A high-temperature resistant and acid / alkali corrosion resistant flat-plate biological packing material and its preparation process

Abstract

This invention discloses a high-temperature resistant and acid / alkali corrosion resistant flat-plate biological filler and its preparation process, belonging to the field of flat-plate biological filler technology. It addresses the technical problem that the specific surface area, mechanical strength, high-temperature resistance, and acid / alkali corrosion resistance of existing flat-plate biological fillers need further improvement. Specifically, it includes the following steps: Modified PP fibers are uniformly laid along the X-axis, followed by uniformly laid ES fibers, and then mixed fibers are laid along the Y-axis. After hydroentangling and drying, a base membrane material is obtained. This invention effectively improves the specific surface area and mechanical strength of the flat-plate biological filler by activating and coupling the PP fibers, combining hydroentangling with in-situ construction of an organosilicon crosslinking network and heat setting treatment.

Description

Technical Field

[0001] This invention relates to the field of flat-plate biological packing technology, specifically to a high-temperature resistant and acid / alkali corrosion resistant flat-plate biological packing and its preparation process. Background Technology

[0002] Biological packing materials are key functional materials in biofilm wastewater treatment, bioreactors, and related environmental engineering fields. Their main function is to provide a carrier for microorganisms to attach, grow, and metabolize, thereby improving the removal efficiency of pollutants. With the increasing demand for the treatment of industrial wastewater, high-temperature wastewater, and strong acid and alkali wastewater, biological packing materials not only need to have a large specific surface area and good pore structure to facilitate rapid microbial attachment and mass transfer, but also need to maintain structural stability and mechanical properties over a long period of time under high temperature and complex chemical environments.

[0003] Currently, flat-plate biological packing materials are mostly made of polymer materials such as polypropylene and polyethylene, and are obtained through extrusion, calendering or simple nonwoven molding. Although these materials are low in cost and have good processability, polypropylene and other materials have strong surface inertness and low polarity, which limits their ability to adhere to microorganisms. Furthermore, they are prone to mechanical property degradation, dimensional deformation or even structural damage in high temperature or acid and alkaline environments, leading to collapse of the packing pore structure and a decrease in specific surface area, which seriously affects the stable operation of the biological treatment system.

[0004] Some existing technologies attempt to improve heat and corrosion resistance by introducing organosilicon materials or cross-linked resins, but these often suffer from problems such as poor compatibility, severe phase separation, and pore blockage, leading to a decrease in specific surface area. This is not conducive to microbial attachment and biofilm formation. In particular, under high temperature and strong acid and strong alkali conditions, the problems of stress concentration and interface failure inside the filler are more prominent, making it difficult to maintain fracture strength and dimensional stability in the long term, thus limiting its application in complex working conditions. Therefore, a solution is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a high-temperature resistant and acid / alkali corrosion resistant flat-plate biological packing material and its preparation process, which solves the technical problem that the specific surface area, mechanical strength, high-temperature resistance and acid / alkali corrosion resistance of existing flat-plate biological packing materials need to be further improved.

[0006] The objective of this invention can be achieved through the following technical solution: a preparation process for a high-temperature resistant and acid / alkali corrosion resistant flat-plate biological packing material, comprising the following steps:

[0007] S1. After the modified PP fiber is evenly laid along the X-axis, ES fiber is evenly laid on it, and then mixed fiber is laid on it along the Y-axis. After hydroentanglement reinforcement and drying, the base film material is obtained.

[0008] S2. The base membrane material is placed in the impregnation liquid for two dips and two rolls, and then cross-linked and cured to obtain a flat biological filler blank;

[0009] S3. Place the flat biological packing blank in a drying oven at 110-120℃ and keep it warm for 50-60 minutes to obtain the flat biological packing.

[0010] Furthermore, in step S1, the web density of the modified PP fiber is 150-170 g / m2, the web density of the ES fiber is 200-240 g / m2, and the web density of the mixed fiber is 180-200 g / m2; the mixed fiber is composed of modified PP fiber and ES fiber in a weight ratio of 6-7:3-4.

[0011] Furthermore, in step S1, during the hydroentangling reinforcement process, the hydroentangling pressure is 26-28 MPa, and the number of hydroentangling passes is 7. After the hydroentangling reinforcement is completed, excess water is removed by negative pressure suction and rolling with a liquid rolling roller. The fiber web is then transferred to a drying oven at a temperature of 80°C and dried to a constant weight to obtain the base film material.

[0012] Furthermore, in step S2, the padding solution is composed of 4-penten-1-ol, trimethylolpropane triacrylate, hydroxyl-modified unsaturated silicone oil, anhydrous ethanol, and azobisisobutyronitrile in a ratio of 5-6g:2-3g:3-4g:30mL:1g. In the two-dip and two-roll process, the first padding pressure is 20-25kPa, and the first padding remnant is 40%. The second padding pressure is 10-15kPa, and the second padding remnant is 60%.

[0013] Furthermore, in step S2, the crosslinking and curing operation includes: placing the impregnated base film material in a curing chamber at a temperature of 70-80℃ and a humidity of 80-90% for 40-60 minutes of heat and moisture treatment; removing the base film material from the curing chamber; washing it three times with anhydrous ethanol; transferring it to a drying oven at a temperature of 70-80℃; and drying it to constant weight to obtain a flat biological filler blank.

[0014] Furthermore, the preparation method of hydroxyl-modified unsaturated silicone oil is as follows: (3-aminopropyl)diethoxymethylsilane, octamethylcyclotetrasiloxane, trivinyltrimethylcyclotrisiloxane and sulfuric acid are mixed and stirred, the reaction system is heated to 85-95℃ and kept at this temperature for 60-80 min, diallyltetramethyldisiloxane is added to the reaction system and kept at this temperature for 40-50 min, glycidyl silicone oil is added to the reaction system and kept at this temperature for 30-50 min, and then post-treatment is performed to obtain hydroxyl-modified unsaturated silicone oil.

[0015] Furthermore, the ratio of (3-aminopropyl)diethoxymethylsilane, octamethylcyclotetrasiloxane, trivinyltrimethylcyclotrisiloxane, sulfuric acid, diallyltetramethyldisiloxane, and glycidyl silicone oil is 5-6g:4-5g:3g:2mL:2g:4g. The post-treatment operation includes: after the reaction is completed, the reaction system is cooled to room temperature, toluene and saturated sodium carbonate solution are added to the reaction system, stirred and dispersed for 20-30 minutes, allowed to stand and separated, the organic phase is washed with purified water until neutral, and then transferred to a rotary evaporator with a water bath temperature of 90℃. The rotary evaporator is evaporated to a negative pressure of -0.1MPa to remove low-boiling substances under reduced pressure, to obtain hydroxyl-modified unsaturated silicone oil.

[0016] Furthermore, the modified PP fiber is obtained through the following steps:

[0017] A1. PP fibers are thermally stretched at a temperature of 130-140℃ with a stretching ratio of 3-4 times to obtain stretched fibers.

[0018] A2. Mix the stretched fiber and the activation solution, heat the reaction system to 60-70℃, keep it at the temperature for 60-80 minutes, and then perform post-treatment to obtain activated PP fiber.

[0019] A3. Mix and stir the activated PP fiber, anhydrous ethanol and KH-570 for 20-30 minutes. Heat the reaction system to 50-60℃, add sodium hydroxide solution to the reaction system, keep the reaction at this temperature for 40-50 minutes, and then perform post-treatment to obtain modified PP fiber.

[0020] Further, in step A2, the solid-liquid ratio of the stretched fiber and the activation solution is 1:3, and the activation solution is composed of 10-20wt% hydrogen peroxide and 6-8mol / L sodium hydroxide solution in a volume ratio of 5:2-3. The post-treatment includes: after the reaction is completed, the reaction system is cooled to room temperature, filtered, the filter cake is washed with purified water until neutral and then dried, the filter cake is transferred to a drying oven at a temperature of 60-70℃ and dried to constant weight to obtain activated PP fiber.

[0021] Further, in step A3, the ratio of activated PP fiber, anhydrous ethanol, KH-570, and sodium hydroxide solution is 10g:100mL:1.8-2.2g:10mL, and the concentration of sodium hydroxide solution is 3-5mol / L. The post-treatment includes: after the reaction is complete, the reaction system is cooled to room temperature, filtered, the filter cake is washed with purified water until neutral, dried, and the filter cake is transferred to a drying oven at 60-70℃ and dried to constant weight to obtain modified PP fiber.

[0022] The present invention also proposes a high-temperature resistant and acid-alkali corrosion resistant flat plate biological packing material, which is prepared by the above-mentioned preparation process of a high-temperature resistant and acid-alkali corrosion resistant flat plate biological packing material.

[0023] The present invention has the following beneficial effects:

[0024] 1. This invention uses modified PP fibers and ES fibers as substrates, employing multi-layer directional web laying and hydroentangling reinforcement to form a stable three-dimensional entangled network. This gives the material a good mechanical support structure in different directions, forming a well-connected porous system. On this basis, the base film is subjected to a two-dip and two-rolling treatment with a padding solution containing polyfunctional acrylates and hydroxyl-modified unsaturated silicone oil. This allows the cross-linked composite network to be evenly distributed at the fiber intersections and pore wall surfaces. While providing bridging reinforcement and chemical protection for the fiber structure, it does not significantly block the pores. As a result, the obtained flat-plate biofiller maintains a high specific surface area while significantly improving its resistance to acid and alkali corrosion and long-term service stability.

[0025] 2. This invention also improves the molecular chain orientation and crystal stability of PP fibers by thermal stretching, and on this basis, constructs a reactive and stable interface layer on the fiber surface through oxidation-alkali activation and silane coupling modification. This enhances the bonding force between the PP fibers and the functional layer of KH-570, thereby providing a reliable anchoring site for the subsequent impregnation and curing system. This allows the load between fibers to be effectively transferred through the interface, thereby significantly improving the tensile strength of the flat biofiller and its strength retention rate after immersion in acid and alkali media. This avoids the performance degradation of traditional PP materials caused by interface failure in corrosive environments.

[0026] 3. This invention also heat-treats the flat biofiller blank under conditions below the melting point of ES fibers, allowing the modified PP fibers to release tensile internal stress and complete heat setting under confined conditions, thereby improving the thermal stability of the material. At the same time, the heat treatment process promotes further stabilization of the impregnation and curing network and its synergistic fixation with the fiber structure, so that the nonwoven structure and pore morphology can be maintained in the high-temperature environment. This allows the flat biofiller to maintain a high dimensional retention and mechanical properties under high temperature and strong acid and alkali media conditions, demonstrating good high temperature resistance and acid and alkali corrosion resistance. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the installation of the flat-plate biological packing material prepared according to the present invention. Detailed Implementation

[0029] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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.

[0030] In this invention, the PP fiber is selected from commercially available materials from Langfang Qizhen Chemical Co., Ltd., with an effective component content of 96% and a thickness of 150-180d;

[0031] In this invention, the ES fiber is selected from commercially available materials from Hebei Jinyou New Material Technology Co., Ltd., with a melting point of 130±5℃;

[0032] In this invention, KH-570 is methacryloyloxypropyltrimethoxysilane, CAS number 2530-85-0.

[0033] Example 1

[0034] This embodiment provides a preparation process for modified PP fibers, specifically including the following steps:

[0035] Step 1: Prepare stretching fibers

[0036] PP fibers are thermally stretched at a temperature of 130℃ with a stretch ratio of 3 times to obtain stretched fibers.

[0037] PP fibers are thermally stretched at high temperatures, which puts the PP fibers into a highly elastic state. Under the action of external force, the molecular chain segments are oriented along the fiber axis, the amorphous region is stretched and partially transformed into the oriented crystalline region, and the crystal size and perfection are improved simultaneously.

[0038] Step 2: Preparation of activated PP fibers

[0039] 10wt% hydrogen peroxide and 6mol / L sodium hydroxide solution were mixed at a volume ratio of 5:2 to obtain the activation solution;

[0040] The stretched fiber and activation solution were added to the reaction flask at a solid-liquid ratio of 1:3 and stirred. The reaction flask was heated to 60°C and kept at that temperature for 60 minutes. The reaction flask was then cooled to room temperature and filtered. The filter cake was washed with purified water until neutral and then dried. The filter cake was transferred to a drying oven at 60°C and dried to constant weight to obtain activated PP fiber.

[0041] Under alkaline conditions, hydrogen peroxide decomposes to generate highly reactive peroxide anions and free radical species. These active species mainly act on the surface of PP fibers, causing selective breakage of CH bonds in the very shallow layer of the fiber surface, generating a small number of oxygen-containing polar groups, accompanied by slight surface etching, which changes the surface from smooth to microscopically rough, thereby improving the surface reactivity of PP fibers.

[0042] Step 3: Preparation of modified PP fibers

[0043] Weigh out 500g of activated PP fiber, 5000mL of anhydrous ethanol and 90g of KH-570 and add them to a reaction flask. Stir for 20min. Heat the reaction flask to 50℃ and add 500mL of 3mol / L sodium hydroxide solution. Keep the reaction at this temperature for 40min. Cool the reaction flask to room temperature and filter. Wash the filter cake with purified water until neutral and then dry it. Transfer the filter cake to a drying oven at 60℃ and dry it to constant weight to obtain modified PP fiber.

[0044] In KH-570, the siloxane bonds undergo hydrolysis under alkaline conditions to generate highly reactive silanols. These silanols condense with polar groups on the surface of activated PP fibers to form stable Si-OC or Si-O-Si bonds. On the other hand, silanols also undergo self-condensation to build a local siloxane network structure on the fiber surface, thereby forming a firmly attached modified layer and creating unsaturated olefin double bond modification on the modified PP fibers.

[0045] Example 2

[0046] This embodiment provides a preparation process for modified PP fibers, specifically including the following steps:

[0047] Step 1: Prepare stretching fibers

[0048] PP fibers are thermally stretched at a temperature of 135℃ with a stretch ratio of 3.5 times to obtain stretched fibers.

[0049] Step 2: Preparation of activated PP fibers

[0050] 15wt% hydrogen peroxide and 7mol / L sodium hydroxide solution were mixed at a volume ratio of 5:2.5 to obtain the activation solution;

[0051] The stretched fiber and activation solution were added to the reaction flask at a solid-liquid ratio of 1:3 and stirred. The reaction flask was heated to 65°C and kept at that temperature for 70 minutes. The reaction flask was then cooled to room temperature and filtered. The filter cake was washed with purified water until neutral and then dried. The filter cake was transferred to a drying oven at 65°C and dried to constant weight to obtain activated PP fiber.

[0052] Step 3: Preparation of modified PP fibers

[0053] Weigh out 500g of activated PP fiber, 5000mL of anhydrous ethanol and 100g of KH-570 and add them to a reaction flask. Stir for 25min. Heat the reaction flask to 55℃ and add 500mL of 4mol / L sodium hydroxide solution. Keep the reaction at this temperature for 45min. Cool the reaction flask to room temperature and filter. Wash the filter cake with purified water until neutral and then dry it. Transfer the filter cake to a drying oven at 65℃ and dry it to constant weight to obtain modified PP fiber.

[0054] Example 3

[0055] This embodiment provides a preparation process for modified PP fibers, specifically including the following steps:

[0056] Step 1: Prepare stretching fibers

[0057] PP fibers were thermally stretched at a temperature of 140℃ with a stretch ratio of 4 times to obtain stretched fibers.

[0058] Step 2: Preparation of activated PP fibers

[0059] 20wt% hydrogen peroxide and 8mol / L sodium hydroxide solution were mixed at a volume ratio of 5:3 to obtain the activation solution;

[0060] The stretched fiber and activation solution were added to the reaction flask at a solid-liquid ratio of 1:3 and stirred. The reaction flask was heated to 70°C and kept at that temperature for 80 minutes. The reaction flask was then cooled to room temperature and filtered. The filter cake was washed with purified water until neutral and then dried. The filter cake was transferred to a drying oven at 70°C and dried to constant weight to obtain activated PP fiber.

[0061] Step 3: Preparation of modified PP fibers

[0062] Weigh out 500g of activated PP fiber, 5000mL of anhydrous ethanol and 110g of KH-570 and add them to a reaction flask. Stir for 30min. Heat the reaction flask to 60℃ and add 500mL of 5mol / L sodium hydroxide solution. Keep the reaction at this temperature for 50min. Cool the reaction flask to room temperature and filter. Wash the filter cake with purified water until neutral and then dry it. Transfer the filter cake to a drying oven at 70℃ and dry it to constant weight to obtain modified PP fiber.

[0063] Example 4

[0064] This embodiment provides a method for preparing hydroxyl-modified unsaturated silicone oil, specifically including the following steps:

[0065] Weigh out 50g of (3-aminopropyl)diethoxymethylsilane, 40g of octamethylcyclotetrasiloxane, 30g of trivinyltrimethylcyclotrisiloxane, and 20mL of 70wt% sulfuric acid and add them to a reaction flask. Stir the mixture and heat it to 85℃. Keep the temperature for 60min. Add 20g of diallyltetramethyldisiloxane to the reaction flask and keep the temperature for 40min. Add 40g of glycidyl silicone oil to the reaction flask and keep the temperature for 30min. Cool the reaction flask to room temperature and add 2L of toluene and 2L of saturated sodium carbonate solution. Stir and disperse for 20min. Let the mixture stand and separate the liquids. Wash the organic phase with purified water until neutral and transfer it to a rotary evaporator with a water bath temperature of 90℃. Purge the rotary evaporator to -0.1MPa and remove low-boiling substances under reduced pressure to obtain hydroxyl-modified unsaturated silicone oil.

[0066] In the reaction, sulfuric acid catalyzes the hydrolysis of (3-aminopropyl)diethoxymethylsilane, octamethylcyclotetrasiloxane, and trivinyltrimethylcyclotrisiloxane to form silanols. The silanols then undergo condensation to form long polysiloxane chains with olefin double bonds and amino modifications. Diallyltetramethyldisiloxane acts as a capping agent to form olefin capping on the long polysiloxane chains. Then, under high temperature conditions, glycidyl condenses with amino groups to form hydroxyl modifications.

[0067] Hydroxyl-modified unsaturated silicone oil can undergo free radical copolymerization with polyfunctional acrylates under the action of an initiator during the subsequent padding and curing process. This allows the silicone oil to be embedded in the cross-linked network in the form of covalent bonds. The hydroxyl functional groups promote the uniform distribution of silicone oil on the fiber surface and pore walls and inhibit phase separation by increasing molecular polarity and interfacial affinity. As a result, the composite network formed has both rigid support and flexible buffering characteristics. This significantly improves the strength retention and durability of the material in acid and alkali media, while also improving the high-temperature stability and pore structure stability of the material through the heat resistance and corrosion resistance of the silicon-oxygen backbone.

[0068] Example 5

[0069] This embodiment provides a method for preparing hydroxyl-modified unsaturated silicone oil, specifically including the following steps:

[0070] Weigh out 55g of (3-aminopropyl)diethoxymethylsilane, 45g of octamethylcyclotetrasiloxane, 30g of trivinyltrimethylcyclotrisiloxane, and 20mL of 75wt% sulfuric acid and add them to a reaction flask. Stir the mixture and heat it to 90℃. Keep the temperature for 70min. Add 20g of diallyltetramethyldisiloxane to the reaction flask and keep the temperature for 45min. Add 40g of glycidyl silicone oil to the reaction flask and keep the temperature for 40min. Cool the reaction flask to room temperature and add 2L of toluene and 2L of saturated sodium carbonate solution. Stir and disperse for 25min. Let the mixture stand and separate the liquids. Wash the organic phase with purified water until neutral and transfer it to a rotary evaporator with a water bath temperature of 90℃. Purge the rotary evaporator to -0.1MPa and remove low-boiling substances under reduced pressure to obtain hydroxyl-modified unsaturated silicone oil.

[0071] Example 6

[0072] This embodiment provides a method for preparing hydroxyl-modified unsaturated silicone oil, specifically including the following steps:

[0073] Weigh out 60g of (3-aminopropyl)diethoxymethylsilane, 50g of octamethylcyclotetrasiloxane, 30g of trivinyltrimethylcyclotrisiloxane, and 20mL of 80wt% sulfuric acid and add them to a reaction flask. Stir the mixture and heat it to 95℃. Keep the temperature for 80min. Add 20g of diallyltetramethyldisiloxane to the reaction flask and keep the temperature for 50min. Add 40g of glycidyl silicone oil to the reaction flask and keep the temperature for 50min. Cool the reaction flask to room temperature and add 2L of toluene and 2L of saturated sodium carbonate solution. Stir and disperse for 30min. Let the mixture stand and separate the liquids. Wash the organic phase with purified water until neutral and transfer it to a rotary evaporator with a water bath temperature of 90℃. Purge the rotary evaporator to -0.1MPa and remove low-boiling substances under reduced pressure to obtain hydroxyl-modified unsaturated silicone oil.

[0074] Example 7

[0075] Please see Figure 1 This embodiment provides a preparation process for a high-temperature resistant and acid / alkali corrosion resistant flat-plate biological packing material, including the following steps:

[0076] Step 1: Preparation of modified PP fibers

[0077] The modified PP fiber and ES fiber prepared in Example 1 were mixed evenly at a weight ratio of 6:3 to obtain mixed fiber;

[0078] The modified PP fibers prepared in Example 1 were applied along the X-axis at a density of 150 g / m. 2 After the mesh is laid at a uniform density, apply a 200g / m² pressure on top. 2 ES fibers are evenly laid on top of each other at a web density of 180 g / m². 2The mixed fibers are laid at a certain density and then hydroentangled for reinforcement. The hydroentanglement pressure is set to 26 MPa and the number of hydroentanglement passes is 7. After the hydroentanglement is completed, excess moisture is removed by negative pressure suction and liquid rolling. The fiber web is then transferred to a drying oven at 80°C and dried to constant weight to obtain the base film material.

[0079] Modified PP fibers are laid along the X-axis, relying on the high orientation and high strength fiber skeleton of the modified PP fibers to bear the main tensile load. ES fibers are located in the middle layer, which undergoes local thermal response during hydroentangling and enhances the mechanical interlocking between fibers. The top layer of mixed fibers is laid along the Y-axis, so that the structure has an effective load-bearing path in two orthogonal directions. Through hydroentangling, the high-speed water flow causes the fibers to fully entangle in the thickness direction and in-plane direction, forming a stable three-dimensional mechanical interlocking structure, while retaining a well-connected pore network.

[0080] Step 2: Preparation of flat-plate biological packing material blanks

[0081] 4-Penten-1-ol, trimethylolpropane triacrylate, the hydroxyl-modified unsaturated silicone oil prepared in Example 4, anhydrous ethanol and azobisisobutyronitrile were mixed evenly at a ratio of 5g:2g:3g:30mL:1g to obtain the padding solution.

[0082] The base film material was placed in an impregnation bath for two dips and two rolls. The first impregnation pressure was set at 20 kPa and the roll residue was 40%. The second impregnation pressure was set at 10 kPa and the roll residue was 60%. The impregnated base film material was placed in a curing chamber at 70°C and 80% humidity for 40 min. The base film material was then removed from the curing chamber, washed three times with anhydrous ethanol, and transferred to a drying oven at 70°C. The material was dried to constant weight to obtain a flat biofiller preform.

[0083] Azobisisobutyronitrile (AIB) decomposes under heating conditions to generate free radicals, inducing free radical polymerization of 4-penten-1-ol and trimethylolpropane triacrylate (TMT), constructing a multifunctional cross-linked backbone. Unsaturated groups in the hydroxyl-modified unsaturated silicone oil simultaneously participate in the copolymerization, allowing silicon-oxygen segments to be covalently embedded in the cross-linked network. Furthermore, since unsaturated groups have been introduced onto the surface of the modified PP fibers using KH-570, the cross-linked network can grow in situ on the fiber surface and achieve chemical anchoring, rather than simple coating. Meanwhile, the 4-penten-1-ol and TMT in the padding solution... Alkyl triacrylate and hydroxyl-modified unsaturated silicone oil are rich in hydroxyl groups. The hydroxyl groups enhance the adsorption and fixation at fiber intersections and pore walls through hydrogen bonding and polar interactions, while improving the hydrophilicity of the material. The silicon-oxygen backbone and cross-linked network are stable in acid and alkali media, and the network does not peel off from the fiber interface, which improves the retention rate of fracture strength after acid and alkali immersion. The flexible silicon-oxygen chain segments buffer stress concentration, inhibit microcrack propagation, and improve the mechanical properties of the material. Furthermore, the reactive silicone oil is chemically fixed to avoid migration and pore blockage, thereby maintaining a high specific surface area.

[0084] Step 3: Preparation of flat-plate biological packing material

[0085] The flat biological packing blank was placed in a drying oven at 110℃ and kept at that temperature for 50 minutes to obtain the flat biological packing.

[0086] The modified PP fiber releases its orientation stress under heating conditions. At the same time, the hydroentangled structure and cross-linked network strongly constrain the fiber shrinkage, transforming the shrinkage into microstructural stabilization. The organosilicon cross-linked network becomes further densified and stabilized under heat. Meanwhile, because the processing temperature is lower than the melting point of ES fiber, structural collapse or pore closure is avoided.

[0087] Example 8

[0088] Please see Figure 1 This embodiment provides a preparation process for a high-temperature resistant and acid / alkali corrosion resistant flat-plate biological packing material, including the following steps:

[0089] Step 1: Preparation of modified PP fibers

[0090] The modified PP fiber and ES fiber prepared in Example 2 were mixed evenly at a weight ratio of 6.5:3.5 to obtain mixed fiber;

[0091] The modified PP fibers prepared in Example 2 were applied along the X-axis at a density of 160 g / m. 2 After the mesh is laid at a uniform density, apply a 220g / m² pressure on top. 2 ES fibers are evenly laid on top of each other at a web density of 190 g / m². 2The mixed fibers are laid at a certain density and then hydroentangled for reinforcement. The hydroentanglement pressure is set to 27 MPa and the number of hydroentanglement passes is 7. After the hydroentanglement is completed, excess moisture is removed by negative pressure suction and liquid rolling. The fiber web is then transferred to a drying oven at 80°C and dried to constant weight to obtain the base film material.

[0092] Step 2: Preparation of flat-plate biological packing material blanks

[0093] 4-Penten-1-ol, trimethylolpropane triacrylate, the hydroxyl-modified unsaturated silicone oil prepared in Example 5, anhydrous ethanol and azobisisobutyronitrile were mixed evenly at a ratio of 5.5g:2.5g:3.5g:30mL:1g to obtain the padding solution.

[0094] The base film material was placed in an impregnation bath for two dips and two rolls. The first impregnation pressure was set at 23 kPa and the roll residue was 40%. The second impregnation pressure was set at 13 kPa and the roll residue was 60%. The impregnated base film material was placed in a curing chamber at 75°C and 85% humidity for 50 min. The base film material was then removed from the curing chamber, washed three times with anhydrous ethanol, and transferred to a drying oven at 75°C. The material was dried to constant weight to obtain a flat biofiller preform.

[0095] Step 3: Preparation of flat-plate biological packing material

[0096] The flat biological packing blank was placed in a drying oven at 115℃ and kept at that temperature for 55 minutes to obtain the flat biological packing.

[0097] Example 9

[0098] Please see Figure 1 This embodiment provides a preparation process for a high-temperature resistant and acid / alkali corrosion resistant flat-plate biological packing material, including the following steps:

[0099] Step 1: Preparation of modified PP fibers

[0100] The modified PP fiber and ES fiber prepared in Example 3 were mixed evenly at a weight ratio of 7:4 to obtain the mixed fiber;

[0101] The modified PP fibers prepared in Example 3 were applied along the X-axis at a density of 170 g / m. 2 After the mesh is laid at a uniform density, apply a 240g / m² pressure on top. 2 ES fibers are evenly laid on top of each other at a web density of 200g / m². 2The mixed fibers are laid at a certain web density and then hydroentangled for reinforcement. The hydroentanglement pressure is set to 28 MPa and the number of hydroentanglement passes is 7. After the hydroentanglement is completed, excess moisture is removed by negative pressure suction and liquid rolling. The fiber web is then transferred to a drying oven at 80°C and dried to constant weight to obtain the base film material.

[0102] Step 2: Preparation of flat-plate biological packing material blanks

[0103] 4-Penten-1-ol, trimethylolpropane triacrylate, the hydroxyl-modified unsaturated silicone oil prepared in Example 6, anhydrous ethanol and azobisisobutyronitrile were mixed evenly at a ratio of 6g:3g:4g:30mL:1g to obtain the padding solution.

[0104] The base film material was placed in an impregnation bath for two dips and two rolls. The first impregnation pressure was set at 25 kPa and the roll residue was 40%. The second impregnation pressure was set at 15 kPa and the roll residue was 60%. The impregnated base film material was placed in a curing chamber at 80°C and 90% humidity for 60 min. The base film material was then removed from the curing chamber, washed three times with anhydrous ethanol, and transferred to a drying oven at 80°C. The material was dried to constant weight to obtain a flat biofiller preform.

[0105] Step 3: Preparation of flat-plate biological packing material

[0106] The flat biological packing blank was placed in a drying oven at 120℃ and kept at that temperature for 60 minutes to obtain the flat biological packing.

[0107] Comparative Example 1

[0108] The difference between this comparative example and Example 9 is that the stretched fiber prepared in Example 3 is used instead of the modified PP fiber.

[0109] Comparative Example 2

[0110] The difference between this comparative example and Example 9 is that the modified PP fiber used in Example 3 is replaced with PP fiber.

[0111] Comparative Example 3

[0112] The difference between this comparative example and Example 9 is that hydroxyl-modified unsaturated silicone oil was not added in step two.

[0113] Comparative Example 4

[0114] The difference between this comparative example and Example 9 is that the hydroxyl-modified unsaturated silicone oil used in step two was not prepared with glycidyl ether.

[0115] Performance testing:

[0116] The breaking strength of the flat biofiller specimens prepared in Examples 7-9 and Comparative Examples 1-4 was determined in accordance with the standard GB / T 24218.3-2010 "Textiles - Nonwovens - Test Methods - Part 3: Determination of breaking strength and elongation at break (strip method)".

[0117] The specific surface area of ​​the flat biological packing samples prepared in Examples 7-9 and Comparative Examples 1-4 was determined according to the standard GB / T 19587-2017 "Determination of Specific Surface Area of ​​Solid Substances by Gas Adsorption BET Method".

[0118] The contact angles of the flat biofiller samples prepared in Examples 7-9 and Comparative Examples 1-4 with water were determined in accordance with the standard GB / T 42694-2023 "Detection and evaluation of the surface anti-wetting properties of textiles - contact angle and roll-off angle method".

[0119] The flat-plate biofiller samples prepared in Examples 7-9 and Comparative Examples 1-4 were cut into regular rectangles, then placed in a 90°C environment for 30 minutes, and then processed according to the formula. The dimensional retention rate of the sample after high-temperature treatment is determined, where S1 is the area of ​​the sample after high-temperature treatment and S0 is the initial area of ​​the sample before high-temperature treatment.

[0120] The flat bio-filler samples prepared in Examples 7-9 and Comparative Examples 1-4 were respectively immersed in hydrochloric acid solution (pH=1) and sodium hydroxide solution (pH=13) at 60°C for 60 min, and then the tensile strength of the samples was measured according to the formula. The retention rate of fracture strength is calculated. In the formula, F1 is the fracture strength of the sample after soaking in hydrochloric acid or sodium hydroxide solution, and F0 is the fracture strength of the sample before soaking in hydrochloric acid or sodium hydroxide solution. The specific test data are shown in Table 1 below.

[0121]

[0122] Performance testing:

[0123] Comparative analysis of the data in Table 1 above shows that the specific surface area of ​​the flat-plate biological packing sample prepared by this invention reaches 10.8-11.5 m². 2 / g, with a water contact angle of 32-35°, a dimensional retention of 99.2-99.5% after heat treatment, a tensile strength of 282-286N, a tensile strength retention of 98.4-98.6% after acid immersion, and a tensile strength retention of 96.2-96.7% after alkali immersion. All performance test data are superior to the comparative example.

[0124] This invention describes a process involving the thermal stretching and orientation of PP fibers, alkaline oxidation activation, and silane coupling modification to construct a surface-reactive unsaturated modified PP fiber skeleton. Based on this skeleton, a stable and highly porous three-dimensional nonwoven base membrane is formed through multi-layer oriented web laying and hydroentangling reinforcement. Subsequently, an organic-organic silicon composite crosslinking network is constructed in situ on the fiber surface and pore walls by impregnating a system containing multifunctional acrylates, hydroxyl-modified unsaturated silicone oil, and free radical initiators. This allows flexible silicon-oxygen segments to be covalently embedded into the network and chemically anchored to the fiber. Finally, controlled heat setting achieves structural locking. This process significantly improves the tensile strength, dimensional stability, and mechanical property retention rate of the flat-plate biofiller under high temperature, strong acid, and strong alkali conditions, while maintaining high specific surface area and good hydrophilicity.

[0125] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A preparation process for a high-temperature resistant and acid / alkali corrosion resistant flat-plate biological packing material, characterized in that, Includes the following steps: S1. After the modified PP fiber is evenly laid along the X-axis, ES fiber is evenly laid on it, and then mixed fiber is laid on it along the Y-axis. After hydroentanglement reinforcement and drying, the base film material is obtained. S2. The base membrane material is placed in the impregnation liquid for two dips and two rolls, and then cross-linked and cured to obtain a flat biological filler blank; S3. Place the flat biological packing blank in a drying oven at 110-120℃ and keep it at that temperature for 50-60 minutes to obtain the flat biological packing.

2. The preparation process of a high-temperature resistant and acid / alkali corrosion resistant flat-plate biological packing material according to claim 1, characterized in that, In step S1, the laying density of the modified PP fiber is 150-170 g / m 2 , the laying density of the ES fiber is 200-240 g / m 2 , the laying density of the mixed fiber is 180-200 g / m 2 ; the mixed fiber is composed of the modified PP fiber and the ES fiber in a weight ratio of 6-7:3-4.

3. The preparation process of a high-temperature resistant and acid / alkali corrosion resistant flat-plate biological packing material according to claim 1, characterized in that, In step S2, the padding solution is composed of 4-penten-1-ol, trimethylolpropane triacrylate, hydroxyl-modified unsaturated silicone oil, anhydrous ethanol, and azobisisobutyronitrile in a ratio of 5-6g:2-3g:3-4g:30mL:1g. In the two-dip and two-roll process, the first padding pressure is 20-25kPa, and the first padding yield is 40%. The second padding pressure is 10-15kPa, and the second padding yield is 60%.

4. The preparation process of a high-temperature resistant and acid / alkali corrosion resistant flat-plate biological packing material according to claim 1, characterized in that, In step S2, the crosslinking and curing operation includes: placing the impregnated base film material in a curing chamber at a temperature of 70-80℃ and a humidity of 80-90% for 40-60 minutes, removing the base film material from the curing chamber, washing it three times with anhydrous ethanol, and then transferring it to a drying oven at a temperature of 70-80℃ to dry it to constant weight to obtain a flat biological filler blank.

5. The preparation process of a high-temperature resistant and acid / alkali corrosion resistant flat-plate biological packing material according to claim 3, characterized in that, The preparation method of hydroxyl-modified unsaturated silicone oil is as follows: (3-aminopropyl)diethoxymethylsilane, octamethylcyclotetrasiloxane, trivinyltrimethylcyclotrisiloxane and sulfuric acid are mixed and stirred. The reaction system is heated to 85-95℃ and kept at this temperature for 60-80 min. Diallyltetramethyldisiloxane is added to the reaction system and kept at this temperature for 40-50 min. Glycidyl silicone oil is added to the reaction system and kept at this temperature for 30-50 min. After post-treatment, hydroxyl-modified unsaturated silicone oil is obtained.

6. The preparation process of a high-temperature resistant and acid / alkali corrosion resistant flat-plate biological packing material according to claim 5, characterized in that, The ratio of (3-aminopropyl)diethoxymethylsilane, octamethylcyclotetrasiloxane, trivinyltrimethylcyclotrisiloxane, sulfuric acid, diallyltetramethyldisiloxane, and glycidyl silicone oil is 5-6g:4-5g:3g:2mL:2g:4g. The post-treatment operation includes: after the reaction is completed, the reaction system is cooled to room temperature, toluene and saturated sodium carbonate solution are added to the reaction system, stirred and dispersed for 20-30 minutes, allowed to stand and separated, the organic phase is washed with purified water until neutral, and then transferred to a rotary evaporator with a water bath temperature of 90℃. The rotary evaporator is evaporated to a negative pressure of -0.1MPa to remove low-boiling substances under reduced pressure, to obtain hydroxyl-modified unsaturated silicone oil.

7. The preparation process of a high-temperature resistant and acid / alkali corrosion resistant flat-plate biological packing material according to claim 1, characterized in that, Modified PP fibers are obtained through the following steps: A1. PP fibers are thermally stretched at a temperature of 130-140℃ with a stretching ratio of 3-4 times to obtain stretched fibers. A2. Mix the stretched fiber and the activation solution, heat the reaction system to 60-70℃, keep it at the temperature for 60-80 minutes, and then perform post-treatment to obtain activated PP fiber. A3. Mix and stir the activated PP fiber, anhydrous ethanol and KH-570 for 20-30 minutes. Heat the reaction system to 50-60℃, add sodium hydroxide solution to the reaction system, keep the reaction at this temperature for 40-50 minutes, and then perform post-treatment to obtain modified PP fiber.

8. The preparation process of a high-temperature resistant and acid / alkali corrosion resistant flat-plate biological packing material according to claim 7, characterized in that, In step A2, the solid-liquid ratio of the stretched fiber and the activation solution is 1:

3. The activation solution is composed of 10-20wt% hydrogen peroxide and 6-8mol / L sodium hydroxide solution in a volume ratio of 5:2-3. The post-treatment includes: after the reaction is completed, the reaction system is cooled to room temperature, filtered, the filter cake is washed with purified water until neutral and then dried, the filter cake is transferred to a drying oven at a temperature of 60-70℃ and dried to constant weight to obtain activated PP fiber.

9. The preparation process of a high-temperature resistant and acid / alkali corrosion resistant flat-plate biological packing material according to claim 7, characterized in that, In step A3, the ratio of activated PP fiber, anhydrous ethanol, KH-570, and sodium hydroxide solution is 10g:100mL:1.8-2.2g:10mL, and the concentration of sodium hydroxide solution is 3-5mol / L. The post-treatment includes: after the reaction is complete, the reaction system is cooled to room temperature, filtered, the filter cake is washed with purified water until neutral, dried, and the filter cake is transferred to a drying oven at 60-70℃ and dried to constant weight to obtain modified PP fiber.

10. A high-temperature resistant and acid / alkali corrosion resistant flat-plate biological packing material, characterized in that, The high-temperature resistant and acid-alkali corrosion resistant flat plate biological packing material is prepared using the preparation process of the high-temperature resistant and acid-alkali corrosion resistant flat plate biological packing material as described in any one of claims 1-9.

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