Core-absorbing geotextile fiber and core-absorbing drainage geotextile tube bag

Abstract

The invention discloses a wicking geotextile fiber and a wicking drainage geotextile tube bag. The wicking geotextile fiber is prepared from the following components in parts by weight: 70-80 parts of polypropylene, 10-15 parts of polyvinyl alcohol, 3-5 parts of an acrylic acid grafting agent, 5-8 parts of nano hydrophilic filler, 2-3 parts of sodium bicarbonate and 5-10 parts of sodium chloride. In the process of uniformly mixing the polypropylene, the powdery polyvinyl alcohol and the acrylic acid grafting agent, the polypropylene can be modified, the polarity of the polypropylene is improved, the polypropylene grafted maleic anhydride is obtained, the contact angle is reduced, and the water absorption rate is improved; meanwhile, immersing the fine fibers into deionized water at 60 DEG C for 1 hour, dissolving sodium chloride in the deionized water, and forming communicated micropores on the surfaces of the fine fibers; then the fine fibers with the communicating micropores are treated in a 120 DEG C hot air circulating oven for 30 minutes, sodium bicarbonate is decomposed into sodium carbonate and carbon dioxide, additional micropores are generated, the porosity of the wicking geotechnical fibers is remarkably increased, and the water absorption performance of the wicking geotechnical fibers is improved.

Description

Technical Field

[0001] This invention relates to the field of wicking geotextile technology, specifically to wicking geotextile fibers and wicking drainage geotextile bags. Background Technology

[0002] Core-absorbing geofibers are geosynthetic materials with capillary water absorption (core absorption) capabilities, primarily used in engineering fields such as drainage, seepage prevention, and soil reinforcement. Their core characteristic is the use of the fiber's porous structure or special surface treatment to achieve rapid absorption and directional transport of moisture.

[0003] Existing wicking geotextiles are usually made of materials such as polypropylene (PP) and polyethylene (PE). Polypropylene (PP) and polyethylene (PE) are non-polar polymers with a contact angle >90° (hydrophobic). Water is difficult to quickly wet the fiber surface. Water can only slowly penetrate through the fiber gaps and cannot be conducted through the internal pores of the fiber. Therefore, this application proposes wicking geotextiles and wicking drainage geotextile bags. Summary of the Invention

[0004] The purpose of this invention is to provide wicking geotextile fibers and wicking drainage geotextile bags to solve the problems mentioned in the background art.

[0005] According to a first aspect of the invention, a wicking geotextile is provided, comprising the following components in parts by weight: 70-80 parts polypropylene, 10-15 parts polyvinyl alcohol, 3-5 parts acrylic acid grafting agent, 5-8 parts nano-hydrophilic filler, 2-3 parts sodium bicarbonate, and 5-10 parts sodium chloride.

[0006] According to an embodiment of the present invention, the nano-hydrophilic filler is one of nano-silica and nano-graphene oxide; The acrylic grafting agent is maleic anhydride.

[0007] According to an embodiment of the present invention, the method for preparing the wicking geotextile fiber is as follows: Step 1, Material Pretreatment: Step 101: Polypropylene drying: Dry in an 80℃ hot air circulating oven for 4-6 hours until the moisture content is ≤0.05%; Step 102, Polyvinyl alcohol pretreatment: Dissolve polyvinyl alcohol particles in deionized water at 90°C, stir for 2 hours until completely dissolved, and then spray dry the solution to obtain powdered polyvinyl alcohol; Step 103, Modification of nano-hydrophilic filler: The nano-hydrophilic filler and coupling agent are ultrasonically dispersed in ethanol for 1 hour, and then dried at 60°C for later use; Step 104: Sodium bicarbonate: pass through a 200-mesh sieve to remove agglomerated particles; Sodium chloride: grind to a particle size <50μm; Step 2, melt co-extrusion: Step 201: Polypropylene, powdered polyvinyl alcohol, and acrylic grafting agent are mixed evenly and added from the main feed port of the twin-screw extruder; Step 202: The modified nano-hydrophilic filler and sodium bicarbonate are added from the side feed port of the twin-screw extruder; Step 203: Sodium chloride powder is directly injected into the melt flow channel via a metering pump; Step 204: Then, the mixture is stirred and mixed into a melt using a twin-screw extruder, and the melt is stretched into fine fibers under hot air at 250°C and a pressure of 0.3 MPa.

[0008] According to an embodiment of the present invention, in step 102, the inlet temperature of the solution spray drying is 180°C and the outlet temperature is 80°C.

[0009] According to an embodiment of the present invention, in step 103, the coupling agent is a silane coupling agent, and the mass ratio of the nano-hydrophilic filler to the silane coupling agent is 7:3.

[0010] According to an embodiment of the present invention, in step 204, the stretched and shaped fine fibers proceed to the following subsequent processing: The fine fibers were immersed in deionized water at 60°C for 1 hour. The deionized water dissolved sodium chloride, and interconnected micropores were formed on the surface of the fine fibers. The fine fibers with interconnected micropores are then treated in a 120°C hot air circulating oven for 30 minutes to decompose sodium bicarbonate into sodium carbonate and carbon dioxide, generating additional micropores. Next, a 0.5% polydopamine aqueous solution is sprayed onto the surface of the fine fibers, and then dried at 80°C for 10 minutes; Finally, the fibers are passed through a 100℃ hot press roller at a pressure of 0.5MPa and a speed of 5m / min to orient the fine fibers and obtain the core-absorbing geotextile fiber.

[0011] According to an embodiment of the present invention, the reaction formula for the decomposition of sodium bicarbonate is 2NaHCO3→Na2CO3+H2O+CO2↑.

[0012] According to an embodiment of the present invention, during the uniform mixing of polypropylene, powdered polyvinyl alcohol, and acrylic grafting agent: Acrylic grafting agents generate free radicals under shear force, which attack the tertiary carbon atoms of polypropylene molecular chains, forming polypropylene macromolecular free radicals. Then the C=C double bond of the acrylic grafting agent opens and combines with the free radical of the polypropylene macromolecule, introducing carboxyl (—COOH) / anhydride (—CO—O—CO—) groups onto the polypropylene chain, forming polypropylene grafted with maleic anhydride.

[0013] According to a second aspect of the present invention, a wicking drainage geotextile bag is provided, the wicking drainage geotextile bag being prepared using the wicking geotextile fibers described above.

[0014] Compared with the prior art, the beneficial effects of the present invention are: In this invention, the polypropylene, powdered polyvinyl alcohol, and acrylic acid grafting agent are uniformly mixed to modify the polypropylene, increasing its polarity and resulting in polypropylene grafted with maleic anhydride. This reduces the contact angle and increases the water absorption rate. Simultaneously, the fine fibers are immersed in 60°C deionized water for 1 hour, where sodium chloride dissolves and interconnected micropores form on the surface of the fine fibers. Then, the fine fibers with interconnected micropores are treated in a 120°C hot air circulating oven for 30 minutes, causing sodium bicarbonate to decompose into sodium carbonate and carbon dioxide, generating additional micropores. This significantly increases the porosity of the wicking geotextile fibers, thereby improving their water absorption performance. Detailed Implementation

[0015] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0016] According to a first aspect of the invention, a wicking geotextile is provided, comprising the following components in parts by weight: 70-80 parts polypropylene, 10-15 parts polyvinyl alcohol, 3-5 parts acrylic acid grafting agent, 5-8 parts nano-hydrophilic filler, 2-3 parts sodium bicarbonate, and 5-10 parts sodium chloride.

[0017] During the uniform mixing of polypropylene, powdered polyvinyl alcohol, and acrylic grafting agent, polypropylene can be modified, increasing its polarity to obtain polypropylene grafted with maleic anhydride, resulting in a lower contact angle and increased water absorption rate. Simultaneously, immersing fine fibers in 60°C deionized water for 1 hour dissolves sodium chloride, forming interconnected micropores on the surface of the fine fibers. Then, the fine fibers with interconnected micropores are treated in a 120°C hot air circulating oven for 30 minutes, causing sodium bicarbonate to decompose into sodium carbonate and carbon dioxide, generating additional micropores. This significantly increases the porosity of the wicking geotextile fibers, thereby improving their water absorption performance.

[0018] According to an embodiment of the present invention, the nano-hydrophilic filler is one of nano-silica and nano-graphene oxide; the nano-silica or nano-graphene oxide is first surface-treated with a silane coupling agent and then melt-blended with polypropylene, which can not only reduce the contact angle of polypropylene, but also improve the UV resistance of polypropylene.

[0019] The acrylic grafting agent is maleic anhydride. During the uniform mixing of polypropylene, powdered polyvinyl alcohol, and the acrylic grafting agent, maleic anhydride can modify polypropylene. During melt blending, maleic anhydride generates free radicals under heat or shear force, which attack the tertiary carbon atoms of the polypropylene molecular chain to form polypropylene macromolecular free radicals. Then, the C=C double bond of maleic anhydride opens and combines with the polypropylene macromolecular free radicals, introducing carboxyl groups (—COOH) or anhydride groups (—CO—O—CO—) onto the polypropylene chain, significantly improving the polarity of polypropylene.

[0020] Furthermore, introducing carboxyl groups (-COOH) onto the polypropylene chain to form hydrogen bonds with the -OH groups of polyvinyl alcohol promotes the compatibility of polypropylene and powdered polyvinyl alcohol.

[0021] According to an embodiment of the present invention, the method for preparing the wicking geotextile fiber is as follows: Step 1, Material Pretreatment: Step 101: Polypropylene drying: Dry in an 80℃ hot air circulating oven for 4-6 hours to achieve a moisture content of ≤0.05% to prevent the formation of bubbles during melt extrusion; Step 102, Polyvinyl alcohol pretreatment: Dissolve polyvinyl alcohol particles in deionized water at 90℃, stir for 2 hours until completely dissolved, and then spray dry the solution to obtain powdered polyvinyl alcohol with a water content of <1%; Step 103, Modification of nano-hydrophilic filler: The nano-hydrophilic filler and coupling agent are ultrasonically dispersed in ethanol for 1 hour, and then dried at 60°C for later use; Step 104: Sodium bicarbonate: remove agglomerated particles by passing through a 200-mesh sieve; Sodium chloride: grind to a particle size <50μm to ensure complete dissolution during water washing; Step 2, melt co-extrusion: Step 201: Polypropylene, powdered polyvinyl alcohol, and acrylic grafting agent are mixed evenly and added from the main feed port of the twin-screw extruder; Step 202: The modified nano-hydrophilic filler and sodium bicarbonate are added from the side feed port of the twin-screw extruder; Step 203: Sodium chloride powder is directly injected into the melt flow channel via a metering pump; Step 204: Then, the mixture is stirred and mixed into a melt using a twin-screw extruder, and the melt is stretched into fine fibers under hot air at 250°C and a pressure of 0.3 MPa.

[0022] Furthermore, the twin-screw extruder has a length-to-diameter ratio of 32:1, a screw diameter of 45 mm, a meltblown die orifice diameter of 0.3 mm, and an airflow temperature of 250 °C.

[0023] According to an embodiment of the present invention, in step 102, the inlet temperature of the solution spray drying is 180°C and the outlet temperature is 80°C.

[0024] According to an embodiment of the present invention, in step 103, the coupling agent is a silane coupling agent, and the mass ratio of the nano-hydrophilic filler to the silane coupling agent is 7:3.

[0025] According to an embodiment of the present invention, in step 204, the stretched and shaped fine fibers proceed to the following subsequent processing: The fine fibers were immersed in deionized water at 60°C for 1 hour. The deionized water dissolved sodium chloride, and interconnected micropores were formed on the surface of the fine fibers. The fine fibers with interconnected micropores are then treated in a 120°C hot air circulating oven for 30 minutes to decompose sodium bicarbonate into sodium carbonate and carbon dioxide, generating additional micropores. Next, a 0.5% polydopamine aqueous solution is sprayed onto the surface of the fine fibers, and then dried at 80°C for 10 minutes; Finally, the fibers are passed through a 100℃ hot press roller at a pressure of 0.5MPa and a speed of 5m / min to orient the fine fibers and obtain the core-absorbing geotextile fiber.

[0026] According to an embodiment of the present invention, the reaction formula for the decomposition of sodium bicarbonate is 2NaHCO3→Na2CO3+H2O+CO2↑.

[0027] According to an embodiment of the present invention, during the uniform mixing of polypropylene, powdered polyvinyl alcohol, and acrylic grafting agent: Acrylic grafting agents generate free radicals under shear force, which attack the tertiary carbon atoms of polypropylene molecular chains, forming polypropylene macromolecular free radicals. Then the C=C double bond of the acrylic grafting agent opens and combines with the free radical of the polypropylene macromolecule, introducing carboxyl (—COOH) / anhydride (—CO—O—CO—) groups onto the polypropylene chain, forming polypropylene grafted with maleic anhydride.

[0028] According to a second aspect of the present invention, a wicking drainage geotextile bag is provided, which is made of the wicking geotextile fiber described above. The wicking drainage geotextile bag made of the wicking geotextile fiber described above has the properties of the wicking geotextile fiber, with a reduced contact angle, increased water absorption rate, and convenient drainage. Example

[0029] The wicking geotextile is composed of the following components in parts by weight: 75 parts polypropylene, 13 parts polyvinyl alcohol, 4 parts maleic anhydride, 6 parts nano silica, 2 parts sodium bicarbonate, and 7 parts sodium chloride.

[0030] Comparative Example 1 The wicking geotextile is composed of the following components in parts by weight: 75 parts polypropylene, 4 parts maleic anhydride, 6 parts nano silica, 2 parts sodium bicarbonate, and 7 parts sodium chloride.

[0031] The difference between Comparative Example 1 and Example 1 is that polyvinyl alcohol is missing, while the other components are the same.

[0032] Comparative Example 2 The wicking geotextile is composed of the following components in parts by weight: 75 parts polypropylene, 13 parts polyvinyl alcohol, 6 parts nano silica, 2 parts sodium bicarbonate, and 7 parts sodium chloride.

[0033] The difference between Comparative Example 2 and Example 1 is that maleic anhydride is missing, while the other components are the same.

[0034] Comparative Example 3 The wicking geotextile is composed of the following components in parts by weight: 75 parts polypropylene, 6 parts nano silica, 2 parts sodium bicarbonate, and 7 parts sodium chloride.

[0035] The difference between Comparative Example 3 and Example 1 is that it lacks polyvinyl alcohol and maleic anhydride, while the other components are the same.

[0036] Experimental example: Water absorption rate test of wicking geofibers; Experimental methods: Sampling: The wicking geotextiles prepared in Example 1 and Comparative Examples 1-3 were woven into fiber cloths, namely the experimental group fiber cloth, comparative example fiber cloth 1, comparative example fiber cloth 2 and comparative example fiber cloth 3. Five samples (100mm×100mm) were then cut from each fiber cloth, with the same thickness (±0.1mm).

[0037] Pretreatment: The sample was dried in a 50℃ drying oven to constant weight (mass change <0.1%), and the initial mass (m0) was recorded.

[0038] Water absorption test: Immerse the sample completely in 23℃ distilled water, avoiding air bubbles (they can be removed by gentle pressure); Samples were taken out at 10 min, 30 min, 1 h, 4 h and 24 h respectively, and weighed (mt) after the surface moisture was absorbed with filter paper.

[0039] Calculate the water absorption rate (Wt): Each group consisted of 5 samples, and the average value was taken.

[0040] The water absorption rate data were then obtained, as shown in Table 1 below: Table 1. Water Absorption Rate Test Data for Fiber Fabric

[0041] As can be seen from the table above, the water absorption rate of the wicking geofiber prepared in Example 1 of this application is significantly better than that of the wicking geofiber prepared in Comparative Examples 1-3. Therefore, during the uniform mixing of polypropylene, powdered polyvinyl alcohol and acrylic acid grafting agent, polypropylene can be modified, the polarity of polypropylene can be improved, and polypropylene grafted with maleic anhydride can be obtained, resulting in a lower contact angle and an increased water absorption rate.

[0042] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A wicking geotextile fiber, characterized in that, It consists of the following components in parts by weight: 70-80 parts polypropylene, 10-15 parts polyvinyl alcohol, 3-5 parts acrylic acid grafting agent, 5-8 parts nano-hydrophilic filler, 2-3 parts sodium bicarbonate, and 5-10 parts sodium chloride.

2. The wicking geotextile fiber according to claim 1, characterized in that: The nano-hydrophilic filler is one of nano-silica and nano-graphene oxide; The acrylic grafting agent is maleic anhydride.

3. The wicking geotextile fiber according to claim 1, characterized in that: The method for preparing the wicking geotextile is as follows: Step 1, Material Pretreatment: Step 101: Polypropylene drying: Dry in an 80℃ hot air circulating oven for 4-6 hours until the moisture content is ≤0.05%; Step 102, Polyvinyl alcohol pretreatment: Dissolve polyvinyl alcohol particles in deionized water at 90°C, stir for 2 hours until completely dissolved, and then spray dry the solution to obtain powdered polyvinyl alcohol; Step 103, Modification of nano-hydrophilic filler: The nano-hydrophilic filler and coupling agent are ultrasonically dispersed in ethanol for 1 hour, and then dried at 60°C for later use; Step 104, Sodium bicarbonate: Remove agglomerated particles by passing through a 200-mesh sieve; Sodium chloride: Grind to a particle size <50μm; Step 2, melt co-extrusion: Step 201: Polypropylene, powdered polyvinyl alcohol, and acrylic grafting agent are mixed evenly and added from the main feed port of the twin-screw extruder; Step 202: The modified nano-hydrophilic filler and sodium bicarbonate are added from the side feed port of the twin-screw extruder; Step 203: Sodium chloride powder is directly injected into the melt flow channel via a metering pump; Step 204: Then, the mixture is stirred and mixed into a melt using a twin-screw extruder, and the melt is stretched into fine fibers under hot air at 250°C and a pressure of 0.3 MPa.

4. The wicking geotextile fiber according to claim 3, characterized in that: In step 102, the inlet temperature of the solution spray dryer is 180°C and the outlet temperature is 80°C.

5. The wicking geotextile fiber according to claim 3, characterized in that: In step 103, the coupling agent is a silane coupling agent, and the mass ratio of the nano-hydrophilic filler to the silane coupling agent is 7:

3.

6. The wicking geotextile fiber according to claim 3, characterized in that: In step 204, the stretched and shaped fine fibers proceed to the following subsequent processing: The fine fibers were immersed in deionized water at 60°C for 1 hour. The deionized water dissolved sodium chloride, and interconnected micropores were formed on the surface of the fine fibers. The fine fibers with interconnected micropores are then treated in a 120°C hot air circulating oven for 30 minutes to decompose sodium bicarbonate into sodium carbonate and carbon dioxide, generating additional micropores. Next, a 0.5% polydopamine aqueous solution is sprayed onto the surface of the fine fibers, and then dried at 80°C for 10 minutes; Finally, the fibers are passed through a 100℃ hot press roller at a pressure of 0.5MPa and a speed of 5m / min to orient the fine fibers and obtain the core-absorbing geotextile fiber.

7. The wicking geofiber according to claim 6, characterized in that: The reaction equation for the decomposition of sodium bicarbonate is 2NaHCO3→Na2CO3+H2O+CO2↑.

8. The wicking geotextile fiber according to claim 3, characterized in that: During the process of uniformly mixing polypropylene, powdered polyvinyl alcohol, and acrylic grafting agent: Acrylic grafting agents generate free radicals under shear force, which attack the tertiary carbon atoms of polypropylene molecular chains, forming polypropylene macromolecular free radicals. Then the C=C double bond of the acrylic grafting agent opens and combines with the free radical of the polypropylene macromolecule, introducing carboxyl (—COOH) / anhydride (—CO—O—CO—) groups onto the polypropylene chain, forming polypropylene grafted with maleic anhydride.

9. A core-suction drainage geotextile bag, characterized in that, The wicking drainage geotextile bag is made of the wicking geotextile fiber described in any one of claims 1-8.

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