Self-cleaning filler and preparation method thereof

Abstract

The invention belongs to the field of cleaning fillers, and particularly relates to a self-cleaning filler and a preparation method thereof. The method comprises the following steps: 1) preparing a strongly acidic permanganate aqueous solution, adding a composite reducing agent, reacting, and crystallizing to obtain a black brown intermediate; 2) placing the black brown intermediate in an organic solvent, heating and boiling to separate a precipitate, repeating the steps until the precipitate is treated to be neutral, and then drying to obtain a manganese-based precursor; (3) adding the manganese-based precursor into an ammonium persulfate aqueous solution, carrying out hydrothermal reaction, and washing to be neutral to obtain a composite manganese-based carrier; and 4) respectively and sequentially adding an organic binder and powder into the composite manganese-based carrier, and carrying out granulation treatment twice to obtain the composite core-shell structure self-cleaning filler. The self-cleaning filler disclosed by the invention can be directly used for filling the interior of the helmet, realizes cleaning and purification of a local atmosphere environment, has extremely strong anti-pollution capability, can resist pollution caused by non-degradable components, and can effectively realize regeneration through solarization.

Description

Technical Field

[0001] The invention belongs to the field of cleaning fillers, and in particular relates to a self-cleaning filler and a preparation method thereof. Background Art

[0002] At present, riding an electric bike has become a convenient and efficient way to travel short distances in urban life. Its advantages such as low road entry threshold, environmental protection and energy saving, low cost, easy parking and effective relief of urban traffic congestion are highly favored. Faced with the growing number of cyclists, how to facilitate everyone's travel while ensuring traffic safety has become the focus of attention of relevant departments. Although the new national standard limits the maximum design speed of electric vehicles to ensure cycling safety. However, it is still necessary to increase efforts to popularize the safety awareness of the majority of cyclists and improve safety protection measures. Among them, wearing a helmet correctly when riding has become the focus of electric vehicle safety precautions. The helmet is the first line of defense when encountering danger and can effectively protect the head from fatal injuries.

[0003] Electric vehicle helmets are mainly composed of a shell, a buffer layer, a wearing device, etc. As a key safety protection equipment for electric vehicle riding, the helmet should not only have excellent safety protection performance, but also take into account wearing comfort and breathability to ensure the user experience during long-term riding. The buffer layer of traditional electric vehicle helmets can be roughly divided into two categories. The former is a hard lining buffer represented by expanded polystyrene (EPS). This type of hard lining material has the characteristics of light weight and good collision energy absorption. However, the hard lining buffer layer has the problem of poor wearing comfort and fit. Elastic polymer foam is widely used in elastic buffers due to its excellent buffering performance and relatively high energy absorption to weight ratio. Commonly used porous elastic polyurethane sponge is a typical lining material. Although the polyurethane sponge comfort lining provides a comfortable fit for the wearer's head, the polyurethane foam has poor air permeability. In a warm, hot and humid environment, the polyurethane foam will make people feel extremely stuffy. Considering the poor thermal comfort of the helmet lining, it is easy to cause heat stress on the head when used in hot summer weather, which poses certain safety hazards to riding safety. In view of this, it is an effective design strategy to further introduce soft pads with thermal and moisture comfort, such as warp-knitted spacer fabrics, into helmets to take into account both impact energy absorption and wearing comfort.

[0004] In addition to safety and comfort, the design considerations for electric vehicle helmets also include the odor caused by the inevitable sweat absorption in the hot summer, which is also a problem that troubles the majority of cyclists. As a non-consumable item, cleaning the odor to ensure the use of helmets has become an urgent problem to be solved. Human sweat is mainly composed of electrolyte, urea, lactic acid, sweat gland substances and oily substances. The sweat accumulated in the helmet emits a serious odor, and in addition, there is also serious bacterial growth. Convenient, efficient and clean electric vehicle helmets have become a boon for the majority of cyclists. In the face of growing market demand, it is urgent to develop safe and comfortable self-cleaning electric vehicle helmets. Previous studies have shown that nano manganese dioxide has efficient catalytic decomposition and bactericidal activity, and is widely used in the catalytic decomposition of formaldehyde. At the same time, its rich specific surface area and strong oxidizability can be used to eliminate odor and efficient sterilization. Its high catalytic activity and chemical stability can ensure its efficient service for a long time, and it is expected to become a key material for the preparation of self-cleaning electric vehicle helmets. Summary of the invention

[0005] In order to solve the problems of poor wearing comfort and air permeability of current electric vehicle helmets, easy residual odor and bacterial growth, etc., the purpose of the present invention is to provide a self-cleaning filler and a preparation method of the self-cleaning filler.

[0006] The main purpose of the present invention is: 1. Ensure that the filler has a good cleaning and purification effect and can improve the atmosphere inside the helmet; 2. Ensure that the filler has the characteristics of efficient cleaning; 3. Ensure that the filler is renewable so that it has a long-lasting and effective cleaning and purification effect.

[0007] To achieve the above objectives, the present invention adopts the following technical solutions.

[0008] A method for preparing a self-cleaning filler, The method comprises: 1) preparing a permanganate aqueous solution, adjusting the pH value to a strong acid, and then slowly adding a composite reducing agent, stirring the mixture under hot conditions, cooling the mixture to crystallize, and evaporating the mixture to obtain a dark brown intermediate; 2) placing the dark brown intermediate in an organic solvent, heating and boiling, and separating the precipitate while hot, repeating the process until the precipitate is treated to be neutral, and then drying to obtain a manganese-based precursor; 3) adding a manganese-based precursor to an aqueous solution of ammonium persulfate, performing a low-temperature hydrothermal reaction, and washing with water and / or an organic solvent until the mixture is neutral to obtain a composite manganese-based carrier; 4) An organic binder and an organic / inorganic mixed powder are added to the composite manganese-based carrier in sequence, and granulation treatment is performed twice to obtain a composite core-shell structured self-cleaning filler.

[0009] As a preference, Step 1) The permanganate concentration in the permanganate aqueous solution is 0.05-1.00 mol / L; Step 1) the composite reducing agent is composed of manganese sulfate and ascorbic acid; The molar ratio of manganese sulfate, ascorbic acid and permanganate is (1.6-1.8):(0.2-0.3):1.

[0010] Preferably, in step 1), the pH value is adjusted to a strong acidity by adjusting the pH value to 1.5 to 2.5, and the pH value is controlled by adding dilute sulfuric acid during the adjustment process; The hot stirring reaction process in step 1) is to stir the reaction at 70-80° C. for 3-6 hours.

[0011] As a preference, Step 2) the organic solvent is anhydrous ethanol and / or anhydrous methanol; Step 2) The amount of the organic solvent used is 5-10 mL / g of the dark brown intermediate.

[0012] As a preference, Step 3) The concentration of the ammonium persulfate aqueous solution is 0.5-1.5 mol / L, and the amount thereof is 10-20 mL / g of the manganese-based precursor.

[0013] As a preference, Step 3) The low-temperature hydrothermal reaction is carried out at a constant temperature of 85 to 105° C. for 18 to 30 hours.

[0014] As a preference, Step 4) the organic binder is a phenolic resin, and its amount is 1 to 3 wt% of the mass of the composite manganese-based carrier; Step 4) the organic / inorganic mixed powder is sepiolite powder and gum arabic, the mass ratio of sepiolite powder to gum arabic is 1:(0.6-0.8), and the amount of the organic / inorganic mixed powder is 1.5-5.0wt% of the composite manganese-based carrier.

[0015] A self-cleaning filler.

[0016] Preferably, the self-cleaning filler is directly used for filling the interior of the helmet, and / or is embedded in an organic material and foamed to serve as a foam filler for filling the interior of the helmet.

[0017] The technical solution of the present invention uses manganese dioxide as a core component for catalytic purification of the atmosphere environment, and constructs a composite structure with twin crystal synergy and multi-shell coordination.

[0018] Among them, the present invention constructs a dark brown intermediate by combining a permanganate composite reducing agent with a hot stirring reaction. In this process, the present invention selects manganese sulfate and ascorbic acid as composite reducing agents because manganese sulfate and permanganate themselves have a tendency to react to form manganese dioxide under hot stirring, and α-crystalline manganese dioxide (α-MnO2) exists as the main product, and its content usually accounts for 70% or even more than 75%. As a polymorphic compound, manganese dioxide has five main crystal forms and dozens of non-main crystal forms, and the five main crystal forms are α-MnO2, β-MnO2, γ-MnO2, δ-MnO2 and ε-MnO2, among which the α-crystal form has unique catalytic properties, which has a good catalytic degradation effect on harmful gas pollutants in helmets such as VOCs, so it is generally necessary to construct a clean filler based on it.

[0019] However, during the simulation test of the research and development process, it was found that a large amount of water vapor is actually formed inside the helmet during use, that is, the humidity inside the helmet is usually high. For researchers in this field, high humidity does not have a negative impact on α-crystalline manganese dioxide. Taking VOCs as an example, although water molecules may compete with VOCs molecules for adsorption in a high humidity environment, resulting in the coverage of active sites on the catalyst surface, thereby affecting the catalytic degradation efficiency, the α-MnO2 catalyst, due to its special physical and chemical properties, can maintain more oxygen vacancies and active sites under high humidity conditions, reducing the influence of sulfate ion residues, thereby maintaining a high catalytic activity. However, helmets are different from general environments. Their high humidity conditions are often accompanied by sweat volatilization, etc., and there are many and complex pollutants. More organic pollutants will be deposited on the surface of the filler and dissolved in the water molecule layer for transportation inside the filler, resulting in more active sites on the catalyst surface Covered, the actual catalytic degradation ability of the filler is extremely restricted.

[0020] In this regard, the present invention uses a composite process, and ascorbic acid is added as a structure-directing agent to guide the formation of an alpha crystal product during the reaction of manganese sulfate and permanganate, so that the proportion of the alpha crystal product can stably reach more than 92%, with a high degree of singleness, and the utilization rate of manganese sulfate is also improved. On the other hand, the manganese sulfate of the present invention needs to be used in excess, and its purpose is not to promote the reaction forward as conventionally, but more importantly, it can form a certain capture effect, and the excess divalent manganese ions are fixed to a certain extent so that the intermediate retains a fixed manganese sulfate component, and because the channel structure of the alpha crystal manganese dioxide is small, it is not enough to realize the transportation of manganese ions, so the manganese ions will be relatively stably enriched on the surface rather than inside the manganese dioxide, but because of its capture effect, the combination of manganese dioxide and manganese sulfate can be better achieved.

[0021] On this basis, the present invention removes other impurities by boiling with organic solvents such as anhydrous ethanol and / or anhydrous methanol, and manganese sulfate is difficult to dissolve at high temperature in anhydrous ethanol and anhydrous methanol, which can reduce its loss. After cleaning and removing impurities, the residual manganese sulfate is converted into another specific crystal form of manganese dioxide, namely δ-MnO2, by reacting ammonium persulfate and residual manganese sulfate in a long-term low-temperature hydrothermal method. This crystal form of manganese dioxide has a larger tunnel structure, and its theoretical tunnel structure is 1×∞, which is much larger than the 2×2 tunnel of the α crystal form, and has a larger interlayer spacing. At the same time, it has a rich mesoporous structure with a pore size distribution between 2 and 30nm. The mesoporous pores have a small transport resistance to the solution and have a large and strong transport capacity, that is, it provides a stronger pollution holding capacity and storage capacity, and can effectively reduce the influence of excessive pollutants on the α crystal form manganese dioxide contained, so that the composite manganese-based carrier has a more efficient cleaning ability, can quickly respond to and adsorb atmospheric pollutants in the helmet, and greatly improves the use effect.

[0022] Based on the above process, the present invention actually constructs a bi-crystalline coordinated manganese dioxide carrier particle, in which α-crystalline manganese dioxide is mainly used, and the δ-crystalline manganese dioxide is fixed and transformed through the ion tunnel of manganese dioxide to form an outer layer, thereby achieving anti-fouling and effectively coping with the complex atmosphere in the helmet and even forming an aerogel-like environment, achieving effective cleaning and purification effects.

[0023] On this basis, due to the coordination of the twin crystals, the δ crystal has a higher vacancy content, which is conducive to the interlayer migration of ions, etc. This is also beneficial for the regeneration of the filler used for self-cleaning helmets, because the filler of the present invention is conveniently regenerated by exposure. During the exposure process, due to the photothermal effect, the reorganization of manganese dioxide and the regeneration of active sites are stimulated. Ion migration is a very important process because ion migration is directly related to the formation and migration of oxygen vacancies during the regeneration process, as well as the redistribution of metal ions. These processes help to restore and enhance the catalytic activity of manganese dioxide. Therefore, the synergy of the twin crystals not only improves the cleaning and purification effect of the filler, but also improves its regeneration ability.

[0024] On this basis, the present invention also uses phenolic resin and composite powder to carry out double-shell coating granulation. The two granulation processes can achieve structural fixation of filler particles, improve their structural stability, and at the same time, the amount of double-shell coating material is small, which can avoid the reduction of active sites caused by the coating granulation process. At the same time, sepiolite also has a certain adsorption and cleaning ability, and it can also block oil secreted by the human body and other substances that have strong pollution to the filler to a certain extent, so as to avoid the decrease in the use effect of the filler.

[0025] The beneficial effects of the present invention are: The self-cleaning filler of the present invention can be directly used for filling the inside of a helmet to achieve cleaning and purification of the local atmosphere environment. It also has extremely strong anti-fouling ability and can resist pollution caused by non-degradable components. It can also be effectively regenerated through exposure to the sun, and has a long-lasting and effective cleaning and purification effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a crystal characterization diagram of manganese dioxide in the dark brown intermediate prepared in Example 1 of the present invention; Figure 2 This is a SEM characterization image of the composite manganese-based carrier prepared in Example 1 of the present invention; Figure 3 This is a comparison chart of experimental data of the dummy simulating VOCs removal rate in Example 1 of the present invention. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below in conjunction with specific embodiments and the accompanying drawings. A person of ordinary skill in the art will be able to implement the present invention based on these descriptions. In addition, the embodiments of the present invention involved in the following description are generally only embodiments of a part of the present invention, rather than all embodiments. Therefore, based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without making creative work should fall within the scope of protection of the present invention.

[0028] Unless otherwise specified, the raw materials used in the examples of the present invention are all commercially available or available to those skilled in the art; unless otherwise specified, the methods used in the examples of the present invention are all methods known to those skilled in the art.

[0029] Example 1 A self-cleaning filler is prepared by the following method: 1) preparing a 0.5 mol / L potassium permanganate aqueous solution, adjusting the pH value to pH=2 with dilute sulfuric acid, adding manganese sulfate and ascorbic acid at the same time, controlling the molar ratio of manganese sulfate, ascorbic acid and potassium permanganate to be 1.8:0.25:1, stirring at 75° C. for 5 h, cooling to room temperature for crystallization, and evaporating the solvent by plate rotary evaporation to obtain a dark brown intermediate; The dark brown intermediate was washed with water to remove manganese sulfate and then the crystal form was characterized. The characterization results are as follows: Figure 1 As shown, Figure 1The α-crystal form is very strong, among which the characteristic peaks at 2θ of 28.6°, 41.0°, 42.7° and 72.7° are obvious, while a small amount of impurity peaks mainly appear near 22.2°, 37.1°, 42.4°, etc., indicating that the manganese dioxide in the black-brown intermediate is mainly in the α-crystal form. The specific crystal form ratio was sent to the cooperative research group of Zhejiang University of Technology for full spectrum fitting and fine characterization. The characterization results of multiple samples showed that the average α-crystal proportion can reach about 92.2%, which has a high degree of singleness and the crystal form is effectively controlled; 2) placing the dark brown intermediate in anhydrous ethanol at a ratio of 1 g dark brown intermediate: 8 mL anhydrous ethanol, heating and boiling, and separating the precipitate while hot, repeating until the precipitate is treated to neutrality, and then drying at 60° C. for 90 min to obtain a manganese-based precursor; 3) adding a manganese-based precursor to a 1.0 mol / L ammonium sulfate aqueous solution, the amount ratio of the manganese-based precursor to the ammonium persulfate aqueous solution is 1 g: 15 mL, performing a low-temperature hydrothermal reaction at 90° C. for 24 h, and then washing with deionized water and anhydrous ethanol in sequence until neutral to obtain a composite manganese-based carrier; A small amount of the obtained composite manganese-based carrier was sampled and sent for SEM characterization. The characterization results are as follows: Figure 2 As shown, from Figure 2 It can be clearly seen that it has a rich mesoporous structure and a large specific surface area, which is consistent with the structural characteristics of the target δ-crystalline manganese dioxide, indicating that the δ-crystalline manganese dioxide is successfully formed; 4) The composite manganese-based carrier is mixed with 2 wt% of phenolic resin powder by weight for the first granulation, and spherical particles coated with molecular sieve are obtained after granulation, and the particle size is controlled to be about 0.7 mm. Subsequently, a mixed powder of 3 wt% of the composite manganese-based carrier by weight is added to the spherical particles, and the mixed powder consists of sepiolite powder and gum arabic in a mass ratio of 1:0.75. The second granulation is carried out, and the particle size is controlled to be about 1.1 mm, so as to obtain a composite core-shell structure self-cleaning filler.

[0030] Taking the commercially available Smart4u helmet as the most basic modified sample, the original data of the helmet with self-cleaning ability was characterized.

[0031] The specific characterization includes dummy simulation and real person simulation. Dummy simulation is to put the helmet on a suitable dummy head, and introduce VOCs at a constant speed through a capillary tube to simulate the volatile components on the human body surface. The VOCs content in the helmet is continuously monitored by PGM-7320 / MiniRAE 3000, and the data is recorded and plotted into a curve. Figure 3 The middle group is marked as PBS group; Subsequently, the EPS cushioning layer on the original helmet was completely disassembled and then molded, and EPS foam of the same specifications was manufactured by conventional processes. The self-cleaning filler prepared in this example was added during the manufacturing process, and the component proportion of the self-cleaning filler was 8wt%, so as to obtain an EPS cushioning layer of the same specifications. After the other components of the original helmet were restored and installed, the dummy simulation was also performed. Unless otherwise specified, each dummy simulation in the embodiment of the present invention was simulated by introducing the same amount of VOCs at the same rate, and the VOCs content in the helmet was continuously monitored by PGM-7320 / MiniRAE3000, and the data was recorded and plotted into a curve, which was recorded in Figure 3 The group marked as CFM.

[0032] from Figure 3 It can be clearly seen that the use of the filler of the present invention can very effectively remove VOCs, and compared with commercially available self-cleaning helmets, it can extremely effectively improve the cleaning and removal effect of volatile pollutants.

[0033] The real person simulation was conducted in the same testing laboratory under constant temperature and humidity conditions. The same experimenter (a technician from the same R&D and testing department of our company) wore the helmet for 10 hours a day for three consecutive days, and then took samples and used gas chromatography to test the VOCs content inside the helmet. The test results showed that the internal characterization results of the original commercially available Smart4u helmet in the control group were 113μg / m 3 , 121 μg / m 3 , 109μg / m 3 The experimental group conducted the same experiment with the CFM group helmets. After wearing them for 10 hours a day for three consecutive days, they took samples and used gas chromatography to test the VOCs content inside the helmets. The test results showed that the VOCs content of the experimental group was 27μg / m 3 22 μg / m 3 , 23 μg / m 3 In addition, after the end of daily wearing, the bacteria were sampled and cultured for 24 hours, and the absorbance value of the bacterial content was detected using CCK-8. The absorbance values ​​of the control group for three days were 0.6, 0.7, and 0.6, respectively, and the absorbance values ​​of the experimental group for three days were 0.2, 0.2, and 0.1, respectively.

[0034] The above characterization results also show that the self-cleaning filler of the present invention has a very excellent cleaning effect.

[0035] In addition, after the CFM experimental group helmet was subjected to dummy simulation until the VOCs removal rate dropped to about 75%, it was exposed upside down (sunlight directly penetrated the EPS buffer layer inside the helmet) for two days, and then the dummy simulation was repeated. The dummy simulation results showed that the VOCs removal rate recovered to 91.2% after 6.5 hours. It can be seen that the filler of the present invention also has a strong regeneration ability through the photothermal effect under exposure conditions.

[0036] Example 2 A self-cleaning filler is prepared by the following method: 1) preparing a 0.5 mol / L potassium permanganate aqueous solution, adjusting the pH value to pH=2 with dilute sulfuric acid, adding manganese sulfate and ascorbic acid at the same time, controlling the molar ratio of manganese sulfate, ascorbic acid and potassium permanganate to be 1.6:0.2:1, stirring and reacting at 70° C. for 6 h, cooling to room temperature for crystallization, and evaporating the solvent by plate rotary evaporation to obtain a dark brown intermediate; 2) placing the dark brown intermediate in anhydrous ethanol at a ratio of 1 g dark brown intermediate: 10 mL anhydrous ethanol, heating and boiling, and separating the precipitate while hot, repeating until the precipitate is treated to neutrality, and then drying at 60° C. for 90 min to obtain a manganese-based precursor; 3) adding a manganese-based precursor to a 1.0 mol / L ammonium sulfate aqueous solution, the amount ratio of the manganese-based precursor to the ammonium persulfate aqueous solution is 1 g: 15 mL, performing a low-temperature hydrothermal reaction at 90° C. for 24 h, and then washing with deionized water and anhydrous ethanol in sequence until neutral to obtain a composite manganese-based carrier; 4) The composite manganese-based carrier is mixed with 2 wt% of phenolic resin powder by weight for the first granulation, and spherical particles coated with molecular sieve are obtained after granulation, and the particle size is controlled to be about 0.7 mm. Subsequently, a mixed powder of 3 wt% of the composite manganese-based carrier by weight is added to the spherical particles, and the mixed powder consists of sepiolite powder and gum arabic in a mass ratio of 1:0.75. The second granulation is carried out, and the particle size is controlled to be about 1.1 mm, so as to obtain a composite core-shell structure self-cleaning filler.

[0037] The filler prepared in this example was characterized in the same manner as in Example 1. The characterization results are shown in the following table.

[0038] The above characterization results show that the self-cleaning filler prepared in this example also has a good cleaning and purification effect.

[0039] Example 3 A self-cleaning filler is prepared by the following method: 1) preparing a 0.5 mol / L potassium permanganate aqueous solution, adjusting the pH value to pH=2 with dilute sulfuric acid, adding manganese sulfate and ascorbic acid at the same time, controlling the molar ratio of manganese sulfate, ascorbic acid and potassium permanganate to be 1.8:0.3:1, stirring at 80° C. for 4.5 h, cooling to room temperature for crystallization, and evaporating the solvent by plate rotary evaporation to obtain a dark brown intermediate; 2) placing the dark brown intermediate in anhydrous ethanol at a ratio of 1 g dark brown intermediate: 7.5 mL anhydrous ethanol, heating and boiling, and separating the precipitate while hot, repeating until the precipitate is treated to neutrality, and then drying at 60° C. for 90 min to obtain a manganese-based precursor; 3) adding a manganese-based precursor to a 1.0 mol / L ammonium sulfate aqueous solution, the amount ratio of the manganese-based precursor to the ammonium persulfate aqueous solution is 1 g: 15 mL, performing a low-temperature hydrothermal reaction at 90° C. for 24 h, and then washing with deionized water and anhydrous ethanol in sequence until neutral to obtain a composite manganese-based carrier; 4) The composite manganese-based carrier is mixed with 2 wt% of phenolic resin powder by weight for the first granulation, and spherical particles coated with molecular sieve are obtained after granulation, and the particle size is controlled to be about 0.7 mm. Subsequently, a mixed powder of 3 wt% of the composite manganese-based carrier by weight is added to the spherical particles, and the mixed powder consists of sepiolite powder and gum arabic in a mass ratio of 1:0.75. The second granulation is carried out, and the particle size is controlled to be about 1.1 mm, so as to obtain a composite core-shell structure self-cleaning filler.

[0040] The filler prepared in this example was characterized in the same manner as in Example 1. The characterization results are shown in the following table.

[0041] The above characterization results show that the self-cleaning filler prepared in this example also has a good cleaning and purification effect.

[0042] Comparative Example 1 A self-cleaning filler is prepared by the following method: 1) preparing a 0.5 mol / L potassium permanganate aqueous solution, adjusting the pH value to pH=2 with dilute sulfuric acid, adding manganese sulfate and ascorbic acid at the same time, controlling the molar ratio of manganese sulfate, ascorbic acid and potassium permanganate to be 1.8:0.25:1, stirring at 75° C. for 5 h, cooling to room temperature for crystallization, and evaporating the solvent by plate rotary evaporation to obtain a dark brown intermediate; 2) washing the dark brown intermediate with deionized water and anhydrous ethanol until it becomes neutral to obtain a manganese-based carrier; 3) The manganese-based carrier is mixed with 2 wt% of phenolic resin powder by weight for the first granulation, and spherical particles coated with molecular sieve are obtained after granulation, and the particle size is controlled to be about 0.7 mm. Subsequently, a mixed powder of 3 wt% of the manganese-based carrier by weight is added to the spherical particles, and the mixed powder consists of sepiolite powder and gum arabic in a mass ratio of 1:0.75. The second granulation is carried out, and the particle size is controlled to be about 1.1 mm, so as to obtain a composite core-shell structure self-cleaning filler.

[0043] The filler prepared in this example was characterized in the same manner as in Example 1. The characterization results are shown in the following table.

[0044] The above characterization results show that in the dummy simulation experiment, the product of this example even shows better effects than Example 1, but in the real person simulation, the actual effect has a very significant decline. According to the subjective evaluation of the experimenters, the product of Example 1 feels drier after wearing, while the product of this example feels slightly stuffy after wearing, which also shows that the adsorption efficiency is different. It can be seen that the cleaning filler of the present invention can significantly optimize its anti-fouling ability and rapid adsorption ability through the coordination of the twin crystals, showing better performance.

[0045] Comparative Example 2 A self-cleaning filler is prepared by the following method: 1) preparing a 0.5 mol / L potassium permanganate aqueous solution, adjusting the pH value to pH=2 with dilute sulfuric acid, adding manganese sulfate at the same time, controlling the molar ratio of manganese sulfate to potassium permanganate to be 2.05:1, stirring at 75°C for 5 hours, cooling to room temperature for crystallization, and evaporating the solvent by plate rotary evaporation to obtain a dark brown intermediate; 2) placing the dark brown intermediate in anhydrous ethanol at a ratio of 1 g dark brown intermediate: 8 mL anhydrous ethanol, heating and boiling, and separating the precipitate while hot, repeating until the precipitate is treated to neutrality, and then drying at 60° C. for 90 min to obtain a manganese-based precursor; 3) adding a manganese-based precursor to a 1.0 mol / L ammonium sulfate aqueous solution, the amount ratio of the manganese-based precursor to the ammonium persulfate aqueous solution is 1 g: 15 mL, performing a low-temperature hydrothermal reaction at 90° C. for 24 h, and then washing with deionized water and anhydrous ethanol in sequence until neutral to obtain a composite manganese-based carrier; 4) The composite manganese-based carrier is mixed with 2 wt% of phenolic resin powder by weight for the first granulation, and spherical particles coated with molecular sieve are obtained after granulation, and the particle size is controlled to be about 0.7 mm. Subsequently, a mixed powder of 3 wt% of the composite manganese-based carrier by weight is added to the spherical particles, and the mixed powder consists of sepiolite powder and gum arabic in a mass ratio of 1:0.75. The second granulation is carried out, and the particle size is controlled to be about 1.1 mm, so as to obtain a composite core-shell structure self-cleaning filler.

[0046] The filler prepared in this example was characterized in the same manner as in Example 1. The characterization results are shown in the following table.

[0047] Although the above characterization results only show the dummy simulation data, the dummy simulation data shows a significant decrease compared with Example 1. This is mainly because in the construction process of the dark brown intermediate in this example, ascorbic acid was not used for crystal form control, which resulted in a decrease in the proportion of α crystal in the matrix and an increase in the proportion of the heterophase γ crystal, resulting in a decrease in its actual catalytic degradation ability.

[0048] Comparative Example 3 A self-cleaning filler is prepared by the following method: 1) preparing a 0.5 mol / L potassium permanganate aqueous solution, adjusting the pH value to pH=2 with dilute sulfuric acid, adding ascorbic acid at the same time, controlling the molar ratio of ascorbic acid to potassium permanganate to be 2.5:1, stirring at 75° C. for 5 h, cooling to room temperature for crystallization, and evaporating the solvent by plate rotary evaporation to obtain a dark brown intermediate; 2) placing the dark brown intermediate in anhydrous ethanol at a ratio of 1 g dark brown intermediate: 8 mL anhydrous ethanol, heating and boiling, and separating the precipitate while hot, repeating until the precipitate is treated to neutrality, and then drying at 60° C. for 90 min to obtain a manganese-based precursor; 3) adding a manganese-based precursor to a 1.0 mol / L ammonium sulfate aqueous solution, the amount ratio of the manganese-based precursor to the ammonium persulfate aqueous solution is 1 g: 15 mL, performing a low-temperature hydrothermal reaction at 90° C. for 24 h, and then washing with deionized water and anhydrous ethanol in sequence until neutral to obtain a composite manganese-based carrier; 4) The composite manganese-based carrier is mixed with 2 wt% of phenolic resin powder by weight for the first granulation, and spherical particles coated with molecular sieve are obtained after granulation, and the particle size is controlled to be about 0.7 mm. Subsequently, a mixed powder of 3 wt% of the composite manganese-based carrier by weight is added to the spherical particles, and the mixed powder consists of sepiolite powder and gum arabic in a mass ratio of 1:0.75. The second granulation is carried out, and the particle size is controlled to be about 1.1 mm, so as to obtain a composite core-shell structure self-cleaning filler.

[0049] The filler prepared in this example was characterized in the same manner as in Example 1. The characterization results are shown in the following table.

[0050] Although the above characterization results only show the dummy simulation data, from the dummy simulation data, a significant decrease is produced compared to Example 1. This is mainly because manganese sulfate is not used in this example and the dark brown intermediate actually has no manganese sulfate residue, and the actual step 2) process does not react effectively. In the case of adding only ascorbic acid, although ascorbic acid has the effect of crystal form regulation, the main product obtained is still α crystal form, but it is precisely because the secondary δ crystal form cannot be formed, resulting in a significant decrease in adsorption degradation efficiency. Compared to Comparative Example 1, although both do not effectively form a δ crystal secondary structure, only under the action of ascorbic acid, the main effect of actual ascorbic acid is converted from crystal form regulation to a reducing agent, and the obtained product is more heterogeneous than Comparative Example 1, so the actual performance result is slightly weaker than the product of Comparative Example 1. It can be seen that the crystal form regulation of manganese dioxide of the present invention is not a single manganese sulfate or ascorbic acid that can be achieved, but the two are achieved by cooperation.

Claims

1. A method for preparing a self-cleaning filler, characterized in that: The method comprises: 1) Prepare a permanganate aqueous solution, adjust the pH value to a strong acid, then slowly add a composite reducing agent, heat and stir to react, cool and crystallize, and evaporate to dryness to obtain a dark brown intermediate; 2) The dark brown intermediate is placed in an organic solvent and heated to a boil, and the precipitate is separated while hot, and the process is repeated until the precipitate is treated to be neutral, and then dried to obtain a manganese-based precursor; 3) adding a manganese-based precursor to an aqueous solution of ammonium persulfate, performing a low-temperature hydrothermal reaction, and washing with water and / or an organic solvent until the mixture is neutral to obtain a composite manganese-based carrier; 4) An organic binder and an organic / inorganic mixed powder are added to the composite manganese-based carrier in sequence, and granulation treatment is performed twice to obtain a composite core-shell structured self-cleaning filler.

2. The method for preparing a self-cleaning filler according to claim 1, characterized in that: Step 1) the permanganate concentration in the permanganate aqueous solution is 0.05-1.00 mol / L; Step 1) the composite reducing agent is composed of manganese sulfate and ascorbic acid; The molar ratio of manganese sulfate, ascorbic acid and permanganate is (1.6-1.8):(0.2-0.3):

1.

3. A method for preparing a self-cleaning filler according to claim 1 or 2, characterized in that: Step 1) wherein the pH value is adjusted to a strong acidity is to adjust the pH value to 1.5 to 2.5, and the pH value is controlled by adding dilute sulfuric acid during the adjustment process; The hot stirring reaction process in step 1) is to stir the reaction at 70-80°C for 3-6 hours.

4. The method for preparing a self-cleaning filler according to claim 1, characterized in that: Step 2) the organic solvent is anhydrous ethanol and / or anhydrous methanol; Step 2) The amount of the organic solvent used is 5-10 mL / g of dark brown intermediate.

5. The method for preparing a self-cleaning filler according to claim 1, characterized in that: Step 3) The concentration of the ammonium persulfate aqueous solution is 0.5-1.5 mol / L, and the amount thereof is 10-20 mL / g of the manganese-based precursor.

6. A method for preparing a self-cleaning filler according to claim 1 or 5, characterized in that: Step 3) The low-temperature hydrothermal reaction is carried out at a constant temperature of 85 to 105°C for 18 to 30 hours.

7. The method for preparing a self-cleaning filler according to claim 1, characterized in that: Step 4) the organic binder is a phenolic resin, and its amount is 1 to 3 wt% of the mass of the composite manganese-based carrier; Step 4) The organic / inorganic mixed powder is sepiolite powder and gum arabic, the mass ratio of sepiolite powder to gum arabic is 1:(0.6-0.8), and the amount of the organic / inorganic mixed powder is 1.5-5.0 wt% of the composite manganese-based carrier.

8. A self-cleaning filler obtained by the method according to any one of claims 1 to 7.

9. A self-cleaning filler according to claim 8, characterized in that: The self-cleaning filler is directly used for filling the interior of the helmet, and / or is embedded and foamed with an organic material and used as a foaming filler for filling the interior of the helmet.

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