Preparation method of fumed silica composite thermal insulation material

Abstract

The invention discloses a preparation method of a fumed silica composite thermal insulation material. The preparation method comprises the following steps: preparing the following raw material components: white Portland cement, fly ash, latex powder, cellulose ether, PP fibers, fumed silica and polyphenyl granules; wherein the fumed silica is subjected to surface hydrophobic modification treatment; premixing the dry powder: putting the white Portland cement, the fly ash, the latex powder, the cellulose ether, the PP fiber and the fumed silica into a mixer for low-speed mixing to obtain a uniform dry powder mixture; the invention has the beneficial effects that white Portland cement is used as a main matrix, fumed silica is used as a core functional filler, an expensive and complex synthesis process of an aerogel material is replaced, the production cost is further reduced, and the processing process is physical mixing and conventional cement-based material maintenance, so that the production cost is reduced. Complicated harsh conditions such as sol, gel, aging, solvent exchange and supercritical drying are not needed, and the production period is remarkably shortened.

Description

Technical Field

[0001] This invention relates to the field of composite thermal insulation materials technology, specifically a method for preparing fumed silica composite thermal insulation materials. Background Technology

[0002] In the field of building and industrial insulation, existing products are mainly divided into two categories: one is organic insulation materials such as polystyrene boards, which have good insulation performance but low fire resistance and are prone to aging; the other is inorganic insulation materials such as rock wool boards, which are fireproof but easily absorb moisture, have low strength and their insulation performance needs to be improved. In order to pursue better performance, aerogel composite materials have emerged.

[0003] A search revealed a patent with publication number CN117510182A, which discloses a method for preparing an aerogel composite insulation material. This method involves complex processes such as sol-gel, gelation, aging, solvent exchange, and supercritical drying. Although it yields an aerogel composite insulation material with low thermal conductivity, the process is complex and time-consuming, resulting in high processing costs. Furthermore, to achieve high fire resistance, a special fire-resistant coating needs to be applied subsequently. Therefore, this application proposes a method for preparing a fumed silica composite insulation material. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing fumed silica composite thermal insulation material to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a fumed silica composite thermal insulation material, comprising the following steps: S1. Prepare the following raw material components: white silicate cement, fly ash, latex powder, cellulose ether, PP fiber, fumed silica, and polystyrene particles; wherein, the fumed silica has undergone surface hydrophobic modification treatment. S2. Dry powder premixing: White silicate cement, fly ash, latex powder, cellulose ether, PP fiber and fumed silica are put into a mixer and mixed at low speed to obtain a uniform dry powder mixture. S3. Slurry preparation: Add water to the dry powder mixture obtained in step S2, and then stir at high speed to form a uniform slurry; S4. Lightweight aggregate blending: Polystyrene particles are added to the slurry prepared in step S3 and dispersed evenly by low-speed stirring to obtain the final composite thermal insulation slurry. S5. Molding and curing: The composite thermal insulation slurry obtained in step S4 is injected into the mold and left to stand at normal pressure for shaping, then demolded and wet cured. S6. Drying treatment: Dry the cured molded body to obtain the fumed silica composite thermal insulation material; S7. Post-processing: The dried fumed silica composite insulation material is cut and polished, and a waterproof membrane is applied to its surface.

[0006] Preferably, the raw materials in step S1 include, by weight: 400-450 parts white silicate cement, 70-80 parts fly ash, 8-12 parts latex powder, 3-5 parts cellulose ether, 0.5-1.5 parts PP fiber, 8-12 parts fumed silica, and 1-2 parts polystyrene particles.

[0007] Preferably, the specific surface area of ​​the fumed silica is 150-400 m² / g.

[0008] Preferably, the modifier used in the surface hydrophobic modification treatment is a silane coupling agent.

[0009] Preferably, in step S2, the rotation speed of the low-speed mixing is 300-500 rpm, and the mixing time is 10-20 minutes.

[0010] Preferably, in step S3, the amount of water added is 40%-60% of the total weight of the dry powder mixture, and the high-speed stirring speed is 600-800 rpm, and the stirring time is 5-15 minutes.

[0011] Preferably, in step S4, the low-speed stirring speed is 100-200 rpm and the stirring time is 2-5 minutes.

[0012] Preferably, the static setting time under normal pressure in step S5 is 24-48 hours.

[0013] Preferably, in step S5, the temperature for wet curing is 20±5℃, the relative humidity is ≥90%, and the curing time is 7-14 days.

[0014] Preferably, the drying temperature in step S6 is 50-70°C until the composite insulation material is formed.

[0015] Compared with the prior art, the beneficial effects of the present invention are: using white silicate cement as the main matrix and fumed silica as the core functional filler, it replaces the expensive and complex synthesis process of aerogel materials, thereby reducing production costs. Moreover, the processing technology is physical mixing and conventional cement-based material curing, which does not require complex sol, gel, aging, solvent exchange and supercritical drying and other harsh conditions. The production cycle is significantly shortened and the energy consumption is low, making it suitable for industrial continuous production and on-site construction. By combining the nanoporous structure of fumed silica with the microporous structure of cement hydration products, the composite insulation material has a low thermal conductivity. At the same time, the cement matrix enables the material to have high compressive strength, overcoming the disadvantage of low strength of pure aerogel materials. The surface waterproof membrane treatment and the hydrophobicity of fumed silica itself can ensure the water resistance of the composite insulation material. Detailed Implementation

[0016] The preparation method of a fumed silica composite thermal insulation material provided by the present invention will be described in detail below with reference to specific embodiments. It should also be noted that, in order to make the embodiments more detailed, the following embodiments are the best and preferred embodiments, and those skilled in the art can also use other alternative methods to implement some known technologies.

[0017] It should be noted that the use of terms such as "an embodiment," "an embodiment," "an exemplary embodiment," and "some embodiments" in the specification indicates that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments (whether explicitly described or not) should be within the knowledge of those skilled in the art.

[0018] Generally, terms can be understood at least partially from their use in context. For example, depending at least partially on the context, the term "one or more" as used herein can be used to describe any feature, structure, or characteristic in a singular sense, or a combination of features, structures, or characteristics in a plural sense. Additionally, the term "based on" can be understood not necessarily to convey an exclusive set of factors, but can instead, depending at least partially on the context, allow for the presence of other factors that are not necessarily explicitly described. All other embodiments obtained by those skilled in the art without inventive effort are within the scope of this invention.

[0019] This invention provides a technical solution: a method for preparing a fumed silica composite thermal insulation material, comprising the following steps: S1. Prepare the following raw material components: white silicate cement, fly ash, latex powder, cellulose ether, PP fiber, fumed silica, and polystyrene particles; wherein, the fumed silica has undergone surface hydrophobic modification treatment. S2. Dry powder premixing: White silicate cement, fly ash, latex powder, cellulose ether, PP fiber and fumed silica are put into a mixer and mixed at low speed to obtain a uniform dry powder mixture. S3. Slurry preparation: Add water to the dry powder mixture obtained in step S2, and then stir at high speed to form a uniform slurry; S4. Lightweight aggregate blending: Polystyrene particles are added to the slurry prepared in step S3 and dispersed evenly by low-speed stirring to obtain the final composite thermal insulation slurry. S5. Molding and curing: The composite thermal insulation slurry obtained in step S4 is injected into the mold and left to stand at normal pressure for shaping, then demolded and wet cured. S6. Drying treatment: Dry the cured molded body to obtain the fumed silica composite thermal insulation material; S7. Post-processing: The dried fumed silica composite insulation material is cut and polished, and a waterproof membrane is applied to its surface. Example

[0020] Raw material ratio: 420 parts white silicate cement, 75 parts fly ash, 10 parts latex powder, 4 parts cellulose ether, 1 part PP fiber, 10 parts fumed silica, and 1.5 parts polystyrene particles. Preparation steps: S2. Dry powder premixing: Put all the above dry powder raw materials except polystyrene particles into a mixer and mix at 350 rpm for 15 minutes to obtain a dry powder mixture. S3. Slurry preparation: Add water equal to 50% of the total weight of the dry powder mixture, then increase the stirring speed to 700 rpm and continue stirring for 10 minutes to form a uniform slurry. S4. Lightweight aggregate blending: Add polystyrene particles to the slurry and stir at 150 rpm for 3 minutes to disperse them evenly. S5. Molding and Curing: The composite slurry is injected into the mold, and after standing at normal pressure for 36 hours to set, it is demolded. Then, the test block is placed in a curing chamber at 20℃ and 95% relative humidity for 10 days. S6. Drying treatment: Place the cured test block in a 60℃ oven to dry completely; S7. Post-treatment: Cut and polish the dried test block, and coat its surface with an organosilicon waterproofing agent to form a waterproof film. Example

[0021] Raw material ratio: 400 parts white silicate cement, 80 parts fly ash, 12 parts latex powder, 3.5 parts cellulose ether, 1.2 parts PP fiber, 12 parts fumed silica, and 1.0 part polystyrene particles; Preparation steps: S2. Dry powder premix: Mix at 400 rpm for 12 minutes; S3. Slurry preparation: Add water at 45% of the total weight of the dry powder mixture and stir at 750 rpm for 8 minutes; S4. Lightweight aggregate blending: Stir at 120 rpm for 4 minutes; S5. Shaping and Curing: Let stand for 24 hours to set the shape, and then cure in a wet environment at a temperature of 18℃ and a relative humidity of 92% for 14 days. S6. Drying treatment: Place the cured test block in a 55℃ oven to dry completely; S7. Post-treatment: Cut and polish the dried test block, and coat its surface with an organosilicon waterproofing agent to form a waterproof film. Example

[0022] Raw material ratio: 450 parts white silicate cement, 70 parts fly ash, 8 parts latex powder, 5 parts cellulose ether, 0.8 parts PP fiber, 8 parts fumed silica, and 2.0 parts polystyrene particles; Preparation steps: S2. Dry powder premix: Mix at 300 rpm for 20 minutes; S3. Slurry preparation: Add water at 55% of the total weight of the dry powder mixture and stir at 650 rpm for 12 minutes; S4. Lightweight aggregate blending: Stir at 180 rpm for 2.5 minutes; S5. Shaping and Curing: Let stand for 48 hours to set the shape, and then cure in a wet environment at 25°C and 90% relative humidity for 7 days. S6. Drying treatment: Place the cured test block in a 70℃ oven to dry completely; S7. Post-treatment: Cut and polish the dried test block, and coat its surface with an organosilicon waterproofing agent to form a waterproof film.

[0023] The test results of the fumed silica composite insulation materials in Examples 1-3 are shown in the table below:

[0024] While embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a fumed silica composite thermal insulation material, characterized in that, Includes the following steps: S1. Prepare the following raw material components: white silicate cement, fly ash, latex powder, cellulose ether, PP fiber, fumed silica, and polystyrene particles; wherein, the fumed silica has undergone surface hydrophobic modification treatment. S2. Dry powder premixing: White silicate cement, fly ash, latex powder, cellulose ether, PP fiber and fumed silica are put into a mixer and mixed at low speed to obtain a uniform dry powder mixture. S3. Slurry preparation: Add water to the dry powder mixture obtained in step S2, and then stir at high speed to form a uniform slurry; S4. Lightweight aggregate blending: Polystyrene particles are added to the slurry prepared in step S3 and dispersed evenly by low-speed stirring to obtain the final composite thermal insulation slurry. S5. Molding and curing: The composite thermal insulation slurry obtained in step S4 is injected into the mold and left to stand at normal pressure for shaping, then demolded and wet cured. S6. Drying treatment: Dry the cured molded body to obtain the fumed silica composite thermal insulation material; S7. Post-processing: The dried fumed silica composite insulation material is cut and polished, and a waterproof membrane is applied to its surface.

2. The method for preparing a fumed silica composite thermal insulation material according to claim 1, characterized in that: The raw materials in step S1, by weight, include: 400-450 parts white silicate cement, 70-80 parts fly ash, 8-12 parts latex powder, 3-5 parts cellulose ether, 0.5-1.5 parts PP fiber, 8-12 parts fumed silica, and 1-2 parts polystyrene particles.

3. The method for preparing a fumed silica composite thermal insulation material according to claim 2, characterized in that: The specific surface area of ​​the fumed silica is 150-400 m² / g.

4. The method for preparing a fumed silica composite thermal insulation material according to claim 2, characterized in that: The modifier used in the surface hydrophobic modification treatment is a silane coupling agent.

5. The method for preparing a fumed silica composite thermal insulation material according to claim 1, characterized in that: In step S2, the low-speed mixing speed is 300-500 rpm, and the mixing time is 10-20 minutes.

6. The method for preparing a fumed silica composite thermal insulation material according to claim 1, characterized in that: In step S3, the amount of water added is 40%-60% of the total weight of the dry powder mixture, and the high-speed stirring speed is 600-800 rpm, and the stirring time is 5-15 minutes.

7. The method for preparing a fumed silica composite thermal insulation material according to claim 1, characterized in that: In step S4, the low-speed stirring speed is 100-200 rpm, and the stirring time is 2-5 minutes.

8. The method for preparing a fumed silica composite thermal insulation material according to claim 1, characterized in that: The time for static setting under normal pressure in step S5 is 24-48 hours.

9. The method for preparing a fumed silica composite thermal insulation material according to claim 1, characterized in that: In step S5, the temperature for wet curing is 20±5℃, the relative humidity is ≥90%, and the curing time is 7-14 days.

10. The method for preparing a fumed silica composite thermal insulation material according to claim 1, characterized in that: The drying temperature in step S6 is 50-70℃ until the composite insulation material is formed.

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