Waterproof putty powder with thermal insulation function and preparation method thereof

Abstract

The invention discloses waterproof putty powder with a heat preservation function and a preparation method thereof, and belongs to the technical field of building paints.The putty powder is composed of white cement, talcum powder, vitrified micro bubbles, hydrophobic silicon dioxide aerogel, redispersible latex powder, polypropylene fibers, a mixed auxiliary agent and capillary crystalline active master batch. The preparation method comprises the following steps: treating the vitrified micro-beads and the aerogel through a silane coupling agent in a dynamic airflow device to form the composite thermal insulation functional micro-beads; mixing the polypropylene fibers subjected to surface treatment with the composite microbeads to construct a fiber-microbead network premix; grinding together with a base material, and then shearing and stirring with latex powder at a high speed under a heating condition; and finally, adding the mixed additive and the active master batch in a negative pressure environment. Through unique core-shell structure design and multi-stage process cooperation, the product has excellent heat preservation performance, lasting water resistance and good crack resistance, and the technical problem that traditional putty powder is difficult to achieve heat preservation and water resistance at the same time is solved.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, specifically relating to a water-resistant putty powder with heat-insulating function and its preparation method. Background Technology

[0002] As a key basic material for leveling and decorating building walls, putty powder's performance directly affects the building's energy efficiency and service life. With the improvement of green building standards and people's increasing requirements for living environments, the market has placed higher comprehensive demands on the thermal insulation and water resistance properties of putty powder.

[0003] Currently, the industry commonly uses the addition of lightweight insulating aggregates to improve the thermal insulation performance of putty powder. Among these, vitrified microspheres are widely used due to their closed-cell hollow structure and low thermal conductivity. However, in practical applications, vitrified microspheres have significant limitations when used alone: ​​their insulation effect is difficult to improve further after reaching a certain level, and uneven dispersion in the material can easily lead to thermal bridging, affecting the overall insulation performance. More importantly, the interfacial bonding between vitrified microspheres and the matrix material is insufficient, making them prone to becoming the starting point for crack propagation under external forces. Furthermore, while the hollow spherical structure of vitrified microspheres is key to their insulation performance, their vitrified outer shell has limited mechanical strength, making them extremely prone to breakage during the high-intensity grinding or shearing processes in traditional putty powder production. This leads to the destruction of the cavity structure, resulting not only in loss of insulation function but also becoming a strength defect in the material.

[0004] In recent years, aerogel materials, especially hydrophobic silica aerogels, have been considered promising new thermal insulation materials due to their extremely low thermal conductivity and excellent fire resistance. However, applying aerogels to putty systems faces severe technical challenges: First, the nanoscale porous structure of aerogels gives them an extremely high specific surface area, making them prone to agglomeration due to van der Waals forces during conventional mixing, making it difficult to achieve uniform dispersion in putty powder. Second, ordinary aerogel materials absorb a large amount of moisture in humid environments due to capillary action, which not only significantly reduces their thermal insulation performance but also causes quality problems such as powdering and blistering of the putty layer. In addition, the skeletal strength of aerogels is relatively low, and their nanoporous structure is easily damaged in the high-shear grinding process of traditional putty production, leading to the failure of their thermal insulation function.

[0005] Polypropylene fibers and redispersible latex powders are commonly used additives to improve the toughness and durability of putty layers. However, the effects of these materials in existing technologies are not ideal: ordinary polypropylene fibers have a smooth surface and are chemically inert, resulting in weak adhesion to inorganic powders. During mixing and construction, they are prone to tangling due to electrostatic effects, failing to form a uniform and effective three-dimensional crack-resistant network in the putty layer. On the other hand, redispersible latex powder exists only as independent particles in traditional dry-mixing processes, and its film-forming properties depend entirely on the on-site hydration environment during construction. This means that it cannot exert its due toughening and bonding effects in the dry powder state, making it difficult to guarantee the stability and consistency of product performance.

[0006] While existing technologies have seen numerous studies attempting to improve the overall performance of putty powder through the compounding of multiple functional components, these approaches mostly remain at the level of simple physical mixing, lacking effective control over the microscopic interfacial structure of the materials. Conventional mechanical mixing methods cannot solve key issues such as the uniform dispersion of functional components in the matrix, interfacial compatibility, and synergistic effects. Consequently, the prepared products often fail to simultaneously achieve excellent thermal insulation, water resistance, and crack resistance, resulting in limited performance improvements and significant fluctuations.

[0007] Therefore, there is an urgent need in this field for a high-performance thermal insulation and water-resistant putty powder and its preparation method that can effectively solve the above-mentioned technical bottlenecks by starting with the microstructure design of materials and through innovative preparation processes. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention provides a water-resistant putty powder with heat-insulating function and its preparation method.

[0009] To achieve the above objectives, the technical solution provided by the present invention is as follows: A method for preparing a water-resistant putty powder with heat-insulating function includes the following steps: (1) In a dynamic airflow device selected from fluidized bed or high-speed vortex mixer, 30-60 parts of vitrified microspheres are brought into full contact with 5-20 parts of hydrophobic silica aerogel powder, and a silane coupling agent is introduced for surface treatment to obtain composite heat-insulating microspheres. (2) Mix 10-20 parts of surface-treated polypropylene fiber with the composite thermal insulation microspheres obtained in step (1) to form a fiber-microsphere network premix. (3) Grind 70-90 parts of talc powder and 100-200 parts of white cement together until the particle size D90 of the mixed powder is ≤45μm to obtain the matrix powder; (4) Mix the matrix powder obtained in step (3) with the fiber-microbead network premix obtained in step (2) evenly; (5) The mixture obtained in step (4) and 10 to 30 parts of redispersible latex powder are subjected to high-speed shearing and stirring at 400 to 600 rpm for 5 to 15 minutes at 50 to 65°C. (6) Under a negative pressure environment of 0.1~0.15MPa, add 2~10 parts of mixing additives and 0.5~3% of penetrating crystalline active masterbatch by mass of white cement to the powder obtained in step (5), and stir to mix evenly.

[0010] Further, in step (1), the dynamic airflow device is a fluidized bed, and the silane coupling agent is sprayed in atomized form at a pressure of 0.05~0.1 MPa. By using a fluidized bed device in conjunction with a precisely controlled atomization spraying system, the silane coupling agent is uniformly distributed in the form of micron-sized droplets at the interface between the aerogel and the vitrified microspheres, forming a dense hydrophobic protective layer through chemical bonding. This process reduces the water absorption rate of the composite microspheres to below 3%, while significantly enhancing the bonding strength between particles, enabling the material to maintain stable thermal insulation performance even in humid and hot environments.

[0011] Further, in step (2), the surface treatment is plasma treatment, which is carried out in an air atmosphere with a power of 800~1200W and a treatment time of 60~120 seconds. Through an optimized plasma treatment process, abundant polar functional groups are introduced onto the surface of the polypropylene fiber, and a nanoscale rough structure is constructed, thereby increasing the interfacial bonding strength between the fiber and the inorganic matrix by more than 30%. This modification treatment not only effectively prevents fiber agglomeration during stirring but also enhances the mechanical interlocking and chemical bonding between the fiber and the matrix, increasing the ultimate tensile strength of the material by 25%.

[0012] Furthermore, in step (2), the surface treatment involves surface coating with a silane coupling agent solution. This innovative silane coupling agent solution coating process constructs a stable organic-inorganic hybrid interface layer on the surface of the polypropylene fiber through molecular self-assembly technology. This method is not only simple and low-cost, but also significantly improves the compatibility between the fiber and the cement matrix, increasing the density of the interface transition zone by 20%, effectively enhancing the overall mechanical properties of the material.

[0013] Further, in step (5), the redispersible latex powder is a mixture of ethylene-vinyl acetate copolymer powder and ethylene tert-carbonate-vinyl acetate copolymer powder in a mass ratio of 1:(1~2). The carefully designed latex powder combination system, through the synergistic effect of the ethylene-vinyl acetate copolymer and the ethylene tert-carbonate-vinyl acetate copolymer, forms an interpenetrating network structure in the putty layer. This unique polymer architecture enables the material to possess both excellent flexibility (compression-to-flexural ratio ≤3.0) and water resistance, solving the technical problem of traditional putty powder being prone to cracking under temperature changes.

[0014] Further, in step (6), the mixed additives include an defoamer, hydroxypropyl methylcellulose ether binder, and nano-titanium dioxide photocatalyst, with a mass ratio of (1.5~2):1:(0.4~0.6). Through this scientifically proportioned mixed additive system, the nano-titanium dioxide photocatalyst is introduced while ensuring construction performance, enabling the putty layer to possess continuous self-cleaning and air purification functions. Testing shows that this material achieves a degradation efficiency of over 85% for organic pollutants, while maintaining excellent construction performance and storage stability.

[0015] Furthermore, in step (6), the penetrating crystalline active masterbatch is composed of calcium silicate and magnesium silicate in a mass ratio of (2.5~3.5):1. Using a specific ratio of calcium silicate-magnesium silicate composite active masterbatch, an insoluble crystalline structure is generated within the putty layer through a penetrating crystallization mechanism, effectively filling the capillaries of the material, reducing water absorption by more than 40%, and achieving a permeability resistance level of P12 or higher, significantly improving the durability and service life of the material.

[0016] This invention also provides a water-resistant putty powder with thermal insulation function prepared by the above method, which is composed of the following components by weight: 100-200 parts white cement; 70-90 parts talc powder; 30-60 parts vitrified microspheres (closed-cell rate of vitrified microspheres ≥95%, particle size 50-100μm); 5-20 parts hydrophobic silica aerogel; 10-30 parts redispersible latex powder; 10-20 parts polypropylene fiber (surface oxygen content of not less than 8 at%) measured by X-ray photoelectron spectroscopy in the flat area in the middle of the fiber); 2-10 parts mixing additives; 0.5-6 parts penetrating crystalline active masterbatch. Through systematic component optimization design, the optimal ratio and synergistic effect of each functional component are achieved. Among them, the thermal insulation component forms a highly efficient heat insulation network, the reinforcing fiber constructs a three-dimensional support system, and the polymer powder provides flexible connection, so that the comprehensive performance of the product reaches the industry-leading level and the service life is extended to more than twice that of traditional products. By precisely controlling the surface oxygen content of polypropylene fibers (≥8 at%), a strong chemical bond is ensured between the fibers and the inorganic matrix. This interface optimization improves the material's impact resistance by 35%, reduces shrinkage by 50%, and significantly improves the long-term performance of the putty layer.

[0017] Compared with the prior art, the present invention has the following beneficial effects: I. This invention, through an optimized process sequence, first constructs an aerogel / vitrified microsphere core-shell structure in a dynamic airflow device, then grinds the base material (talc powder, white cement) without vitrified microspheres separately to the required fineness, and finally composites each functional unit step by step. This process design perfectly avoids the damage to the cavity structure of vitrified microspheres caused by mechanical force during grinding, ensuring the integrity of its closed-cell hollow structure, thereby fully leveraging the synergistic effect of the dual thermal insulation system of "vitrified microsphere macro-insulation + aerogel nano-insulation". Tests show that this structure reduces the thermal conductivity of the material to 0.048-0.065 W / (m·K), improving the thermal insulation performance by more than 35% compared to traditional thermal insulation putty, and significantly improving the thermal insulation stability, with the thermal insulation performance attenuation rate not exceeding 5% after 50 freeze-thaw cycles.

[0018] II. This invention employs an innovative process for constructing a fiber-microsphere network premix in stages. By precisely controlling the mixing energy input and the interaction time, surface-treated polypropylene fibers are anchored to the surface of the composite microspheres with optimized spatial orientation. This design forms a multi-level reinforced three-dimensional network structure of "point-line-surface," which not only improves the crack resistance of the material by 40-50%, but also effectively disperses local stress throughout the entire network system through a unique stress transfer mechanism. Experiments have shown that this structure increases the ultimate strain capacity of the putty layer to 0.35%, more than twice that of traditional products, significantly improving the wall's ability to adapt to deformation.

[0019] Third, this invention achieves a perfect combination of materials at the micro, meso, and macro scales through the precise coordination of multi-level process parameters. Specifically, particle size control to D90≤45μm ensures the optimal bulk density of the base material; high-speed shear stirring at 50-65℃ promotes the thermoplastic activation of the latex powder, forming a continuous polymer film; and a negative pressure environment of 0.1-0.15MPa completely eliminates interfacial air gaps. This multi-scale synergistic effect enables the product to simultaneously possess: excellent thermal insulation properties with a thermal conductivity ≤0.065 W / (m·K), durable water resistance with a bond strength ≥0.65 MPa after immersion in water for 96 hours, and good workability with a scraping resistance ≤85N, solving industry technical bottlenecks such as low strength of thermal insulation materials and difficult construction of water-resistant materials. Detailed Implementation

[0020] The specific embodiments are described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. Unless otherwise specified, the raw materials and reagents used in the examples are commercially available.

[0021] Example 1 A method for preparing a water-resistant putty powder with heat-insulating function, the specific steps of which are as follows: (1) In a fluidized bed apparatus, 45 kg of vitrified microspheres and 12 kg of hydrophobic silica aerogel powder were thoroughly mixed at 50°C. At the same time, 0.8 kg of silane coupling agent (KH-550) ethanol solution was sprayed in at an atomization pressure of 0.08 MPa for surface treatment to obtain composite heat-insulating microspheres. (2) After 15 kg of polypropylene fiber is treated with plasma (air atmosphere, power 1000 W, treatment time 90 seconds), it is mixed with the composite heat-insulating microspheres obtained in step (1) under low speed stirring to form a fiber-microsphere network premix. (3) Put 80 kg of talc powder and 150 kg of white cement into a vertical grinding mill and grind them until the particle size of the mixed powder is D90=40μm to obtain the matrix powder. (4) The matrix powder obtained in step (3) and the fiber-microbead network premix obtained in step (2) are mixed evenly under low-speed stirring; (5) The mixture obtained in step (4) is mixed with 20 kg of redispersible latex powder (which includes 8 kg of ethylene-vinyl acetate copolymer powder and 12 kg of ethylene tert-carbonate-vinyl acetate copolymer powder) and subjected to high-speed shearing and stirring at 500 rpm for 10 minutes at 60°C. (6) Under a negative pressure of 0.12 MPa, add 6 kg of mixing additive (including 3 kg of defoamer, 1.5 kg of hydroxypropyl methylcellulose ether binder and 1.5 kg of nano titanium dioxide photocatalyst) and 4.5 kg of penetrating crystalline active masterbatch (including 3.4 kg of calcium silicate and 1.1 kg of magnesium silicate) to the powder obtained in step (5), stir and mix evenly to obtain water-resistant putty powder with heat insulation function.

[0022] Example 2 A method for preparing a water-resistant putty powder with heat-insulating function, the specific steps of which are as follows: (1) In a high-speed vortex mixer, 50 kg of vitrified microspheres and 15 kg of hydrophobic silica aerogel powder were thoroughly mixed at 55°C. At the same time, 1.2 kg of silane coupling agent (KH-560) ethanol solution was sprayed in at an atomization pressure of 0.1 MPa for surface treatment to obtain composite heat-insulating microspheres. (2) After coating the surface of 18 kg of polypropylene fiber with silane coupling agent solution, it is mixed with the composite heat-insulating microspheres obtained in step (1) under low-speed stirring to form a fiber-microsphere network premix. (3) 75 kg of talc powder and 180 kg of white cement were put into a vertical grinding mill and ground until the particle size of the mixed powder was D90=35μm to obtain the matrix powder. (4) The matrix powder obtained in step (3) and the fiber-microbead network premix obtained in step (2) are mixed evenly under low-speed stirring; (5) The mixture obtained in step (4) is mixed with 25 kg of redispersible latex powder (which includes 10 kg of ethylene-vinyl acetate copolymer powder and 15 kg of ethylene tert-carbonate-vinyl acetate copolymer powder) and subjected to high-speed shearing and stirring at 600 rpm for 8 minutes at 65°C. (6) Under a negative pressure of 0.15 MPa, add 8 kg of mixing additive (including 4 kg of defoamer, 2 kg of hydroxypropyl methylcellulose ether binder and 2 kg of nano titanium dioxide photocatalyst) and 5.4 kg of penetrating crystalline active masterbatch (including 4.0 kg of calcium silicate and 1.4 kg of magnesium silicate) to the powder obtained in step (5), stir and mix evenly to obtain a water-resistant putty powder with heat insulation function.

[0023] Example 3 A method for preparing a water-resistant putty powder with heat-insulating function, the specific steps of which are as follows: (1) In a fluidized bed device, 35 kg of vitrified microspheres and 8 kg of hydrophobic silica aerogel powder were thoroughly mixed at 45°C. At the same time, 0.5 kg of silane coupling agent (KH-550) ethanol solution was sprayed in at an atomization pressure of 0.05 MPa for surface treatment to obtain composite heat-insulating microspheres. (2) After 12 kg of polypropylene fiber is treated with plasma (air atmosphere, power 800 W, treatment time 120 seconds), it is mixed with the composite heat-insulating microspheres obtained in step (1) under low speed stirring to form a fiber-microsphere network premix. (3) 85 kg of talc powder and 120 kg of white cement were put into a vertical grinding mill and ground until the particle size of the mixed powder was D90=45μm to obtain the matrix powder. (4) The matrix powder obtained in step (3) and the fiber-microbead network premix obtained in step (2) are mixed evenly under low-speed stirring; (5) The matrix powder obtained in step (4) is mixed with 15 kg of redispersible latex powder (which includes 6 kg of ethylene-vinyl acetate copolymer powder and 9 kg of ethylene tert-carbonate-vinyl acetate copolymer powder) at 50°C and 400 rpm for 15 minutes. (6) Under a negative pressure of 0.1 MPa, add 4 kg of mixing additive (including 2 kg of defoamer, 1 kg of hydroxypropyl methylcellulose ether binder and 1 kg of nano titanium dioxide photocatalyst) and 3.6 kg of penetrating crystalline active masterbatch (including 2.7 kg of calcium silicate and 0.9 kg of magnesium silicate) to the powder obtained in step (5), stir and mix evenly to obtain the water-resistant putty powder with heat insulation function.

[0024] Comparative Example 1 (Traditional Mechanical Mixing Method) Preparation method: (1) 80 kg of talc powder and 150 kg of white cement were put into a vertical grinding mill and ground until the particle size of the mixed powder was D90=40 μm to obtain the base material; (2) Add 45 kg of vitrified microspheres, 12 kg of hydrophobic silica aerogel powder, 15 kg of untreated polypropylene fiber, 20 kg of redispersible latex powder (including 8 kg of ethylene-vinyl acetate copolymer powder and 12 kg of ethylene tert-carbonate-vinyl acetate copolymer powder), 6 kg of mixing additives (including 3 kg of defoamer, 1.5 kg of hydroxypropyl methylcellulose ether binder and 1.5 kg of nano-titanium dioxide photocatalyst) and 4.5 kg of penetrating crystalline active masterbatch (including 3.4 kg of calcium silicate and 1.1 kg of magnesium silicate) into a conventional mixer; (2) Under normal temperature and pressure conditions, the base material obtained in step (1) and all the materials in step (2) are stirred at a speed of 200 rpm for 30 minutes. After being mixed evenly, putty powder is obtained.

[0025] Comparative Example 2 (aerogel surface treatment omitted) Preparation method: (1) 45 kg of vitrified microspheres and 12 kg of hydrophobic silica aerogel powder were simply mixed in a conventional mixer without surface treatment; (2) After 15 kg of polypropylene fiber is treated with plasma (air atmosphere, power 1000 W, treatment time 90 seconds), it is mixed with the mixed powder obtained in step (1) under low speed stirring to form a premix. (3) Put 80 kg of talc powder and 150 kg of white cement into a vertical grinding mill and grind them until the particle size of the mixed powder is D90=40μm to obtain the matrix powder. (4) Mix the matrix powder obtained in step (3) with the premix obtained in step (2) evenly; (5) The matrix powder obtained in step (4) is mixed with 20 kg of redispersible latex powder (which includes 8 kg of ethylene-vinyl acetate copolymer powder and 12 kg of ethylene tert-carbonate-vinyl acetate copolymer powder) at 60°C and 500 rpm for 10 minutes. (6) Under a negative pressure of 0.12 MPa, add 6 kg of mixing agent and 4.5 kg of penetrating crystallization active masterbatch to the powder obtained in step (5) and stir to mix evenly.

[0026] Comparative Example 3 (fiber surface treatment omitted) Preparation method: (1) In a fluidized bed apparatus, 45 kg of vitrified microspheres and 12 kg of hydrophobic silica aerogel powder were thoroughly mixed at 50°C. At the same time, 0.8 kg of silane coupling agent (KH-550) ethanol solution was sprayed in at an atomization pressure of 0.08 MPa for surface treatment to obtain composite heat-insulating microspheres. (2) Mix 15 kg of untreated polypropylene fiber with the composite heat-insulating microspheres obtained in step (1) under low-speed stirring; (3) Put 80 kg of talc powder and 150 kg of white cement into a vertical grinding mill and grind them until the particle size of the mixed powder is D90=40μm to obtain the matrix powder. (4) Mix the matrix powder obtained in step (3) with the mixture obtained in step (2) evenly; (5) The mixture obtained in step (4) and 20 kg of redispersible latex powder are subjected to high-speed shearing and stirring at 500 rpm for 10 minutes at 60°C. (6) Under a negative pressure of 0.12 MPa, add 6 kg of mixing agent and 4.5 kg of penetrating crystallization active masterbatch to the powder obtained in step (5) and stir to mix evenly.

[0027] Comparative Example 4 (Use of Ordinary Latex Powder as a Substitute) Preparation method: (1) In a fluidized bed apparatus, 45 kg of vitrified microspheres and 12 kg of hydrophobic silica aerogel powder were thoroughly mixed at 50°C. At the same time, 0.8 kg of silane coupling agent (KH-550) ethanol solution was sprayed in at an atomization pressure of 0.08 MPa for surface treatment to obtain composite heat-insulating microspheres. (2) After 15 kg of polypropylene fiber is treated with plasma (air atmosphere, power 1000 W, treatment time 90 seconds), it is mixed with the composite heat-insulating microspheres obtained in step (1) under low speed stirring to form a fiber-microsphere network premix. (3) Put 80 kg of talc powder and 150 kg of white cement into a vertical grinding mill and grind them until the particle size of the mixed powder is D90=40μm to obtain the matrix powder. (4) Mix the matrix powder obtained in step (3) with the mixture obtained in step (2) evenly; (5) The mixture obtained in step (4) is mixed with 20 kg of ordinary redispersible latex powder (a mixture with no specific ratio) and subjected to high-speed shearing and stirring at 500 rpm for 10 minutes at 60°C. (6) Under a negative pressure of 0.12 MPa, add 6 kg of mixing agent and 4.5 kg of penetrating crystallization active masterbatch to the powder obtained in step (5) and stir to mix evenly.

[0028] Comparative Example 5 (mixing under normal pressure) Preparation method: (1) In a fluidized bed apparatus, 45 kg of vitrified microspheres and 12 kg of hydrophobic silica aerogel powder were thoroughly mixed at 50°C. At the same time, 0.8 kg of silane coupling agent (KH-550) ethanol solution was sprayed in at an atomization pressure of 0.08 MPa for surface treatment to obtain composite heat-insulating microspheres. (2) After 15 kg of polypropylene fiber is treated with plasma (air atmosphere, power 1000 W, treatment time 90 seconds), it is mixed with the composite heat-insulating microspheres obtained in step (1) under low speed stirring to form a fiber-microsphere network premix. (3) Put 80 kg of talc powder and 150 kg of white cement into a vertical grinding mill and grind them until the particle size of the mixed powder is D90=40μm to obtain the matrix powder. (4) Mix the matrix powder obtained in step (3) with the mixture obtained in step (2) evenly; (5) The mixture obtained in step (4) is mixed with 20 kg of redispersible latex powder (which includes 8 kg of ethylene-vinyl acetate copolymer powder and 12 kg of ethylene tert-carbonate-vinyl acetate copolymer powder) and subjected to high-speed shearing and stirring at 500 rpm for 10 minutes at 60°C. (6) Under normal pressure, add 6 kg of mixing agent and 4.5 kg of penetrating crystallization active masterbatch to the powder obtained in step (5) and stir to mix evenly.

[0029] Comparative Example 6 (Comparison of Grinding Damage) Preparation method: (1) In a fluidized bed apparatus, 45 kg of vitrified microspheres and 12 kg of hydrophobic silica aerogel powder were thoroughly mixed at 50°C. At the same time, 0.8 kg of silane coupling agent (KH-550) ethanol solution was sprayed in at an atomization pressure of 0.08 MPa for surface treatment to obtain composite heat-insulating microspheres. (2) After 15 kg of polypropylene fiber is treated with plasma (air atmosphere, power 1000 W, treatment time 90 seconds), it is mixed with the composite heat-insulating microbeads obtained in step (1) under low-speed stirring. (3) Put 80 kg of talc powder, 150 kg of white cement and the fiber-microsphere network premix obtained in step (2) into a vertical grinding mill and grind until the particle size of the mixed powder is D90=40 μm to obtain the matrix powder; (this step deliberately destroys the vitrified microspheres) (4) The matrix powder obtained in step (3) is mixed with 20 kg of redispersible latex powder (which includes 8 kg of ethylene-vinyl acetate copolymer powder and 12 kg of ethylene tert-carbonate-vinyl acetate copolymer powder) at 60°C and 500 rpm for 10 minutes. (5) Under a negative pressure of 0.12 MPa, add 6 kg of mixing agent and 4.5 kg of penetrating crystallization active masterbatch to the powder obtained in step (4) and stir to mix evenly.

[0030] The performance of Examples 1-3 and Comparative Examples 1-6 was compared and analyzed using the following test methods: 1. Thermal conductivity test: The test was conducted using the protective hot plate method according to GB / T 10294-2008 "Determination of Steady-State Thermal Resistance and Related Properties of Thermal Insulation Materials". The sample was prepared as a 300mm×300mm×20mm specimen, and its thermal conductivity was measured using a thermal conductivity meter under a standard environment of 23±2℃ and 50±5% relative humidity.

[0031] 2. Bond Strength Test: Tensile bond strength was tested according to JG / T 298-2010 "Building Interior Putty" standard. The putty powder was mixed according to the standard water-cement ratio and applied to a cement mortar substrate. After curing for 28 days, the bond strength was determined using a universal testing machine at a loading rate of 5 mm / min. The water immersion test involved immersing the specimen in water at 23±2℃ for 96 hours and then immediately testing.

[0032] 3. Compressive strength test: According to GB / T 17671-1999 "Test method for strength of cement mortar", the sample is made into a specimen of 40mm×40mm×160mm. After curing under standard conditions for 28 days, the compressive strength is tested using a pressure testing machine at a loading rate of 2400N / s±200N / s.

[0033] 4. Linear shrinkage rate test: According to the drying shrinkage test method in JC / T 985-2017 "Cement-based self-leveling mortar for flooring", a 25mm×25mm×280mm mold was used and cured under standard conditions. The length change was measured at 1 day, 7 days and 28 days respectively, and the linear shrinkage rate was calculated.

[0034] 5. Water absorption test: According to GB / T 1462-2005 "Test method for water absorption properties of fiber reinforced plastics", the specimens were dried to constant weight at 50±2℃, weighed, and then immersed in distilled water at 23±2℃ for 24 hours. After removing and wiping off the surface moisture, the specimens were weighed immediately and the percentage increase in mass was calculated.

[0035] 6. Compression-flexural ratio test: According to JC / T 984-2011 "Polymer Cement Waterproof Mortar" standard, the compressive strength and flexural strength of the material are tested respectively, and the ratio of the two is calculated.

[0036] The comparison data is shown in the table below: Test Project Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Thermal conductivity (W / m·K) 0.052 0.058 0.062 0.098 0.089 0.071 0.069 0.074 0.085 Bond strength (MPa) after immersion in water for 96 hours 0.72 0.68 0.65 0.28 0.45 0.52 0.49 0.54 0.58 Compressive strength (MPa) 8.9 8.6 8.3 5.2 6.8 7.1 6.9 7.3 7.0 Linear shrinkage rate (%) 0.18 0.22 0.25 0.68 0.52 0.48 0.55 0.42 0.41 Water absorption rate (%) 2.9 3.2 3.5 8.5 6.2 5.8 5.6 4.8 5.5 Compression ratio 2.8 2.9 3.0 4.8 4.1 3.9 4.2 3.6 3.8 Analysis of the table data reveals the following: 1. Thermal Insulation Performance System Analysis The thermal conductivity of the three embodiments ranges from 0.052 to 0.062 W / (m·K), exhibiting excellent and stable thermal insulation performance. Example 1, using the optimal combination of process parameters, has the lowest thermal conductivity (0.052 W / (m·K)), improving thermal insulation performance by 88.5% compared to Comparative Example 1 (0.098 W / (m·K)). Although the parameters of Examples 2 and 3 are slightly adjusted, their thermal insulation performance is still significantly better than all comparative examples, demonstrating the robustness of the process formulation of this invention.

[0037] Of particular note is that, due to the omission of aerogel surface treatment, the thermal conductivity of Comparative Example 2 increased to 0.089 W / (m·K), a 71.2% increase compared to Example 1. This fully demonstrates the crucial role of surface treatment in preventing aerogel agglomeration and constructing a complete thermal resistance network in the dynamic airflow device. The minor differences in the thermal insulation performance of the three examples mainly stem from the reasonable adjustment of the amount of vitrified microspheres (35-50 kg) and the aerogel content (8-15 kg), all of which are within the scope of the claims and maintain excellent performance.

[0038] 2. Comprehensive evaluation of water resistance performance Regarding water resistance, the bond strength of the three embodiments after 96 hours of immersion in water ranged from 0.65 to 0.72 MPa, significantly higher than the 0.28 MPa of Comparative Example 1. Example 1's 0.72 MPa was the optimal value, representing a 157% improvement over Comparative Example 1. The excellent performance of Examples 2 (0.68 MPa) and 3 (0.65 MPa) demonstrates that the present invention maintains superior water resistance under different process parameters.

[0039] This advantage stems from the synergistic effect of multiple waterproofing mechanisms: a hydrophobic protective layer formed by a silane coupling agent, a dense structure ensured by a negative pressure environment, and a dense polymer film formed by a specific combination of latex powders. Comparative Example 5, mixed under normal pressure, exhibited a bond strength of only 0.54 MPa, significantly lower than all other examples, demonstrating the crucial role of the negative pressure environment in eliminating interfacial air gaps. The water absorption rates of all three examples were at a low level of 2.9-3.5%, significantly lower than the 8.5% of Comparative Example 1, further validating the excellent impermeability of this invention.

[0040] 3. Verification of synergistic effect of mechanical properties Mechanical property tests showed that the compressive strength of the three embodiments was in the range of 8.3-8.9 MPa, which was significantly better than the 5.2 MPa of Comparative Example 1. Example 1 achieved the highest strength of 8.9 MPa, which was 71% higher than Comparative Example 1. The excellent performance of Examples 2 (8.6 MPa) and 3 (8.3 MPa) proves that the process of the present invention can ensure good mechanical properties under different implementation methods.

[0041] This enhancement effect stems from a multi-level synergistic mechanism: plasma-treated fiber surfaces enhance mechanical interlocking force, the fiber-microsphere network premix forms three-dimensional support, and precisely controlled grinding particle size ensures optimal packing density. Comparative Example 3, by omitting fiber surface treatment, exhibits a compressive strength of 7.1 MPa, significantly lower than all other examples, demonstrating the importance of surface treatment for interfacial bonding. The compression-to-flexural ratios of all three examples are within the ideal range of 2.8-3.0, indicating that the material maintains excellent flexibility while retaining high strength.

[0042] 4. In-depth analysis of dimensional stability and durability Regarding dimensional stability, the linear shrinkage rates of the three embodiments ranged from 0.18% to 0.25%, significantly lower than the 0.68% of Comparative Example 1. Example 1's 0.18% was the optimal value, representing a 73.5% reduction compared to Comparative Example 1. This superior performance is attributed to the combined effect of several factors: the surface-treated polypropylene fibers effectively suppressed plastic shrinkage, the specific latex powder combination provided flexibility to compensate for drying shrinkage, and the penetrating crystalline active masterbatch reduced the number of capillaries.

[0043] Durability indicators show that the water absorption rate of all three embodiments remained at a low level of less than 3.5%, far lower than the 8.5% of Comparative Example 1. Comparative Example 4, using ordinary latex powder, achieved a shrinkage rate of 0.55%, significantly higher than all other embodiments, demonstrating the necessity of specific polymer combinations for improving dimensional stability. All three embodiments maintained excellent durability under different process parameters, proving the reliability and stability of the technical solution of this invention.

[0044] 5. Process parameter optimization and performance balance analysis By comparing the performance data of the three embodiments, it can be found that Embodiment 1 performs best in all indicators, which is attributed to its precisely optimized process parameters: fluidized bed treatment temperature of 50°C, atomization pressure of 0.08 MPa, and plasma treatment power of 1000 W. Embodiments 2 and 3 have some adjustments to some parameters, but the core process steps remain unchanged, thus maintaining excellent overall performance.

[0045] It is particularly noteworthy that the performance differences among the three embodiments are entirely within reasonable expectations, and all are significantly superior to all comparative examples. This indicates that the technical solution of the present invention has a certain degree of parameter adjustment space, and can be appropriately adjusted according to specific needs in actual production without affecting the core performance of the product. This flexibility is of great significance for industrial production, and also proves the rationality and necessity of the parameter range in the claims.

[0046] 6. Verification of the effectiveness of core process steps Comparative Example 6 and Example 1 form the most crucial comparison group. Both are identical in raw materials and formulations. The only difference is that Example 1 uses a protective process of "grinding the base material first, then compounding the functional components," while Comparative Example 6 uses a destructive process of "grinding the functional components and base material together." This single change in step alone increased the thermal conductivity from 0.052 to 0.085, an increase of 63.5%, demonstrating that grinding significantly reduces the thermal insulation function of the vitrified microspheres. Simultaneously, the bonding strength decreased by 19.4%, and the compressive strength decreased by 21.3%, indicating that broken vitrified microspheres not only lose their thermal insulation ability but also become a strength defect in the material. The compression-folding ratio of Example 1 is 2.8, while that of Comparative Example 6 is as high as 3.8. This significant difference (Comparative Example 6 is 35.7% higher than Example 1) demonstrates that maintaining the spherical integrity of the vitrified microspheres is crucial for improving the flexibility and crack resistance of the putty layer. The ground vitrified microsphere fragments cannot effectively transfer and disperse stress, leading to increased material brittleness. Furthermore, Comparative Example 6 is also inferior to Example 1 in all other indicators, including bond strength, linear shrinkage, and water absorption. This comparison strongly proves that "avoiding grinding the composite containing vitrified microspheres" is not an obvious conventional choice, but rather an indispensable core element in resolving the contradiction between thermal insulation and strength, and achieving performance breakthroughs in the technical solution of this invention.

[0047] 7. Comprehensive evaluation of technological innovation and practicality The comprehensive test data demonstrates that the technological innovation of this invention lies not only in the improvement of individual process steps, but more importantly in the synergistic effect between these steps. While improvements to a single process step in Comparative Examples 2-5 may bring some performance gains, none can achieve the combined performance level of the three embodiments. This fully proves that the process combination of this invention produces a synergistic effect of "1+1>2," representing an innovative embodiment of the overall technical solution.

[0048] In summary, all three embodiments maintain excellent and stable performance under different parameter configurations, demonstrating the good practicality and industrialization prospects of this invention. The consistency of the performance data also reflects the maturity and reliability of the technical solution, providing solid technical support for the practical application of the patent.

[0049] It should be understood that the above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. It should not be considered that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for preparing a water-resistant putty powder having a heat retaining function, characterized by, The method comprises the following steps: (1) fully contacting 30-60 parts of vitrified microbeads with 5-20 parts of hydrophobic silica aerogel powder in a dynamic airflow device selected from a fluidized bed or a high-speed vortex mixer, while introducing a silane coupling agent for surface treatment, to obtain composite heat-insulation functional microbeads; (2) mixing 10-20 parts of polypropylene fibers subjected to surface treatment with the composite heat-insulation functional microbeads obtained in step (1) to form a fiber-microbead network premix; (3) jointly grinding 70-90 parts of talc powder with 100-200 parts of white cement to a mixed powder having a particle size D90≤45 μm, to obtain a base powder; (4) uniformly mixing the base powder obtained in step (3) with the fiber-microbead network premix obtained in step (2); (5) high-speed shearing and stirring the mixture obtained in step (4) with 10-30 parts of redispersible latex powder at a rotation speed of 400-600 rpm at 50-65°C for 5-15 minutes; (6) under a negative pressure environment of 0.1-0.15 MPa, adding 2-10 parts of a mixing aid and 0.5-3% of a permeation crystalline active masterbatch based on the mass of the white cement to the powder obtained in step (5) and uniformly stirring and mixing.

2. The method of claim 1, wherein: In step (1), the dynamic airflow device is a fluidized bed, and the silane coupling agent is sprayed in the form of atomization at a pressure of 0.05-0.1 MPa.

3. The method according to claim 1 or 2, characterized in that: In step (2), the surface treatment is plasma treatment, which is performed in an air atmosphere at a power of 800-1200 W for 60-120 seconds.

4. The method of claim 1 or 2, wherein: In step (2), the surface treatment is surface coating with a silane coupling agent solution.

5. The method of claim 1, wherein: In step (5), the redispersible latex powder is a mixture of ethylene-vinyl acetate copolymer powder and tertiary carbon acid ethylene-vinyl acetate copolymer powder at a mass ratio of 1:(1-2).

6. The method of claim 1, 2, or 5, wherein: In step (6), the mixing aid comprises a defoaming agent, a hydroxypropyl methyl cellulose ether binder and a nano titanium dioxide photocatalyst at a mass ratio of (1.5-2):1:(0.4-0.6).

7. The method of claim 1, 2, or 5, wherein: In step (6), the permeation crystalline active masterbatch is composed of calcium silicate and magnesium silicate at a mass ratio of (2.5-3.5):

1.

8. A water-resistant putty powder with heat-insulation function prepared by the method of any one of claims 1-7.

9. A water-resistant putty powder having a heat retaining function, characterized by comprising, The putty powder is composed of the following components by weight: 100-200 parts of white cement; 70-90 parts of talc powder; 30-60 parts of vitrified microbeads; 5-20 parts of hydrophobic silica aerogel; 10-30 parts of redispersible latex powder; 10-20 parts of polypropylene fibers; 2-10 parts of a mixing aid; and 0.5-6 parts of a permeation crystalline active masterbatch; wherein the vitrified microbeads have a closed pore rate of ≥95% and a particle size of 50-100 μm.

10. Putty according to claim 9, characterized in that: The polypropylene fibers have a surface oxygen element content of not less than 8 at%.