A water seepage prevention material for municipal works and a preparation method thereof

Abstract

The application discloses a kind of municipal engineering water seepage prevention material and preparation method thereof, belong to water seepage prevention material technical field, by two layers of nonwoven fabric and middle layer of water seepage prevention film composition, water seepage prevention film according to weight fraction, including the following components: high-density polyethylene 25-33 parts, linear low-density polyethylene 15-22 parts, metallocene polyethylene 15-20 parts, ethylene-vinyl acetate copolymer 15-20 parts, modified polytetrafluoroethylene fiber 1-3.5 parts, modified montmorillonite 3-7 parts, antistatic agent 0.5-2 parts;The application introduces self-made modified polytetrafluoroethylene fiber and modified montmorillonite in water seepage prevention material, and the water seepage prevention material obtained compared with existing polyethylene-based water seepage prevention film, with excellent corrosion resistance, aging resistance, can adapt to municipal engineering, especially the harsh environment of garbage landfill, with higher application value.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of water-impermeable materials, and particularly relates to a water-impermeable material for municipal engineering and a preparation method thereof. BACKGROUND

[0002] Municipal engineering refers to municipal infrastructure construction engineering, such as common urban roads, bridges, subways, underground pipelines, tunnels, river courses, rail transit, sewage treatment, garbage disposal and the like. The common method for garbage disposal is landfill, which promotes the development of solid waste pollution prevention and control work. However, landfill sites also have many negative effects, such as the presence of high concentrations of organic matter, heavy metals and other pollutants in the leachate generated during the landfill process, which will pose potential hazards to the surrounding groundwater, soil, ecological environment and human health if leaked. At present, a water-impermeable system with a high-density polyethylene film as the core is often used to prevent the leakage of leachate and protect the safety of soil and groundwater.

[0003] An important component of the water-impermeable system with the high-density polyethylene film as the core is a geomembrane. For example, Chinese patent CN111070836B discloses a long-life high-impervious composite geomembrane and a preparation method. The geomembrane comprises a non-woven fabric layer and an impervious film. The required masterbatch of the impervious film comprises medium-high-density polyethylene, ethylene-vinyl alcohol copolymer, myrcene, filler, vinyl acetate copolymer and coupling agent. Although certain puncture resistance and impermeability are obtained, the geomembrane will face great challenges when applied in landfill, i.e., light radiation and acid-alkali corrosion in waste liquid. Therefore, it is necessary to provide a water-impermeable material for municipal engineering with better performance. SUMMARY

[0004] The application aims to provide a water-impermeable material for municipal engineering and a preparation method thereof to solve the problems in the background.

[0005] The object of the application can be achieved by the following technical solutions.

[0006] The water-impermeable material for municipal engineering is composed of upper and lower non-woven fabrics and an intermediate impervious film. The non-woven fabric is polypropylene fiber non-woven fabric or polyester fiber non-woven fabric. The impervious film comprises the following components in terms of weight fraction: high-density polyethylene 25-33 parts, linear low-density polyethylene 15-22 parts, metallocene polyethylene 15-20 parts, ethylene-vinyl acetate copolymer 15-20 parts, modified polytetrafluoroethylene fiber 1-3.5 parts, modified montmorillonite 3-7 parts and antistatic agent 0.5-2 parts.

[0007] Further, the modified polytetrafluoroethylene fiber is prepared by the following steps:

[0008] Step S1, polytetrafluoroethylene fibers are soaked in acetone for 12 hours, then dried to constant weight, loaded into a polyethylene bag, and irradiated with Co source γ-rays in air at 50 kGy. 60 The irradiated polytetrafluoroethylene fibers are placed in a flask, and glycidyl methacrylate, 1,4-dioxane, ferrous ammonium sulfate hexahydrate, and concentrated sulfuric acid are added. Nitrogen is introduced for 20 minutes, and then the flask is sealed. The reaction is stirred at 60°C for 3-4 hours. After the reaction is completed, the mixture is filtered, and the filter cake is washed with 40% ethanol solution and dried to obtain the epoxidized polytetrafluoroethylene fibers.

[0009] In the above steps, the length of the polytetrafluoroethylene fibers is 3-12 mm, and the ratio of the amounts of the irradiated polytetrafluoroethylene fibers, glycidyl methacrylate, 1,4-dioxane, ferrous ammonium sulfate hexahydrate, and concentrated sulfuric acid is 4-5 g: 0.6-1.1 g: 60-80 mL: 0.08-0.1 g: 1.3-1.5 mL. The concentration of the concentrated sulfuric acid is 95%. The γ-rays are used to irradiate the polytetrafluoroethylene fibers to generate trapped free radicals and peroxides. The trapped free radicals and peroxides are activated by heating to initiate the grafting reaction of glycidyl methacrylate, and active epoxy groups are introduced onto the surface of the polytetrafluoroethylene fibers.

[0010] Step S2, the epoxidized polytetrafluoroethylene fibers are added to a mixture of 4-(2H-benzotriazole-2-yl)-1,3-benzenediol, potassium hydroxide, and 1,4-dioxane. The reaction is carried out at 60°C for 24 hours under a nitrogen atmosphere. After the reaction is completed, the mixture is filtered, and the filter cake is washed with anhydrous ethanol and dried at 60°C to obtain the modified polytetrafluoroethylene fibers.

[0011] In the above steps, the ratio of the amounts of the epoxidized polytetrafluoroethylene fibers, 4-(2H-benzotriazole-2-yl)-1,3-benzenediol, potassium hydroxide, and 1,4-dioxane is 1 g: 0.3-0.6 g: 0.01-0.02 g: 40 mL. The benzotriazole structure is introduced onto the surface of the polytetrafluoroethylene fibers through the ring-opening reaction between the phenolic hydroxyl group and the epoxy group, and new hydroxyl groups are formed to obtain the modified polytetrafluoroethylene fibers.

[0012] Further, the modified montmorillonite is prepared by the following steps:

[0013] Sodium-based montmorillonite is added into distilled water, stirred for 30 min, and then ultrasonically dispersed for 30 min, 5-carboxy-pentyl triphenyl phosphonium bromide is added, ultrasonically dispersed for 30 min, and then stirred at 80 DEG C for 4-6 h, filtered, the filter cake is washed with distilled water until the washing liquid is free of bromide ions (titrated with silver nitrate solution), and then dried at 60 DEG C until the weight is constant, the ratio of sodium-based montmorillonite, distilled water and 5-carboxy-pentyl triphenyl phosphonium bromide is 30-40 g: 800 mL: 0.05-0.08 mol, based on the good barrier shielding performance and temperature resistance of montmorillonite, 5-carboxy-pentyl triphenyl phosphonium bromide is used as an intercalation agent to replace the cations in the interlayer of montmorillonite, organic chains are introduced into the interlayer, the hydrophilicity of montmorillonite is reduced, the compatibility with organic polymers is improved, and active carboxyl groups are introduced.

[0014] Further, the antistatic agent is a polyether amide.

[0015] A preparation method of a water seepage prevention material for municipal engineering, comprising the following steps:

[0016] In the first step, the raw materials are weighed according to the above-mentioned formula of the water seepage prevention film, and then put into a mixer, and mixed at a temperature of 105-115 DEG C for 15-20 min, and then transferred to a single screw extruder, and extruded at a temperature of 172-175 DEG C, and the screw rotation speed is controlled at 70-75 rmd / min, and the temperature after extrusion is kept at 95-97 DEG C, and the film is blown by an extrusion film blowing machine, and then water-cooled and solidified to obtain the water seepage prevention film.

[0017] In the second step, the water seepage prevention film and the non-woven fabric are heated and cold-pressed to be compounded, and the heating temperature is 180-200 DEG C, and the water seepage prevention material for municipal engineering is obtained.

[0018] Further, the temperature of the extrusion film blowing is gradually increased from the feeding port to the die head, and is divided into three sections, and is controlled at 110-140 DEG C, 140-180 DEG C and 180-215 DEG C respectively, and the screw rotation speed is controlled at 100 rmd / min, and the blow ratio is 2:3-5, and the water-cooled solidification adopts 5 DEG C cold water.

[0019] The present application has the following advantages:

[0020] 1. The present application provides a water seepage prevention material for municipal engineering and a preparation method thereof, specifically a geotechnical composite film composed of upper and lower non-woven fabrics and a middle layer of water seepage prevention film, and the highlight is that the water seepage prevention film has excellent corrosion resistance and aging resistance compared with the existing polyethylene-based water seepage prevention film, and can adapt to the harsh environment of municipal engineering, especially garbage landfill, and has high application value.

[0021] 2. Based on the excellent mechanical properties, temperature resistance, and corrosion resistance of polytetrafluoroethylene (PTFE) fibers, this invention modifies PTFE fibers by chemically grafting benzotriazole structures onto their surface to form new hydroxyl groups. This introduces modified PTFE fibers into the geomembrane, which firstly endows the geomembrane with excellent tear and puncture resistance; secondly, overcomes the problems of easy migration and precipitation of existing ultraviolet absorbers, thus endowing the geomembrane with excellent aging resistance; and thirdly, endows the geomembrane with excellent corrosion resistance.

[0022] 3. Based on the excellent barrier properties of lamellar montmorillonite, this invention obtains modified montmorillonite by intercalating sodium-based montmorillonite. Introducing modified montmorillonite into the geomembrane serves two purposes: firstly, it utilizes the hydrogen bonding or chemical reaction between the carboxyl groups of modified montmorillonite and the hydroxyl groups of modified polytetrafluoroethylene fibers to increase the internal density of the geomembrane and improve the material's puncture resistance; secondly, it forms a three-dimensional dense shielding mesh to block the intrusion of corrosive media and ensure the corrosion resistance of the geomembrane material. Detailed Implementation

[0023] 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.

[0024] Example 1

[0025] A modified polytetrafluoroethylene fiber is prepared by the following steps:

[0026] Step S1: Soak polytetrafluoroethylene fibers in acetone for 12 hours, then dry them to constant weight and pack them into polyethylene bags. 60 A Co-source gamma ray was used to irradiate air at 50 kGy. 4 g of irradiated polytetrafluoroethylene (PTFE) fiber was placed in a flask, and 0.6 g of glycidyl methacrylate, 60 mL of 1,4-dioxane, 0.08 g of ferrous ammonium sulfate hexahydrate, and 1.3 mL of concentrated sulfuric acid were added. Nitrogen gas was introduced for 20 min, and the flask was sealed. The mixture was stirred at 60 °C for 3 h. After the reaction was complete, the mixture was filtered, and the filter cake was washed with a 40% ethanol solution and dried to obtain epoxidized PTFE fiber. The PTFE fiber length was 3-12 mm, and the concentrated sulfuric acid concentration was 95%.

[0027] Step S2, 1 g of the epoxidized polytetrafluoroethylene fiber was added into a mixture of 0.3 g of 4-(2H-benzotriazol-2-yl)-1,3-benzenediol, 0.01 g of potassium hydroxide and 40 mL of 1,4-dioxane, and reacted at 60°C for 24 h under a nitrogen atmosphere. After the reaction, the product was filtered, the filter cake was washed with anhydrous ethanol, and dried at 60°C to obtain the modified polytetrafluoroethylene fiber.

[0028] Example 2

[0029] A modified polytetrafluoroethylene fiber was prepared by the following steps:

[0030] Step S1, the polytetrafluoroethylene fiber was soaked in acetone for 12 h, then dried to constant weight, and then placed in a polyethylene bag. The bag was sealed and placed in a 60°C oven for 24 h. 60 Co source gamma rays were irradiated in air for 50 kGy. 5 g of the irradiated polytetrafluoroethylene fiber was placed in a flask, and 1.1 g of glycidyl methacrylate, 80 mL of 1,4-dioxane, 0.1 g of ferrous ammonium sulfate hexahydrate and 1.5 mL of concentrated sulfuric acid were added. After purging with nitrogen for 20 min, the flask was sealed and stirred at 60°C for 4 h. After the reaction, the product was filtered, the filter cake was washed with a 40% ethanol solution, and then dried to obtain the epoxidized polytetrafluoroethylene fiber. The length of the polytetrafluoroethylene fiber was 3-12 mm, and the mass fraction of concentrated sulfuric acid was 95%.

[0031] Step S2, 1 g of the epoxidized polytetrafluoroethylene fiber was added into a mixture of 0.6 g of 4-(2H-benzotriazol-2-yl)-1,3-benzenediol, 0.02 g of potassium hydroxide and 40 mL of 1,4-dioxane, and reacted at 60°C for 24 h under a nitrogen atmosphere. After the reaction, the product was filtered, the filter cake was washed with anhydrous ethanol, and dried at 60°C to obtain the modified polytetrafluoroethylene fiber.

[0032] Example 3

[0033] A modified montmorillonite was prepared by the following steps:

[0034] 30 g of sodium-based montmorillonite was added to 800 mL of distilled water, stirred for 30 min, and then ultrasonically dispersed for 30 min. 0.05 mol of 5-carboxy-pentyltriphenylphosphonium bromide was added, ultrasonically dispersed for 30 min, and then stirred at 80°C for 4 h. The product was filtered, the filter cake was washed with distilled water until the washing liquid was bromide-free (titrated with silver nitrate solution), and then dried at 60°C to constant weight.

[0035] Example 4

[0036] A modified montmorillonite was prepared by the following steps:

[0037] Put 40 g sodium-based montmorillonite into 800 mL distilled water, stir for 30 min, then ultrasonic dispersion for 30 min, add 0.08 mol 5-carboxyl pentyl triphenyl phosphonium bromide, ultrasonic dispersion for 30 min, then stir at 80℃ for 6 h, filter, wash the filter cake with distilled water until the washing liquid is bromide-free (titrated with silver nitrate solution), and dry at 60℃ until the weight is constant.

[0038] Example 5

[0039] A water-impermeable material for municipal engineering, which is composed of two layers of non-woven fabric and a middle layer of impermeable film, the non-woven fabric being polypropylene fiber non-woven fabric or polyester fiber non-woven fabric, the impermeable film comprising the following components by weight fraction: high-density polyethylene 25 parts, linear low-density polyethylene 15 parts, metallocene polyethylene 15 parts, ethylene-vinyl acetate copolymer 15 parts, modified polytetrafluoroethylene fiber of Example 1 1 part, modified montmorillonite of Example 3 3 parts, and polyether amide 0.5 part.

[0040] The preparation method of the water-impermeable material for municipal engineering comprises the following steps:

[0041] Firstly, the raw materials are weighed according to the above impermeable film formula and put into a mixer, mixed at a temperature of 105℃ for 15 min, then transferred to a single-screw extruder, extruded at a temperature of 172℃, with the screw speed controlled at 70 rmd / min, and the extrusion temperature maintained at 95℃, then blown into a film by an extrusion film blowing machine, and water-cooled to solidify, obtaining an impermeable film with a thickness of 1 mm.

[0042] Secondly, the impermeable film and polypropylene filament geotextile (150 g / m 2 ) are placed flat in an oven, the oven temperature is controlled at 180℃, and the cloth speed is controlled at 3 m / min, the added impermeable film and geotextile are softened on the surface and are compounded together under the pressure of a cold rolling mill to form a two-fabric and one-film impermeable material, which is then edge-cut, metered and wound to obtain the water-impermeable material for municipal engineering.

[0043] Among them, the temperature of extrusion film blowing gradually increases from the feeding port to the machine head, and is divided into three sections, which are controlled at 110℃, 140℃ and 180℃ respectively, the screw speed is controlled at 100 rmd / min, the blow ratio is 2:3, and the water cooling solidification adopts 5℃ cold water.

[0044] Example 6

[0045] A kind of municipal engineering impermeable material, it is composed of upper and lower two layers of non-woven fabric and middle layer impermeable membrane, non-woven fabric is polypropylene fiber non-woven fabric or polyester fiber non-woven fabric, impermeable membrane includes the following ingredients according to weight fraction: high density polyethylene 30 parts, linear low density polyethylene 20 parts, metallocene polyethylene 18 parts, ethylene-vinyl acetate copolymer 18 parts, modified polytetrafluoroethylene fiber of example 1 2 parts, modified montmorillonite of example 4 4 parts, polyetheramide 1 part;

[0046] The preparation method of the municipal engineering impermeable material, including the following steps:

[0047] First, according to the above impermeable membrane formula proportion, the raw materials are weighed and put into the mixer, the temperature is 108℃, mixed for 18min, then transferred to single screw extruder, the temperature is 174℃, the screw rotation speed is controlled at 72rmd / min, the extrusion temperature is maintained at 96℃, and the film is blown by extrusion film blowing machine, water-cooled solidification, to obtain the impermeable membrane with a thickness of 1mm;

[0048] Secondly, the impermeable membrane and polypropylene filament geotextile (150g / m 2 ) are placed flat in the oven together, the oven temperature is controlled at 190℃, and the cloth speed is 3m / min. The added impermeable membrane and geotextile are softened on the surface and compounded together under the pressure of the cold rolling mill to form a two-cloth-one-membrane impermeable material. After trimming, metering and winding, the municipal engineering impermeable material is obtained.

[0049] Among them, the temperature of extrusion film blowing gradually increases from the feeding port to the head, and is divided into three sections, which are controlled at 120℃, 160℃ and 195℃ respectively, the screw rotation speed is controlled at 100rmd / min, the blow ratio is 2:4, and the water cooling solidification adopts 5℃ cold water.

[0050] Example 7

[0051] A kind of municipal engineering impermeable material, it is composed of upper and lower two layers of non-woven fabric and middle layer impermeable membrane, non-woven fabric is polypropylene fiber non-woven fabric or polyester fiber non-woven fabric, impermeable membrane includes the following ingredients according to weight fraction: high density polyethylene 30 parts, linear low density polyethylene 20 parts, metallocene polyethylene 18 parts, ethylene-vinyl acetate copolymer 18 parts, modified polytetrafluoroethylene fiber of example 1 2 parts, modified montmorillonite of example 4 4 parts, polyetheramide 1 part;

[0052] The preparation method of the municipal engineering impermeable material, including the following steps:

[0053] First step, according to the above-mentioned impermeable membrane formula proportion of raw materials and put into the mixer, temperature 115℃ mixed 20min, then transferred to single screw extruder, temperature 175℃ extrusion, screw rotation speed control in 75rmd / min, the temperature after extrusion is maintained at 97℃, using extrusion blowing film machine blowing film, water cooling solidification, get thickness 1mm impermeable membrane;

[0054] Second step, the impermeable membrane and polypropylene filament geotextile (150g / m 2 ) together flatly put into the oven, control oven temperature is 200℃, the cloth speed is 3m / min, the added impermeable membrane and geotextile under the condition of surface softening through cold roll, under the pressure of cold roll, composite together, form two cloth one membrane impermeable material, again through edge cutting, metering winding, get municipal engineering impermeable water material.

[0055] Among them, the temperature of extrusion blowing film gradually increases from the feeding port to the head, and is divided into three sections, respectively controlled at 140℃, 180℃, 215℃, the screw rotation speed control in 100rmd / min, the blow ratio is 2:5, water cooling solidification uses 5℃ cold water.

[0056] Comparative example 1

[0057] Compared with example 5, replace the modified polytetrafluoroethylene fiber in example 5 with polytetrafluoroethylene fiber, and the rest of the raw materials and preparation process are the same as example 5.

[0058] Comparative example 2

[0059] Compared with example 5, remove the modified montmorillonite in example 5, and the rest of the raw materials and preparation process are the same as example 5.

[0060] The impermeable materials obtained in example 5- example 7 and comparative example 1- comparative example 3 are tested for performance, the puncture strength is tested according to the provisions of 5.3.10 in TB / T3360.1-2014; corrosion resistance: select 50wt% sulfuric acid solution and 20wt% sodium hydroxide solution, immerse the impermeable materials obtained in examples and comparative examples in the above solutions for 24h, and detect the puncture strength of the impermeable materials; aging resistance: place the impermeable materials obtained in examples and comparative examples in the aging box with ultraviolet lamp power of 300W for 8h, and detect the puncture strength of the impermeable materials, the results are shown in table 1:

[0061] Table 1

[0062]

[0063]

[0064] As can be seen from Table 1, the anti-infiltration materials prepared in Example 5, Example 6 and Example 7 not only have good mechanical properties, but also have corrosion resistance and aging resistance compared with Comparative Example 1 and Comparative Example 2.

[0065] It should be noted that the relational terms herein such as first and second and the like are used solely to distinguish one entity or action from another, without necessarily requiring or implying any such actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0066] While embodiments of the present application have been shown and described, it is to be understood that the embodiments described are merely divergences, modifications, replacements and variations of the embodiments of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A water-impermeable material for civil engineering, comprising an upper and a lower nonwoven fabric and a water-impermeable film interposed therebetween, characterized in that, The impermeable membrane comprises the following components in parts by weight: high-density polyethylene 25-33 parts, linear low-density polyethylene 15-22 parts, metallocene polyethylene 15-20 parts, ethylene-vinyl acetate copolymer 15-20 parts, modified polytetrafluoroethylene fiber 1-3.5 parts, modified montmorillonite 3-7 parts, and antistatic agent 0.5-2 parts; The modified polytetrafluoroethylene fiber is prepared by the following steps: The epoxidized polytetrafluoroethylene fiber is added into a mixture of 4-(2H-benzotriazol-2-yl)-1,3-benzenediol, potassium hydroxide and 1,4-dioxane, and reacted at 60°C for 24 hours in a nitrogen atmosphere to obtain the modified polytetrafluoroethylene fiber; The epoxidized polytetrafluoroethylene fiber, 4-(2H-benzotriazol-2-yl)-1,3-benzenediol, potassium hydroxide and 1,4-dioxane are used in a ratio of 1g:0.3-0.6g:0.01-0.02g:40mL; The modified montmorillonite is prepared by the following steps: Sodium-based montmorillonite is added into distilled water, stirred for 30 minutes, and then ultrasonically dispersed for 30 minutes. Then 5-carboxy-pentyl triphenyl phosphonium bromide is added, ultrasonically dispersed for 30 minutes, and then stirred at 80°C for 4-6 hours. After filtration, the filter cake is washed with distilled water until the washing liquid is free of bromide ions, and then dried at 60°C until the weight is constant. The sodium-based montmorillonite, distilled water and 5-carboxy-pentyl triphenyl phosphonium bromide are used in a ratio of 30-40g:800mL:0.05-0.08mol.

2. The water seepage preventing material for municipal works according to claim 1, wherein The epoxidized polytetrafluoroethylene fiber is prepared by the following steps: The polytetrafluoroethylene fiber was soaked in acetone for 12 h, dried to constant weight, and then loaded into a polyethylene bag, and then irradiated with a Co source γ-ray in air at 50 kGy. 60 The irradiated polytetrafluoroethylene fiber was placed in a flask, and glycidyl methacrylate, 1,4-dioxane, ferrous ammonium sulfate hexahydrate, and concentrated sulfuric acid were added. Nitrogen was introduced for 20 min, and then the flask was sealed. The mixture was stirred at 60°C for 3-4 h to obtain an epoxidized polytetrafluoroethylene fiber.

3. The water seepage preventing material for municipal works according to claim 2, characterized by The irradiated polytetrafluoroethylene fiber, glycidyl methacrylate, 1,4-dioxane, ferrous ammonium sulfate hexahydrate and concentrated sulfuric acid are used in a ratio of 4-5g:0.6-1.1g:60-80mL:0.08-0.1g:1.3-1.5mL.

4. The method for preparing a waterproofing material for municipal engineering according to claim 1, characterized in that, The steps include: In the first step, the raw materials are weighed according to the above-mentioned impermeable membrane formulation ratio and put into a mixer, mixed at a temperature of 105-115°C for 15-20 minutes, then transferred to a single-screw extruder, extruded at a temperature of 172-175°C, the screw rotation speed is controlled at 70-75r / min, and the extrusion temperature is maintained at 95-97°C. The film is blown by an extrusion film blowing machine, water-cooled and solidified to obtain the impermeable membrane; In the second step, the impermeable membrane and the non-woven fabric are heated and cold-pressed to obtain the impermeable water material for municipal engineering.

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