An inorganic dissolvable fiberboard and a method of making the same

Abstract

The application provides an inorganic soluble fiber board and a preparation method thereof. The method comprises the following steps: S10: dispersing inorganic soluble fibers, a silica sol binder and an unsaturated silane coupling agent in water to graft unsaturated carbon-carbon bonds on the surfaces of the inorganic soluble fibers and the silica sol, so as to obtain a mixed solution; S20: adding an acrylamide monomer and a crosslinking agent to the mixed solution to flocculate through an initiation polymerization reaction, so as to obtain a slurry; and S30: wet vacuum forming the slurry, and drying to obtain the inorganic soluble fiber board. According to the application, the inorganic soluble fiber board has good moisture resistance and strength.

Description

Technical Field

[0001] This application relates to the field of fiberboard technology, specifically to an inorganic soluble fiberboard and its preparation method. Background Technology

[0002] Traditional ceramic fiber (alumina silicate refractory fiber) products are mainly composed of Al2O3 and SiO2. However, this type of ceramic fiber has a fatal flaw in its production and use in other insulation materials: because the diameter of the ceramic fibers is very small, mostly below 6μm; and because they are brittle, they are prone to breakage, generating fiber dust that is easily inhaled and can affect human health.

[0003] Inorganic soluble fiber is an alkaline earth silicate fiber with SiO2, MgO, and CaO as its main components. Because it has a certain degree of solubility in human body fluids, it reduces potential harm to human health, allowing it to remain in the body for a short time and thus minimizing any potential harm. Therefore, it is called inorganic soluble fiber. Consequently, inorganic soluble fiberboard, made from inorganic soluble fibers, holds promise for replacing inorganic ceramic fiberboard in some fields and represents an important development direction in this area.

[0004] Currently, there are numerous technologies for preparing soluble fiberboard. For example, patent CN1544373A provides an inorganic silicate fiberboard soluble in human body fluids and its manufacturing method. The main components of this fiberboard, by weight percentage, are: 70-85% soluble fiber, 12-25% inorganic binder, and 3-5% organic binder. The manufacturing method uses soluble fiber as the main material, adds inorganic and organic binders, and processes it through sheet forming, vacuum filtration or pressure filtration, followed by drying and post-processing. This type of board can minimize the harm to the human body during manufacturing, transportation, cutting, installation, and use.

[0005] Patent CN107986768A discloses a soluble fiber that extensively utilizes K2O, which has a low melting point. When K2O with a low melting point is co-melted with other components of the invention in a specific ratio, the resulting soluble fiber exhibits an effectively increased service temperature. This soluble fiber possesses superior high-temperature mechanical properties without compromising its solubility. When the obtained soluble fiber is applied to soluble fiberboard, the resulting soluble fiberboard exhibits a high service temperature and superior high-temperature mechanical properties, while its solubility remains unaffected.

[0006] The inventors noted that inorganic soluble fibers generally have a higher silica content than ceramic fibers and are typically glassy fibers, which have stronger hygroscopicity. This may weaken the bond between the fibers and the binder in the inorganic soluble fiberboard. Additionally, water can dissolve the alkali metal oxides in the inorganic soluble fibers, leading to a decrease in the strength of the inorganic soluble fiberboard.

[0007] Therefore, there is a need to provide an inorganic soluble fiberboard that is moisture-resistant and has high strength. Summary of the Invention

[0008] This application provides an inorganic soluble fiberboard and its preparation method, which has good moisture resistance and strength.

[0009] In a first aspect, this application provides a method for preparing inorganic soluble fiberboard, comprising the following steps: S10: Disperse inorganic soluble fibers, silica sol binder and unsaturated silane coupling agent in water, so that unsaturated carbon-carbon bonds are grafted onto the surfaces of inorganic soluble fibers and silica sol to obtain a mixture; S20: Add acrylamide monomers and crosslinking agents to the mixture to initiate a polymerization reaction and flocculate, thereby obtaining a slurry; S30: The slurry is wet-vacuum formed and dried to obtain an inorganic soluble fiberboard.

[0010] According to this application, by treating the surface of inorganic soluble fibers and silica sol with an unsaturated silane coupling agent, the hygroscopicity can be reduced by decreasing the content of silanol groups on the surface. On the other hand, the grafted unsaturated double bonds can participate in the cross-linking polymerization reaction of acrylamide monomers, thereby significantly improving the bonding strength of each component in the inorganic soluble fiberboard. The in-situ cross-linking polymerization can also inhibit the floating of the binder during the drying process, thus obtaining a uniform and dense inorganic soluble fiberboard. This gives the inorganic soluble fiberboard high strength, and the structure can also inhibit the diffusion of moisture into the fiberboard, further improving its moisture resistance.

[0011] In some embodiments, the inorganic soluble fiber is an inorganic alkaline earth silicate fiber, and the length of the inorganic soluble fiber is 0.1~10mm.

[0012] In some embodiments, S10 specifically includes: dispersing 10 parts by mass of inorganic soluble fiber, 1-5 parts by mass of silica sol binder with a solid content of 20wt%-40wt%, and 0.1-3 parts by mass of unsaturated silane coupling agent in 50-200 parts by mass of acidic aqueous solution with pH=2-5, so that unsaturated carbon-carbon bonds are grafted onto the surfaces of inorganic soluble fiber and silica sol to obtain a mixture.

[0013] In some embodiments, the acrylamide monomer includes at least one of acrylamide and methacrylamide.

[0014] In some embodiments, the crosslinking agent includes N,N'-methylenebisacrylamide and modified graphene oxide, the modified graphene oxide being obtained by modifying graphene oxide with an unsaturated silane coupling agent and a fluorinated silane coupling agent.

[0015] In some embodiments, the crosslinking agent is a mixture of N,N'-methylenebisacrylamide and modified graphene oxide in a mass ratio of 1:3 to 6.

[0016] In some embodiments, the modified graphene oxide is prepared by the following method: 10 parts by mass of graphene oxide are dispersed in 200-500 parts by mass of ethanol, ultrasonically dispersed, and then 5-10 parts by mass of vinyltrimethoxysilane and 1-5 parts by mass of (3,3,3,-trifluoropropyl)methyldimethoxysilane are added, and the mixture is heated to react and obtain the modified graphene oxide.

[0017] In some embodiments, the mass ratio of the inorganic soluble fiber to the acrylamide monomer is 1:0.05~0.1; and the mass ratio of the acrylamide monomer to the crosslinking agent is 1:0.01~0.2.

[0018] In some embodiments, step S30, the wet vacuum forming specifically includes: using a vacuum degree of 0.03~0.06MPa for filtration, and using a pressure roller for pressing, with a pressing pressure of 0.05~0.1MPa.

[0019] Secondly, this application provides an inorganic soluble fiberboard prepared according to the method described in any embodiment of the first aspect. Detailed Implementation

[0020] The various embodiments or implementation schemes in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments.

[0021] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0023] As described in the background section above, the inventors discovered that although inorganic soluble fiberboard has better safety than ordinary ceramic fiberboard, it has strong hygroscopicity, and the strength of inorganic soluble fiberboard decreases when it comes into contact with water. Therefore, there is a need to provide an inorganic soluble fiberboard with good moisture resistance and strength.

[0024] In related technologies, fibers are generally modified to reduce their hygroscopicity by hydrophobic modification. However, this has two problems: firstly, the adhesion to most existing adhesives is reduced after hydrophobic modification; secondly, the current process for preparing high-density fiberboard is generally wet molding, and its main dispersion system is water. Hydrophobic modified fibers have problems in traditional preparation processes.

[0025] Based on this, the inventors realized that the hygroscopicity of inorganic soluble fibers mainly originates from the silanol groups on their surface. Positively charged hydrogen ions in water molecules will bond with them, and the hydroxide ions generated after the water molecules are polarized will continue to adsorb water molecules, thus exhibiting high hygroscopicity. Therefore, bonding with the silanol groups on the surface can effectively reduce its hygroscopicity. Simultaneously, by improving the internal structure of the inorganic soluble fiberboard, the diffusion of moisture within the fiberboard can be inhibited, reducing its impact on the inorganic soluble fibers. Therefore, this application provides an inorganic soluble fiberboard and its preparation method. This inorganic soluble fiberboard has good moisture resistance and strength. The specific embodiments of this application are described in detail below.

[0026] In a first aspect, this application provides a method for preparing inorganic soluble fiberboard, comprising the following steps: S10: Disperse inorganic soluble fibers, silica sol binder and unsaturated silane coupling agent in water, so that unsaturated carbon-carbon bonds are grafted onto the surfaces of inorganic soluble fibers and silica sol to obtain a mixture; S20: Add acrylamide monomers and crosslinking agents to the mixture to initiate a polymerization reaction and flocculate, thus obtaining a slurry; S30: The slurry is wet-vacuum formed and dried to obtain an inorganic soluble fiberboard.

[0027] According to this application, by treating the surface of inorganic soluble fibers and silica sol with an unsaturated silane coupling agent, the hygroscopicity can be reduced by decreasing the content of silanol groups on the surface. On the other hand, the grafted unsaturated double bonds can participate in the cross-linking polymerization reaction of acrylamide monomers, thereby significantly improving the bonding strength of each component in the inorganic soluble fiberboard. The in-situ cross-linking polymerization can also inhibit the floating of the binder during the drying process, thus obtaining a uniform and dense inorganic soluble fiberboard. This gives the inorganic soluble fiberboard high strength, and the structure can also inhibit the diffusion of moisture into the fiberboard, further improving its moisture resistance.

[0028] Specifically, in step S10, since the silica surface in the inorganic soluble fibers and silica sol contains silanol groups, the siloxane groups in the unsaturated silane coupling agent undergo hydrolysis and dehydrate to bond with the silanol groups on its surface. This allows the unsaturated silane coupling agent to be grafted onto the silica surface in the inorganic soluble fibers and silica sol. On the one hand, this reduces water absorption by binding to the silanol groups on its surface; on the other hand, the unsaturated carbon-carbon bonds on the surface give it good reactivity. It should be noted that "unsaturated silane coupling agent" has a meaning known in the art; an unsaturated silane coupling agent is a silane coupling agent containing unsaturated carbon-carbon bonds. As an example, the unsaturated silane coupling agent can be vinyltrimethoxysilane.

[0029] In step S20, acrylamide monomers and crosslinking agents are added to the mixture to initiate polymerization and flocculation. Since both the inorganic soluble fibers in the mixture and the silica sol have unsaturated carbon-carbon bonds on their surfaces, in-situ polymerization can occur. The use of acrylamide monomers as a binder is advantageous because the inorganic soluble fibers and silica sol surfaces contain unreacted silanol groups, which are negatively charged, while the acrylamide monomers are positively charged due to the presence of amide groups. Electrostatic interactions facilitate their bonding and polymerization. The advantages of in-situ polymerization flocculation are as follows: Unlike general binders that mainly bind through intermolecular forces and electrostatic interactions, the components of this application are mainly bonded together by covalent bonds. Since intermolecular forces (such as hydrogen bonds) and electrostatic forces are easily affected by moisture, fiberboard generally suffers from reduced adhesion and strength due to moisture absorption. Therefore, this application can effectively suppress the influence of moisture on the bonding force between the components. On the other hand, the slurry obtained by in-situ polymerization flocculation has strong interactions between the components. During the subsequent drying process, the binder is less likely to float, thus obtaining a uniform and dense inorganic soluble fiberboard. This effectively suppresses the diffusion of moisture in the fiberboard. Therefore, from the above aspects, the inorganic soluble fiberboard has good moisture resistance and strength.

[0030] In step S30, wet vacuum forming is used, which helps to increase the density of the wet blank after forming, thereby increasing the density of the inorganic soluble fiberboard and enabling the inorganic soluble fiberboard to have good moisture resistance and strength.

[0031] In some embodiments, the inorganic soluble fiber is an inorganic alkaline earth silicate fiber, and the length of the inorganic soluble fiber is 0.1~10mm.

[0032] In some of the above embodiments, the inorganic soluble fiber is an inorganic alkaline earth silicate fiber with SiO2, MgO and CaO as the main components, which has strong in vitro solubility. Using the above fiber can make the inorganic soluble fiber have better biological safety. As an example, the inorganic soluble fiber used in this application is Insulfrax® soluble fiber cotton purchased from Suzhou Gaowei Thermal Energy Technology Co., Ltd.

[0033] Meanwhile, the length of the inorganic soluble fiber is limited to 0.1~10mm. Shorter inorganic soluble fibers are beneficial to further increase the density of the inorganic soluble fiberboard, thereby further improving the moisture resistance and strength of the inorganic soluble fiber.

[0034] In some embodiments, S10 specifically includes: dispersing 10 parts by mass of inorganic soluble fiber, 1 to 5 parts by mass of silica sol binder with a solid content of 20 wt% to 40 wt%, and 0.1 to 3 parts by mass of unsaturated silane coupling agent in 50 to 200 parts by mass of acidic aqueous solution with pH=2 to 5, so that unsaturated carbon-carbon bonds are grafted onto the surfaces of inorganic soluble fiber and silica sol to obtain a mixture.

[0035] In some of the above embodiments, the specific mass fractions of each raw material and the specific conditions for silane grafting are defined. In an acidic aqueous solution, the unsaturated silane coupling agent can be better grafted onto the surface of silica in inorganic soluble fibers and silica sol. Under these conditions, the inorganic soluble fiberboard obtained has better moisture resistance and strength. It is understood that the silica sol binder is a water-dispersed silica sol. As an example, this application uses a silica sol binder with a solid content of 30 wt% and a silica particle size of 10-15 nm.

[0036] In some embodiments, the acrylamide monomers include at least one of acrylamide and methacrylamide. These acrylamide monomers have good water solubility, are more prone to cross-linking polymerization in slurry, and exhibit good reactivity with inorganic soluble fibers grafted with unsaturated carbon-carbon bonds and silica in silica sol, resulting in better bonding performance and further improving the moisture resistance and strength of inorganic soluble fiberboard.

[0037] In some embodiments, the crosslinking agent includes N,N'-methylenebisacrylamide and modified graphene oxide, which is obtained by modifying graphene oxide with an unsaturated silane coupling agent and a fluorinated silane coupling agent.

[0038] In some of the above embodiments, the crosslinking agent includes N,N'-methylenebisacrylamide and modified graphene oxide. The main function of N,N'-methylenebisacrylamide is to increase the crosslinking sites of the polymer, thereby increasing the degree of crosslinking. The modified graphene oxide is obtained by modifying graphene oxide with unsaturated silane coupling agents and fluorinated silane coupling agents. Therefore, unsaturated bonds and fluorinated segments are grafted onto the modified graphene oxide. The unsaturated bonds can react with acrylamide monomers and be grafted onto the crosslinked polymer. Because the modified graphene oxide is a two-dimensional structure, it has a large... The larger specific surface area results in greater steric hindrance in the slurry system, making it less likely for the cross-linked polymer to float during subsequent drying. Furthermore, its two-dimensional structure further inhibits moisture diffusion within the inorganic soluble fiberboard, enhancing its moisture resistance. Additionally, the fluorine atoms in the fluorinated segments of the modified graphene oxide exhibit strong interactions with both the inorganic soluble fiber and the silica sol, further strengthening the interactions between the components. The low surface energy of the fluorinated segments also improves the moisture resistance of the inorganic soluble fiberboard, thereby further enhancing its moisture resistance and strength.

[0039] It should be noted that fluorinated silane coupling agents have the meaning known in the art. As an example, a fluorinated silane coupling agent can be (3,3,3,-trifluoropropyl)methyldimethoxysilane.

[0040] In some embodiments, the crosslinking agent is a mixture of N,N'-methylenebisacrylamide and modified graphene oxide in a mass ratio of 1:3 to 6. In this case, the inorganic soluble fiberboard exhibits better moisture resistance and strength.

[0041] In some embodiments, modified graphene oxide is prepared by the following method: 10 parts by mass of graphene oxide are dispersed in 200-500 parts by mass of ethanol, ultrasonically dispersed, and then 5-10 parts by mass of vinyltrimethoxysilane and 1-5 parts by mass of (3,3,3,-trifluoropropyl)methyldimethoxysilane are added, followed by heating to react and obtain modified graphene oxide. The modified graphene oxide obtained in this way can further improve the interaction between the components of the inorganic soluble fiberboard, and can better suppress the floating of the binder during the drying process, resulting in a more uniform and dense inorganic soluble fiberboard. It also further suppresses the diffusion of moisture in the inorganic soluble fiberboard, giving the inorganic soluble fiberboard better moisture resistance and strength.

[0042] In some embodiments, the mass ratio of inorganic soluble fiber to acrylamide monomer is 1:0.05~0.1; the mass ratio of acrylamide monomer to crosslinking agent is 1:0.01~0.2. In this case, the crosslinked polymer obtained by crosslinking polymerization can effectively bond the components, and the binder is less likely to float during the drying process of the resulting wet preform, further making the inorganic soluble fiberboard more uniform and dense, thereby further improving the moisture resistance and strength of the inorganic soluble fiberboard.

[0043] In some embodiments, flocculation by initiating a polymerization reaction specifically includes: adding an initiator, and initiating a polymerization reaction at 50-70°C for 3-8 hours, with the mass ratio of acrylamide monomer to crosslinking agent being 1:0.01-0.05. Initiators include, but are not limited to, ammonium persulfate, potassium persulfate, etc.

[0044] In some embodiments, step S30, wet vacuum forming specifically includes: using a vacuum degree of 0.03~0.06MPa for filtration, and using a pressure roller for pressing, with a pressing pressure of 0.05~0.1MPa.

[0045] In some of the above embodiments, vacuum filtration and roller pressing under the above conditions can further increase the density of inorganic soluble fiberboard, thereby further improving the moisture resistance and strength of inorganic soluble fiberboard.

[0046] In some embodiments, the drying conditions are drying at 100~150°C for 5~12 hours.

[0047] It should also be noted that the unsaturated silane coupling agents used in this application for modifying graphene oxide and inorganic soluble fibers may be the same or different; preferably, they are the same unsaturated silane coupling agent.

[0048] Secondly, this application provides an inorganic soluble fiberboard prepared according to the method described in any embodiment of the first aspect.

[0049] According to this application, since the inorganic soluble fiberboard is prepared according to the method of any embodiment of the first aspect, it has the beneficial effects of the first aspect. The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0050] Inorganic soluble fiber: The raw material is Insulfrax® soluble fiber cotton purchased from Suzhou Gaowei Thermal Energy Technology Co., Ltd. The soluble fiber cotton is dispersed in water and chopped using a ceramic fiber chopped short machine. It is then screened and washed with a filter screen with a mesh size of 5mm to obtain inorganic soluble fiber for later use.

[0051] The silica sol was purchased from Shandong Baite New Materials Co., Ltd., model SS3015, with a particle size of 10~15nm and a silica content of 30%±1%.

[0052] The graphene oxide was purchased from Shanghai Maclean Biotechnology Co., Ltd., with a purity >98.5%, an oxygen content of approximately 35%, a thickness of 0.6~1.2nm, and a length of 0.8~2μm. Example

[0053] Preparation of inorganic soluble fiberboard: 300g of inorganic soluble fiber was dispersed in 3000g of water. After uniform dispersion, 90g of 30wt% silica sol binder and 35g of vinyltrimethoxysilane were added to obtain a mixture. The pH of the mixture was adjusted to 3 using hydrochloric acid and stirred for 12h. Then, 20g of acrylamide, 0.5g of N,N'-methylenebisacrylamide, 2g of modified graphene oxide, and 1g of ammonium persulfate were added, and the mixture was reacted at 60℃ for 7h to obtain a slurry.

[0054] The filter was subjected to vacuum filtration at a pressure of 0.05 MPa and then pressed with a pressure roller at a pressure of 0.05 MPa to obtain a wet blank. The blank was then dried at 105°C for 8 hours to obtain an inorganic soluble fiberboard.

[0055] Modified graphene oxide was prepared by the following method: 10g of graphene oxide was dispersed in 400g of ethanol and ultrasonically dispersed. Then, 7g of vinyltrimethoxysilane and 3g of (3,3,3,-trifluoropropyl)methyldimethoxysilane were added. The mixture was heated to 50℃ and stirred for 24h. After the reaction was completed, the mixture was centrifuged to remove the supernatant. The precipitate was dried at 70℃ for 24h to obtain modified graphene oxide for later use. Example

[0056] Preparation of inorganic soluble fiberboard: 300g of inorganic soluble fiber was dispersed in 3000g of water. After the dispersion was uniform, 90g of 30wt% silica sol binder and 35g of vinyltrimethoxysilane were added to obtain a mixture. The pH of the mixture was adjusted to 3 using hydrochloric acid and stirred for 12h. Then, 20g of acrylamide, 2.5g of modified graphene oxide and 1g of ammonium persulfate were added and reacted at 60℃ for 7h to obtain a slurry.

[0057] The filter was subjected to vacuum filtration at a pressure of 0.05 MPa and then pressed with a pressure roller at a pressure of 0.05 MPa to obtain a wet blank. The blank was then dried at 105°C for 8 hours to obtain an inorganic soluble fiberboard.

[0058] Modified graphene oxide was prepared by the following method: 10g of graphene oxide was dispersed in 400g of ethanol and ultrasonically dispersed. Then, 7g of vinyltrimethoxysilane and 3g of (3,3,3,-trifluoropropyl)methyldimethoxysilane were added. The mixture was heated to 50℃ and stirred for 24h. After the reaction was completed, the mixture was centrifuged to remove the supernatant. The precipitate was dried at 70℃ for 24h to obtain modified graphene oxide for later use. Example

[0059] Preparation of inorganic soluble fiberboard: 300g of inorganic soluble fiber was dispersed in 3000g of water. After the dispersion was uniform, 90g of 30wt% silica sol binder and 35g of vinyltrimethoxysilane were added to obtain a mixture. The pH of the mixture was adjusted to 3 using hydrochloric acid and stirred for 12h. Then, 20g of acrylamide, 2.5g of N,N'-methylenebisacrylamide and 1g of ammonium persulfate were added and reacted at 60℃ for 7h to obtain a slurry.

[0060] The filter was subjected to vacuum filtration at a pressure of 0.05 MPa and then pressed with a pressure roller at a pressure of 0.05 MPa to obtain a wet blank. The blank was then dried at 105°C for 8 hours to obtain an inorganic soluble fiberboard. Example

[0061] Preparation of inorganic soluble fiberboard: 300g of inorganic soluble fiber was dispersed in 3000g of water. After uniform dispersion, 90g of 30wt% silica sol binder and 35g of vinyltrimethoxysilane were added to obtain a mixture. The pH of the mixture was adjusted to 3 using hydrochloric acid and stirred for 12h. Then, 20g of acrylamide, 0.5g of N,N'-methylenebisacrylamide, 2g of modified graphene oxide, and 1g of ammonium persulfate were added, and the mixture was reacted at 60℃ for 7h to obtain a slurry.

[0062] The filter was subjected to vacuum filtration at a pressure of 0.05 MPa and then pressed with a pressure roller at a pressure of 0.05 MPa to obtain a wet blank. The blank was then dried at 105°C for 8 hours to obtain an inorganic soluble fiberboard.

[0063] Modified graphene oxide was prepared by the following method: 10g of graphene oxide was dispersed in 400g of ethanol and ultrasonically dispersed. Then, 7g of vinyltrimethoxysilane was added, and the mixture was heated to 50℃ and stirred for 24h. After the reaction was completed, the mixture was centrifuged to remove the supernatant. The precipitate was dried at 70℃ for 24h to obtain modified graphene oxide for later use. Comparative Example 1 Preparation of inorganic soluble fiberboard: 300g of inorganic soluble fiber was dispersed in 3000g of water. After the dispersion was uniform, 90g of 30wt% silica sol binder and 35g of vinyltrimethoxysilane were added to obtain a mixture. The pH of the mixture was adjusted to 3 using hydrochloric acid and stirred for 12 hours. Then 20g of polyacrylamide was added, and the mixture was flocculated and precipitated to obtain a slurry.

[0064] The filter was subjected to vacuum filtration at a pressure of 0.05 MPa and then pressed with a pressure roller at a pressure of 0.05 MPa to obtain a wet blank. The blank was then dried at 105°C for 8 hours to obtain an inorganic soluble fiberboard. Comparative Example 2 Preparation of inorganic soluble fiberboard: 300g of inorganic soluble fiber was dispersed in 3000g of water. After the dispersion was uniform, 90g of 30wt% silica sol binder was added to obtain a mixture. Then, 20g of polyacrylamide was added, and the mixture was flocculated and precipitated to obtain a slurry.

[0065] The filter was subjected to vacuum filtration at a pressure of 0.05 MPa and then pressed with a pressure roller at a pressure of 0.05 MPa to obtain a wet blank. The blank was then dried at 105°C for 8 hours to obtain an inorganic soluble fiberboard. The inorganic soluble fiberboards obtained in Examples 1-4 and Comparative Examples 1 and 2 were tested for flexural strength according to GB / T 3001-2017. The inorganic soluble fiberboards were then placed in an insulated chamber at 80°C and 100% relative humidity for 48 hours, removed, cooled to room temperature, and then tested for flexural strength again. The strength difference before and after insulation was calculated, and the results are shown in Table 1.

[0066] Table 1

[0067] According to Table 1, the inorganic soluble fiberboards obtained in each embodiment of this application exhibit better moisture resistance and strength than the comparative examples, indicating that the uniform and dense inorganic soluble fiberboards prepared by the method of this application possess excellent moisture resistance and strength. It should be noted that, to verify the moisture resistance of the inorganic soluble fiberboard of this application, accelerated moisture absorption simulation was conducted in an oven with high temperature and high humidity. The strength difference before and after heat preservation was calculated to evaluate the moisture resistance of the inorganic soluble fiberboard. Comparative Example 1 had the worst strength, but its moisture resistance was better than that of Comparative Example 2. This may be because the treatment of the inorganic soluble fiber and silica sol with an unsaturated silane coupling agent can improve its hydrophobicity and thus its moisture resistance, but its adhesion to the binder is poor, resulting in lower strength under normal conditions. Comparative Example 2 had the worst moisture resistance, which may be because its strong hygroscopicity reduces the interaction force between the inorganic soluble fiber and the binder, and the strength of the inorganic soluble fiber itself also decreases. Therefore, its flexural strength after insulation is significantly reduced, resulting in poor moisture resistance.

[0068] According to Examples 1-4, the inorganic soluble fiberboard obtained in Example 1 has the best moisture resistance and strength. This may be because: in Example 2, only modified graphene oxide was used as a crosslinking agent, which may result in fewer crosslinking sites and a lower crosslinking density, thus its moisture resistance and strength are not as good as in Example 1; in Example 3, only N,N'-methylenebisacrylamide was used as a crosslinking agent, which can provide more crosslinking sites, but it does not have the effect of modified graphene oxide in inhibiting the diffusion of moisture in the fiberboard and in-situ strengthening the fiberboard, thus its moisture resistance and strength are not as good as in Example 1; in Example 4, only unsaturated bonds were used for grafting in the modified graphene oxide, which reduces the interaction force between the components compared to Example 1, and the fluorinated segments in Example 1 can further reduce the diffusion of moisture in the fiberboard, so its moisture resistance and strength are not as good as in Example 1. However, since modified graphene oxide has the effect of inhibiting the diffusion of moisture in the fiberboard and in-situ strengthening the fiberboard, its moisture resistance and strength are better than in Examples 2 and 3. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for preparing inorganic soluble fiberboard, characterized in that, Includes the following steps: S10: Disperse 10 parts by mass of inorganic soluble fiber, 1-5 parts by mass of silica sol binder with a solid content of 20wt%-40wt% and 0.1-3 parts by mass of unsaturated silane coupling agent in 50-200 parts by mass of acidic aqueous solution with pH=2-5, so that unsaturated carbon-carbon bonds are grafted onto the surface of inorganic soluble fiber and silica sol to obtain a mixture; S20: Add acrylamide monomers and crosslinking agents to the mixture, and flocculate by initiating a polymerization reaction to obtain a slurry; the crosslinking agent is a mixture of N,N'-methylenebisacrylamide and modified graphene oxide in a mass ratio of 1:3~6, and the modified graphene oxide is obtained by modifying graphene oxide with unsaturated silane coupling agents and fluorinated silane coupling agents. S30: The slurry is wet-vacuum formed and dried to obtain an inorganic soluble fiberboard.

2. The method according to claim 1, characterized in that, The inorganic soluble fiber is an inorganic alkaline earth silicate fiber, and the length of the inorganic soluble fiber is 0.1~10mm.

3. The method according to claim 1, characterized in that, The acrylamide monomers include at least one of acrylamide and methacrylamide.

4. The method according to claim 1, characterized in that, The modified graphene oxide was prepared by the following method: Ten parts by mass of graphene oxide were dispersed in 200-500 parts by mass of ethanol and ultrasonically dispersed. Then, 5-10 parts by mass of vinyltrimethoxysilane and 1-5 parts by mass of (3,3,3-trifluoropropyl)methyldimethoxysilane were added and heated to react to obtain modified graphene oxide.

5. The method according to any one of claims 1 to 4, characterized in that, The mass ratio of the inorganic soluble fiber to the acrylamide monomer is 1:0.05~0.1; the mass ratio of the acrylamide monomer to the crosslinking agent is 1:0.01~0.

2.

6. The method according to claim 5, characterized in that, In step S30, the wet vacuum forming specifically includes: using a vacuum degree of 0.03~0.06MPa for filtration, and using a pressure roller for pressing, with a pressing pressure of 0.05~0.1MPa.

7. An inorganic soluble fiberboard, characterized in that, Prepared according to the method according to any one of claims 1 to 6.

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