), 0.9 parts of p-toluenesulfonic acid, and 195 parts of acetic anhydride to 195 parts of acetic acid, stir and react at 72℃ for 40min, filter, wash with 5wt% sodium bicarbonate solution, wash with deionized water, and dry to obtain acetylated bamboo fiber; (2) Add vinyltriethoxysilane to 75wt% ethanol aqueous solution (volume ratio of the two is 0.06:1), add acetic acid to adjust pH to 5, stir and mix for 40min to obtain silane hydrolysate; (3) Immerse acetylated bamboo fiber and silicon dioxide (average particle size 100nm) in silane hydrolysate (the ratio of the three is 1g:1g:5mL), soak for 1h, take out, dry to obtain modified filler;

[0082] S14: Add 70 parts high-density polyethylene, 35 parts recycled polyethylene, 25 parts modified filler, 20 parts maleic anhydride grafted polyethylene, 1.5 parts vinyltriethoxysilane, 1 part antioxidant 1076, 2 parts polyethylene wax, and 1 part dicumyl peroxide into a mixer and mix them evenly to obtain a mixture.

[0083] Step 2: Add the mixture into a twin-screw extruder, melt-mix, extrude and granulate to obtain T-shaped filter brick shell granules;

[0084] The twin-screw extruder is divided into seven heating zones. The temperature of the first heating zone is 160±1℃, the temperature of the second heating zone is 175±1℃, the temperature of the third heating zone is 190±1℃, the temperature of the fourth heating zone is 195±1℃, the temperature of the fifth heating zone is 195±1℃, the temperature of the sixth heating zone is 185±1℃, and the temperature of the seventh heating zone is 180±1℃. The extrusion temperature is 180±1℃, and the screw speed is 250 rpm.

[0085] Step 3: Add the T-shaped filter brick shell granules into the injection molding machine, heat and melt them, injection mold them, and cool them to obtain the T-shaped filter brick shell;

[0086] The heating and melting temperature is 180±2℃, the injection molding pressure is 90MPa, and the injection molding time is 10s;

[0087] Step 4: Inject C30 concrete into the shell of the T-shaped filter brick, and wait for the concrete to solidify and form to obtain the environmentally friendly permeable T-shaped filter brick.

[0088] The following is a control experiment based on Example 1, with comparative examples 1 to 7, as detailed below:

[0089] Comparative Example 1: Comparative Example 1 is based on Example 1, with the following adjustment: no modification treatment is performed on the pretreated waste polyethylene, while other processes remain unchanged. Specifically:

[0090] Step 1: S11: Preparation of recycled polyethylene: (1) After crushing the waste polyethylene into fragments of 5~10cm, wash it with clean water, then dry it at 70℃ until the moisture content is ≤0.3%, and finally crush it into particles of 1~5mm to obtain pretreated waste polyethylene (recycled polyethylene).

[0091] Comparative Example 2: Comparative Example 2 is based on Example 1, with the following adjustment: no modified lignin is added in the preparation of recycled polyethylene, while other processes remain unchanged. Specifically:

[0092] Step 1: S11: Preparation of recycled polyethylene: (1) After crushing waste polyethylene into fragments of 5-10cm, wash it with clean water, dry it at 70℃ until the moisture content is ≤0.3%, and finally crush it into particles of 1-5mm to obtain pretreated waste polyethylene; (2) Add 40 parts of pretreated waste polyethylene, 3 parts of hexafluorobutyl acrylate, 0.06 parts of diisopropylbenzene peroxide, and 0.2 parts of antioxidant 1076 into a twin-screw extruder, melt graft, extrude and pelletize to obtain recycled polyethylene.

[0093] Comparative Example 3: Comparative Example 3 is based on Example 1, with the following adjustment: fluorinated acrylates are not added in the preparation of recycled polyethylene, while other processes remain unchanged. Specifically:

[0094] S12: Preparation of recycled polyethylene: (1) After crushing waste polyethylene into fragments of 5-10cm, wash it with clean water, dry it at 70℃ until the moisture content is ≤0.3%, and finally crush it into particles of 1-5mm to obtain pretreated waste polyethylene; (2) Add 40 parts of pretreated waste polyethylene, 6 parts of modified lignin, 0.06 parts of diisopropylbenzene peroxide and 0.2 parts of antioxidant 1076 into a twin-screw extruder, melt graft, extrude and pelletize to obtain recycled polyethylene.

[0095] Comparative Example 4: Comparative Example 4 is based on Example 1, with the following adjustment: GS-type lignin (hardwood lignin) was used in the preparation of modified lignin, while other processes remained unchanged. Specifically:

[0096] Step 1: S11: Preparation of modified lignin: (1) Add the lignin of broad-leaved wood to a 0.15 mol / L sodium hydroxide solution (the ratio of the two is 1 g: 5 mL), stir and mix at 130 °C for 2 h to obtain activated lignin; (2) Under nitrogen protection, add 0.9 parts of maleic anhydride and 6 parts of activated lignin to 60 parts of acetic acid, stir and react at 35 °C for 2 h, filter, wash, and dry to obtain modified lignin.

[0097] Comparative Example 5: Comparative Example 5 is based on Example 1, with the following adjustment: the modified filler is obtained only from acetylated bamboo fiber, while other processes remain unchanged. Specifically:

[0098] S13: Preparation of modified filler: (1) Add 15 parts of bamboo fiber (length-to-diameter ratio 50, length 5mm), 0.9 parts of p-toluenesulfonic acid, and 195 parts of acetic anhydride to 195 parts of acetic acid, stir and react at 72℃ for 40min, filter, wash with 5wt% sodium bicarbonate solution, wash with deionized water, and dry to obtain acetylated bamboo fiber; (2) Add vinyltriethoxysilane to 75wt% ethanol aqueous solution (volume ratio of the two is 0.06:1), add acetic acid to adjust pH to 5, stir and mix for 40min to obtain silane hydrolysate; (3) Immerse acetylated bamboo fiber in silane hydrolysate (the ratio of the three is 2g:5mL), soak for 1h, take out, dry to obtain modified filler.

[0099] Comparative Example 6: Comparative Example 6 is based on Example 1, with the following adjustments: maleic anhydride-grafted polyethylene is not added to the raw material components, while other processes remain unchanged. Specifically:

[0100] S14: Add 70 parts of high-density polyethylene, 35 parts of recycled polyethylene, 25 parts of modified filler, 1.5 parts of vinyltriethoxysilane, 1 part of antioxidant 1076, 2 parts of polyethylene wax, and 1 part of dicumyl peroxide into a mixer and mix them evenly to obtain a mixture.

[0101] Comparative Example 7: Comparative Example 7 is based on Example 1, with the following adjustment: vinyltriethoxysilane is not added to the raw material components, while other processes remain unchanged. Specifically:

[0102] S14: Add 70 parts high-density polyethylene, 35 parts recycled polyethylene, 25 parts modified filler, 20 parts maleic anhydride grafted polyethylene, 1 part antioxidant 1076, 2 parts polyethylene wax, and 1 part dicumyl peroxide into a mixer and mix them evenly to obtain a mixture.

[0103] Performance Testing: To demonstrate that the T-shaped filter bricks prepared in Examples 1-3 and Comparative Examples 1-7 possess excellent mechanical properties, wear resistance, and corrosion resistance, this invention will conduct performance tests on the outer shell granules of the T-shaped filter bricks corresponding to each example. The specific test content and methods are as follows:

[0104] (1) Tensile strength test: According to the standard of ASTM D638-14, the T-type filter brick shell granules corresponding to each example were added into the injection molding machine, heated and melted at 180±2℃, and prepared into standard dumbbell-shaped specimens under a molding pressure of 90MPa. The tensile properties were tested at 23±2℃.

[0105] (2) Wear resistance test: The T-shaped filter brick shell granules corresponding to each example were added into the injection molding machine and heated to melt at 180±2℃. Under the molding pressure of 90MPa, a sample with a length of 10cm×width×thickness of 10cm×thickness was prepared. Then, the wear resistance test was carried out using a Taber abrasion tester. Under a load of 500g, the CS-10 grinding wheel was used to rotate 1000 times. The wear rate was calculated based on the wear amount before and after.

[0106] (3) Corrosion resistance test: According to the standard GB / T 23257-2017, at 23±2℃, the standard dumbbell-shaped sample in (1) was immersed in 80wt% sulfuric acid solution and 3mol / L sodium hydroxide solution for 24h respectively, and then taken out for tensile strength test.

[0107] The data results for the above test items are shown in Table 1 below:

[0108] Table 1

[0109]

[0110] Results Analysis: As shown in Table 1 above, comparing Examples 1-3 reveals that the amount of modified lignin added has a significant impact on the performance of recycled polyethylene. Insufficient addition results in low modification levels, while excessive addition leads to an excessive number of phenolic hydroxyl groups in the modified lignin, which reduces its compatibility and causes the performance of the recycled polyethylene to begin to decline. Comparing the data from Example 1 and Comparative Examples 1-4 shows that this invention, by selecting and modifying G-type lignin, and then synergistically combining it with fluorinated acrylates, effectively improves waste polyethylene, thereby enabling the T-type filter brick shell to exhibit excellent mechanical properties. Performance and corrosion resistance; Comparative Example 1 and Comparative Example 5 show that the synergistic use of fibers and nanoparticles in this invention enhances the mechanical properties and corrosion resistance of the T-shaped filter brick shell to a certain extent; Comparative Example 1 and Comparative Example 6 show that the addition of compatibilizer greatly promotes the compatibility of each component, resulting in the T-shaped filter brick particles exhibiting excellent performance; Comparative Example 1 and Comparative Example 7 show that the addition of vinyl silane coupling agent can form a dense Si-O-Si network protective film on the surface of the T-shaped filter brick shell, greatly avoiding the potential risk of bamboo fiber swelling due to water absorption.

[0111] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A preparation process for an environmentally friendly permeable T-shaped filter brick, characterized in that: Includes the following steps: Step 1: Add high-density polyethylene, recycled polyethylene, modified filler, maleic anhydride grafted polyethylene, vinyl silane coupling agent, antioxidant, lubricant, and initiator into a mixer and mix them evenly to obtain a mixture. Step 2: Add the mixture into a twin-screw extruder, melt-mix, extrude and granulate to obtain T-shaped filter brick shell granules; Step 3: Add the T-shaped filter brick shell granules into the injection molding machine, heat and melt them, injection mold them, and cool them to obtain the T-shaped filter brick shell; Step 4: Inject concrete into the outer shell of the T-shaped filter brick, and wait for the concrete to solidify and form to obtain the environmentally friendly permeable T-shaped filter brick. The T-shaped filter brick shell comprises the following raw material components: by weight, 70 parts high-density polyethylene, 30-40 parts recycled polyethylene, 20-30 parts modified filler, 15-25 parts maleic anhydride grafted polyethylene, 1-2 parts vinyl silane coupling agent, 0.5-1.5 parts antioxidant, 1-3 parts lubricant, and 0.5-1 part initiator; The preparation method of the recycled polyethylene material is as follows: (1) After crushing the waste polyethylene into fragments of 5-10cm, wash it with clean water, dry it in an environment of 60-80℃ until the moisture content is ≤0.3%, and finally crush it into particles of 1-5mm to obtain pretreated waste polyethylene. (2) Add pretreated waste polyethylene, modified lignin, fluorinated acrylate, antioxidant and initiator into a twin-screw extruder, melt graft, extrude and pelletize to obtain recycled polyethylene material; The method for preparing the modified lignin: (1) Add lignin to a 0.1~0.2mol / L sodium hydroxide solution and stir and mix at 120~140℃ for 1~4h to obtain activated lignin; (2) Under nitrogen protection, maleic anhydride and activated lignin were added to acetic acid and stirred at 30-40°C for 1-4 hours. The mixture was then filtered, washed, and dried to obtain modified lignin. The lignin is G-type lignin; The modified filler is prepared by: (1) Add bamboo fiber, p-toluenesulfonic acid and acetic anhydride to acetic acid, stir and react at 70~75℃ for 20~60min, filter, wash with 5wt% sodium bicarbonate solution, wash with deionized water, and dry to obtain acetylated bamboo fiber. (2) Add the vinylsilane coupling agent to a 75wt% ethanol aqueous solution, add acetic acid to adjust the pH to 4-6, stir and mix for 20-60 min to obtain silane hydrolysate; (3) Immerse acetylated bamboo fiber and silicon dioxide in silane hydrolysate for 0.5-1.5 h, remove and dry to obtain modified filler.

2. The preparation process of an environmentally friendly permeable T-shaped filter brick according to claim 1, characterized in that: The raw materials required for the preparation of the polyethylene recycled material include the following components: by weight, 40 parts of pretreated waste polyethylene, 4-8 parts of modified lignin, 2-4 parts of fluorinated acrylate, 0.05-0.07 parts of initiator, and 0.1-0.3 parts of antioxidant.

3. The preparation process of an environmentally friendly permeable T-shaped filter brick according to claim 1, characterized in that: The ratio of lignin to sodium hydroxide solution is 1g:5mL; the mass ratio of maleic anhydride, activated lignin, and acetic acid is (0.1~0.2):1:

10.

4. The preparation process of an environmentally friendly permeable T-shaped filter brick according to claim 1, characterized in that: The fluorinated acrylates include one or a combination of several of the following: hexafluorobutyl acrylate, hexafluorobutyl methacrylate, trifluoroethyl methacrylate, dodecafluoroheptyl methacrylate, dodecafluoroheptyl acrylate, nonadecafluoro acrylate, and perfluorobutyl ethyl methacrylate.

5. The preparation process of an environmentally friendly permeable T-shaped filter brick according to claim 1, characterized in that: In step (2) of the method for preparing recycled polyethylene, the twin-screw extruder is divided into seven heating zones, with a temperature range of 130~200℃. Specifically, the temperature of the first heating zone is 130~150℃, the temperature of the second heating zone is 150~170℃, the temperature of the third heating zone is 150~170℃, the temperature of the fourth heating zone is 180~200℃, the temperature of the fifth heating zone is 180~190℃, the temperature of the sixth heating zone is 170~180℃, and the temperature of the seventh heating zone is 160~170℃. The extrusion temperature is 160~170℃, and the screw speed is 200~300 rpm.

6. The preparation process of an environmentally friendly permeable T-shaped filter brick according to claim 1, characterized in that: The mass ratio of bamboo fiber, p-toluenesulfonic acid, acetic anhydride, and acetic acid is 1:(0.04~0.08):(10~16):(10~16); the volume ratio of vinyl silane coupling agent and ethanol aqueous solution is (0.04~0.08):1; and the ratio of acetylated bamboo fiber, silicon dioxide, and silane hydrolysate is 1g:1g:5mL.

7. The preparation process of an environmentally friendly permeable T-shaped filter brick according to claim 1, characterized in that: The vinyl silane coupling agent includes one or a combination of several of vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri(2-methoxyethoxy)silane, vinyldimethylethoxysilane, and vinylmethyldiethoxysilane.

8. The preparation process of an environmentally friendly permeable T-shaped filter brick according to claim 1, characterized in that: In step 2, the twin-screw extruder is divided into seven heating zones, with a temperature range of 150~200℃. Specifically, the temperature of the first heating zone is 150~170℃, the second heating zone is 170~185℃, the third heating zone is 185~195℃, the fourth heating zone is 190~200℃, the fifth heating zone is 190~200℃, the sixth heating zone is 180~190℃, and the seventh heating zone is 175~185℃. The extrusion temperature is 175~185℃, and the screw speed is 200~300 rpm. In step 3, the relevant parameters of the injection molding machine are: the heating and melting temperature is 175~185℃, the injection molding pressure is 80~100MPa, and the injection molding time is 5~15s.

9. The environmentally friendly permeable T-shaped filter brick prepared by the preparation process according to any one of claims 1 to 8, characterized in that: It includes the T-shaped filter brick shell and the concrete filling inside it.

Images