Special waterproof cement, straw carbonization waterproof treatment agent, straw composite external wall board and preparation method thereof

Abstract

The application discloses a special waterproof cement, a straw carbonization waterproof treatment agent, a straw composite external wall board and a preparation method thereof, and belongs to the technical field of novel building materials. The preparation method of the external wall board comprises the following steps: preparing special waterproof cement pressure plate slurry, preparing special waterproof cement pressure plates, preparing a straw carbonization waterproof treatment agent, preparing carbonized waterproof straw fragments, preparing a straw core material adhesive, preparing a waterproof and fireproof straw core material, preparing an inorganic foamed ceramic adhesive, and combining the face plate and the core material into an integrated body. The application has the advantages of: (1) the preparation method is easy to implement and low in cost, the remaining crop straw is fully utilized, environmental pollution is avoided, and the ecological environment is protected; and (2) the prepared straw composite external wall board has excellent properties such as light weight, waterproofness, fireproofness, corrosion resistance, sound insulation, heat preservation and impact resistance.

Description

Technical Field

[0001] This invention relates to a special waterproof cement, a straw carbonization waterproofing agent, a straw composite exterior wall panel and its preparation method, specifically to a straw composite exterior wall panel that integrates waterproofing, fireproofing, corrosion resistance, sound insulation and heat preservation, and its preparation method, belonging to the field of new building materials technology. Background Technology

[0002] Chinese patent CN203961112U (Ecological Fireproof and Thermal Insulation Exterior Wall Composite Board) discloses an ecological fireproof and thermal insulation exterior wall composite board. This composite board encapsulates plant straw within the cavity of a cement fireproof board. The back of the top and bottom panels are coated with a water glass sealant for waterproofing, and the sides are sealed with polyurethane foam boards. The joints are also sealed with water glass sealant. This practice of relying on a cement fireproof board and water glass sealant for the waterproofing, fireproofing, and corrosion resistance of the straw core board is extremely unscientific and impractical, for the following reasons: 1. Commercially available cement fireproof boards are made of cement and fine sand. They are a building material with extremely high porosity. While they are resistant to water immersion, they cannot prevent water penetration and are extremely prone to absorbing water, allowing water to permeate, and becoming damp. 2. Water glass sealant (commonly known as sodium silicate) is used for the waterproof protective layer. Due to the presence of a large number of sodium ions, the water glass sealant will dissolve when it comes into contact with water after it solidifies, and the sodium ions will precipitate out, returning to a liquid state. Therefore, using water glass sealant as a waterproof protective layer cannot play a waterproof and protective role at all. 3. When cement fireproof boards absorb and permeate water, they will dissolve the water glass sealant on the back of the fireproof board, causing the water glass sealant to lose its waterproof function. When water permeates the cement fireproof board and dissolves the water glass sealant on the back of the fireproof board, the water enters the straw core board. When the straw core board comes into contact with water, it will become damp, swell, mold, and rot, causing water to seep into the room from the exterior wall, with a very strong odor, making it impossible for people to live there.

[0003] 4. The exterior wall composite panels are prefabricated in a standardized factory, and it is difficult to achieve the same size module as the exterior wall on the construction site. The size error is large. During construction and installation, almost every composite wall panel has to be cut on site, resulting in a large amount of straw core board being exposed. The waterproofing problem of the cut surface of the board cannot be solved. After one or two years, the walls of the house will have problems such as water seepage, mold and straw rotting.

[0004] Chinese patent CN204676768U (High-Temperature Extruded Glue-Free Straw Building Board) discloses a high-temperature extruded glue-free straw building board, Chinese patent CN206067070U (High-Temperature Extruded Straw Building Board) discloses a high-temperature extruded straw building board, and Chinese patent CN204299032U (Straw Polyurethane Wall Panel) discloses a straw polyurethane wall panel. These boards are all encapsulated composite straw wall panels. Since the straw core board itself is not waterproof, they are prone to common problems such as water absorption and permeability at the cut surface, easy mold growth, and easy rot. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a straw composite exterior wall panel with excellent waterproof, fireproof, corrosion-resistant, soundproof, and heat-insulating properties, as well as its preparation method.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing straw composite exterior wall panels includes the following steps: (1) Preparation of special waterproof cement pressure board slurry: By weight, add 60-70 parts of tap water into a forced mixer, and then add 0.3-0.6 parts of dispersant, 100-120 parts of cement, 300-360 parts of sand, 3-5 parts of silica powder, 1-2 parts of crack-resistant fiber and 0.2-0.4 parts of waterproofing agent to the forced mixer in sequence under the mixing condition. Stir for 10-15 minutes, and finally add 5-7 parts of waterproofing reinforcing agent to the forced mixer. After dispersing and mixing evenly, the special waterproof cement pressure board slurry is prepared. (2) Preparation of special waterproof cement pressure board: The special waterproof cement pressure board slurry obtained in step (1) is made into a special waterproof cement pressure board using a board making machine; (3) Preparation of straw carbonization waterproofing agent: By weight, add 90-100 parts of tap water to a mixing tank equipped with a heating device and heat it to 60-70°C. Then add 6-7 parts of borax, 8-9 parts of ammonium sulfate and 8-10 parts of ammonium polyphosphate to the mixing tank in sequence. After all the above raw materials are fully dissolved, add 2-3 parts of waterproofing agent and 0.4-0.6 parts of penetrant. After mixing evenly, the straw carbonization waterproofing agent is prepared. (4) Preparation of carbonized waterproof straw fragments: Plant straw fragments with a length of 100mm to 200mm are fed into a mixer. Under low-speed mixing conditions, the carbonized waterproof straw treatment agent prepared above is sprayed onto the surface of the plant straw fragments using a high-pressure spraying method. The amount of spraying is 16 to 20% of the weight of the plant straw fragments. After thorough mixing, the plant straw fragments are sent into a hot air dryer and dried until the moisture content is less than 5%, thus obtaining carbonized waterproof straw fragments. (5) Preparation of straw core material adhesive: By weight, add 100-120 parts of tap water to a mixing tank equipped with a heating device and heat it to 50-60°C. Then, add 50-60 parts of industrial gelatin or polyethylene or petroleum resin, 5-6 parts of alcohol and 0.2-0.3 parts of aluminum chloride to the mixing tank in sequence. After stirring thoroughly, stop heating and stirring. The esterification reaction takes 120-160 minutes. Finally, under stirring conditions, add 10-12 parts of water-based epoxy resin, 10-12 parts of sodium thiocyanate or potassium thiocyanate, 10-12 parts of preservative, 0.4-0.6 parts of wetting agent and 0.1-0.2 parts of bactericide to the mixing tank in sequence. After mixing evenly, the straw core material adhesive is prepared. (6) Preparation of waterproof and fireproof straw core material: By weight, add 100-120 parts of carbonized waterproof straw fragments prepared above into a mixer. Under low-speed mixing conditions, add 20-25 parts of heat insulation fiber and 5-7 parts of hollow microspheres into the mixer and mix for 3-5 minutes. Then, use a high-pressure spray gun to spray the straw core material adhesive prepared above onto the surface of the carbonized waterproof straw fragments. After mixing evenly, put it into a mold and cold press to form a waterproof and fireproof straw core board. (7) Preparation of inorganic foamed ceramic adhesive: The inorganic foamed ceramic adhesive is a two-component adhesive. Component A is a crosslinking agent. The preparation method of component B is as follows: by weight, add 40-55 parts of tap water into a mixer, and then add 100-120 parts of magnesium oxide, 10-12 parts of fly ash, 5-12 parts of borax, 1-1.5 parts of coupling agent, 5-6 parts of LWJ-400B JS waterproof emulsion and 1-1.2 parts of foaming agent to the mixer in sequence under stirring conditions. After thorough mixing, component B is prepared. When using, add 25-30 parts of component A to 162-211 parts of component B for rapid curing. (8) Composite panel and core material into one: Use the inorganic foamed ceramic adhesive prepared above to composite two special waterproof cement pressure boards prepared above and three waterproof and fireproof straw core materials prepared above into one. The composite order is: cement pressure board - straw core material - straw core material - cement pressure board. Cold press for 30 minutes to obtain straw composite exterior wall panel.

[0007] Preferably, in step (1), the dispersant is sodium hexametaphosphate or dispersant 5040; the cement is ordinary silicate cement, composite silicate cement, high alumina cement or magnesium oxysulfate cement; the sand is quartz sand, river sand, tailings sand or manufactured sand; the crack-resistant fiber is polyester fiber, PP fiber, glass fiber or carbon fiber; the waterproofing agent is organosilicon waterproofing agent, sodium methylsiloxane waterproofing agent, potassium methylsilicate alkaline waterproofing agent, potassium methylsilicate neutral waterproofing agent, calcium stearate, zinc stearate or liquid wax; the waterproofing reinforcing agent is LWJ-400B JS waterproof emulsion or waterborne polyurethane.

[0008] Preferably, in step (2), alkali-resistant glass mesh is pre-laid on the substrate of the board making machine, and another layer of alkali-resistant glass mesh is immediately laid on the surface after the previous process is smoothed.

[0009] Preferably, in step (3), the waterproofing agent is neutral potassium methylsilicate, neutral sodium methylsilicate or sodium methylsiloxane; the penetrant is fast penetrant T or wetting agent.

[0010] Preferably, in step (4), the plant straw used is wheat straw, rice straw, corn straw, soybean straw or cotton straw; the gradation requirements of the plant straw fragments are: 30% of the fragments are 100mm long, 40% are 150mm long, and 30% are 200mm long.

[0011] Preferably, in step (6), the heat insulation fiber is selected from asbestos fiber, sepiolite fiber, aluminum silicate fiber or rock wool fiber; the hollow microspheres are selected from hollow glass microspheres, hollow ceramic microspheres or hollow silica microspheres.

[0012] Preferably, in step (7), the coupling agent is silane coupling agent KH-560; the foaming agent is cement foaming agent.

[0013] A straw composite exterior wall panel prepared by the method described in any one of the preceding claims.

[0014] The advantages of this invention are: 1. The method for preparing the straw composite exterior wall panel provided by the present invention is easy to implement and has a low cost. It not only makes full use of the remaining crop straw, which belongs to the comprehensive utilization of renewable resources and avoids environmental pollution, but also saves a lot of cement, sand and gravel and mineral resources, thus protecting the ecological environment. 2. The straw composite exterior wall panel prepared by the method provided in this invention has excellent properties such as light weight, waterproof, fireproof, corrosion-resistant, sound insulation, heat insulation, and impact resistance. Detailed Implementation

[0015] The present invention will be described in detail below with reference to specific embodiments.

[0016] 1. Preparation of special waterproof cement pressure board slurry The raw materials required for preparing the special waterproof cement pressure board slurry, by weight, are as follows: Dispersant 0.3-0.6 parts, cement 100-120 parts, sand 300-360 parts, silica powder 3-5 parts, crack-resistant fiber 1-2 parts, waterproofing agent 0.2-0.4 parts, waterproofing reinforcing agent 5-7 parts, tap water 60-70 parts.

[0017] in: (1) Dispersant: Industrial grade sodium hexametaphosphate or dispersant 5040 (an anionic surfactant) can be selected. (2) Cement: Ordinary silicate cement, composite silicate cement, high alumina cement or magnesium oxysulfate cement can be selected; (3) Sand: Quartz sand, river sand, tailings sand or manufactured sand can be selected, with a particle size in the range of 40 to 70 mesh; (4) Silica powder: active or non-active silica powder can be selected, with a particle size in the range of 2000 to 2300 mesh; (5) Crack-resistant fiber: Polyester fiber, PP fiber, glass fiber or carbon fiber can be selected, with a length in the range of 8 to 10 mm; (6) Waterproofing agent: You can choose organosilicon waterproofing agent, sodium methylsiloxane waterproofing agent, potassium methylsilicate alkaline waterproofing agent, potassium methylsilicate neutral waterproofing agent, calcium stearate (industrial grade), zinc stearate (industrial grade) or liquid wax. (7) Waterproofing enhancer: LWJ-400B JS waterproof emulsion or water-based polyurethane can be selected.

[0018] The specific method for preparing special waterproof cement pressure board slurry is as follows: Add tap water to a forced mixer, and then add dispersant, cement, sand, silica powder, crack-resistant fiber and waterproofing agent to the forced mixer in sequence under mixing conditions (60-80 rpm). Mix for 10-15 minutes, and finally add waterproofing reinforcing agent to the forced mixer. After dispersing and mixing evenly, special waterproof cement pressure board slurry is prepared.

[0019] In this specific embodiment, three portions of special waterproof cement pressure board slurry were prepared, and the specific formulations of each portion are shown in Table 1.

[0020] Table 1. Formulation of Special Waterproof Cement Pressure Board Grout

[0021] The special waterproof cement pressure board slurry corresponding to Formula 1 is designated as Cement Pressure Board Slurry A, the special waterproof cement pressure board slurry corresponding to Formula 2 is designated as Cement Pressure Board Slurry B, and the special waterproof cement pressure board slurry corresponding to Formula 3 is designated as Cement Pressure Board Slurry C.

[0022] This invention adds silica powder, waterproofing agent, waterproofing enhancer, and crack-resistant fiber to ordinary cement pressure board slurry, making the cement pressure board denser, impermeable, and non-absorbent, thus truly providing waterproof and moisture-proof protection. Moreover, its flexibility, flexural strength, and impact resistance are greatly improved, thereby protecting the straw core material from water damage and achieving the purpose of waterproofing, moisture-proofing, and corrosion prevention for straw composite exterior wall panels.

[0023] 2. Preparation of special waterproof cement pressure board The specific method for preparing special waterproof cement pressure boards is as follows: Adjust the distance between the upper and lower rollers of the board making machine (to match the thickness of the special waterproof cement pressure board). Lay a layer of alkali-resistant glass mesh cloth on the substrate of the board making machine (as a reinforcing layer for the cement pressure board). Feed the special waterproof cement pressure board slurry prepared earlier into the storage cylinder of the board making machine. Then, the special waterproof cement pressure board slurry flows into the substrate pre-laid with alkali-resistant glass mesh cloth. After the previous process is smoothed, immediately lay another layer of alkali-resistant glass mesh cloth on the surface. After the rollers flatten it, immediately cut it into the required specifications. Then send it into the heat curing room for curing to obtain the special waterproof cement pressure board.

[0024] In this specific embodiment, the alkali-resistant glass mesh used weighs 160g / m². 2 The mesh size is 2mm×3mm; the specifications of the special waterproof cement pressure board prepared are 3000mm (length)×1200mm (width)×10mm (thickness).

[0025] The special waterproof cement pressure board corresponding to cement pressure board slurry A is denoted as cement pressure board A, the special waterproof cement pressure board corresponding to cement pressure board slurry B is denoted as cement pressure board B, and the special waterproof cement pressure board corresponding to cement pressure board slurry C is denoted as cement pressure board C.

[0026] The waterproofing and seepage resistance, as well as the flexural strength and impact resistance, of each cement pressure board were tested. The specific methods used to test the waterproofing and seepage resistance are as follows: (1) Cut a 300mm×300mm test block from each of cement pressure board A, cement pressure board B, cement pressure board C and commercially available cement fireproof board. (2) Seal the top of each test block with waterproof sealant to form a water-blocking platform with a height of 20mm, and dry for 24 hours; (3) Pour tap water on top of each test block to a depth of 15 mm, observe the water permeability of each test block, and record the time.

[0027] The test results of the waterproofing and seepage resistance, as well as the flexural strength and impact resistance of each cement pressure board are shown in Table 2.

[0028] Table 2. Waterproofing and seepage status, and test results of flexural strength and impact resistance of various cement pressure boards.

[0029] As shown in Table 2, the cement pressure board prepared by this invention is denser, impermeable, and non-absorbent, and can truly play a role in waterproofing and moisture-proofing. Moreover, its flexural strength and impact resistance are greatly improved.

[0030] 3. Preparation of straw carbonization waterproofing agent The raw materials required for preparing the straw carbonization and waterproofing treatment agent, by weight, are as follows: Borax 6-7 parts, ammonium sulfate 8-9 parts, ammonium polyphosphate 8-10 parts, waterproofing agent 2-3 parts, penetrant 0.4-0.6 parts, tap water 90-100 parts.

[0031] in: (1) Borax, ammonium sulfate and ammonium polyphosphate are all industrial grade, and their content is all above 95%; (2) Waterproofing agent: Neutral potassium methylsilicate, neutral sodium methylsilicate or sodium methylsiloxane can be selected; (3) Penetrant: Fast penetrant T or wetting agent can be selected.

[0032] The specific method for preparing straw carbonization waterproofing agent is as follows: Add tap water to a mixing tank equipped with a heating device. Under stirring conditions (100-120 rpm), heat the tap water in the mixing tank to 60-70°C. Then increase the stirring speed (150-200 rpm) and continue to add borax, ammonium sulfate, and ammonium polyphosphate to the mixing tank in sequence. After all the above raw materials are fully dissolved, add the waterproofing agent and penetrant. After mixing evenly, the straw carbonization waterproofing treatment agent is prepared.

[0033] In this specific embodiment, three straw carbonization and waterproofing treatment agents were prepared, and the specific formulations of each are shown in Table 3.

[0034] Table 3 Formulation of Straw Carbonization Waterproofing Agent

[0035] The straw carbonization and waterproofing treatment agent corresponding to Formula 1 is denoted as Carbonization and Waterproofing Treatment Agent A, the straw carbonization and waterproofing treatment agent corresponding to Formula 2 is denoted as Carbonization and Waterproofing Treatment Agent B, and the straw carbonization and waterproofing treatment agent corresponding to Formula 3 is denoted as Carbonization and Waterproofing Treatment Agent C.

[0036] After treating straw fragments with the above-mentioned straw carbonization and waterproofing agent provided by this invention, the straw fragments can be carbonized directly without burning when exposed to open flame. The carbonized layer can isolate oxygen and prevent the spread of fire, thereby greatly improving the fire resistance limit of straw composite exterior wall panels and solving the major problem of straw's flammability. Moreover, the treated straw fragments themselves become hydrophobic, do not absorb water or moisture, and will not mold, rot, or swell when exposed to water, solving the problem of straw easily rotting during long-term storage and greatly improving the storage safety of straw. In addition, borax has anti-corrosion and bactericidal functions, which can play a protective role for straw.

[0037] 4. Preparation of carbonized waterproof straw fragments The raw materials required for preparing carbonized waterproof straw fragments are: plant straw and straw carbonization and waterproofing agent.

[0038] The specific method for preparing carbonized waterproof straw fragments is as follows: Plant straw is fed into a straw crusher for crushing to obtain plant straw fragments with a length of 100mm to 200mm. Then, the plant straw fragments are fed into a mixer, and under low-speed mixing conditions (60 to 80 rpm), the previously prepared straw carbonization and waterproofing treatment agent is sprayed onto the surface of the plant straw fragments using a high-pressure spray method. The amount of straw carbonization and waterproofing treatment agent sprayed is 16 to 20% of the weight of the plant straw fragments. After being thoroughly mixed, the plant straw fragments are fed into a hot air dryer and dried until the moisture content is less than 5%, thus obtaining carbonized waterproof straw fragments.

[0039] Among them, plant straw can be selected from wheat straw, rice straw, corn straw, soybean straw, cotton straw, etc.

[0040] In this specific embodiment, wheat straw is selected as the plant straw. After being crushed by a straw crusher, the wheat straw meets the following gradation requirements: 30% of the fragments are 100mm long, 40% are 150mm long, and 30% are 200mm long.

[0041] The crushed straw fragments were divided into three parts and sprayed with carbonization and waterproofing agent A, carbonization and waterproofing agent B, and carbonization and waterproofing agent C, respectively. The spraying amounts were 16%, 18%, and 20% of the weight of the straw fragments, respectively. The resulting carbonization and waterproofing straw fragments were then designated as carbonization and waterproofing fragment A, carbonization and waterproofing fragment B, and carbonization and waterproofing fragment C.

[0042] The fire resistance and water absorption of each carbonized waterproof aggregate were tested. The specific testing methods are as follows: (1) Weigh out carbonized waterproof fragments A, carbonized waterproof fragments B, carbonized waterproof fragments C and straw fragments that have not been sprayed with carbonized waterproof treatment agent. Weigh out two portions of each type, each portion being 500g, and put them into 20L metal buckets respectively. (2) Divide the weighed carbonized waterproof fragments A, B, and C, as well as the straw fragments without carbonized waterproof treatment agent, into two groups. One group is used for a combustion test, and the other group is used for a water absorption test.

[0043] The test results of the fire resistance and water absorption of each carbonized waterproof aggregate are shown in Table 4.

[0044] Table 4. Test results of fire resistance and water absorption of various carbonized waterproof aggregates (500g sample)

[0045] As shown in Table 4, the straw fragments treated with the carbonization and waterproofing agent provided by this invention do not burn when exposed to open flame and are directly carbonized. They are also not prone to absorbing water. This solves both the major problem of straw being flammable and the problem of straw easily rotting during long-term storage, greatly improving the storage safety of straw.

[0046] 5. Preparation of straw core material adhesive The raw materials required for preparing straw core material adhesive, by weight, are as follows: 50-60 parts industrial gelatin (or polyethylene, petroleum resin), 5-6 parts alcohol, 0.2-0.3 parts aluminum chloride, 10-12 parts water-based epoxy resin, 10-12 parts sodium / potassium thiocyanate, 10-12 parts preservative, 0.4-0.6 parts wetting agent, 0.1-0.2 parts bactericide, and 100-120 parts tap water.

[0047] in: (1) The alcohol, aluminum chloride, sodium thiocyanate and potassium thiocyanate are all industrial grade and have a content of more than 95%; (2) Preservative: 1000-1250 mesh calcium hydroxide can be selected; (3) Bactericide: Silver ion bactericide can be selected.

[0048] The specific method for preparing straw core material adhesive is as follows: Tap water is added to a mixing tank equipped with a heating device. Under stirring conditions (100-200 rpm), the tap water in the mixing tank is heated to 50-60°C. Then, the stirring speed is increased (200-250 rpm), and gelatin is added to the mixing tank. After the industrial gelatin (or polyethylene, petroleum resin) has completely dissolved, alcohol and aluminum chloride are added to the mixing tank in sequence. After stirring thoroughly, heating and stirring are stopped. The esterification reaction is carried out for 120-160 minutes. Finally, under stirring conditions, water-based epoxy resin, sodium thiocyanate (or potassium thiocyanate), preservative, wetting agent, and bactericide are added to the mixing tank in sequence. After mixing evenly, the straw core material adhesive is prepared.

[0049] In this specific embodiment, three straw core material adhesives were prepared, and the specific formulations of each are shown in Table 5.

[0050] Table 5 Formulation of Straw Core Material Adhesive

[0051] The straw core material adhesive corresponding to Formula 1 is denoted as Core Material Adhesive A, the straw core material adhesive corresponding to Formula 2 is denoted as Core Material Adhesive B, and the straw core material adhesive corresponding to Formula 3 is denoted as Core Material Adhesive C.

[0052] 6. Preparation of waterproof and fireproof straw core material The raw materials required for preparing waterproof and fireproof straw core material, by weight, are as follows: 100-120 parts of carbonized waterproof straw fragments, 20-25 parts of heat-insulating fiber, 5-7 parts of hollow microspheres, and 10-12 parts of straw core material adhesive.

[0053] in: (1) Thermal insulation fiber: asbestos fiber, sepiolite fiber, aluminum silicate fiber or rock wool fiber can be selected; (2) Hollow microspheres: Hollow glass microspheres, hollow ceramic microspheres or hollow silica microspheres can be selected.

[0054] The specific method for preparing waterproof and fireproof straw core material is as follows: Add the carbonized waterproof straw fragments prepared earlier into a mixer. Under low-speed mixing conditions (50-60 rpm), add the heat-insulating fiber and vacuum glass microspheres into the mixer and mix for 3-5 minutes. Then, use a high-pressure spray gun to spray the straw core material adhesive prepared earlier onto the surface of the carbonized waterproof straw fragments while spraying and mixing rapidly to ensure that the surface of each straw is covered with straw core material adhesive. After thorough mixing, pour the mixture into a mold. The prepared dimensions of the straw core material are 3000mm (length) × 1200mm (width) × 90mm (thickness). The thickness of the material is controlled at a ratio of finished board to blank of 1:5. Cold press the mixture at a pressure of 5-6 MPa for 20-30 minutes to obtain the waterproof and fireproof straw core board.

[0055] In this specific embodiment, three waterproof and fireproof straw core materials were prepared, and the specific formulations of each are shown in Table 6.

[0056] Table 6 Formulation of Waterproof and Fireproof Straw Core Material

[0057] The waterproof and fireproof straw core material corresponding to Formula 1 is designated as Straw Core Material A, the waterproof and fireproof straw core material corresponding to Formula 2 is designated as Straw Core Material B, and the waterproof and fireproof straw core material corresponding to Formula 3 is designated as Straw Core Material C.

[0058] This invention incorporates heat-insulating fibers during the preparation of waterproof and fireproof straw core materials. These fibers act as heat-insulating performance enhancers, significantly improving the energy efficiency of the resulting straw composite exterior wall panels.

[0059] 7. Preparation of inorganic foamed ceramic adhesive The inorganic foamed ceramic adhesive is packaged in two components (component A and component B). Component A has a relatively simple composition and is a crosslinking agent, such as industrial-grade granular potassium dihydrogen phosphate with a content of over 95%. Component B has a more complex composition. The raw materials required to prepare component B, by weight, are as follows: Magnesium oxide 100-120 parts, fly ash 10-12 parts, borax 5-12 parts, coupling agent 1-1.5 parts, LWJ-400BJS waterproof emulsion 5-6 parts, foaming agent 1-1.2 parts, tap water 40-55 parts.

[0060] in: (1) Magnesium oxide is calcined at high temperature of 1500-1700℃ with a content of more than 85% and the fly ash is Grade I fly ash and the borax is industrial grade borax with a content of more than 95%. (2) Coupling agent: Silane coupling agent KH-560 can be selected; (3) Foaming agent: Cement foaming agent can be selected.

[0061] The specific method for preparing component B is as follows: Add tap water into the mixer, and then add magnesium oxide, fly ash, borax, coupling agent, LWJ-400B JS waterproof emulsion and foaming agent to the mixer in sequence under stirring conditions (60-80 rpm). After mixing thoroughly, component B is prepared.

[0062] Before use, components A and B are packaged separately. To use, add 25-30 parts of component A to 162-211 parts of component B for rapid curing.

[0063] In this specific embodiment, three inorganic foamed ceramic adhesives were prepared, and the specific formulations of each are shown in Table 7.

[0064] Table 7 Formulation of Inorganic Foamed Ceramic Adhesive

[0065] The inorganic foamed ceramic adhesive corresponding to Formula 1 is denoted as Foamed Ceramic Adhesive A, the inorganic foamed ceramic adhesive corresponding to Formula 2 is denoted as Foamed Ceramic Adhesive B, and the inorganic foamed ceramic adhesive corresponding to Formula 3 is denoted as Foamed C.

[0066] 8. Integrate the panel and core material into one piece. Each straw composite exterior wall panel is composed of two special waterproof cement pressure boards and three waterproof and fireproof straw core materials. The specific composite method is as follows: (1) Take a special waterproof cement pressure board, apply inorganic foamed ceramic adhesive to one side of it, and then composite the first layer of waterproof and fireproof straw core material. (2) Apply inorganic foamed ceramic adhesive to the other side of the first layer of waterproof and fireproof straw core material, and then composite the second layer of waterproof and fireproof straw core material; (3) Apply inorganic foamed ceramic adhesive to the other side of the second layer of waterproof and fireproof straw core material, and then composite the third layer of waterproof and fireproof straw core material. (4) Apply inorganic foamed ceramic adhesive to the other side of the third layer of waterproof and fireproof straw core material, and then laminate another special waterproof cement pressure board. (5) Cold press for 30 minutes to obtain straw composite exterior wall panel.

[0067] In this specific embodiment, three straw composite exterior wall panels were prepared, specifically: (1) Use the foamed ceramic adhesive A prepared above to combine two cement pressure boards A prepared above and three straw core materials A prepared above in the order of "cement pressure board A-straw core material A-straw core material A-straw core material A-cement pressure board A" to prepare the first straw composite exterior wall panel, which is denoted as exterior wall panel A; (2) Using the foamed ceramic adhesive B prepared above, two cement pressure boards B prepared above and three straw core materials B prepared above are combined together in the order of "cement pressure board B-straw core material B-straw core material B-straw core material B-cement pressure board B" to prepare the second straw composite exterior wall panel, which is denoted as exterior wall panel B. (3) The foamed ceramic adhesive C prepared above is used to combine the two cement pressure boards C prepared above and the three straw core materials C prepared above in the order of "cement pressure board C-straw core material C-straw core material C-straw core material C-cement pressure board C" to prepare the third straw composite exterior wall panel, which is denoted as exterior wall panel C.

[0068] The dimensions of the cement pressure board are 3000mm (length) × 1200mm (width) × 10mm (thickness), and the dimensions of the straw core material are 3000mm (length) × 1200mm (width) × 90mm (thickness). The amount of foamed ceramic adhesive required to prepare one straw composite exterior wall panel is 20kg.

[0069] Before pressing the straw composite exterior wall panel, the present invention first treats the straw fragments with waterproofing, fireproofing, and anti-corrosion. When pressing the straw core material, a special straw core material adhesive is used for pressing and molding. Therefore, the pressed straw composite exterior wall panel has waterproofing, fireproofing, and anti-corrosion functions. It also has high strength, good nail-holding power, can be nailed, sawed, and planed, and can be cut arbitrarily, making installation very convenient.

[0070] The technical properties of the prepared exterior wall panels A, B, and C, including compressive strength, impact resistance, water absorption, thermal conductivity, and fire resistance limit, were tested. The test results are shown in Table 8.

[0071] Table 8 Technical performance test results of each exterior wall panel

[0072] As shown in Table 8, compared with existing ecological fireproof exterior wall composite panels, the straw composite exterior wall panels prepared by the method provided by this invention have excellent waterproof, fireproof and heat insulation properties (the heat transfer performance index is reduced by nearly 10 times compared with the JC / T2629-2001 industry standard, reaching the highest national energy-saving standard of 83% energy saving in Beijing, Shanghai and Shandong), and the bending and impact resistance are greatly improved.

[0073] Furthermore, since the straw composite exterior wall panel prepared by this invention is made of three layers of 90mm thick straw core material bonded together with inorganic foamed ceramic adhesive, it can effectively block the transmission of sound waves of various frequencies, resulting in excellent sound insulation. Testing showed that the straw composite exterior wall panel prepared using the method provided by this invention achieved a sound insulation of 70-80dB, which is nearly 100% higher than the 35-45dB of the industry standard JC / T2629-2001 "Straw Composite Wall Panels".

[0074] It should be noted that the above embodiments are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is impossible to exhaustively list all possible implementations here. All obvious variations or modifications derived from the technical solutions of this invention are still within the protection scope of this invention.

Claims

1. A method for preparing straw composite exterior wall panels, characterized in that, Includes the following steps: (1) Preparation of special waterproof cement pressure board slurry: By weight, add 60-70 parts of tap water into a forced mixer, and then add 0.3-0.6 parts of dispersant, 100-120 parts of cement, 300-360 parts of sand, 3-5 parts of silica powder, 1-2 parts of crack-resistant fiber and 0.2-0.4 parts of waterproofing agent to the forced mixer in sequence under the mixing condition. Stir for 10-15 minutes, and finally add 5-7 parts of waterproofing reinforcing agent to the forced mixer. After dispersing and mixing evenly, the special waterproof cement pressure board slurry is prepared. (2) Preparation of special waterproof cement pressure board: The special waterproof cement pressure board slurry obtained in step (1) is made into a special waterproof cement pressure board using a board making machine; (3) Preparation of straw carbonization waterproofing agent: By weight, add 90-100 parts of tap water to a mixing tank equipped with a heating device and heat it to 60-70°C. Then add 6-7 parts of borax, 8-9 parts of ammonium sulfate and 8-10 parts of ammonium polyphosphate to the mixing tank in sequence. After all the above raw materials are fully dissolved, add 2-3 parts of waterproofing agent and 0.4-0.6 parts of penetrant. After mixing evenly, the straw carbonization waterproofing agent is prepared. (4) Preparation of carbonized waterproof straw fragments: Plant straw fragments with a length of 100mm to 200mm are fed into a mixer. Under low-speed mixing conditions, the carbonized waterproof straw treatment agent prepared above is sprayed onto the surface of the plant straw fragments using a high-pressure spraying method. The amount of spraying is 16 to 20% of the weight of the plant straw fragments. After thorough mixing, the plant straw fragments are sent into a hot air dryer and dried until the moisture content is less than 5%, thus obtaining carbonized waterproof straw fragments. (5) Preparation of straw core material adhesive: By weight, add 100-120 parts of tap water to a mixing tank equipped with a heating device and heat it to 50-60°C. Then, add 50-60 parts of industrial gelatin or polyethylene or petroleum resin, 5-6 parts of alcohol and 0.2-0.3 parts of aluminum chloride to the mixing tank in sequence. After stirring thoroughly, stop heating and stirring. The esterification reaction takes 120-160 minutes. Finally, under stirring conditions, add 10-12 parts of water-based epoxy resin, 10-12 parts of sodium thiocyanate or potassium thiocyanate, 10-12 parts of preservative, 0.4-0.6 parts of wetting agent and 0.1-0.2 parts of bactericide to the mixing tank in sequence. After mixing evenly, the straw core material adhesive is prepared. (6) Preparation of waterproof and fireproof straw core material: By weight, add 100-120 parts of carbonized waterproof straw fragments prepared above into a mixer. Under low-speed mixing conditions, add 20-25 parts of heat insulation fiber and 5-7 parts of hollow microspheres into the mixer and mix for 3-5 minutes. Then, use a high-pressure spray gun to spray the straw core material adhesive prepared above onto the surface of the carbonized waterproof straw fragments. After mixing evenly, put it into a mold and cold press to form a waterproof and fireproof straw core board. (7) Preparation of inorganic foamed ceramic adhesive: The inorganic foamed ceramic adhesive is a two-component adhesive. Component A is a crosslinking agent. The preparation method of component B is as follows: by weight, add 40-55 parts of tap water into a mixer, and then add 100-120 parts of magnesium oxide, 10-12 parts of fly ash, 5-12 parts of borax, 1-1.5 parts of coupling agent, 5-6 parts of LWJ-400B JS waterproof emulsion and 1-1.2 parts of foaming agent to the mixer in sequence under stirring conditions. After thorough mixing, component B is prepared. When using, add 25-30 parts of component A to 162-211 parts of component B for rapid curing. (8) Composite panel and core material into one: Use the inorganic foamed ceramic adhesive prepared above to composite two special waterproof cement pressure boards prepared above and three waterproof and fireproof straw core materials prepared above into one. The composite order is: cement pressure board - straw core material - straw core material - cement pressure board. Cold press for 30 minutes to obtain straw composite exterior wall panel.

2. The method for preparing straw composite exterior wall panels according to claim 1, characterized in that, In step (1), the dispersant used is sodium hexametaphosphate or dispersant 5040; the cement used is ordinary silicate cement, composite silicate cement, high alumina cement or magnesium oxysulfate cement; the sand used is quartz sand, river sand, tailings sand or manufactured sand; the crack-resistant fiber used is polyester fiber, PP fiber, glass fiber or carbon fiber; the waterproofing agent used is organosilicon waterproofing agent, sodium methylsiloxane waterproofing agent, potassium methylsilicate alkaline waterproofing agent, potassium methylsilicate neutral waterproofing agent, calcium stearate, zinc stearate or liquid wax; the waterproofing reinforcing agent used is LWJ-400B JS waterproof emulsion or waterborne polyurethane.

3. The method for preparing straw composite exterior wall panels according to claim 1, characterized in that, In step (2), alkali-resistant glass mesh cloth is pre-laid on the substrate of the board making machine, and another layer of alkali-resistant glass mesh cloth is immediately laid on the surface after the previous process is smoothed.

4. The method for preparing straw composite exterior wall panels according to claim 1, characterized in that, In step (3), the waterproofing agent selected is neutral potassium methylsilicate, neutral sodium methylsilicate or sodium methylsiloxane; the penetrant selected is fast penetrant T or wetting agent.

5. The method for preparing straw composite exterior wall panels according to claim 1, characterized in that, In step (4), the plant straw used is wheat straw, rice straw, corn straw, soybean straw or cotton straw; the gradation requirements of the plant straw fragments are: 30% of the fragments are 100mm long, 40% are 150mm long, and 30% are 200mm long.

6. The method for preparing straw composite exterior wall panels according to claim 1, characterized in that, In step (6), the heat insulation fiber is selected from asbestos fiber, sepiolite fiber, aluminum silicate fiber or rock wool fiber; the hollow microspheres are selected from hollow glass microspheres, hollow ceramic microspheres or hollow silica microspheres.

7. The method for preparing straw composite exterior wall panels according to claim 1, characterized in that, In step (7), the coupling agent used is silane coupling agent KH-560; the foaming agent used is cement foaming agent.

8. A straw composite exterior wall panel prepared by the method according to any one of claims 1 to 7.

9. A special waterproof cement, characterized in that, Made from the following raw materials in parts by weight: Dispersant 0.3-0.6 parts, cement 100-120 parts, sand 300-360 parts, silica fume 3-5 parts, crack-resistant fiber 1-2 parts, waterproofing agent 0.2-0.4 parts, waterproofing reinforcing agent 5-7 parts, tap water 60-70 parts, wherein: The dispersant used is industrial-grade sodium hexametaphosphate or dispersant 5040; The cement used is ordinary silicate cement, composite silicate cement, high-alumina cement, or magnesium oxysulfate cement. The sand used is quartz sand, river sand, tailings sand, or manufactured sand; The crack-resistant fibers used are polyester fiber, PP fiber, glass fiber or carbon fiber; The waterproofing agents used are organosilicon waterproofing agents, sodium methylsiloxane waterproofing agents, potassium methylsilicate alkaline waterproofing agents, potassium methylsilicate neutral waterproofing agents, calcium stearate, zinc stearate, or liquid wax. The waterproofing enhancer used is LWJ-400B JS waterproof emulsion or water-based polyurethane.

10. A straw carbonization and waterproofing treatment agent, characterized in that, Made from the following raw materials in parts by weight: Borax 6-7 parts, ammonium sulfate 8-9 parts, ammonium polyphosphate 8-10 parts, waterproofing agent 2-3 parts, penetrant 0.4-0.6 parts, tap water 90-100 parts, wherein: The waterproofing agent used is neutral potassium methylsilicate, neutral sodium methylsilicate, or sodium methylsiloxane; The penetrant used is either a fast penetrant T or a wetting agent.

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