An H-type reinforced composite drainage net and its preparation method

Abstract

This invention discloses an H-type reinforced composite drainage net and its preparation method, relating to the field of drainage net technology. The composite drainage net includes a core and geotextiles fixed on both sides of the core. The geotextiles are made of the following components by weight: 90-120 parts polypropylene, 4-12 parts modified calcium sulfate whiskers, and 2-10 parts calcium carbonate. This invention, through the composite structural design of the core and functionalized geotextile, combined with the reinforcing and anti-aging effects of modified calcium sulfate whiskers and the wear-resistant and compressive-resistant properties of calcium carbonate, significantly improves the overall mechanical strength and service life of the composite drainage net, giving the product excellent structural stability and durability, and meeting the long-term performance requirements in engineering applications.

Description

Technical Field

[0001] This invention relates to the field of drainage net technology, specifically to an H-type reinforced composite drainage net and its preparation method. Background Technology

[0002] Composite drainage nets are an important geosynthetic material widely used in drainage systems of highways, railways, water conservancy projects, and other engineering projects. Currently, common composite drainage nets are mainly composed of a plastic drainage net core and geotextile. The net core provides drainage channels, while the geotextile provides filtration and protection. As a new type of material to replace traditional sand cushions and gravel layers, composite drainage nets play a vital role in projects such as landfills and landslide tunnels, effectively draining water accumulated between the foundation and the waste substrate and preventing the infiltration and diffusion of pollutants.

[0003] CN109137879A discloses a high-strength drainage net, including a drainage net core. The upper and lower surfaces of the drainage net core are respectively provided with non-woven geotextile. The drainage net core includes an upper rib, a middle rib, and a lower rib. The upper rib and the lower rib are respectively located on the upper and lower end faces of the middle rib. The upper rib, the middle rib, and the lower rib are all spaced apart. The upper and lower end faces of the middle rib are respectively provided with grooves to accommodate the upper rib and the lower rib. The non-woven geotextile is bonded to the upper and lower surfaces of the drainage net core by an adhesive.

[0004] However, traditional composite drainage nets face several pressing problems in practical applications. Firstly, the geotextile layer of existing composite drainage nets is generally made of a single polypropylene material. While polypropylene possesses good chemical stability and corrosion resistance, its mechanical properties are limited, making it prone to deformation and damage under heavy loads, thus affecting drainage performance. Secondly, polypropylene molecules lack UV-resistant functional groups, and long-term exposure to the natural environment leads to oxidative aging and a decline in mechanical properties, significantly shortening the service life of the composite drainage net.

[0005] Currently, domestic and international scholars' research on the modification of composite drainage nets mainly focuses on two aspects: optimization of the core structure and modification of geotextiles. Regarding geotextile modification, common methods include adding inorganic fillers and blending modification; however, these methods often suffer from poor dispersibility and interfacial compatibility, making it difficult to simultaneously achieve the goals of improving mechanical properties and anti-aging performance. In particular, traditional single-layer grid structures are prone to mesh clogging, requiring frequent manual cleaning and maintenance, significantly increasing operating costs. Therefore, developing a composite drainage net product with excellent comprehensive performance is of significant practical importance. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide an H-type reinforced composite drainage net and its preparation method. Through the composite structural design of the net core and functionalized geotextile, combined with the reinforcing and anti-aging effects of modified calcium sulfate whiskers and the wear-resistant and compressive strength of calcium carbonate, the overall mechanical strength and service life of the composite drainage net are significantly improved, giving the product excellent structural stability and durability, and meeting the long-term performance requirements in engineering applications.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] An H-type reinforced composite drainage net includes a core and geotextile fixed on both sides of the core. The geotextile is made of the following components by weight: 90-120 parts polypropylene, 4-12 parts modified calcium sulfate whiskers, and 2-10 parts calcium carbonate.

[0009] Preferably, the method for preparing the modified calcium sulfate whiskers includes the following steps:

[0010] (1) Calcium sulfate whiskers were dispersed in an aqueous ethanol solution, ultrasonically treated, 3-isocyanate propyltriethoxysilane was added, heated and stirred, and the product was filtered, washed with alcohol and dried to obtain isocyanate modified whiskers.

[0011] Silane coupling reaction: The ethoxy group of 3-isocyanatepropyltriethoxysilane hydrolyzes in the presence of trace amounts of water to generate silanol (-Si-OH), which then undergoes a condensation reaction with the hydroxyl groups on the whisker surface to form Si-O-whisker covalent bonds, releasing ethanol simultaneously. This process acquires active isocyanate groups (-NCO) on the whisker surface, providing reaction sites for subsequent modification.

[0012] Preferably, in step (1), the volume ratio of ethanol to deionized water in the ethanol aqueous solution is 85-95:15-5; the ratio of calcium sulfate whiskers, ethanol aqueous solution, and 3-isocyanate propyltriethoxysilane is 10g:100-150mL:0.5-3g.

[0013] Preferably, in step (1), the ultrasonic treatment lasts for 15 to 30 minutes; the heating and stirring conditions are 60 to 75°C for 2 to 5 hours.

[0014] (2) Disperse the isocyanate-modified whiskers in DMF, sonicate them, add 4-hydroxycinnamic acid and dibutyltin dilaurate, stir the reaction, centrifuge, wash and dry the product to obtain cinnamic acid-modified whiskers.

[0015] Isocyanate-hydroxy addition reaction: Under the catalysis of dibutyltin dilaurate, the isocyanate groups (-NCO) on the whisker surface undergo an addition reaction with the hydroxyl groups (-OH) of 4-hydroxycinnamic acid. The catalyst first forms an active intermediate with the isocyanate, increasing the polarization of the C=N bond. Subsequently, the hydroxyl group attacks to form a carbamate bond (-NH-COO-), introducing the cinnamic acid group into the whisker surface and exposing a new carboxyl group (-COOH) on the surface.

[0016] Preferably, in step (2), the ratio of isocyanate-modified whiskers, DMF, 4-hydroxycinnamic acid, and dibutyltin dilaurate is 10g: 100-150mL: 0.5-2g: 0.01-0.1g.

[0017] Preferably, in step (2), the ultrasonic treatment is performed for 15 to 30 minutes; the stirring reaction is carried out at 65 to 80°C for 5 to 8 hours; and the product is washed with DMF and acetone 2 to 4 times in sequence.

[0018] (3) Cinnamic acid modified whiskers were dispersed in DMF, ultrasonically treated, DCC and NHS were added, and the mixture was stirred and activated at room temperature. Then 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid was added, and the mixture was heated and stirred to react. The product was centrifuged, washed and dried to obtain modified calcium sulfate whiskers.

[0019] Esterification grafting: The carboxyl groups on the whisker surface first react with DCC to form an O-acylurea intermediate. NHS then attacks this intermediate to generate an active ester and release DCC byproducts. The activated ester group undergoes a nucleophilic substitution reaction with the hydroxyl group of 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, attaching the UV absorber molecule to the whisker surface through an ester bond (-COO-), while simultaneously releasing NHS.

[0020] Preferably, in step (3), the ratio of cinnamic acid modified whiskers, DMF, DCC, NHS, and 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid is 10g: 100-150mL: 0.5-1g: 0.25-0.5g: 0.8-2.4g.

[0021] Preferably, in step (3), the ultrasonic treatment is performed for 15 to 30 minutes; the stirring activation conditions are stirring and activating at room temperature for 30 to 60 minutes; the stirring reaction conditions are stirring and reacting at 65 to 80°C for 4 to 7 hours; and the product is washed with DMF and acetone 2 to 4 times in sequence.

[0022] This invention also claims a method for preparing the H-type reinforced composite drainage net, comprising the following steps: after the raw materials are mixed evenly, they are fed into a screw extruder, melted and extruded, and then transferred to a spinning box. The filaments are ejected from the spinneret holes of the spinning box and cooled by a side fan. The cooled filament bundles are then drawn by an airflow through a tubular drawer to achieve uniform filament splitting. The filaments are evenly laid on the condensing net curtain under the control of the side-blown airflow, and output to a needle punching machine through a pre-pressing roller. The formed filament fiber net is then reinforced by pre-needling and main needle punching to obtain the geotextile. The geotextile and the net core are then prepared by online thermal bonding to obtain the H-type reinforced composite drainage net.

[0023] Preferably, the heating temperatures of each section of the screw extruder are 160℃, 180℃, 200℃, and 210℃, respectively, and the screw speed is 70~90r / min.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The H-type reinforced composite drainage net provided by this invention adopts a composite structure of a mesh core and geotextile, which improves the overall strength and stability of the drainage net. Modified calcium sulfate whiskers added to the geotextile provide reinforcement through their high aspect ratio needle-like structure, while surface modification imparts excellent interfacial compatibility and UV resistance. Calcium carbonate improves the wear resistance and compressive strength of the geotextile, and works synergistically with the polypropylene matrix to significantly improve the mechanical properties and service life of the geotextile. The preparation method uses a screw extruder for melt extrusion, and precise control of the temperature and rotation speed of each section ensures uniform dispersion of each component. An airflow drawing process achieves uniform fiber splitting, combined with needle punching reinforcement, resulting in a dense and uniform geotextile structure. Finally, an online thermal composite process is used to bond with the mesh core, ensuring the bonding strength of the composite interface and improving the overall performance of the product.

[0026] 2. This invention provides a modified calcium sulfate whisker that significantly improves the overall performance of the composite material. First, calcium sulfate whiskers themselves possess excellent mechanical properties; their high aspect ratio (approximately 20-50) needle-like structure can form a three-dimensional network support structure within the polypropylene matrix, significantly improving the tensile strength and modulus of the geotextile. Second, isocyanate groups are introduced onto the whisker surface using a silane coupling agent, forming molecular bridges and effectively improving the interfacial compatibility and bonding strength between the whiskers and the polypropylene matrix. Furthermore, by grafting 4-hydroxycinnamic acid, a cinnamic acid ester structure with a high molar absorption coefficient is introduced, providing excellent ultraviolet light absorption capability. The unsaturated double bonds in its molecular structure may also provide additional interfacial interactions during processing. Finally, by introducing 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, a composite ultraviolet light absorption system is formed with the cinnamic acid ester structure, synergistically improving the anti-aging performance of the geotextile. Simultaneously, the introduction of sulfonic acid groups increases the hydrophilicity of the modified whisker surface; this hydrophilic modification helps improve the permeability of the geotextile. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. Of course, the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0028] Unless otherwise specified, all chemical reagents and materials in this invention are purchased from the market or synthesized from raw materials purchased from the market.

[0029] The polypropylene was purchased from Liaoning Huajin Tongda Chemical Co., Ltd., model T30S.

[0030] Calcium sulfate whiskers were purchased from Dongguan Wangda Plastics Factory in Guangdong Province. They had an average length of 50–200 μm, an average diameter of 1–5 μm, and an elastic modulus of 20.5 GPa.

[0031] Calcium carbonate was purchased from Beijing Deco Island Gold Technology Co., Ltd., with an average particle size of 20 nm.

[0032] A method for preparing an H-type reinforced composite drainage net includes the following steps:

[0033] (1) Disperse 10g of calcium sulfate whiskers into 100-150mL of ethanol aqueous solution (the volume ratio of ethanol to deionized water is 85-95:15-5), sonicate for 15-30min, add 0.5-3g of 3-isocyanate propyltriethoxysilane, heat and stir at 60-75℃ for 2-5h, filter the product, wash with alcohol and dry to obtain isocyanate modified whiskers;

[0034] (2) Disperse 10g of isocyanate-modified whiskers into 100-150mL of DMF, sonicate for 15-30min, add 0.5-2g of 4-hydroxycinnamic acid and 0.01-0.1g of dibutyltin dilaurate, stir and react at 65-80℃ for 5-8h, centrifuge the product, wash with DMF and acetone 2-4 times in sequence, and dry to obtain cinnamic acid-modified whiskers;

[0035] (3) Disperse 10g of cinnamic acid modified whiskers into 100-150mL of DMF, sonicate for 15-30min, add 0.5-1g of DCC and 0.25-0.5g of NHS, stir and activate at room temperature for 30-60min, then add 0.8-2.4g of 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, heat to 65-80℃ and stir for 4-7h, centrifuge the product, wash with DMF and acetone 2-4 times in sequence, and dry to obtain modified calcium sulfate whiskers;

[0036] (4) After mixing 90-120 parts of polypropylene, 4-12 parts of modified calcium sulfate whiskers and 2-10 parts of calcium carbonate evenly, the mixture is fed into a screw extruder. The heating temperatures of each section of the screw extruder are 160℃, 180℃, 200℃ and 210℃, respectively, and the screw speed is 70-90 r / min. After melting and extrusion, the mixture is transferred to the spinning box and ejected from the spinneret holes of the spinning box. The mixture is cooled by a side fan. The cooled filament bundle is then stretched by a tubular stretcher to achieve uniform filament splitting. The filaments are evenly laid on the condensing screen under the control of the side blowing airflow and output to the needle punching machine through the pre-pressing roller. The resulting filament web is reinforced by pre-needling and main needle punching to obtain the geotextile. The geotextile and the core are then prepared by online thermal composite to obtain the H-type reinforced composite drainage net.

[0037] The present invention will be further described below through specific embodiments.

[0038] Example 1

[0039] A method for preparing an H-type reinforced composite drainage net includes the following steps:

[0040] (1) Disperse 10g of calcium sulfate whiskers into 100mL of ethanol aqueous solution (the volume ratio of ethanol to deionized water is 90:10), sonicate for 30min, add 3g of 3-isocyanate propyltriethoxysilane, heat and stir at 75℃ for 2h, filter, wash with alcohol and dry to obtain isocyanate modified whiskers.

[0041] (2) Disperse 10g of isocyanate-modified whiskers into 100mL of DMF, sonicate for 30min, add 2g of 4-hydroxycinnamic acid and 0.1g of dibutyltin dilaurate, stir and react at 80℃ for 5h, centrifuge the product, wash it three times with DMF and acetone in sequence, and dry it to obtain cinnamic acid-modified whiskers.

[0042] (3) Disperse 10g of cinnamic acid modified whiskers into 100mL of DMF, sonicate for 30min, add 1g of DCC and 0.5g of NHS, stir and activate at room temperature for 45min, then add 2.4g of 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, heat to 80℃ and stir for 4h, centrifuge the product, wash with DMF and acetone three times in sequence, and dry to obtain modified calcium sulfate whiskers;

[0043] (4) After mixing 1200g of polypropylene, 120g of modified calcium sulfate whiskers and 100g of calcium carbonate evenly, the mixture is fed into a screw extruder. The heating temperatures of each section of the screw extruder are 160℃, 180℃, 200℃ and 210℃, respectively, and the screw speed is 80r / min. After melting and extrusion, the mixture is transferred to the spinning box and ejected from the spinneret of the spinning box. The mixture is cooled by a side fan. The cooled filament bundle is then stretched by a tubular stretcher to achieve uniform filament splitting. The filaments are evenly laid on the condensing screen under the control of the side blowing airflow and output to the needle punching machine through the pre-pressing roller. The resulting filament web is reinforced by pre-needling and main needle punching to obtain the geotextile. The geotextile and the core are then prepared by online thermal composite to obtain the H-type reinforced composite drainage net.

[0044] Example 2

[0045] A method for preparing an H-type reinforced composite drainage net includes the following steps:

[0046] (1) Disperse 10g of calcium sulfate whiskers into 100mL of ethanol aqueous solution (the volume ratio of ethanol to deionized water is 90:10), sonicate for 30min, add 2g of 3-isocyanate propyltriethoxysilane, heat and stir at 70℃ for 3h, filter, wash with alcohol and dry to obtain isocyanate modified whiskers.

[0047] (2) Disperse 10g of isocyanate-modified whiskers into 100mL of DMF, sonicate for 30min, add 1.5g of 4-hydroxycinnamic acid and 0.07g of dibutyltin dilaurate, stir and react at 75℃ for 6h, centrifuge the product, wash it three times with DMF and acetone in sequence, and dry it to obtain cinnamic acid-modified whiskers.

[0048] (3) Disperse 10g of cinnamic acid modified whiskers into 100mL of DMF, sonicate for 30min, add 0.8g of DCC and 0.4g of NHS, stir and activate at room temperature for 45min, then add 2g of 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, heat to 75℃ and stir for 5h, centrifuge the product, wash with DMF and acetone three times in sequence, and dry to obtain modified calcium sulfate whiskers;

[0049] (4) After mixing 1100g of polypropylene, 100g of modified calcium sulfate whiskers and 80g of calcium carbonate evenly, the mixture is fed into a screw extruder. The heating temperatures of each section of the screw extruder are 160℃, 180℃, 200℃ and 210℃, respectively, and the screw speed is 80r / min. After melting and extrusion, the mixture is transferred to the spinning box and ejected from the spinneret of the spinning box. The mixture is cooled by a side fan. The cooled filament bundle is then stretched by a tubular stretcher to achieve uniform filament splitting. The filaments are evenly laid on the condensing screen under the control of the side blowing airflow and output to the needle punching machine through the pre-pressing roller. The resulting filament web is reinforced by pre-needling and main needle punching to obtain the geotextile. The geotextile and the core are then prepared by online thermal composite to obtain the H-type reinforced composite drainage net.

[0050] Example 3

[0051] A method for preparing an H-type reinforced composite drainage net includes the following steps:

[0052] (1) Disperse 10g of calcium sulfate whiskers into 100mL of ethanol aqueous solution (the volume ratio of ethanol to deionized water is 90:10), sonicate for 30min, add 1g of 3-isocyanate propyltriethoxysilane, heat and stir at 65℃ for 4h, filter, wash with alcohol and dry to obtain isocyanate modified whiskers.

[0053] (2) Disperse 10g of isocyanate-modified whiskers into 100mL of DMF, sonicate for 30min, add 1g of 4-hydroxycinnamic acid and 0.04g of dibutyltin dilaurate, stir and react at 70℃ for 7h, centrifuge the product, wash it three times with DMF and acetone in sequence, and dry it to obtain cinnamic acid-modified whiskers.

[0054] (3) Disperse 10g of cinnamic acid modified whiskers into 100mL of DMF, sonicate for 30min, add 0.7g of DCC and 0.35g of NHS, stir and activate at room temperature for 45min, then add 1.4g of 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, heat to 70℃ and stir for 6h, centrifuge the product, wash with DMF and acetone three times in sequence, dry, and obtain modified calcium sulfate whiskers;

[0055] (4) After mixing 1000g of polypropylene, 60g of modified calcium sulfate whiskers and 40g of calcium carbonate evenly, the mixture is fed into a screw extruder. The heating temperatures of each section of the screw extruder are 160℃, 180℃, 200℃ and 210℃, respectively, and the screw speed is 80r / min. After melting and extrusion, the mixture is transferred to the spinning box and ejected from the spinneret of the spinning box. The mixture is cooled by a side fan. The cooled filament bundle is then stretched by a tubular stretcher to achieve uniform filament splitting. The filaments are evenly laid on the condensing screen under the control of the side blowing airflow and output to the needle punching machine through the pre-pressing roller. The resulting filament web is reinforced by pre-needling and main needle punching to obtain the geotextile. The geotextile and the mesh core are then prepared by online thermal composite to obtain the H-type reinforced composite drainage net.

[0056] Example 4

[0057] A method for preparing an H-type reinforced composite drainage net includes the following steps:

[0058] (1) Disperse 10g of calcium sulfate whiskers into 100mL of ethanol aqueous solution (the volume ratio of ethanol to deionized water is 90:10), sonicate for 30min, add 0.5g of 3-isocyanate propyltriethoxysilane, heat and stir at 60℃ for 5h, filter the product, wash with alcohol and dry to obtain isocyanate modified whiskers.

[0059] (2) Disperse 10g of isocyanate-modified whiskers into 100mL of DMF, sonicate for 30min, add 0.5g of 4-hydroxycinnamic acid and 0.01g of dibutyltin dilaurate, stir and react at 65℃ for 8h, centrifuge the product, wash it three times with DMF and acetone in sequence, and dry it to obtain cinnamic acid-modified whiskers.

[0060] (3) Disperse 10g of cinnamic acid modified whiskers into 100mL of DMF, sonicate for 30min, add 0.5g of DCC and 0.25g of NHS, stir and activate at room temperature for 45min, then add 0.8g of 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, heat to 65℃ and stir for 7h, centrifuge the product, wash with DMF and acetone three times in sequence, and dry to obtain modified calcium sulfate whiskers;

[0061] (4) After mixing 900g of polypropylene, 40g of modified calcium sulfate whiskers and 20g of calcium carbonate evenly, the mixture is fed into a screw extruder. The heating temperatures of each section of the screw extruder are 160℃, 180℃, 200℃ and 210℃, respectively, and the screw speed is 80r / min. After melting and extrusion, the mixture is transferred to the spinning box and ejected from the spinneret of the spinning box. The mixture is cooled by a side fan. The cooled filament bundle is then stretched by a tubular stretcher to achieve uniform filament splitting. The filaments are evenly laid on the condensing screen under the control of the side blowing airflow and output to the needle punching machine through the pre-pressing roller. The resulting filament web is reinforced by pre-needling and main needle punching to obtain the geotextile. The geotextile and the core are then prepared by online thermal composite to obtain the H-type reinforced composite drainage net.

[0062] Comparative Example 1

[0063] A method for preparing an H-type reinforced composite drainage net includes the following steps:

[0064] (1) Disperse 10g of calcium sulfate whiskers into 100mL of ethanol aqueous solution (the volume ratio of ethanol to deionized water is 90:10), sonicate for 30min, add 3g of 3-isocyanate propyltriethoxysilane, heat and stir at 75℃ for 2h, filter, wash with alcohol and dry to obtain isocyanate modified whiskers.

[0065] (2) Disperse 10g of isocyanate-modified whiskers into 100mL of DMF, sonicate for 30min, add 2g of 4-hydroxycinnamic acid and 0.1g of dibutyltin dilaurate, stir and react at 80℃ for 5h, centrifuge the product, wash it three times with DMF and acetone in sequence, and dry it to obtain cinnamic acid-modified whiskers.

[0066] (3) After mixing 1200g of polypropylene, 120g of modified calcium sulfate whiskers and 100g of calcium carbonate evenly, the mixture is fed into a screw extruder. The heating temperatures of each section of the screw extruder are 160℃, 180℃, 200℃ and 210℃, respectively, and the screw speed is 80r / min. After melting and extrusion, the mixture is transferred to the spinning box and ejected from the spinneret of the spinning box. The mixture is cooled by a side fan. The cooled filament bundle is then stretched by a tubular stretcher to achieve uniform filament splitting. The filaments are evenly laid on the condensing screen under the control of the side blowing airflow and output to the needle punching machine through the pre-pressing roller. The resulting filament web is reinforced by pre-needling and main needle punching to obtain the geotextile. The geotextile and the core are then prepared by online thermal composite to obtain the H-type reinforced composite drainage net.

[0067] Comparative Example 2

[0068] A method for preparing an H-type reinforced composite drainage net includes the following steps:

[0069] (1) Disperse 10g of calcium sulfate whiskers into 100mL of ethanol aqueous solution (the volume ratio of ethanol to deionized water is 90:10), sonicate for 30min, add 3g of 3-isocyanate propyltriethoxysilane, heat and stir at 75℃ for 2h, filter, wash with alcohol and dry to obtain isocyanate modified whiskers.

[0070] (2) After mixing 1200g of polypropylene, 120g of modified calcium sulfate whiskers and 100g of calcium carbonate evenly, the mixture is fed into a screw extruder. The heating temperatures of each section of the screw extruder are 160℃, 180℃, 200℃ and 210℃, respectively, and the screw speed is 80r / min. After melting and extrusion, the mixture is transferred to the spinning box and ejected from the spinneret holes of the spinning box. The mixture is cooled by a side fan. The cooled filament bundle is then stretched by a tubular stretcher to achieve uniform filament splitting. The filaments are evenly laid on the condensing screen under the control of the side blowing airflow and output to the needle punching machine through the pre-pressing roller. The resulting filament web is reinforced by pre-needling and main needle punching to obtain the geotextile. The geotextile and the core are then prepared by online thermal composite to obtain the H-type reinforced composite drainage net.

[0071] The geotextiles prepared in Examples 1-4 and Comparative Examples 1-2 were subjected to performance tests. The tensile breaking strength of the geotextiles was tested according to GB / T 3923.1-2013 "Textiles - Tensile Properties of Fabrics - Part 1: Determination of Breaking Strength and Elongation at Break (Strip Method)". The geotextiles were subjected to UV irradiation at 340 nm wavelength for 200 hours according to GB / T 31899-2015 "Textiles - Weather Resistance Tests - Ultraviolet Exposure", with other experimental conditions referring to experimental condition 2 of the same standard, for 7 cycles. The retention rate of mechanical properties of the geotextiles was then tested. The number of abrasion cycles was tested according to GB / T 21196.2-2007 "Textiles - Martindale Method - Determination of Abrasion Resistance of Fabrics - Part 2: Determination of Specimen Breakage". The vertical permeability was tested according to GB / T 15789-2016 "Geotextiles and Related Products - Determination of Vertical Permeability under No Load". Specific data are shown in Table 1.

[0072] Table 1. Test results of geotextile performance

[0073]

[0074] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An H-type reinforced composite drainage net, comprising a core mesh and geotextile fixed to both sides of the core mesh, characterized in that, The geotextile is made of the following components by weight: 90-120 parts polypropylene, 4-12 parts modified calcium sulfate whiskers, and 2-10 parts calcium carbonate. The method for preparing the modified calcium sulfate whiskers includes the following steps: (1) Calcium sulfate whiskers were dispersed in an ethanol aqueous solution, sonicated, and 3-isocyanate propyltriethoxysilane was added. The mixture was heated and stirred. The product was filtered, washed with alcohol, and dried to obtain isocyanate modified whiskers. (2) Disperse the isocyanate-modified whiskers in DMF, sonicate them, add 4-hydroxycinnamic acid and dibutyltin dilaurate, stir the reaction, centrifuge, wash and dry the product to obtain cinnamic acid-modified whiskers; (3) Cinnamic acid modified whiskers were dispersed in DMF, ultrasonically treated, DCC and NHS were added, and the mixture was stirred and activated at room temperature. Then 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid was added, and the mixture was heated and stirred to react. The product was centrifuged, washed and dried to obtain modified calcium sulfate whiskers. In step (1), the volume ratio of ethanol to deionized water in the ethanol-water solution is 85~95:15~5; the ratio of calcium sulfate whiskers, ethanol-water solution, and 3-isocyanate propyltriethoxysilane is 10g:100~150mL:0.5~3g. In step (2), the ratio of isocyanate-modified whiskers, DMF, 4-hydroxycinnamic acid, and dibutyltin dilaurate is 10g: 100~150mL: 0.5~2g: 0.01~0.1g; In step (3), the ratio of cinnamic acid modified whiskers, DMF, DCC, NHS, and 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid is 10g: 100~150mL: 0.5~1g: 0.25~0.5g: 0.8~2.4g.

2. The H-type reinforced composite drainage net according to claim 1, characterized in that, In step (1), ultrasonic treatment is performed for 15-30 minutes; heating and stirring are carried out at 60-75℃ for 2-5 hours.

3. The H-type reinforced composite drainage net according to claim 1, characterized in that, In step (2), the ultrasonic treatment is performed for 15-30 min; the stirring reaction is carried out at 65-80℃ for 5-8 h; and the product is washed with DMF and acetone 2-4 times in sequence.

4. The H-type reinforced composite drainage net according to claim 1, characterized in that, In step (3), the ultrasonic treatment is performed for 15-30 min; the stirring activation conditions are 30-60 min at room temperature; the stirring reaction conditions are 4-7 h at 65-80℃; and the product is washed 2-4 times with DMF and acetone in sequence.

5. A method for preparing an H-type reinforced composite drainage net as described in any one of claims 1 to 4, characterized in that, The process includes the following steps: After the raw materials for geotextile are mixed evenly, they are fed into a screw extruder, melted and extruded, and then transferred to a spinning box. The filaments are ejected from the spinneret holes of the spinning box and cooled by a side fan. The cooled filament bundles are then stretched by an airflow through a tubular stretcher to achieve uniform filament splitting. The filaments are evenly laid on the condensing net curtain under the control of the side-blown airflow, and output to a needle punching machine through a pre-compression roller. The resulting filament web is reinforced by pre-needling and main needle punching to obtain the geotextile. The geotextile and the net core are then combined online to prepare the H-type reinforced composite drainage net.

6. The preparation method according to claim 5, characterized in that, The heating temperatures of each section of the screw extruder are 160℃, 180℃, 200℃, and 210℃, respectively, and the screw speed is 70~90 r / min.

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