Preparation method of seaweed fiber wallpaper

Abstract

This invention relates to a method for preparing seaweed fiber wallpaper, which modifies diatomaceous earth and then heat-presses it with a pore-forming agent, a PVC substrate, and a porous nonwoven fabric. Compared with existing products, the seaweed fiber wallpaper prepared by this process has the advantages of simple operation, low cost, and high efficiency in degrading indoor organic pollutants.

Description

Technical Field

[0001] This invention relates to a method for preparing seaweed fiber wallpaper, which modifies diatomaceous earth and then heat-presses it with a pore-forming agent, a PVC substrate, and a porous nonwoven fabric. This process has the advantages of simple operation, low cost, and high efficiency in degrading indoor organic pollutants. Background Technology

[0002] With the rapid development of science and technology and the continuous improvement of people's living standards, quality of life and health have become increasingly important concerns. Surveys show that modern people spend an average of 80% to 90% of their time indoors, and the quality of indoor air directly affects human health. In recent years, the sources and types of indoor air pollutants have been increasing, and indoor air pollution has attracted widespread attention and become a hot research topic.

[0003] The main sources of indoor air pollution are as follows: first, pollution from indoor decoration materials and furniture; second, pollution from the building itself; third, outdoor air pollution; and fourth, pollution from human activities, such as kitchen fumes and cigarette smoke, which contain a variety of pollutants. In addition, household cleaning agents, pesticides, and appliances also release organic substances, and poor indoor air quality can harm human health.

[0004] The advantage of using wallpaper for indoor air purification is that wallpaper has a large surface area in contact with the air, thus its air purification efficiency is significantly better than that of activated carbon with limited adsorption. At the same time, the targeted purification materials on the wallpaper surface can also decompose harmful gases. Diatomaceous earth, due to its special adsorption properties, has been widely used in wallpaper and paint. Diatomaceous earth wallpaper is an interior decorative wall material with diatomaceous earth as its main raw material. Using diatomaceous earth throughout a room provides functions such as eliminating formaldehyde, purifying the air, regulating humidity, releasing negative oxygen ions, fire resistance, self-cleaning walls, sterilization, and deodorization.

[0005] Seaweed fiber is a flame-retardant fiber. Studies on the combustion process of seaweed fiber have shown that the fiber residue has a high degree of carbonization, which effectively hinders the transfer of heat and causes the fiber to extinguish after leaving the flame. However, with increasingly stringent safety requirements, there is still room for improvement in its flame-retardant performance.

[0006] Titanium dioxide photocatalysts, as environmentally friendly materials capable of converting light energy into chemical energy at room temperature, have attracted widespread attention and great interest. In recent years, titanium dioxide photocatalysts have been widely used in various applications, including indoor air purification, antibacterial, and deodorizing materials; however, their degradation activity still does not meet the requirements for degradation activity. Summary of the Invention

[0007] In order to overcome the shortcomings of the prior art and further improve the overall performance of wallpaper, the present invention aims to provide a method for preparing seaweed fiber wallpaper, which uses diatomaceous earth to improve the wallpaper's adsorption performance for indoor pollutants and Mn-doped α-Fe2O3 to improve the wallpaper's degradation activity for indoor pollutants.

[0008] A method for preparing seaweed fiber wallpaper involves preparing a PVC substrate through extrusion foaming, pre-forming a slurry with modified diatomaceous earth containing Mn-containing seaweed fibers, a pore-forming agent, and water, then spraying the slurry onto the substrate surface and covering it with a layer of porous non-woven fabric. The substrate is then immersed in a roller press for hot pressing and bonding. The gas generated by the decomposition of the pore-forming agent prevents the pores of the diatomaceous earth from being sealed, thus obtaining the wallpaper. The specific preparation steps are as follows: (1) The raw materials PVC, coupling agent, stearic acid, plasticizer, wood flour, azodicarbonamide, foaming regulator and polyethylene wax are added to a high-speed mixer in a certain mass ratio for cold rolling, and then extruded in an extruder. A special flow channel structure for skin foaming board is adopted to make the material foam evenly during the extrusion process. Then it is immersed in a cooling and shaping system and a traction cutting system to obtain foamed PVC substrate. (2) Mix the modified diatomaceous earth containing Mn seaweed fiber and the pore-forming agent in a certain mass ratio, add an appropriate amount of deionized water, stir evenly, so that the pore-forming agent is loaded on the inner surface of the pores of the diatomaceous earth as much as possible to obtain a slurry. (3) The slurry obtained in step (2) is sprayed onto the surface of the PVC substrate in step (1) using a fully automatic spraying machine to form a uniform coating, and then covered with a layer of porous non-woven fabric. (4) The composite material obtained in step (3) is hot-pressed by a roller press. On the one hand, the PVC substrate is bonded to the non-woven fabric, and the diatomaceous earth loaded with sodium alginate is fixed between the two layers. On the other hand, the temperature rise causes the pore-forming agent to decompose and generate gas, which effectively prevents the micropores of diatomaceous earth from being closed during hot bonding and the active components from being covered, and finally wallpaper is obtained.

[0009] Diatomaceous earth contains no less than 85 wt% silica, 0.5-1 wt% iron oxide, and 3-5 wt% aluminum oxide, with a density of 2-2.2 g / cm³. 3 The bulk density is 0.4-0.6 g / cm³. 3 Specific surface area is 45-60m² 2 / g, pore volume is 0.5-0.8m³ 3 / g, water absorption rate is 200-400%.

[0010] The pore-forming agent is at least one of ammonium carbonate and ammonium bicarbonate, and its added mass is 3 to 5 wt% of the mass of the modified diatomaceous earth containing Mn seaweed fiber.

[0011] The coupling agent is at least one of KH550, KH570, KH560 or KH792; the plasticizer is at least one of dioctyl phthalate, benzyl phthalate, dibutyl phthalate, diethyl phthalate, dicyclohexyl phthalate or diisobutyl phthalate; and the foaming regulator is at least one of methyl methacrylate, ethyl acrylate or ethyl methacrylate.

[0012] The weight parts of each component in the raw materials mentioned in step (1) are as follows: PVC 72-85 parts, coupling agent 0.1-0.2 parts, stearic acid 0.1-0.2 parts, plasticizer 2-5 parts, wood flour 6-10 parts, azodicarbonamide 0.5-1.5 parts, foaming regulator 6-10 parts, and polyethylene wax 0.2-0.4 parts.

[0013] The stirring speed of the cold mixing in step (1) is 80-100 r / min, and the stirring time is 30-40 min.

[0014] The extruder in step (1) is a twin-screw extruder with a screw length-to-diameter ratio of 40:1 to 60:1; the cooling and shaping system adopts a pressure plate structure and is hydraulically controlled to ensure precise control of the thickness of the PVC substrate, which should be controlled to be 0.2 to 0.5 mm.

[0015] The fully automatic spraying machine described in step (3) is a pressure type, and the spray gun is round or fan-shaped.

[0016] The roller load of the roller press in step (4) is 15-25N, the inter-plate pressure is 80-120N, the number of rolling cycles is 2-4, and the hot pressing temperature is 100-120℃. The temperature should not be too high, as it can easily lead to carbonization of seaweed fibers.

[0017] The specific method for preparing diatomaceous earth containing Mn seaweed fibers is as follows: Wet spinning is the most common method for preparing seaweed fibers. The prepared spinning solution is extruded from the spinneret into a suitable liquid coagulation bath, and the thin stream solidifies into filaments to obtain solid fibers.

[0018] A spinning solution of a certain concentration, usually a 5% sodium alginate solution, is prepared. Impurities and insoluble small particles are removed by filtration, and small air bubbles are degassed. The spinning solution, after standing in a storage tank for 1 hour, is extruded under nitrogen pressure, passing through a metering pump and filter, and then solidified in a coagulation bath. When the coagulation bath is calcium chloride, the resulting solid alginate filament is calcium alginate fiber. Further processes such as washing, drawing, and setting are then performed to obtain the finished product.

[0019] The alginate fibers obtained above were soaked in a 1 mol / L HCl solution and shaken at room temperature for 6 hours to remove calcium and sodium ions and other metal ions from the fibers, thus obtaining seaweed fibers. The seaweed fibers were then soaked in manganese chloride (MnCl2) solutions of different concentrations and shaken at 50°C for 6 hours to remove transition metal Mn. 2+ Ions enter the alginate molecules through adsorption and chelate with the G segment to obtain Mn-containing seaweed fibers with different Mn contents. The suitable contents are 1-8 wt%, 2-6 wt%, and 3-4 wt% of the weight of the seaweed fiber.

[0020] 对含Mn海藻纤维的硅藻土进行改性的是Mn掺杂α-Fe2O3纳米粒子，其制备方法具体如下 : Prepare a 0.5M FeCl3 solution, a 5wt% MnCl2 solution, and a 0.1wt% hexyltrimethylammonium bromide solution. Stir each solution independently for 1 hour. Then, while continuously stirring, add the MnCl2 solution and the hexyltrimethylammonium bromide solution dropwise to the FeCl3 solution to obtain a mixed solution. Stir the mixed solution at room temperature for 4 hours, then slowly add an ammonia solution to produce a precipitate. Wash the precipitate 10 times with deionized water, then irradiate it with microwaves at a frequency of 2.41 GHz for 15 minutes. After grinding, calcine at 400℃ for 5 hours, and then grind again to obtain Mn-doped α-Fe2O3 nanoparticles. The suitable Mn doping amounts are 1-5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, and 4.5wt% of the α-Fe2O3 nanoparticles.

[0021] The specific method for preparing diatomaceous earth loaded with modified Mn-containing seaweed fibers is as follows: The aforementioned Mn-containing seaweed fiber was added to an appropriate amount of water, and a nonionic surfactant was added to disperse it evenly. Then, an appropriate amount of Mn-doped α-Fe2O3 nanoparticles were added to it, and the mixture was impregnated and loaded for 30 minutes. Then, it was washed 10 times with deionized water and vacuum dried at 50°C to obtain the modified Mn-containing seaweed fiber.

[0022] Diatomaceous earth is acid-washed to remove organic impurities, washed and dried with deionized water, and then added to an appropriate amount of deionized water. A nonionic surfactant is added and dispersed evenly. Modified Mn-containing seaweed fiber is then added and impregnated for 30 minutes, allowing the seaweed fiber to be loaded into the pores of the diatomaceous earth. This not only utilizes the adsorption properties of diatomaceous earth but also further improves the degradation efficiency of seaweed fiber for indoor pollutants.

[0023] Compared with the prior art, the present invention has the following advantages: 1. Loading with Mn ions can effectively inhibit the combustion of seaweed fibers and improve their flame retardant properties.

[0024] 2. Due to its special adsorption properties, diatomaceous earth is often used as an adsorption layer in wallpaper and paint. Ordinary diatomaceous earth wallpaper only has the function of adsorbing and purifying air, and its ability to degrade organic pollutants in the air is very weak. However, this invention introduces highly active components into the pores of diatomaceous earth, making full use of the adsorption properties of diatomaceous earth and the degradation activity of the active components loaded on the surface of its pores, so as to achieve efficient degradation of indoor pollutants.

[0025] 3. Compared with common photocatalytic active components such as TiO2 or simply modified TiO2, Mn-doped α-Fe2O3 nanoparticles have higher formaldehyde degradation activity, can purify the air in a shorter time, and protect human health.

[0026] 4. In the thermal bonding process, the gas generated by the decomposition of the pore-forming agent is used to prevent the pore structure of the diatomaceous earth loaded with active components from being blocked, so as to ensure that the diatomaceous earth has enough effective active surface to adsorb indoor pollutants, thereby further promoting the degradation effect of photocatalytic active components on pollutants. Detailed Implementation

[0027] The present invention will be further described below with reference to specific embodiments.

[0028] Example 1 The specific preparation method of seaweed fiber is as follows: A 5% sodium alginate solution was prepared, filtered to remove impurities and insoluble small particles, and defoamed to remove small air bubbles. The spinning solution, which had been standing in a storage tank for 1 hour, was extruded under nitrogen pressure, passing through a metering pump and a filter, and then solidified in a calcium chloride coagulation bath to form solid alginate filaments, which were then processed into calcium alginate fibers. These fibers were then washed, drawn, and set to obtain the finished product.

[0029] The specific preparation method of Mn-containing seaweed fiber is as follows: The alginate fibers obtained above were soaked in a 1 mol / L HCl solution and shaken at room temperature for 6 hours to remove calcium and sodium ions and other metal ions from the fibers, thus obtaining seaweed fibers. The seaweed fibers were then soaked in a manganese chloride (MnCl2) solution and shaken at 50°C for 6 hours to remove transition metal Mn. 2+ Ions enter the alginate molecules through adsorption and chelate with the G segment to obtain Mn-containing alginate fibers with an Mn content of 3% of the weight of the alginate fibers.

[0030] 3wt% Mn 掺杂α-Fe2O3纳米粒子的制备方法具体如下： Prepare a 0.5M FeCl3 solution, a 5wt% MnCl2 solution, and a 0.1wt% hexyltrimethylammonium bromide solution. Stir each solution independently for 1 hour. Then, while continuously stirring, add the MnCl2 solution and the hexyltrimethylammonium bromide solution dropwise to the FeCl3 solution to obtain a mixed solution. Stir the mixed solution at room temperature for 4 hours, then slowly add an ammonia solution to produce a precipitate. Wash the precipitate 10 times with deionized water, then irradiate it with microwaves at a frequency of 2.41 GHz for 15 minutes. After grinding, calcine at 400℃ for 5 hours, and then grind again to obtain Mn-doped α-Fe2O3 nanoparticles, where the Mn doping amount is 3wt% of the α-Fe2O3 nanoparticles.

[0031] The specific method for preparing diatomaceous earth loaded with modified Mn-containing seaweed fibers is as follows: The aforementioned Mn-containing seaweed fiber was added to an appropriate amount of water, and a nonionic surfactant was added to disperse it evenly. Then, the aforementioned Mn-doped α-Fe2O3 nanoparticles were added to it, and the mixture was impregnated and loaded for 30 minutes. Then, it was washed 10 times with deionized water and vacuum dried at 50°C to obtain the modified Mn-containing seaweed fiber.

[0032] Diatomaceous earth was acid-washed to remove organic impurities, washed and dried with deionized water, and then added to an appropriate amount of deionized water. A nonionic surfactant was added and dispersed evenly. Modified Mn-containing seaweed fiber was then added and impregnated for 30 minutes to obtain diatomaceous earth loaded with modified Mn-containing seaweed fiber at a mass of 15 wt%.

[0033] The specific preparation method of seaweed fiber wallpaper is as follows: (1) The raw materials PVC, KH550, stearic acid, dioctyl phthalate, wood flour, azodicarbonamide, methyl methacrylate and polyethylene wax are added to a high-speed mixer in a mass ratio of 80:0.2:0.1:3:8:1:8:0.2 for cold rolling. The stirring speed is 80-100 r / min and the stirring time is 30-40 min. Then, the mixture is extruded in an extruder. A special flow channel structure for skin foaming board is adopted to make the material foam evenly during the extrusion process. Then, it is immersed in a cooling and shaping system and a traction cutting system to obtain foamed PVC substrate. (2) Mix diatomaceous earth loaded with modified Mn seaweed fiber and ammonium carbonate at a mass ratio of 100:4.5, add an appropriate amount of deionized water, and stir evenly so that the pore-forming agent is loaded on the inner surface of the pores of the diatomaceous earth as much as possible to obtain a slurry. (3) The slurry obtained in step (2) is sprayed onto the surface of the PVC substrate in step (1) using a fully automatic spraying machine to form a uniform coating, and then covered with a layer of porous non-woven fabric. The composite material obtained in step (3) is hot-pressed by a roller press. The roller load of the roller press is 20N, the inter-plate pressure is 100N, the number of rolling cycles is 4, and the hot-pressing temperature is 100℃, finally obtaining seaweed fiber wallpaper.

[0034] Comparative Example 1 The limiting oxygen index (LOI) of the seaweed fiber prepared in Example 1 and the 3% Mn-containing seaweed fiber were tested. The LOI value of the seaweed fiber was 24.0, while the LOI value of the 3% Mn-containing seaweed fiber was 45. This shows that the loading of Mn ions can effectively inhibit the combustion of the fiber and improve the flame retardant performance of the seaweed fiber.

[0035] Comparative Example 2 The preparation method is the same as in Example 1, except that the components with photocatalytic degradation activity are the same amount of undoped α-Fe2O3 nanoparticles (sample A), Mn-doped TiO2 nanoparticles (sample B), and TiO2 nanoparticles (sample C), and the diatomaceous earth is replaced with a specific surface area of ​​12 m². 2 / g of silicon dioxide (the resulting sample is denoted as D).

[0036] Using formaldehyde as a representative indoor pollutant, the removal rate of seaweed fiber wallpapers from Example 1 and samples A, B, C, and D was measured as follows: After placing each wallpaper test piece into a Tedler bag, 100 ppm of formaldehyde was introduced into it, and the amount of residual formaldehyde in the bag was measured every 15 minutes under a fluorescent lamp for a total of 60 minutes. The relevant data are listed in Table 1.

[0037] Table 1 Formaldehyde content inside Tydele bags As can be seen from Table 1, compared with samples A, B, and C, the seaweed fiber wallpaper of the present invention has a significantly higher purification effect on formaldehyde, which fully demonstrates that Mn-doped α-Fe2O3 nanoparticles have the best photocatalytic degradation activity. Compared with sample D, the seaweed fiber wallpaper of the present invention also has a significantly higher purification efficiency for formaldehyde, which fully demonstrates that diatomaceous earth with high specific surface area, high adsorption performance, and rich pore structure can adsorb more formaldehyde, thereby further promoting the more efficient degradation of the photocatalytic active components loaded in its pores.

[0038] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing seaweed fiber wallpaper, characterized in that, PVC substrates are prepared by extrusion foaming. A slurry is pre-formed from diatomaceous earth loaded with modified Mn-containing seaweed fibers, a pore-forming agent, and water. This slurry is then sprayed onto the substrate surface and covered with a layer of porous nonwoven fabric. The substrate is then immersed in a roller press for hot pressing and bonding. The specific preparation steps are as follows: (1) The raw materials PVC, coupling agent, stearic acid, plasticizer, wood flour, azodicarbonamide, foaming regulator and polyethylene wax are added to a high-speed mixer in a certain mass ratio for cold rolling, and then extruded in an extruder. A special flow channel structure for skin foaming board is adopted to make the material foam evenly during the extrusion process. Then it is immersed in a cooling and shaping system and a traction cutting system to obtain foamed PVC substrate. (2) The modified diatomaceous earth containing Mn seaweed fiber loaded with porogen and the porogen are mixed in a certain mass ratio, and an appropriate amount of deionized water is added. The mixture is stirred evenly so that the porogen is loaded on the inner surface of the pores of the diatomaceous earth to obtain a slurry. (3) The slurry obtained in step (2) is sprayed onto the surface of the PVC substrate in step (1) using a fully automatic spraying machine to form a uniform coating, and then covered with a layer of porous non-woven fabric. (4) The composite material obtained in step (3) is hot-pressed by a roller press to finally obtain seaweed fiber wallpaper; a certain concentration of sodium alginate spinning solution is prepared, and impurities and insoluble small particles in the solution are removed by filtration, degassing, and the spinning solution that has been standing in the storage tank for 1 hour is extruded under nitrogen pressure, passing through a metering pump and filter, and solidified in a coagulation bath to form solid alginate filaments, which are calcium alginate fibers. After washing, stretching and setting processes, the finished product is obtained; the alginate fibers obtained above are soaked in 1 mol / L HCl solution and placed in a shaker to shake at room temperature for 6 hours to remove calcium and sodium ions from the fibers to obtain seaweed fibers. The seaweed fibers are soaked in manganese chloride solutions of different concentrations, placed in a shaker, and shaken at 50°C for 6 hours to remove transition metal Mn 2+ Ions enter the alginate molecules through adsorption and chelate with the G segment to obtain Mn-containing alginate fibers with a content of 1-8 wt% Mn; the diatomaceous earth contains no less than 85 wt% silica, 0.5-1 wt% iron oxide, and 3-5 wt% alumina, with a density of 2-2.2 g / cm³. 3 The bulk density is 0.4-0.6 g / cm³. 3 Specific surface area is 45-60m² 2 / g, pore volume is 0.5-0.8m³ 3 / g, water absorption rate 200-400%; Mn-containing seaweed fiber was added to an appropriate amount of water, and a nonionic surfactant was added to disperse it evenly. Then, an appropriate amount of Mn-doped α-Fe2O3 nanoparticles were added, and the mixture was impregnated and loaded for 30 minutes. After washing with deionized water 10 times, the mixture was vacuum dried at 50°C to obtain modified Mn-containing seaweed fiber. Diatomaceous earth was acid-washed to remove organic impurities. After washing with deionized water and drying, it was added to an appropriate amount of deionized water, and a nonionic surfactant was added to disperse it evenly. Then, modified Mn-containing seaweed fiber was added to it, and the mixture was impregnated and loaded for 30 minutes. Prepare a 0.5M FeCl3 solution, a 5wt% MnCl2 solution, and a 0.1wt% hexyltrimethylammonium bromide solution. Stir each of the three solutions independently for 1 hour. Then, while stirring continuously, add the MnCl2 solution and the hexyltrimethylammonium bromide solution dropwise to the FeCl3 solution to obtain a mixed solution. Stir the mixed solution at room temperature for 4 hours, then slowly add ammonia solution to produce a precipitate. Wash the precipitate 10 times with deionized water, then irradiate it with microwave at a frequency of 2.41 GHz for 15 minutes. After grinding, calcine at 400℃ for 5 hours, and then grind again to obtain Mn-doped α-Fe2O3 nanoparticles. The suitable Mn doping amount is 1-5wt% of the α-Fe2O3 nanoparticles.

2. The preparation method according to claim 1, characterized in that, The pore-forming agent is at least one of ammonium carbonate and ammonium bicarbonate, and its added mass is 3 to 5 wt% of the mass of the modified diatomaceous earth containing Mn seaweed fiber.

3. The preparation method according to claim 1, characterized in that, The roller load of the roller press in step (4) is 15-25N, the inter-plate pressure is 80-120N, the number of rolling cycles is 2-4, and the hot pressing temperature is 100-120℃.

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