Moisture-proof durable calcium silicate board and preparation method thereof

Abstract

The application relates to the technical field of building materials, in particular to a moisture-proof durable calcium silicate board and a preparation method thereof. The calcium silicate board is composed of diatomite, quicklime, silicate cement, alkali-resistant glass fiber, modified montmorillonite and deionized water. The modified montmorillonite is obtained by ion exchange intercalation of sodium-based montmorillonite with sodium 4-styrene sulfonate, and then free radical polymerization grafting of sodium 4-styrene sulfonate, a silane coupling agent and a fluorine-containing monomer. The introduction of the modified montmorillonite effectively improves the microstructure of the calcium silicate board, and enhances the compactness and water resistance of the calcium silicate board. The calcium silicate board exhibits excellent bending strength, moisture-proof performance and durability in a long-term humid environment, and has important practical application value and popularization significance.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, and in particular to a moisture-proof and durable calcium silicate board and its preparation method. Background Technology

[0002] Calcium silicate board, as an important building material, is widely used in interior and exterior walls, ceilings, and partitions due to its excellent fire resistance, heat insulation, and mechanical properties. Calcium silicate board possesses advantages such as lightweight, high strength, fire resistance, heat insulation, and sound insulation, while also exhibiting good environmental performance, thus gaining widespread recognition and promotion in modern construction. However, with the construction industry's increasingly stringent requirements for material performance, some problems have emerged in the practical application of calcium silicate board, particularly its performance in high humidity or long-term damp environments, becoming a significant factor limiting its application scope.

[0003] Traditional calcium silicate boards are prone to problems such as strength degradation, high water absorption, and poor dimensional stability in humid environments. This is mainly determined by the internal microstructure characteristics of calcium silicate boards. The main components of calcium silicate boards are siliceous materials (such as quartz powder and silica fume) and calcareous materials (such as lime and cement), which generate hydration products such as tobermorite through hydration reactions. These hydration products form a porous microstructure inside the material. Although this structure gives calcium silicate boards good thermal insulation properties, it also leads to high water absorption, especially in humid environments, where moisture easily seeps into the material through the pores, causing a series of problems.

[0004] First, moisture penetration can cause further hydration reactions or dissolution of the hydration products inside the calcium silicate board, damaging the material's microstructure and reducing its mechanical strength. Second, the dimensional stability of the material is affected after water absorption, potentially leading to expansion and warping, thus impacting its lifespan. Furthermore, prolonged exposure to damp environments can cause mold growth on the surface of the calcium silicate board, further reducing its performance and aesthetics. Therefore, improving the durability and moisture resistance of calcium silicate boards in humid environments has become an important research and application topic. Summary of the Invention

[0005] In view of this, the purpose of this invention is to propose a moisture-proof and durable calcium silicate board and its preparation method, so as to solve the problems of existing calcium silicate boards being prone to strength reduction and high water absorption rate in humid environments.

[0006] To achieve the above objectives, the present invention provides a moisture-proof and durable calcium silicate board, which is prepared from the following raw materials by weight: 400-450 parts diatomaceous earth, 300-350 parts quicklime, 160-200 parts silicate cement, 15-25 parts alkali-resistant glass fiber, 5-15 parts modified montmorillonite, and 300-350 parts deionized water.

[0007] Preferably, the silica content of the diatomaceous earth is ≥85wt%.

[0008] Preferably, the quicklime contains ≥89wt% calcium oxide.

[0009] Preferably, the silicate cement is P·II 52.5.

[0010] Preferably, the average length of the alkali-resistant glass fiber is 4-10 mm.

[0011] Furthermore, the preparation steps of the modified montmorillonite are as follows:

[0012] S1: Sodium-based montmorillonite and sodium 4-styrene sulfonate were added to an ethanol / water mixture, sonicated for 20-40 min, and then subjected to ion exchange at 80-90℃ under reflux for 5-7 h. After centrifugation, washing, and vacuum drying, intercalated montmorillonite was obtained.

[0013] S2: Under nitrogen protection, intercalated montmorillonite was added to toluene solution and sonicated for 20-40 min. Then sodium styrene sulfonate, γ-methacryloyloxypropyltrimethoxysilane and perfluorooctyl ethyl acrylate were added and stirred for 20-40 min. Then benzoyl peroxide was added and stirred at 75-85℃ for 4-6 h. After centrifugation, washing and vacuum drying were performed to obtain modified montmorillonite.

[0014] Preferably, the volume ratio of the ethanol / water mixture in step S1 is 3-5:1.

[0015] Preferably, in step S1, the weight ratio of sodium montmorillonite, sodium styrene sulfonate, and the ethanol / water mixed solution is 5-15:3-6:40-60.

[0016] Preferably, in step S2, the weight ratio of intercalated montmorillonite, toluene, sodium styrene sulfonate, γ-methacryloyloxypropyltrimethoxysilane, perfluorooctyl ethyl acrylate and benzoyl peroxide is 5-15:50-200:2-6:6-18:1.2-3.6:0.2-0.5.

[0017] Furthermore, the present invention also provides a method for preparing a moisture-proof and durable calcium silicate board, comprising the following steps:

[0018] (1) Mix diatomaceous earth, quicklime, silicate cement, alkali-resistant glass fiber and modified montmorillonite for 15-25 minutes, then add deionized water and stir at 1000-1500 rpm for 10-20 minutes at 40-50℃ to obtain slurry;

[0019] (2) Inject the slurry into the mold, hold it under pressure of 13-15MPa for 15-25min, and then seal and cure for 20-28h to obtain the slab;

[0020] (3) The slab is transferred into an autoclave and heated to 175-185℃ at a rate of 8-12℃ / min. It is then treated at a saturated steam pressure of 1.2-1.5MPa for 7-10h. After that, the pressure is reduced to atmospheric pressure at a rate of 0.2-0.8MPa / h and dried to obtain a moisture-proof and durable calcium silicate board.

[0021] Preferably, the drying step in step (3) is as follows: drying at 55-65℃ for 3-5 hours, drying at 80-90℃ for 5-7 hours, drying at 100-110℃ for 1-3 hours, and then cooling down.

[0022] The beneficial effects of this invention are:

[0023] This invention significantly improves the flexural strength, moisture resistance, and long-term durability of calcium silicate boards through modification of montmorillonite and a rational component ratio. The introduction of modified montmorillonite creates a more uniformly dispersed structure within the material, enhancing its surface activity and interfacial compatibility, thereby effectively improving the microstructure of the calcium silicate board and reducing porosity and water absorption channels. The functional groups in the modified montmorillonite can chemically react or physically bond with silicate cement and other components, further improving the material's density and water resistance.

[0024] This invention significantly enhances the interfacial bonding strength between the inorganic and organic phases by using polymers on the surface of montmorillonite as a bridge. This synergistic effect of structural optimization and interfacial enhancement allows the calcium silicate board to maintain high strength and a low strength degradation rate even in long-term humid environments, exhibiting excellent moisture resistance and durability. This has significant practical implications and promotional value. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0026] In the specific embodiments of this invention, the sodium-based montmorillonite was sourced from NANOCOR Corporation of the United States, model PGW; the diatomaceous earth was purchased from Kunjian Mineral Products Processing Plant in Lingshou County, with a silica content of 85 wt%; the quicklime was purchased from Longde Mineral Products Sales Co., Ltd. in Lingshou County, with a calcium oxide content ≥89 wt%; the silicate cement conformed to the P·II 52.5 standard in GB 175-2020; and the average length of the alkali-resistant glass fiber was 6 mm.

[0027] Example 1

[0028] (1) Add 5g sodium montmorillonite and 3g sodium 4-styrene sulfonate to 40g ethanol / water mixed solution (volume ratio 3:1), sonicate for 20min, then reflux at 80℃ for 5h for ion exchange, centrifuge, wash, and vacuum dry to obtain intercalated montmorillonite;

[0029] (2) Under nitrogen protection, 5g of intercalated montmorillonite was added to 50g of toluene solution and sonicated for 20min. Then, 2g of sodium styrene sulfonate, 6g of γ-methacryloyloxypropyltrimethoxysilane and 1.2g of perfluorooctyl ethyl acrylate were added and stirred for 20min. Then, 0.2g of benzoyl peroxide was added and stirred at 75℃ for 4h. After centrifugation, washing and vacuum drying were performed to obtain modified montmorillonite.

[0030] (3) Mix 400g diatomaceous earth, 300g quicklime, 160g silicate cement, 15g alkali-resistant glass fiber and 5g modified montmorillonite for 15min, then add 300g deionized water and stir at 1000rpm for 10min at 40℃ to obtain slurry.

[0031] (4) Inject the slurry into the mold, hold it under pressure of 13MPa for 15min, and then seal and cure for 20h to obtain the slab;

[0032] (5) The slab is transferred into an autoclave and heated to 175°C at a rate of 8°C / min. It is then treated at a saturated steam pressure of 1.2MPa for 7 hours. Subsequently, the pressure is reduced to atmospheric pressure at a rate of 0.2MPa / h. The slab is then dried at 55°C for 3 hours, 80°C for 5 hours, and 100°C for 1 hour. The temperature is then lowered to obtain a moisture-proof and durable calcium silicate board.

[0033] Example 2

[0034] (1) Add 10g sodium montmorillonite and 4.5g sodium 4-styrene sulfonate to 50g ethanol / water mixed solution (volume ratio 4:1), sonicate for 30min, then reflux at 85℃ for 6h for ion exchange, centrifuge, wash, and vacuum dry to obtain intercalated montmorillonite.

[0035] (2) Under nitrogen protection, 10g of intercalated montmorillonite was added to 100g of toluene solution and sonicated for 30min. Then, 4.1g of sodium styrene sulfonate, 12.4g of γ-methacryloyloxypropyltrimethoxysilane and 2.6g of perfluorooctyl ethyl acrylate were added and stirred for 30min. Then, 0.3g of benzoyl peroxide was added and stirred at 80℃ for 5h. After centrifugation, washing and vacuum drying were performed to obtain modified montmorillonite.

[0036] (3) Mix 420g diatomaceous earth, 330g quicklime, 180g silicate cement, 20g alkali-resistant glass fiber and 10g modified montmorillonite for 20min, then add 330g deionized water and stir at 1200rpm for 15min at 45℃ to obtain slurry.

[0037] (4) Inject the slurry into the mold, hold it under pressure of 14.5 MPa for 20 min, and then seal and cure for 24 h to obtain the slab;

[0038] (5) The slab is transferred into an autoclave and heated to 180°C at a rate of 10°C / min. It is then treated at a saturated steam pressure of 1.35MPa for 9 hours. Subsequently, the pressure is reduced to atmospheric pressure at a rate of 0.5MPa / h. The slab is then dried at 60°C for 4 hours, 85°C for 6 hours, and 105°C for 2 hours. The temperature is then reduced to obtain a moisture-proof and durable calcium silicate board.

[0039] Example 3

[0040] (1) Add 15g sodium montmorillonite and 6g sodium 4-styrene sulfonate to 60g ethanol / water mixed solution (volume ratio 3-5:1), sonicate for 40min, then reflux at 90℃ for 7h for ion exchange, centrifuge, wash, and vacuum dry to obtain intercalated montmorillonite.

[0041] (2) Under nitrogen protection, 15g of intercalated montmorillonite was added to 200g of toluene solution and sonicated for 40min. Then, 6g of sodium styrene sulfonate, 18g of γ-methacryloyloxypropyltrimethoxysilane and 3.6g of perfluorooctyl ethyl acrylate were added and stirred for 40min. Then, 0.5g of benzoyl peroxide was added and stirred at 85℃ for 6h. After centrifugation, washing and vacuum drying were performed to obtain modified montmorillonite.

[0042] (3) Mix 450g diatomaceous earth, 350g quicklime, 200g silicate cement, 25g alkali-resistant glass fiber and 15g modified montmorillonite for 25min, then add 350g deionized water and stir at 1500rpm for 20min at 50℃ to obtain slurry.

[0043] (4) Inject the slurry into the mold, hold it under pressure of 15MPa for 25min, and then seal and cure for 28h to obtain the slab;

[0044] (5) The slab is transferred into an autoclave and heated to 185°C at a rate of 12°C / min. It is then treated at a saturated steam pressure of 1.5MPa for 10 hours. Subsequently, the pressure is reduced to atmospheric pressure at a rate of 0.8MPa / h. The slab is then dried at 65°C for 5 hours, 90°C for 7 hours, and 110°C for 3 hours. The temperature is then reduced to obtain a moisture-proof and durable calcium silicate board.

[0045] Comparative Example 1:

[0046] The difference between Comparative Example 1 and Example 2 is that sodium styrene sulfonate was not added in step (2);

[0047] The specific steps are as follows:

[0048] (1) Add 10g sodium montmorillonite and 4.5g sodium 4-styrene sulfonate to 50g ethanol / water mixed solution (volume ratio 4:1), sonicate for 30min, then reflux at 85℃ for 6h for ion exchange, centrifuge, wash, and vacuum dry to obtain intercalated montmorillonite.

[0049] (2) Under nitrogen protection, 10g of intercalated montmorillonite was added to 100g of toluene solution and sonicated for 30min. Then, 12.4g of γ-methacryloxypropyltrimethoxysilane and 2.6g of perfluorooctyl ethyl acrylate were added and stirred for 30min. Then, 0.3g of benzoyl peroxide was added and stirred at 80℃ for 5h. After centrifugation, washing and vacuum drying were performed to obtain modified montmorillonite.

[0050] (3) Mix 420g diatomaceous earth, 330g quicklime, 180g silicate cement, 20g alkali-resistant glass fiber and 10g modified montmorillonite for 20min, then add 330g deionized water and stir at 1200rpm for 15min at 45℃ to obtain slurry.

[0051] (4) Inject the slurry into the mold, hold it under pressure of 14.5 MPa for 20 min, and then seal and cure for 24 h to obtain the slab;

[0052] (5) The slab is transferred into an autoclave and heated to 180°C at a rate of 10°C / min. It is then treated at a saturated steam pressure of 1.35MPa for 9 hours. Subsequently, the pressure is reduced to atmospheric pressure at a rate of 0.5MPa / h. The slab is then dried at 60°C for 4 hours, 85°C for 6 hours, and 105°C for 2 hours. The slab is then cooled to obtain calcium silicate board.

[0053] Comparative Example 2:

[0054] The difference between Comparative Example 2 and Example 2 is that γ-methacryloyloxypropyltrimethoxysilane was not added in step (2);

[0055] The specific steps are as follows:

[0056] (1) Add 10g sodium montmorillonite and 4.5g sodium 4-styrene sulfonate to 50g ethanol / water mixed solution (volume ratio 4:1), sonicate for 30min, then reflux at 85℃ for 6h for ion exchange, centrifuge, wash, and vacuum dry to obtain intercalated montmorillonite.

[0057] (2) Under nitrogen protection, 10g of intercalated montmorillonite was added to 100g of toluene solution, sonicated for 30min, then 4.1g of sodium styrene sulfonate and 2.6g of perfluorooctyl ethyl acrylate were added, stirred for 30min, then 0.3g of benzoyl peroxide was added, and the mixture was stirred at 80℃ for 5h. After centrifugation, washing, and vacuum drying, modified montmorillonite was obtained.

[0058] (3) Mix 420g diatomaceous earth, 330g quicklime, 180g silicate cement, 20g alkali-resistant glass fiber and 10g modified montmorillonite for 20min, then add 330g deionized water and stir at 1200rpm for 15min at 45℃ to obtain slurry.

[0059] (4) Inject the slurry into the mold, hold it under pressure of 14.5 MPa for 20 min, and then seal and cure for 24 h to obtain the slab;

[0060] (5) The slab is transferred into an autoclave and heated to 180°C at a rate of 10°C / min. It is then treated at a saturated steam pressure of 1.35MPa for 9 hours. Subsequently, the pressure is reduced to atmospheric pressure at a rate of 0.5MPa / h. The slab is then dried at 60°C for 4 hours, 85°C for 6 hours, and 105°C for 2 hours. The slab is then cooled to obtain calcium silicate board.

[0061] Comparative Example 3:

[0062] The difference between Comparative Example 3 and Example 2 is that perfluorooctyl ethyl acrylate was not added in step (2);

[0063] The specific steps are as follows:

[0064] (1) Add 10g sodium montmorillonite and 4.5g sodium 4-styrene sulfonate to 50g ethanol / water mixed solution (volume ratio 4:1), sonicate for 30min, then reflux at 85℃ for 6h for ion exchange, centrifuge, wash, and vacuum dry to obtain intercalated montmorillonite.

[0065] (2) Under nitrogen protection, 10g of intercalated montmorillonite was added to 100g of toluene solution and sonicated for 30min. Then, 4.1g of sodium styrene sulfonate and 12.4g of γ-methacryloyloxypropyltrimethoxysilane were added and stirred for 30min. Then, 0.3g of benzoyl peroxide was added and stirred at 80℃ for 5h. After centrifugation, washing, and vacuum drying, modified montmorillonite was obtained.

[0066] (3) Mix 420g diatomaceous earth, 330g quicklime, 180g silicate cement, 20g alkali-resistant glass fiber and 10g modified montmorillonite for 20min, then add 330g deionized water and stir at 1200rpm for 15min at 45℃ to obtain slurry.

[0067] (4) Inject the slurry into the mold, hold it under pressure of 14.5 MPa for 20 min, and then seal and cure for 24 h to obtain the slab;

[0068] (5) The slab is transferred into an autoclave and heated to 180°C at a rate of 10°C / min. It is then treated at a saturated steam pressure of 1.35MPa for 9 hours. Subsequently, the pressure is reduced to atmospheric pressure at a rate of 0.5MPa / h. The slab is then dried at 60°C for 4 hours, 85°C for 6 hours, and 105°C for 2 hours. The slab is then cooled to obtain calcium silicate board.

[0069] Comparative Example 4:

[0070] The difference between Comparative Example 4 and Example 2 is that the modified montmorillonite in step (3) is replaced with intercalated montmorillonite;

[0071] The specific steps are as follows:

[0072] (1) Add 10g sodium montmorillonite and 4.5g sodium 4-styrene sulfonate to 50g ethanol / water mixed solution (volume ratio 4:1), sonicate for 30min, then reflux at 85℃ for 6h for ion exchange, centrifuge, wash, and vacuum dry to obtain intercalated montmorillonite.

[0073] (2) Mix 420g diatomaceous earth, 330g quicklime, 180g silicate cement, 20g alkali-resistant glass fiber and 10g intercalated montmorillonite for 20min, then add 330g deionized water and stir at 1200rpm for 15min at 45℃ to obtain slurry.

[0074] (3) Inject the slurry into the mold, hold it under pressure of 14.5MPa for 20 minutes, and then seal and cure for 24 hours to obtain the slab;

[0075] (4) The slab is transferred into an autoclave and heated to 180°C at a rate of 10°C / min. It is then treated at a saturated steam pressure of 1.35MPa for 9 hours. Subsequently, the pressure is reduced to atmospheric pressure at a rate of 0.5MPa / h. The slab is then dried at 60°C for 4 hours, 85°C for 6 hours, and 105°C for 2 hours. The slab is then cooled to obtain calcium silicate board.

[0076] Performance testing:

[0077] Flexural strength: According to the JC / T 564.1-2018 standard, a three-point bending test was conducted using a WDW-100 microcomputer-controlled electronic universal testing machine. The span was set to 100 mm and the loading rate was 2 mm / min. The maximum load at which the specimen broke was recorded, and the flexural strength was calculated. The results are shown in Table 1.

[0078] Water absorption rate determination: The sample was dried in an oven at 105℃ to constant weight (m0), completely immersed in deionized water at 25℃ for 24 hours, then removed, the surface moisture was wiped off with a damp cloth and weighed immediately (m1). The water absorption rate was calculated according to W=(m1-m0) / m0×100%, and the results are shown in Table 1.

[0079] Long-term immersion strength decay: According to the JC / T 564.1-2018 standard, the sample was completely immersed in deionized water at 25℃, and the flexural strength was tested at 0d, 30d, 90d and 180d respectively. The strength decay rate relative to 0d was calculated, and the results are shown in Table 1.

[0080] Table 1 Performance Test Results

[0081]

[0082] Data Analysis:

[0083] As can be seen from the data in Examples 1-3 of Table 1, the moisture-proof and durable calcium silicate board prepared by this invention exhibits excellent flexural strength, low water absorption, and a small long-term immersion strength decay rate. This indicates that the mechanical properties and durability of calcium silicate board can be significantly improved through modification of montmorillonite and a reasonable component ratio. The introduction of modified montmorillonite may form a more uniformly dispersed structure within the material, while its surface activity and interfacial compatibility are enhanced, thereby effectively improving the microstructure of the calcium silicate board and reducing porosity and water absorption channels. In addition, the functional groups in the modified montmorillonite may chemically react or physically combine with silicate cement and other components, further improving the material's density and water resistance. This synergistic effect of structural optimization and interfacial enhancement allows the calcium silicate board to maintain high strength and a low strength decay rate even under long-term immersion conditions, demonstrating excellent moisture-proof and durable performance.

[0084] As can be seen from the data in Table 1 for Example 2 and Comparative Example 1, the introduction of sodium styrene sulfonate plays a significant role in improving the performance of calcium silicate boards through two-stage functionalization. This is mainly because, during the ion exchange stage, the substitution effect of its sulfonic acid groups with the interlayer cations of montmorillonite not only expands the interlayer spacing but also provides active sites for subsequent polymerization reactions. In the toluene phase reaction, sodium styrene sulfonate participates in grafting as a comonomer, and its rigid benzene ring structure enhances the steric hindrance effect of the montmorillonite layers, effectively preventing the re-stacking of the layers. Simultaneously, the sulfonic acid groups react with Ca in the cement hydration products... 2+ Coordination bonds are formed, constructing an ionic cross-linked network at the matrix-reinforcing phase interface. This dual-action mechanism not only improves the dispersion stability of montmorillonite but also enhances the interfacial bonding strength between the inorganic and organic phases through chemical bonding, thereby significantly improving the material's resistance to hydration erosion.

[0085] As can be seen from the data in Example 2 and Comparative Example 2 in Table 1, the introduction of γ-methacryloxypropyltrimethoxysilane significantly improved the flexural strength and moisture resistance of calcium silicate board. This is mainly because γ-methacryloxypropyltrimethoxysilane forms a reactive organic transition layer on the surface of montmorillonite, which not only improves the compatibility between the inorganic and polymeric phases, but also provides heterogeneous nucleation sites for cement hydration products, and forms an interpenetrating network structure that runs through the inorganic and organic phases, significantly improving the flexural strength and moisture resistance of the material.

[0086] As can be seen from the data in Example 2 and Comparative Example 3 in Table 1, the introduction of perfluorooctyl ethyl acrylate plays an important role in improving the moisture resistance and durability of calcium silicate boards, while having little impact on flexural strength. This is because perfluorooctyl ethyl acrylate, as a fluorinated functional monomer, contains strongly hydrophobic perfluorinated segments in its molecular structure, which can significantly improve water resistance.

[0087] As can be seen from the data in Example 2 and Comparative Example 4 in Table 1, the use of modified montmorillonite has a significant effect on improving the performance of calcium silicate boards. This is because, compared with unmodified intercalated montmorillonite, modified montmorillonite shows significant improvements in dispersibility, activity, and interfacial compatibility. During the modification process, by introducing functional monomers and coupling agents, a stable organic-inorganic composite structure may be formed on the surface of montmorillonite, thereby significantly improving its bonding force with the matrix material. This composite structure not only forms a denser microstructure within the material but also effectively reduces porosity and water absorption channels, thus significantly reducing the material's water absorption rate.

[0088] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

Claims

1. A moisture-proof durable calcium silicate board, characterized by, Prepared from the following raw materials by weight parts: diatomite 400-450 parts, quicklime 300-350 parts, Portland cement 160-200 parts, alkali-resistant glass fiber 15-25 parts, modified montmorillonite 5-15 parts and deionized water 300-350 parts; The preparation steps of the modified montmorillonite are as follows: S1: Sodium-based montmorillonite and sodium 4-styrene sulfonate are added into an ethanol / water mixed solution, ultrasonic treatment is performed for 20-40 min, ion exchange is performed at 80-90℃ under refluxing condition for 5-7 h, centrifugation, washing, vacuum drying, and intercalated montmorillonite is obtained; S2: Under nitrogen protection, the intercalated montmorillonite is added into a toluene solution, ultrasonic treatment is performed for 20-40 min, sodium styrene sulfonate, γ-methacryloyloxypropyl trimethoxysilane and perfluorooctyl ethyl acrylate are added, stirring is performed for 20-40 min, benzoyl peroxide is added, stirring is performed at 75-85℃ for 4-6 h, centrifugation, washing, vacuum drying, and the modified montmorillonite is obtained; The weight ratio of sodium-based montmorillonite, sodium styrene sulfonate and the ethanol / water mixed solution in step S1 is 5-15:3-6:40-60; The weight ratio of intercalated montmorillonite, toluene, sodium styrene sulfonate, γ-methacryloyloxypropyl trimethoxysilane, perfluorooctyl ethyl acrylate and benzoyl peroxide in step S2 is 5-15:50-200:2-6:6-18:1.2-3.6:0.2-0.

5.

2. The moisture-proof durable calcium silicate board according to claim 1, characterized in that, The diatomite has a silicon dioxide content of ≥85wt%.

3. The moisture-proof durable calcium silicate board according to claim 1, characterized in that, The quicklime has a calcium oxide content of ≥89wt%.

4. The moisture-proof durable calcium silicate board according to claim 1, characterized in that, The Portland cement is P·II 52.

5.

5. The moisture-proof durable calcium silicate board according to claim 1, characterized in that, The alkali-resistant glass fiber has an average length of 4-10 mm. 6.The moisture-proof durable calcium silicate board according to claim 1, characterized in that, The volume ratio of the ethanol / water mixed solution in step S1 is 3-5:

1.

7. A method for producing the moisture-proof durable calcium silicate board according to any one of claims 1 to 6, characterized by, Comprising the following steps: (1) Diatomite, quicklime, Portland cement, alkali-resistant glass fiber and modified montmorillonite are mixed and stirred for 15-25 min, deionized water is added, stirring is performed at 40-50℃ and a speed of 1000-1500 rpm for 10-20 min, and a slurry is obtained; (2) The slurry is injected into a mold, pressure is maintained at 13-15 MPa for 15-25 min, and then sealed and cured for 20-28 h, and a green body is obtained; (3) The green body is moved into a steam autoclave, heated to 175-185℃ at a rate of 8-12℃ / min, treated at a saturated steam pressure of 1.2-1.5 MPa for 7-10 h, then depressurized to normal pressure at a rate of 0.2-0.8 MPa / h, and dried, and a moisture-resistant durable calcium silicate board is obtained. 8.The method for preparing the moisture-proof durable calcium silicate board according to claim 7, characterized in that, The drying step in step (3) is: drying at 55-65℃ for 3-5 h, 80-90℃ for 5-7 h, and 100-110℃ for 1-3 h, and cooling.

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