Lightweight high-strength base building decorative plate and preparation method thereof

Abstract

The application discloses a kind of light high-strength salt-based building decoration plate and preparation method thereof, belong to building decoration material technical field.To solve the problems of existing building decoration plate, such as high density, weak interface bonding force between inorganic filler and organic binder, salt-based filler easy to absorb moisture and return halogen, hollow glass bead mixture easy to break, insufficient waterproof, weather resistance and flame retardant performance.The plate includes the following components: quartz sand 300-480 parts, salt powder 180-260 parts, hollow glass beads 40-70 parts, epoxy resin 20-39 parts, epoxy reactive diluent 3-6 parts, curing agent 6-13 parts, and silane coupling agent 1-2 parts.The prepared plate has a weight reduction of up to 30% or more, with significantly improved interface bonding strength, a surface static water contact angle of ≥130°, and a 24h water absorption rate of ≤0.54%.The plate has excellent mechanical properties, weather resistance, and flame retardant and antibacterial functions, effectively solving the moisture absorption and halogen return defects of salt-based plate, and is suitable for various building decoration projects.

Description

Technical Field

[0001] This invention belongs to the technical field of building decoration materials, and particularly relates to one type. Background Technology

[0002] Building decorative panels are widely used basic materials in interior and exterior decoration projects. Existing products mainly include artificial stone panels, MDF (medium-density fiberboard), ceramic panels, and PVC composite panels. These products generally suffer from the following technical problems:

[0003] First, the density is relatively high. The density of traditional artificial stone slabs is usually between 2.0-2.3 g / cm3. Large-sized slabs are heavy, making construction and installation difficult, and imposing strict requirements on the structural load of buildings, which increases the overall construction cost.

[0004] Second, the interfacial bonding is unstable. In existing composite panels, the interfacial bonding between inorganic fillers and organic binders relies on physical adsorption. During long-term use, the interface is prone to debonding, leading to a decrease in strength.

[0005] Third, it lacks waterproof and weather resistance. Ordinary boards lack effective hydrophobic treatment on their surface, resulting in high water absorption in humid environments. After long-term use, they warp and deform, affecting their service life.

[0006] Currently, there are no systematic reports on the application of NaCl (sodium chloride) as a functional filler and hollow glass microspheres as a lightweight component in building decorative panels. The density of NaCl is 2.16 g / cm³. 3 (lower than quartz sand (2.65 g / cm³)) 3 Salt powder is widely available and inexpensive, and under specific processing conditions, it can impart flame-retardant and antibacterial properties to boards. However, the ionic crystal structure of salt powder leads to problems such as weak interfacial bonding with organic binders and high hygroscopicity, which limits its application in the board industry.

[0007] Therefore, developing a lightweight, high-strength building decorative panel that can effectively utilize the advantages of salt powder and hollow microsphere fillers while overcoming their inherent defects has significant technical value and market significance. Summary of the Invention

[0008] To address the technical shortcomings of existing building decorative panels, such as high density, weak interfacial bonding between inorganic fillers and organic binders, easy moisture absorption and efflorescence of salt-based fillers, easy breakage during the mixing process of hollow glass microspheres, and insufficient waterproof and flame-retardant properties, this invention provides a lightweight, high-strength salt-based building decorative panel and its preparation method. This invention utilizes a ternary particle size distribution design, dual-path interface modification, hollow microsphere integrity protection technology, and a double-layer hydrophobic surface treatment system to achieve significant lightweighting of the panel while ensuring mechanical strength, waterproof and weather-resistant properties, and flame-retardant functions, thus realizing the efficient functional application of salt powder in building decorative panels.

[0009] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0010] A lightweight, high-strength salt-based building decorative board, which, by weight, is mainly composed of the following components: 300-480 parts of quartz sand, 180-260 parts of salt powder, 40-70 parts of hollow glass microspheres, 20-39 parts of epoxy resin, 3-6 parts of epoxy reactive diluent, 6-13 parts of curing agent, and 1-2 parts of silane coupling agent.

[0011] Furthermore, the quartz sand, salt powder, and hollow glass microspheres constitute a ternary particle size distribution system: the quartz sand has a particle size of 120-160 mesh, providing strength support as the main skeleton of the board; the salt powder has a particle size of 800-1000 mesh, filling the voids in the skeleton formed by the quartz sand; the hollow glass microspheres have a particle size of 10-20 μm, a compressive strength ≥60 MPa, and fill the secondary voids to achieve lightweighting. The particle size ratio of quartz sand to salt powder is 6:1-10:1, and this multi-stage particle size matching significantly improves the packing density of the filler.

[0012] Further, the epoxy resin is a bisphenol A type epoxy resin or a modified epoxy resin, wherein the bisphenol A type epoxy resin is selected from at least one of E51 and E44, and the modified epoxy resin is a CTBN modified epoxy resin; the epoxy reactive diluent is a monofunctional glycidyl ether reactive diluent, including but not limited to at least one of lauryl glycidyl ether LS-AGE, allyl glycidyl ether AGE, and butyl glycidyl ether BGE; the curing agent is a polyetheramine curing agent, including but not limited to at least one of polyetheramine D230 and polyetheramine D400; and the silane coupling agent is an epoxy silane coupling agent, including but not limited to at least one of γ-glycidyl etheroxypropyltrimethoxysilane KH-560 and γ-glycidyl etheroxypropyltriethoxysilane KH-561.

[0013] Preferably, the mass ratio of epoxy resin, epoxy reactive diluent, and curing agent is 7:1:(2.2-2.4), and the total amount of amino active hydrogen in the curing agent is strictly matched with the total amount of epoxy groups in the epoxy resin and epoxy reactive diluent to ensure that the curing reaction is complete without any small molecule residues and that the cross-linking structure of the board is stable.

[0014] Furthermore, the surface of the salt powder is coated with an epoxy resin pre-coating layer, with the amount of epoxy resin used in the pre-coating being 3%-5% of the salt powder mass. This pre-coating layer transforms the ionic crystal surface of the salt powder into an epoxy resin surface, forming a homogeneous interface with the resin matrix in the board, thus solving the problem of poor interfacial compatibility between the salt powder and the organic binder. The surface of the quartz sand is hydrolyzed and modified with a silane coupling agent, forming an organic-inorganic chemical bridge between the quartz sand and the resin matrix, thereby improving the interfacial bonding strength.

[0015] Furthermore, the surface of the board is provided with an organic-inorganic hybrid double-layer hydrophobic coating, consisting of a dense layer of phosphorus silica sol cured from the inside out and a hydrophobic layer of silica sol cured from the inside out; after treatment, the static water contact angle of the board surface is ≥130° and the water absorption rate is ≤0.54% after 24 hours, which can effectively suppress the moisture absorption and efflorescence phenomenon of salt-based boards.

[0016] The above-mentioned method for preparing lightweight high-strength salt-based building decorative panels includes the following steps: (1) Raw material pretreatment: Quartz sand, salt powder, and hollow glass microspheres are dried and sieved to obtain raw materials that meet the target particle size requirements. After cooling, they are sealed in a low-humidity environment for later use; (2) Quartz sand surface modification: A silane coupling agent hydrolysate is prepared and the quartz sand is surface modified by spraying. Then, it is dried and cured to obtain modified quartz sand; (3) Salt powder pre-coating treatment: Epoxy resin is diluted with an organic solvent and mixed evenly with salt powder. The solvent is allowed to evaporate to obtain pre-coated salt powder with epoxy resin coating on the surface; (4) Mixing: First, the quartz sand is dried and sieved by spraying. Hollow glass microspheres are dispersed in a mixture of preheated epoxy resin and epoxy reactive diluent, and then pre-coated salt powder and modified quartz sand are added in sequence. Finally, curing agent is added and mixed evenly to obtain a mixture; (5) Hot pressing molding: The mixture is layered and laid into the mold. After compaction, it is subjected to segmented pressure increase and hot pressing curing. After cooling, it is demolded to obtain the substrate; (6) Curing and sanding: The demolded substrate is cured at room temperature until it is completely cured, and then sanded step by step; (7) Double-layer hydrophobic surface treatment: The surface of the sanded substrate is coated with silane coupling agent primer, phosphosilica sol inner layer and silica sol containing long-chain alkyl in sequence. After layer curing, the finished substrate is obtained.

[0017] Further, in step (2), the amount of silane coupling agent is 0.35%-0.40% of the mass of quartz sand; the hydrolysate adopts an ethanol-water system with a mass ratio of ethanol to water of 95:5, the pH is adjusted to 4.0-5.0 with glacial acetic acid, and the hydrolysate is allowed to stand for 15-20 minutes; the modified quartz sand is cured at 80℃ for 25 minutes.

[0018] Further, in step (3), the amount of epoxy resin used for pre-coating is 5%-8% of the total amount of epoxy resin; acetone is used as the diluent, and the mass ratio of epoxy resin to acetone is 1:2; after mixing, it is left to stand at 40°C for 20-30 minutes to allow the acetone to evaporate completely.

[0019] Further, in step (4), after the epoxy resin and epoxy reactive diluent are mixed, they are preheated at 55-60℃ for 15-20 minutes to reduce the viscosity of the system and facilitate the dispersion of microspheres; after the hollow glass microspheres are added, they are gently stirred manually and mechanical stirring is prohibited; the quartz sand is added in 3 batches, and after all the sand is added, it is stirred at a low speed of ≤100rpm for 3-5 minutes; the curing agent is added last, and the mixing operation time is controlled within 3 minutes and the mold is laid immediately to avoid premature gelation of the system.

[0020] Further, in step (5), the mold is sprayed with PTFE release agent at room temperature before the material is laid and the mold is closed. Then the heating program is started to ensure that the release agent forms a uniform film. The mixture is laid in 3 layers, each layer is vibrated and compacted, and the outermost layer is sprinkled with fine quartz sand to improve the surface density. The hot pressing process parameters are: pre-press 2MPa, final pressure 10-15MPa, hot pressing temperature 90-110℃, and heat preservation and pressure holding time 10-30 minutes. The mold is demolded after the mold temperature drops below 60℃ to avoid thermal stress cracking.

[0021] Further, in step (7), the inner layer of the phosphosilicate sol is prepared by tetraethyl orthosilicate (TEOS) and triethyl phosphate (TEP) in a mass ratio of 6:1-10:1; the outer layer of the silica sol containing long-chain alkyl groups is prepared by TEOS, methyltriethoxysilane (MTES) and dodecyltriethoxysilane (C12-TEOS), and is diluted with ethanol 1.5-2 times before use; after the inner layer is cured, it is aged for 24 hours before the outer layer is coated. The curing temperature of each layer is 80°C and the curing time is 1-2 hours.

[0022] The beneficial effects of this invention are:

[0023] 1. This invention reduces the density of the slab to 1.4-1.75 g / cm³ by introducing high-strength hollow glass microspheres to replace high-density quartz sand, without changing the slab's volume and structural dimensions. 3 Compared to the traditional 2.0-2.3g / cm³ 3 Artificial stone slabs can reduce weight by up to 30%, significantly reducing the difficulty of construction and handling and the load on the building structure.

[0024] 2. Quartz sand, salt powder, and hollow glass microspheres form a gradient particle size distribution system. Large-diameter quartz sand constructs a rigid skeleton, medium and fine-diameter salt powder fills the skeleton voids, and micro-nano-level hollow microspheres fill secondary pores. The packing density of the fillers is increased by 15%-25%, resulting in higher board density and mechanical properties with the same amount of binder.

[0025] 3. Epoxy resin, reactive diluent and curing agent are strictly matched in equivalent ratio, and the curing reaction is complete with no residual active groups; the monofunctional reactive diluent participates in the crosslinking reaction, does not form free suspended chain ends, has minimal impact on the crosslinking density of the system, and ensures the long-term stability of the mechanical properties of the board.

[0026] 4. For quartz sand, chemical grafting with silane coupling agent is used to establish covalent bond bridging between inorganic and organic phases, improving the interfacial bonding strength by 30%-50%; for salt powder, epoxy resin pre-coating process is used to transform the ionic crystal surface into a resin-compatible surface, achieving homogeneous interfacial bonding, fundamentally solving the industry problem of weak interfacial bonding between salt powder and organic binder.

[0027] 5. The feeding sequence of “pre-dispersing microspheres in resin buffer solution and then adding hard quartz sand” is adopted, combined with a low-speed stirring process. The buffering effect of the resin liquid is used to weaken the mechanical impact of quartz sand on hollow microspheres, effectively avoiding microsphere breakage during the mixing process and ensuring the batch stability and repeatability of the lightweight effect of the board.

[0028] 6. This invention constructs a dual-layer protective system consisting of a dense inner layer of phosphorus silica sol and an outer layer of organic-inorganic hybrid hydrophobic material. The inner layer seals the pores on the surface of the board and blocks the water vapor penetration channels, while the outer layer provides low surface energy hydrophobic properties. The synergistic effect makes the static water contact angle of the board surface ≥130° and reduces the water absorption rate by more than 90% in 24 hours. This completely solves the defects of salt-based boards that are prone to moisture absorption and efflorescence, as well as warping and deformation, and significantly improves their weather resistance life.

[0029] 7. The hydrogen chloride gas released by the high-temperature decomposition of salt powder can capture combustion free radicals, inhibit chain combustion reactions, and work synergistically with the resin carbonization layer to play a flame-retardant role. Its flame-retardant performance is superior to that of traditional pure quartz sand artificial stone. At the same time, the salt powder itself can give the board a certain antibacterial property, expanding the application scenarios of the product. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 The images shown are surface scanning electron microscope images and elemental analyses from Example 1.

[0032] Figure 2 The image shows a cross-sectional scanning electron microscope image and elemental analysis of Example 1.

[0033] Figure 3 These are optical photographs of Examples 1 and 2.

[0034] Figure 4 This is a photograph of the contact angle test in Example 1. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Example 1

[0037] A lightweight, high-strength salt-based building decorative board, with the following raw material composition: 480g of 120-160 mesh quartz sand, 180g of 800-1000 mesh industrial salt powder, 40g of high-strength hollow glass microspheres (particle size 10-20μm, compressive strength ≥60 MPa), 39g of E51 bisphenol A type epoxy resin, 5.5g of LS-AGE epoxy reactive diluent, 12.8g of polyetheramine D230 curing agent, and 1.7g of KH-560 silane coupling agent.

[0038] The preparation method of this embodiment includes the following steps:

[0039] Raw material pretreatment: Quartz sand and salt powder were dried in an oven at 105℃ for 2 hours to remove surface adsorbed water; a thin layer of hollow glass microspheres (layer thickness ≤ 5 mm) was spread out and dried in an oven at 120℃ for 45 minutes to activate the active hydroxyl groups on the glass surface. All dried raw materials were placed in a drying oven with relative humidity ≤ 30% to cool to room temperature and sealed for later use.

[0040] Silane modification of quartz sand surface: Add 1.7g KH-560 to 32.3g anhydrous ethanol, then add 1.7g deionized water, and adjust the pH to 4.0-5.0 by adding glacial acetic acid dropwise. Let stand for hydrolysis for 15 minutes until the solution is clear. Spray the hydrolysate evenly onto the stirred quartz sand surface using a spray method. After spraying, place it in an 80℃ oven for curing for 25 minutes, remove, cool, and seal for later use.

[0041] Salt powder epoxy pre-coating treatment: Take 7.2g of E51 epoxy resin and add acetone to dilute evenly at a mass ratio of 1:2; mix the diluted resin solution with 180g of salt powder and gently stir until the salt powder particles are completely wetted by the resin; spread the mixture out at 40℃ and let it dry for 25 minutes to allow the acetone to evaporate completely, thus obtaining modified salt powder with an epoxy resin pre-coating layer on the surface.

[0042] Mixture preparation:

[0043] S1 resin system preheating: Mix the remaining 31.1g E51 epoxy resin with 5.5g LS-AGE reactive diluent evenly, and preheat in a water bath at 55-60℃ for 18min to reduce the viscosity of the system to 200-500mPa・s.

[0044] S2 Hollow Microsphere Dispersion: Add 40g of hollow glass microspheres to the preheated resin mixture and gently stir manually with a silicone spatula until evenly dispersed. Mechanical stirring is prohibited throughout the process to avoid the microspheres being broken by impact.

[0045] S3 Salt Powder Mixing: Slowly add the pre-coated salt powder to the system and manually stir for 2 minutes until evenly dispersed.

[0046] S4 Quartz Sand Mixing: Add the modified quartz sand in 3 batches, and manually stir after each batch to initially mix; after all the sand is added, mechanically stir at a low speed of 90 rpm for 4 minutes to fully impregnate the filler and resin.

[0047] S5 curing agent mixing: Add 12.8g of D230 curing agent to the mixture, stir quickly and evenly, and control the total operation time within 3 minutes. Immediately after completion, lay the mold.

[0048] Segmented pressurization hot pressing molding:

[0049] (1) Mold pretreatment: Use a stainless steel mold with an inner cavity size of 300mm×300mm. Polish the mold surface to a roughness Ra≤0.8μm. Spray PTFE release agent evenly at room temperature, spray twice in thin layers, with an interval of 4min between each layer. Let it dry for 8min before use.

[0050] (2) Layered material laying: The mixture is laid into the mold in 3 layers. After each layer is leveled, the side of the mold is tapped lightly to compact it. The last layer is evenly sprinkled with fine quartz sand with a thickness of about 0.8 mm to improve the surface density. The total amount of material fed into each mold is controlled within ±2%.

[0051] (3) Hot pressing curing: After the mold is closed, apply a pre-pressure of 2MPa and hold for 3 minutes, then gradually increase the pressure to 12MPa and at the same time raise the temperature to 100℃. Keep the temperature and pressure for 20 minutes to allow the epoxy system to be completely cured. After curing, slowly reduce the pressure to zero to avoid the board from rebounding and cracking.

[0052] (4) Cooling and demolding: Demold after the mold temperature naturally drops to below 60℃ to avoid thermal stress cracks caused by high temperature demolding.

[0053] After demolding, the substrate of the board is placed in a 50℃ oven for 48 hours to allow the curing reaction to be complete. After curing, the surface is sanded in sequence with 180 grit, 400 grit and 800 grit sandpaper to control the surface flatness to Ra≤1.6μm.

[0054] Double-layer hydrophobic surface treatment:

[0055] (1) Pre-drying and primer: Place the sanded board in a 50℃ oven to dry for 18 hours, and blow away the surface dust with compressed air; prepare a 0.5% KH-560 ethanol solution and spray it evenly on the entire surface of the board, and let it air dry at room temperature for 10 minutes to unify the surface activity.

[0056] (2) Dense inner layer coating of phosphosilicate sol: Add 8.0g of tetraethyl orthosilicate (TEOS) and 1.0g of triethyl phosphate (TEP) to 70mL of ethanol and stir evenly. Slowly add 10mL of deionized water containing 0.3mL of glacial acetic acid. Stir for 60min and age for 1h to obtain phosphosilicate sol. Spray two thin layers onto the surface of the board with a spray gun, with an 8min interval between each layer. After coating, cure at 80℃ for 1.5h and age at room temperature for 48h.

[0057] (3) Hydrophobic outer coating of long-chain alkyl silica sol: 8.0g TEOS, 2.0g methyltriethoxysilane (MTES) and 0.5mL dodecyltriethoxysilane (C12-TEOS) were added to 70mL ethanol and mixed evenly. 12mL deionized water containing 0.3mL glacial acetic acid was slowly added dropwise. After stirring for 45min, the mixture was aged for 1.5h. The mixture was diluted 1.8 times with anhydrous ethanol to obtain a hydrophobic sol. Three thin layers were sprayed on the inner surface. Each layer was dried at 60℃ for 40min. Finally, the mixture was cured at 80℃ for 1.5h to obtain the finished board.

[0058] The salt-based building decoration panels prepared using the above method have a smooth surface and dense structure, with a Brinell hardness of 23 and a flexural strength of over 17.6 MPa. After surface protection treatment, the static water contact angle of the panel surface is ≥130°, the water absorption rate is ≤0.54% after 24 hours, and no obvious deformation, efflorescence, or salt precipitation was observed after 60 days of placement in a constant temperature and humidity environment of 35℃ and 80% relative humidity.

[0059] Example 2

[0060] A lightweight salt-based building decorative panel further reduces the panel density by increasing the volume replacement ratio of hollow glass microspheres, making it suitable for scenarios with stringent building load requirements, such as light steel keel partition walls and interior decoration of high-rise buildings. The raw materials, by weight, are as follows: 380g quartz sand, 180g salt powder, 60g hollow glass microspheres, 39g E51 epoxy resin, 5.5g LS-AGE diluent, 12.8g polyetheramine D230 curing agent, and 1.33g KH-560.

[0061] The preparation method in this embodiment is the same as in Embodiment 1.

[0062] Example 3

[0063] A toughened salt-based building decorative panel improves the toughness and impact resistance of the panel by replacing part of the bisphenol A type epoxy resin with CTBN modified epoxy resin. It is suitable for applications with high impact resistance requirements, such as walls and countertops in public areas.

[0064] The raw materials, by weight, are composed as follows:

[0065] 480g quartz sand, 180g salt powder, 40g hollow glass microspheres, 30.64g E51 epoxy resin, 7.66g CTBN modifier, 5.5g LS-AGE epoxy reactive diluent, 12.2g polyetheramine D230 curing agent, and 1.7g KH-560 silane coupling agent.

[0066] The preparation method in this embodiment is the same as in Embodiment 1.

[0067] Tests showed that the flexural strength of the sheet material prepared in this embodiment reached 21.3 MPa, exhibiting good toughness and impact resistance.

[0068] Example 4

[0069] A high-salt-content salt-based building decoration board improves the utilization rate of salt resources by increasing the proportion of salt powder and reducing the proportion of quartz sand. It is suitable for salt-based functional decorative materials and large-area wall decoration applications.

[0070] The raw materials, by weight, are composed as follows:

[0071] 300g quartz sand, 260g salt powder, 50g hollow glass microspheres, 30g E51 epoxy resin, 4g LS-AGE epoxy reactive diluent, 10g polyetheramine D230 curing agent, and 1.5g KH-560 silane coupling agent.

[0072] The preparation method in this embodiment is the same as in Embodiment 1.

[0073] Tests showed that the sheet material prepared in this embodiment has a complete structure, no obvious cracks or efflorescence, and good molding performance.

[0074] Example 5

[0075] An ultra-lightweight salt-based building decorative panel, by further increasing the amount of hollow glass microspheres added and reducing the overall density of the panel, is suitable for applications with high building load requirements, such as light steel keel partition walls and interior decoration of high-rise buildings.

[0076] The raw materials, by weight, are composed as follows:

[0077] 380g quartz sand, 220g salt powder, 70g hollow glass microspheres, 35g E51 epoxy resin, 5g LS-AGE epoxy reactive diluent, 12g polyetheramine D230 curing agent, and 1.5g KH-560 silane coupling agent.

[0078] The preparation method in this embodiment is the same as in Embodiment 1.

[0079] Tests showed that the density of the board prepared in this embodiment was further reduced while maintaining good mechanical properties and surface waterproofing performance.

[0080] Example 6

[0081] A low-resin-content salt-based building decoration board, by reducing the amount of epoxy resin, increases the proportion of inorganic components while ensuring the stability of the filler skeleton structure, making it suitable for cost-sensitive building decoration applications.

[0082] The raw materials, by weight, are composed as follows:

[0083] 450g quartz sand, 200g salt powder, 50g hollow glass microspheres, 20g E51 epoxy resin, 3g LS-AGE epoxy reactive diluent, 6g polyetheramine D230 curing agent, and 1.5g KH-560 silane coupling agent.

[0084] The preparation method in this embodiment is the same as in Embodiment 1.

[0085] Tests showed that the sheet material prepared in this embodiment still has good molding integrity and mechanical properties.

[0086] Comparative Example 1

[0087] To investigate the effect of hollow glass microspheres on the lightweighting and overall performance of the substrate, Comparative Example 1 was set up. Except for the absence of hollow glass microspheres, the composition of the raw materials and the preparation process were the same as in Example 1.

[0088] The raw materials, by weight, are composed as follows:

[0089] 480g quartz sand, 180g salt powder, 38.3g E51 epoxy resin, 5.5g LS-AGE epoxy reactive diluent, 12.8g polyetheramine D230 curing agent, and 1.7g KH-560 silane coupling agent.

[0090] The preparation method for this comparative example is the same as that for Example 1.

[0091] Tests showed that the board prepared in Comparative Example 1 could be formed normally, but the density of the board increased significantly due to the lack of low-density hollow glass microsphere filling structure.

[0092] Comparative Example 2

[0093] To investigate the effects of epoxy pre-coating of salt powder on the dispersibility, interfacial bonding properties, and water resistance of salt powder, comparative example 2 was set up.

[0094] Except for the salt powder, which is not pre-coated with epoxy, the composition of the other raw materials and the preparation process are the same as in Example 1.

[0095] The raw materials, by weight, are composed as follows:

[0096] 480g of quartz sand, 180g of salt powder without epoxy pre-coating, 40g of hollow glass microspheres, 38.3g of E51 epoxy resin, 5.5g of LS-AGE epoxy reactive diluent, 12.8g of polyetheramine D230 curing agent, and 1.7g of KH-560 silane coupling agent.

[0097] In this case, the salt powder is directly mixed with the quartz sand, hollow glass microspheres and epoxy resin system, without the epoxy resin pre-coating treatment as in Example 1.

[0098] The subsequent preparation method for this comparative example is the same as that for Example 1.

[0099] like Figure 1 The image shown is a scanning electron microscope (SEM) photograph of the substrate surface and corresponding elemental distribution analysis from Example 1. The SEM images reveal a relatively dense surface structure with no obvious through-holes or large-area defects, indicating that the resin matrix effectively impregnates inorganic filler particles such as quartz sand and salt powder during hot pressing, forming a continuous resin-inorganic composite structure. Elemental analysis shows that carbon (C) mainly originates from the epoxy resin matrix and is uniformly distributed on the substrate surface; silicon (Si) corresponds to the quartz sand and silicon-based hydrophobic coating components, showing a relatively uniform distribution; sodium (Na) and chloride (Cl) correspond to the salt powder components, maintaining uniform dispersion within the substrate without significant agglomeration, indicating that the salt powder, after epoxy resin pre-coating, exhibits good interfacial compatibility with the resin matrix.

[0100] like Figure 2 The image shown is a scanning electron microscope (SEM) photograph of the cross-section of the plate from Example 1, along with elemental distribution analysis. The cross-sectional morphology reveals a relatively uniform multiphase composite structure within the plate. The quartz sand particles, salt powder particles, and the continuous resin phase are tightly bonded together, with no obvious interfacial debonding. Furthermore, Si, Na, and Cl elements are uniformly distributed across the cross-sectional area, indicating that the salt powder and quartz sand are uniformly embedded within the resin network structure. These results demonstrate that silane coupling modification of quartz sand and epoxy pre-coating treatment with salt powder can effectively improve the interfacial bonding between inorganic fillers and organic resin, thereby enhancing the overall mechanical properties and structural stability of the plate.

[0101] like Figure 3The figures show optical photographs of the plates prepared in Examples 1 and 2. As can be seen from the figures, the surfaces of the plates obtained in Examples 1 and 2 are smooth and dense, without obvious cracks, holes, or macroscopic defects. This indicates that by replacing part of the high-density filler with hollow glass microspheres, combined with segmented material laying and hot-pressing processes, the structural integrity of the plate can be guaranteed. In particular, Example 2, by increasing the amount of hollow glass microspheres added, further reduced the material density while maintaining the surface integrity of the plate, proving the feasibility of the lightweight design scheme of this invention.

[0102] like Figure 4 The image shows the static water contact angle test results for the board surface in Example 1. The test results show that water droplets form distinct spherical droplets on the board surface, with a static contact angle reaching 132°, exhibiting excellent hydrophobic properties. This is mainly attributed to the dual-layer protective structure constructed on the board surface: a dense phosphorus silica sol layer + a hydrophobic layer containing long-chain alkyl silica sol. The inner layer seals surface micropores, reducing water penetration channels, while the outer layer's low surface energy alkyl structure enhances surface hydrophobicity. Therefore, this surface treatment method effectively reduces the risk of moisture absorption and efflorescence in salt-based boards, improving their environmental durability.

[0103] As shown in Tables 1 and 2, although the board obtained in Comparative Example 2 can be molded, the lack of an epoxy resin coating layer on the surface of the salt powder particles reduces the interfacial bonding ability between the salt powder and the resin matrix, making it prone to local defects. At the same time, due to the strong hygroscopicity of the salt powder, the water absorption rate of the board increases, and salt precipitation or efflorescence may occur on the surface. Its water resistance stability is significantly lower than that of Example 1.

[0104] Table 1. Formulations and performance test results of each embodiment.

[0105]

[0106] Table 2 Comparative Performance Table

[0107]

Claims

1. A lightweight, high-strength salt-based building decorative panel, characterized in that, By weight, it includes the following components: 300-480 parts quartz sand, 180-260 parts salt powder, 40-70 parts hollow glass microspheres, 20-39 parts epoxy resin, 3-6 parts epoxy reactive diluent, 6-13 parts curing agent, and 1-2 parts silane coupling agent.

2. The lightweight, high-strength salt-based building decorative panel according to claim 1, characterized in that, The quartz sand has a particle size of 120-160 mesh; the salt powder has a particle size of 800-1000 mesh; and the hollow glass microspheres have a particle size of 10-20 μm and a compressive strength ≥60 MPa.

3. The lightweight, high-strength salt-based building decorative panel according to claim 1, characterized in that, The epoxy resin is a bisphenol A type epoxy resin or a modified epoxy resin, wherein the bisphenol A type epoxy resin is selected from at least one of E51 and E44, and the modified epoxy resin is a CTBN modified epoxy resin; the epoxy reactive diluent is a monofunctional glycidyl ether reactive diluent, selected from at least one of lauryl glycidyl ether LS-AGE, allyl glycidyl ether AGE, and butyl glycidyl ether BGE; the curing agent is a polyether amine curing agent, selected from at least one of polyether amine D230 and polyether amine D400; and the silane coupling agent is an epoxy silane coupling agent, selected from γ-glycidyl etheroxypropyltrimethoxysilane or γ-glycidyl etheroxypropyltriethoxysilane.

4. The lightweight, high-strength salt-based building decorative panel according to claim 1, characterized in that, The surface of the lightweight, high-strength salt-based building decorative panel is coated with an organic-inorganic hybrid hydrophobic layer; the hydrophobic layer has a double-layer structure, consisting of a phosphorus silica sol curing layer and a silica sol curing layer containing long-chain alkyl groups from the inside out.

5. The method for preparing the lightweight, high-strength salt-based building decorative panel according to any one of claims 1-4, characterized in that, Includes the following steps: (1) Raw material pretreatment: Dry and sieve the quartz sand, salt powder and hollow glass microspheres to the target particle size for later use; (2) Surface modification of quartz sand: Silane coupling agent hydrolysate is used to modify the surface of quartz sand and then solidify it; (3) Salt powder pre-coating treatment: The salt powder is pre-coated with epoxy resin diluent, and the pre-coated salt powder is obtained after the solvent evaporates; (4) Mixing: First, disperse the hollow glass microspheres in the preheated epoxy resin and epoxy reactive diluent mixture, then add the pre-coated salt powder and quartz sand in sequence, and finally add the curing agent and mix evenly to obtain the mixture. (5) Hot pressing: The mixture is laid into the mold and hot pressed to cure; (6) Curing and sanding: After demolding, room temperature curing and sanding are carried out.

6. The preparation method according to claim 5, characterized in that, The specific steps for surface modification of quartz sand in step (2) are as follows: the silane coupling agent is dispersed in an aqueous ethanol solvent for hydrolysis, the hydrolyzed silane coupling agent dispersion is evenly sprayed onto the stirred quartz sand, and the spraying is completed by drying and curing.

7. The preparation method according to claim 5, characterized in that, The specific steps of the salt powder pre-coating treatment in step (3) are as follows: take 5%-8% of the total amount of epoxy resin, dilute it with organic solvent, add salt powder and mix evenly, spread it out to dry, and let the organic solvent evaporate completely.

8. The preparation method according to claim 5, characterized in that, In step (4), after the epoxy resin and epoxy reactive diluent are mixed, they are preheated at 55-60℃ for 15-20 minutes, and then hollow glass microspheres are added for dispersion.

9. The preparation method according to claim 5, characterized in that, In step (5), the temperature for hot pressing and curing is 90-110℃, the pressure is 10-15MPa, and the heat and pressure holding time is 10-30min.

10. The preparation method according to claim 5, characterized in that, After sanding in step (6), a silane coupling agent primer is first sprayed onto the surface of the board, followed by a phosphosilicate sol and a silica sol containing a long-chain alkyl silane end-capping agent. After curing, an organic-inorganic hybrid hydrophobic layer is prepared.

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