Composite thermal insulation material suitable for A-grade fire prevention and preparation method thereof

Abstract

The invention discloses a composite thermal insulation material suitable for A-grade fire prevention and a preparation method thereof, relates to the technical field of building composite materials, and solves the problem that an existing building material is difficult to meet the comprehensive requirements of fire prevention, thermal insulation and freezing resistance in alpine regions. Comprising quick-hardening sulphoaluminate cement, silica powder, MDI-50, polyether polyol, silane coupling agent modified basalt fibers, silane coupling agent modified polyvinyl alcohol fibers, triethanolamine, a thickening foam stabilizer, fatty alcohol ether sodium sulfate and 1-1.5 parts of a calcium nitrite antifreezing agent. The thickening foam stabilizer is a compound of hydroxypropyl methyl cellulose and polyether modified silicone oil. The material can be prepared without special construction equipment, can be accurately adapted to construction scenes of traffic inconvenience and energy shortage in alpine regions, and has extremely high engineering application value and popularization prospect.

Description

Technical Field

[0001] This invention relates to the field of building composite materials technology, specifically to a thermal insulation material suitable for Class A fire resistance and its preparation method. Background Technology

[0002] In building insulation projects in high-altitude and cold regions, insulation materials must simultaneously meet the requirements of excellent thermal insulation performance, reliable fire safety, and cold resistance. Currently widely used polystyrene-based organic insulation materials, although having a low thermal conductivity and good insulation effect, have significant flammability defects. They easily release toxic gases when burning, making it difficult to meet the Class A fire protection standard, and posing serious safety hazards in building use.

[0003] Existing insulation materials are insufficient to simultaneously meet the diverse performance requirements of high-altitude and cold regions. Specifically, while organic insulation materials such as polystyrene boards and extruded polystyrene boards have low thermal conductivity and excellent insulation performance, their oxygen index is generally below 20%, and their flammability rating is only B3. They are prone to melting and dripping when exposed to fire, releasing toxic gases and posing a serious fire safety hazard. Traditional cement-based inorganic insulation materials, such as foamed concrete, can achieve a flammability rating of A2 or higher, but due to their large pore structure, low closed-cell rate, and high thermal conductivity, their insulation performance is insufficient. Furthermore, these materials are brittle and have weak interfacial bonding. Under low temperatures below -20°C and freeze-thaw cycles, their strength loss rate often exceeds 20% after 30 cycles, making them prone to cracking, hollowing, and even detachment. Their service life is typically less than 5 years.

[0004] Furthermore, while organic-inorganic composite insulation materials developed in recent years have attempted to combine the advantages of both, they generally suffer from poor synergy. Some materials are primarily inorganic with only a small amount of organic fiber added, failing to improve the material's insulation performance and brittleness. Other materials have excessively high organic content, leading to a downgrade in fire resistance to Class B. Moreover, the lack of an effective interfacial bonding design between the organic and inorganic phases makes them prone to phase separation after freeze-thaw cycles, making it difficult to meet the comprehensive needs of fire prevention, insulation, and freeze resistance in high-altitude and cold regions. Summary of the Invention

[0005] To address the challenge that existing building materials cannot simultaneously meet the comprehensive needs of fire prevention, heat insulation, and frost resistance in high-altitude and cold regions, this invention proposes a heat insulation material suitable for Class A fire resistance and its preparation method.

[0006] The specific technical solution of the present invention is as follows: A thermal insulation material suitable for Class A fire resistance, comprising the following components in parts by weight: Rapid-hardening sulfoaluminate cement, 35-40 parts; silica fume, 5-8 parts; MDI-50, 10-15 parts; polyether polyol, 8-12 parts; silane coupling agent modified basalt fiber, 6-8 parts; silane coupling agent modified polyvinyl alcohol fiber, 2-3 parts. Triethanolamine, 0.3-0.5 parts; Thickening and foam stabilizing agent, 0.3-0.6 parts; Sodium fatty alcohol ether sulfate, 1.5-2 parts; Calcium nitrite antifreeze, 1-1.5 parts; The thickening and foam stabilizing agent is a compound of hydroxypropyl methylcellulose and polyether-modified silicone oil.

[0007] Preferably, the SiO2 content in the silicon micropowder is ≥92wt%; and the particle size of the silicon micropowder is ≤1μm.

[0008] Preferably, the molecular weight of the polyether polyol is 2000-3000.

[0009] Preferably, the basalt fibers have a diameter of 13-18 μm and a length of 12-15 mm.

[0010] Preferably, the diameter of the polyvinyl alcohol fiber is 20~25μm.

[0011] Preferably, the silane coupling agent is KH-550 or KH-580.

[0012] Preferably, the mass ratio of the hydroxypropyl methylcellulose to the polyether-modified silicone oil is 2:1.

[0013] The present invention also provides a preparation process for the above-mentioned thermal insulation material suitable for Class A fire resistance, comprising the following steps: S1. At 5~10℃, mix rapid-hardening sulfoaluminate cement, silica powder, basalt fiber modified with silane coupling agent, and polyvinyl alcohol fiber modified with silane coupling agent, add an aqueous solution containing hydroxypropyl methylcellulose, and stir at 800~1000 rpm for 3 minutes to form an inorganic base slurry. S2. Add MDI-50, polyether polyol, triethanolamine and part of the fatty alcohol ether sulfate to the inorganic base slurry, stir at 1500 rpm until uniform, and at the same time pass in the foam generated by the remaining fatty alcohol ether sulfate, and stir until the foam is evenly dispersed. S3. Inject the obtained mixed slurry into the mold and cure it naturally at 5~15℃ for 24 hours, followed by curing at room temperature for 28 days.

[0014] Preferably, the foam generated by the sodium fatty alcohol ether sulfate is obtained by the following method: Mix sodium fatty alcohol ether sulfate with warm water at 5~10℃ to prepare a sodium fatty alcohol ether sulfate aqueous solution with a concentration of 10%~15%. Simultaneously add 1 / 3 of the formula amount of thickening and foam stabilizing agent and stir until completely dissolved. Pour into a foaming machine and stir at 1200~1500 rpm for 3~5 minutes to form stable foam.

[0015] Compared with the prior art, the specific beneficial effects of the present invention are as follows: 1. In this invention, the rapid-hardening sulfoaluminate cement in the inorganic phase, after hydration with silica fume, forms a dense ettringite and CSH gel skeleton, which can physically block flame spread and inhibit heat conduction. The micro-filling effect of silica fume further reduces the porosity of the material, significantly improving fire resistance. The organic phase polyurethane network reduces air convection heat transfer by generating a closed-pore structure. In addition, the long-chain structure of polyether polyol inhibits molecular thermal motion. Tests show that the thermal conductivity of the material is stably controlled at 0.040~0.045 W / (m·K). The final product achieves an A1 flammability rating with an oxygen index of 32.5%~34.0%, completely solving the industry problem of the flammability of traditional organic materials and the poor insulation effect of inorganic materials.

[0016] 2. The material of this invention can withstand low temperatures and frequent freeze-thaw cycles in extremely cold regions. The rapid-hardening sulfoaluminate cement has a high early-stage hydration heat release rate, and the combination with calcium nitrite antifreeze lowers the freezing point of the liquid phase, effectively reducing the damage to the internal structure caused by ice crystal formation. The basalt fibers modified with silane coupling agents form stable chemical bonds with the organic and inorganic phases, significantly improving the interfacial bonding strength. Combined with the bridging effect of polyvinyl alcohol fibers, it can efficiently disperse the internal stress generated by freeze-thaw cycles. Tests show that after 50 freeze-thaw cycles at -40℃, the strength loss rate is only 5.2%-7.8%, and the 28-day compressive strength reaches 1.5~2.0 MPa, far exceeding the performance of existing materials and suitable for the needs of extremely cold environments.

[0017] 3. This invention modifies the surface of reinforcing fibers with a silane coupling agent, simultaneously grafting hydroxyl and amino groups. This allows the fibers to form hydroxyl bonds with cement hydration products and urethane bonds with the polyurethane network, fundamentally solving the problem of phase separation in existing composite insulation materials. This results in an interfacial bonding strength of 1.2~1.5MPa, significantly higher than ordinary composite insulation materials. The synergistic improvement in both toughness and rigidity effectively prevents cracking and detachment caused by sudden temperature changes in cold regions, extending the material's service life.

[0018] The material prepared by this invention requires no special construction equipment and can be precisely adapted to construction scenarios in high-altitude and cold regions where transportation is inconvenient and energy is scarce, thus possessing strong engineering application value and promotion prospects. Detailed Implementation

[0019] To make the technical solutions of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. It should be noted that the following embodiments are only used to better understand the technical solutions of the present invention and should not be construed as limiting the present invention.

[0020] Example 1. The group allocation example in this embodiment is as follows: Rapid-hardening sulfoaluminate cement 1.75kg, silica fume 0.25kg, MDI-50 0.5kg, polyether polyol (molecular weight 2000) 0.4kg, KH-550 modified basalt fiber (diameter 13μm, length 12mm) 0.3kg, polyvinyl alcohol fiber (diameter 20μm) 0.1kg, triethanolamine 0.015kg, hydroxypropyl methylcellulose 0.01kg, polyether modified silicone oil 0.005kg, sodium fatty alcohol ether sulfate (AES, purity ≥92%) 0.075kg, calcium nitrite 0.05kg, water 0.695kg.

[0021] The specific operation process is as follows: At 5~10℃, rapid-hardening sulfoaluminate cement, silica powder, silane coupling agent modified basalt fiber, and silane coupling agent modified polyvinyl alcohol fiber are mixed, and an aqueous solution containing hydroxypropyl methylcellulose is added. The mixture is stirred at 900 rpm for 3 minutes to form an inorganic slurry. Mix sodium fatty alcohol ether sulfate with warm water at 5~10℃ to prepare a 10% sodium fatty alcohol ether sulfate aqueous solution. Simultaneously add 1 / 3 of the formula amount of thickening and foam stabilizer and stir until completely dissolved. Pour into a foaming machine and stir at 1300rpm for 4 minutes to form stable foam. Add MDI-50, polyether polyol, triethanolamine and 2 / 3 of the formula amount of sodium fatty alcohol ether sulfate to the inorganic base slurry, stir at 1500 rpm until uniform, and simultaneously introduce the foam generated by the sodium fatty alcohol ether sulfate, and stir until the foam is evenly dispersed. The resulting mixed slurry was injected into a mold and cured naturally at 5~15℃ for 24 hours, followed by curing at room temperature for 28 days.

[0022] Example 2. The group allocation example in this embodiment is as follows: Rapid-hardening sulfoaluminate cement 1.9kg, silica fume 0.35kg, MDI-50 0.6kg, polyether polyol (molecular weight 2500) 0.5kg, KH-580 modified basalt fiber (diameter 15μm, length 14mm) 0.35kg, polyvinyl alcohol fiber (diameter 22μm) 0.125kg, triethanolamine 0.02kg, hydroxypropyl methylcellulose 0.015kg, polyether modified silicone oil 0.0075kg, sodium fatty alcohol ether sulfate (AES, purity ≥92%) 0.09kg, calcium nitrite 0.06kg, water 0.5325kg.

[0023] The specific operation process is as follows: At 5~10℃, rapid-hardening sulfoaluminate cement, silica powder, silane coupling agent modified basalt fiber, and silane coupling agent modified polyvinyl alcohol fiber are mixed, and an aqueous solution containing hydroxypropyl methylcellulose is added. The mixture is stirred at 900 rpm for 3 minutes to form an inorganic slurry. Mix sodium fatty alcohol ether sulfate with warm water at 5~10℃ to prepare a 10% sodium fatty alcohol ether sulfate aqueous solution. Simultaneously add 1 / 3 of the formula amount of thickening and foam stabilizer and stir until completely dissolved. Pour into a foaming machine and stir at 1300rpm for 4 minutes to form stable foam. Add MDI-50, polyether polyol, triethanolamine and 2 / 3 of the formula amount of sodium fatty alcohol ether sulfate to the inorganic base slurry, stir at 1500 rpm until uniform, and simultaneously introduce the foam generated by the sodium fatty alcohol ether sulfate, and stir until the foam is evenly dispersed. The resulting mixed slurry was injected into a mold and cured naturally at 5~15℃ for 24 hours, followed by curing at room temperature for 28 days.

[0024] Example 3. The group allocation example in this embodiment is as follows: Rapid-hardening sulfoaluminate cement 2.0kg, silica fume 0.4kg, MDI-50 0.75kg, polyether polyol (molecular weight 3000) 0.6kg, KH-550 modified basalt fiber (diameter 18μm, length 15mm) 0.4kg, polyvinyl alcohol fiber (diameter 25μm) 0.15kg, triethanolamine 0.025kg, hydroxypropyl methylcellulose 0.02kg, polyether modified silicone oil 0.01kg, sodium fatty alcohol ether sulfate (AES, purity ≥92%) 0.1kg, calcium nitrite 0.075kg, water 0.47kg.

[0025] The specific operation process is as follows: At 5~10℃, rapid-hardening sulfoaluminate cement, silica powder, silane coupling agent modified basalt fiber, and silane coupling agent modified polyvinyl alcohol fiber are mixed, and an aqueous solution containing hydroxypropyl methylcellulose is added. The mixture is stirred at 900 rpm for 3 minutes to form an inorganic slurry. Mix sodium fatty alcohol ether sulfate with warm water at 5~10℃ to prepare a 10% sodium fatty alcohol ether sulfate aqueous solution. Simultaneously add 1 / 3 of the formula amount of thickening and foam stabilizer and stir until completely dissolved. Pour into a foaming machine and stir at 1300rpm for 4 minutes to form stable foam. Add MDI-50, polyether polyol, triethanolamine and 2 / 3 of the formula amount of sodium fatty alcohol ether sulfate to the inorganic base slurry, stir at 1500 rpm until uniform, and simultaneously introduce the foam generated by the sodium fatty alcohol ether sulfate, and stir until the foam is evenly dispersed. The resulting mixed slurry was injected into a mold and cured naturally at 5~15℃ for 24 hours, followed by curing at room temperature for 28 days.

[0026] Comparative Example 1. Traditional polystyrene board material composition ratio (based on a total weight of 5kg): 4.6kg polystyrene resin, 0.25kg foaming agent, and 0.15kg flame retardant.

[0027] Preparation process: Dry polystyrene resin granules and flame retardant were added to a high-speed mixer and stirred for 10 minutes at 80°C and 500 r / min. The premix was then fed into a twin-screw extruder. During the melting process, foaming agent was added through the side feed port. The molten material was extruded through the die to an atmospheric pressure environment, where it instantly foamed to form a continuous plate-shaped preform. The preform was cooled and shaped by cold air, cut into standard samples, and then left to stand for 7 days at 25°C and 50% relative humidity for later use.

[0028] Comparative Example 2. Traditional cement-based thermal insulation material composition ratio (based on a total weight of 5kg): 2.25kg ordinary Portland cement, 0.75kg fly ash, 1.0kg river sand, 0.15kg sodium fatty alcohol ether sulfate (AES, purity ≥92%), 0.05kg water-reducing agent, and 0.8kg water.

[0029] Preparation process: Ordinary silicate cement, fly ash, river sand, and water-reducing agent were added to a planetary mixer and dry-mixed until the powder was uniformly mixed. All the water was slowly added to the dry material and stirred to form a uniform, lump-free cement-based slurry. AES was added to the slurry and stirred at high speed until the slurry volume expanded to 2.5 times its original volume, forming a foamed slurry with uniform pores. The foamed slurry was poured into a mold, vibrated to compact it, and then the surface was smoothed. The mold was first placed at 20℃ and relative humidity ≥90% for 4 hours, and then transferred to a steam curing chamber at 50℃ and relative humidity ≥95% for 12 hours. After steam curing, the mold was removed and continued to be cured at 25℃ in a natural environment for 21 days to complete the sample preparation.

[0030] Example of results. The following performance tests were performed on the samples from Examples 1-3 and Comparative Examples 1-2: The flammability rating is determined and the oxygen index is tested according to GB8624-2012 "Classification of Combustion Performance of Building Materials and Products". The thermal conductivity was tested according to GB / T10294-2008 "Determination of Steady-State Thermal Resistance and Related Properties of Thermal Insulation Materials - Protective Hot Plate Method" at a test temperature of 25℃. According to GB / T50082-2009 "Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete", the freeze-thaw resistance was tested by using a -40℃ freeze-thaw cycle test, with each cycle lasting 24 hours (12 hours of freezing and 12 hours of thawing), for a total of 50 cycles. The strength loss rate was calculated. The interfacial bond strength was tested using the tensile method.

[0031]

[0032] The test results above confirm that Examples 1-3 of this invention all meet the A1 fire resistance standard, with an oxygen index significantly higher than the comparative example, thus solving the flammability defect of the polystyrene board in Comparative Example 1. The thermal conductivity is close to that of Comparative Example 1 and far superior to that of Comparative Example 2, achieving a balance between thermal insulation and fire resistance. The freeze-thaw resistance and compressive strength far exceed those of the two comparative examples, with Example 3 showing the best performance in all aspects. The interface bonding strength is significantly superior, proving the effectiveness of the fiber-organic-inorganic interface reinforcement design. In summary, the overall performance of the material of this invention is superior to existing technologies and is suitable for use in cold regions.

[0033] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A composite thermal insulation material suitable for Class A fire resistance, characterized in that, The components include the following parts by mass: Rapid-hardening sulfoaluminate cement, 35-40 parts; silica fume, 5-8 parts; MDI-50, 10-15 parts; polyether polyol, 8-12 parts; 6-8 parts of silane coupling agent modified basalt fiber; 2-3 parts of silane coupling agent modified polyvinyl alcohol fiber; Triethanolamine, 0.3-0.5 parts; Thickening and foam stabilizing agent, 0.3~0.6 parts; Sodium fatty alcohol ether sulfate, 1.5-2 parts; calcium nitrite antifreeze, 1-1.5 parts; The thickening and foam stabilizing agent is a compound of hydroxypropyl methylcellulose and polyether-modified silicone oil.

2. The composite thermal insulation material suitable for Class A fire resistance according to claim 1, characterized in that, The silicon micropowder contains ≥92wt% SiO2 and has a particle size ≤1μm.

3. The composite thermal insulation material suitable for Class A fire resistance according to claim 1, characterized in that, The molecular weight of the polyether polyol is 2000~3000.

4. The composite thermal insulation material suitable for Class A fire resistance according to claim 1, characterized in that, The basalt fibers have a diameter of 13~18μm and a length of 12~15mm.

5. The composite thermal insulation material suitable for Class A fire resistance according to claim 1, characterized in that, The diameter of the polyvinyl alcohol fiber is 20~25μm.

6. The composite thermal insulation material suitable for Class A fire resistance according to claim 1, characterized in that, The silane coupling agent is KH-550 or KH-580.

7. The composite thermal insulation material suitable for Class A fire resistance according to claim 1, characterized in that, The mass ratio of hydroxypropyl methylcellulose to polyether-modified silicone oil is 2:

1.

8. A preparation process for a composite thermal insulation material suitable for Class A fire resistance as described in any one of claims 1 to 7, characterized in that, Includes the following steps: S1. At 5~10℃, mix rapid-hardening sulfoaluminate cement, silica powder, basalt fiber modified with silane coupling agent, and polyvinyl alcohol fiber modified with silane coupling agent, add an aqueous solution containing hydroxypropyl methylcellulose, and stir at 800~1000 rpm for 3 minutes to form an inorganic base slurry. S2. Add MDI-50, polyether polyol, triethanolamine and part of the fatty alcohol ether sulfate to the inorganic base slurry, stir at 1500 rpm until uniform, and at the same time pass in the foam generated by the remaining fatty alcohol ether sulfate, and stir until the foam is evenly dispersed. S3. Inject the obtained mixed slurry into the mold and cure it naturally at 5~15℃ for 24 hours, followed by curing at room temperature for 28 days.

9. The preparation process of the composite thermal insulation material suitable for Class A fire resistance according to claim 8, characterized in that, The foam generated by the sodium fatty alcohol ether sulfate is obtained by the following method: Mix sodium fatty alcohol ether sulfate with warm water at 5~10℃ to prepare a sodium fatty alcohol ether sulfate aqueous solution with a concentration of 10%~15%. Simultaneously add 1 / 3 of the formula amount of thickening and foam stabilizing agent and stir until completely dissolved. Pour into a foaming machine and stir at 1200~1500 rpm for 3~5 minutes to form stable foam.

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