Flexible sound insulation tile adhesive and preparation method thereof

Abstract

The invention relates to the field of colloid materials, and provides a flexible sound insulation tile adhesive and a preparation method thereof, the tile adhesive comprises a boron nitride nanotube / silicon dioxide hollow-core microsphere composite filler, a waterborne polyurethane emulsion, talcum powder, mica powder, quartz powder, a leveling agent, a defoaming agent, a dispersing agent, an anti-settling agent, a thickening agent and deionized water. The composite filler is composed of silicon dioxide hollow-core microspheres and boron nitride nanotubes distributed on the surfaces of the silicon dioxide hollow-core microspheres, and has excellent sound insulation and enhancement performance. The filler is synthesized through a catalytic gas-solid reaction, raw materials and process parameters are clear, the preparation method comprises the steps of raw material premixing, dispersing, defoaming, assistant regulation and control, homogenizing, vacuum defoaming and the like, and the obtained ceramic tile adhesive has good flexibility, thixotropy and construction performance, is suitable for various sound insulation engineering scenes such as building interior walls and floors, and has wide application prospects. And the method has excellent practical value and popularization prospect.

Description

Technical Field

[0001] The present invention relates to the field of colloidal materials, and particularly to a flexible sound-insulating tile adhesive and a preparation method thereof. Background Art

[0002] In the field of modern architectural decoration, with people's high attention to residential comfort and spatial privacy, tiles, as floor and wall covering materials, are widely used in various functional spaces such as residences, office buildings, hotels, and public places. However, traditional tile adhesives are mainly rigid inorganic cementitious materials, which perform well in terms of bonding strength but have obvious limitations in dealing with structural deformation, absorption of micro-cracks in the base layer, and high-frequency noise interference. Especially in high-rise buildings, prefabricated components, and lightweight partition wall systems, tile adhesives not only need to have excellent bonding and construction performance but also should simultaneously meet the dual requirements of flexible adaptability and sound-insulating damping ability to ensure the long-term stability of the decorative layer and the acoustic comfort of the use scenario. Therefore, the development of high-performance tile adhesives with flexible buffering characteristics and sound wave attenuation ability is of great significance for improving the durability, safety, and comfort of the building interior decoration system. On the one hand, the flexible performance can effectively relieve the stress concentration caused by the thermal expansion and contraction of the base layer, vibration of lightweight structures, etc., and prevent the tiles from becoming hollow and falling off; on the other hand, excellent sound-insulating performance helps to reduce the transmission of structure-borne sound and air-borne sound, creating a quiet and private use environment. Therefore, in the research and development of new functional bonding materials, tile adhesives with both flexible and sound-insulating properties are becoming an important direction for the development of high-end building materials, and the innovation of their material design and preparation methods has positive significance for promoting the industrial application of green buildings and intelligent building materials.

[0003] Although some functional tile adhesive products in the current market have tried to introduce organic polymers or hollow fillers to improve the physical properties of traditional colloids, there are still significant deficiencies in the coordinated improvement of flexibility regulation and sound insulation performance. The fundamental reason lies in the failure to effectively coordinate the material structure design and the functional filler system. For example, the Chinese patent with the publication number CN104293230A discloses a sound insulation sponge foaming glue for the interior of a security door. Although the addition of microsphere fillers improves the partial sound wave reflection ability, the matching of the flexible matrix and the filler interface in its overall formulation is not systematically optimized, resulting in weak overall compliance of the material and difficulty in adapting to the dynamic deformation of complex substrates. Another example is the Chinese patent with the publication number CN113249064A, which proposes a flexible glue with good water resistance and weather resistance. An elastomer is introduced into the colloid to enhance flexibility, but density regulation and sound impedance matching are not taken into account, and the sound insulation performance is limited. These technical solutions generally have the problems of single function and insufficient coordination mechanism, mainly due to the immature concept of structural coupling design for the "flexibility - sound insulation" dual performance in the existing technology, and the lack of composite filler support with high interfacial efficiency and system construction methods with controllable configurations. Therefore, there is an urgent need to develop a new type of flexible sound insulation tile adhesive with controllable structure and significant interfacial synergistic effect. Through material morphology regulation, functional filler construction, and multi-component coordinated optimization strategies, the coordinated improvement of flexibility and sound insulation performance can be achieved, so as to meet the comprehensive performance requirements of functional adhesive materials for high-standard building decoration applications. Summary of the Invention

[0004] (1) Technical problems to be solved: The purpose of the present invention is to provide a flexible sound insulation tile adhesive and its preparation method to solve the problems of insufficient flexibility and sound insulation performance of current tile adhesives.

[0005] (2) Technical solutions: To achieve the above purpose, the present invention provides the following technical solutions: A flexible sound insulation tile adhesive, comprising the following raw materials in parts by weight: 10.0 - 25.0 parts of boron nitride nanotube / silica hollow microsphere composite filler, 80.0 - 130.0 parts of aqueous polyurethane emulsion, 5.0 - 12.0 parts of talc powder, 5.0 - 10.0 parts of mica powder, 3.0 - 6.0 parts of quartz powder, 2.0 - 5.0 parts of leveling agent, 1.0 - 3.0 parts of defoaming agent, 2.0 - 5.0 parts of dispersant, 1.0 - 3.0 parts of anti-settling agent, 2.0 - 5.5 parts of thickening agent, and 8.0 - 20.0 parts of deionized water; The boron nitride nanotube / silica hollow microsphere composite filler is composed of silica hollow microspheres and boron nitride nanotubes distributed in a divergent manner on the surface of the silica hollow microspheres; Further, the mass ratio of the silica hollow microspheres to the boron nitride nanotubes is: 5:(0.5 - 1.2).

[0006] Further, the average diameter of the silica hollow microspheres is 10~30 µm; Further, the average diameter of the boron nitride nanotubes is 50~100 nm, and the average length is 2.0~3.5 µm; Further, the preparation method of the boron nitride nanotube / silica hollow microsphere composite filler is as follows: by weight, 1.0~3.5 parts of yttrium nitrate and 0.5~2.0 parts of lithium nitrate are dry-ground in an agate mortar for 15~30 min to form a uniform catalyst mixture, and then 10.0~25.0 parts of amorphous boron nitride powder and 50.0~80.0 parts of silica hollow microspheres are added to a planetary ball mill together. Wet ball milling is carried out at a speed of 300~500 rpm for 60~120 min to obtain a premix. The ball milling medium is anhydrous ethanol and the ratio of material to liquid is 1:3~1:5; the premix is transferred to an alumina crucible and placed in a tubular furnace. It is heated to 800~1000 °C at a heating rate of 5~10 °C / min in a flowing ammonia atmosphere, the holding time is 60~180 min, the ammonia flow rate is 5~15 mL / min, and the system pressure is 0.1~0.5 MPa. During this period, yttrium nitrate and lithium nitrate decompose into a composite catalyst and promote the gas-solid phase growth of amorphous boron powder on the surface of silica microspheres to form boron nitride nanotubes; after the reaction, the temperature is programmed to decrease at a rate of 2~5 °C / min to below 200 °C and the product is taken out. It is washed 3~5 times with 0.1~0.5 mol / L hydrochloric acid solution, deionized water and anhydrous ethanol in sequence to remove residual catalysts and unreacted boron powder. Finally, it is treated in a vacuum drying oven at 80~120 °C for 120~240 min to obtain the boron nitride nanotube / silica hollow microsphere composite filler.

[0007] Furthermore, the preparation method of the silica hollow microspheres is as follows: by weight, 1.0 - 3.0 parts of polystyrene microspheres are dispersed in a mixed solvent of 30.0 - 50.0 parts of absolute ethanol and 20.0 - 40.0 parts of deionized water. 0.5 - 2.0 parts of surfactant CTAB are added and mechanically stirred at 200 - 400 rpm for 10 - 20 min to form a homogeneous dispersion. Subsequently, 3.0 - 8.0 parts of tetraethyl orthosilicate are added and the system temperature is controlled at 25 - 40 °C. 0.5 - 1.5 parts of ammonia water catalyst are injected dropwise to make the pH value 9.0 - 10.5. The stirring rate is maintained at 300 - 500 rpm for hydrolysis and condensation reaction for 1 - 3 h. After the reaction is completed, the core - shell microspheres coated with a silica shell layer are collected by centrifugation and washed 3 - 5 times each with absolute ethanol and deionized water to remove the unreacted silicon source and surfactant. The above - mentioned product is placed in a muffle furnace and heated to 500 - 650 °C at a heating rate of 2 - 5 °C / min, and the calcination time is 2 - 5 h to completely remove the polystyrene template to form a cavity structure, or the core - shell microspheres are impregnated in 10.0 - 20.0 parts of tetrahydrofuran by solvent extraction method, ultrasonically treated at 50 - 70 °C for 6 - 12 h to dissolve the template, then centrifuged and pickled with 0.5 - 2.0 mol / L hydrochloric acid solution at 30 - 50 °C for 1 - 3 h to remove residual metal ions, and finally washed with deionized water to neutrality and vacuum - dried at 60 - 90 °C for 4 - 8 h to obtain monodisperse silica hollow microspheres.

[0008] Furthermore, the preparation method of the amorphous boron nitride powder is as follows: by weight, 10.0 - 30.0 parts of crystalline boron powder and stainless - steel grinding balls are loaded into a high - energy ball - milling tank according to a material - to - ball ratio of 1:5 - 1:10. After vacuumizing, ammonia gas is filled until the pressure in the tank is 0.1 - 0.3 MPa, and dry ball - milling is carried out at a ball - milling speed of 200 - 500 rpm for 30 - 120 min. During this period, a mechanical chemical reaction occurs between ammonia gas and boron powder to generate an amorphous boron nitride precursor. The ball - milled product is transferred to a tubular furnace and heated to 500 - 800 °C at a heating rate of 5 - 10 °C / min in a flowing nitrogen atmosphere. The holding time is 60 - 180 min and the nitrogen flow rate is 5 - 15 mL / min to completely nitride the unreacted boron powder and inhibit the crystallization process. After cooling to room temperature, the product is taken out, ultrasonically treated with 0.1 - 0.5 mol / L hydrochloric acid solution for 10 - 30 min to remove metal impurities, then washed with deionized water to neutrality, and finally treated in a vacuum drying oven at 60 - 90 °C for 120 - 360 min to obtain amorphous boron nitride powder.

[0009] The design of the present invention using boron nitride nanotube / silica hollow microsphere composite filler is mainly used to enhance the comprehensive performance of flexibility and sound insulation. Its technical solution aims to achieve a dual improvement in the deformation adaptation ability and sound energy attenuation ability of flexible building adhesive materials in a complex stress environment by constructing a functional filler system with multi-scale structural characteristics and interface synergistic effects. The composite filler uses silica hollow microspheres as the structural matrix, and its unique hollow spherical structure endows the material with excellent lightness and elastic recovery performance, which can form an effective mechanical buffer zone in the colloid system, thereby enhancing the overall flexibility performance; at the same time, the cavity structure has good multiple scattering and reflection capabilities during the propagation of sound waves, which helps to reduce the sound energy transmittance and enhance the sound insulation effect. Boron nitride nanotubes are uniformly distributed on the surface of silica hollow microspheres in a divergent manner. They have excellent mechanical strength and interface strengthening characteristics. In the composite system, they can not only construct a stable three-dimensional support network, effectively improve the stability of the skeleton structure of the colloid, but also further enhance the sound insulation performance through interface interference and elastic absorption of sound waves. The formation of this composite structure depends on using yttrium nitrate and lithium nitrate as precursor catalysts, and controlling the in-situ growth of boron nitride nanotubes on the surface of hollow microspheres through gas-solid phase reaction in an ammonia atmosphere to ensure the formation of a dense and stable interface bond between the two. This interface structure not only endows the filler with excellent dispersibility and emulsion compatibility, but also provides a good interface force transmission path in the aqueous polyurethane emulsion system, thereby realizing the synergistic enhancement of flexible responsiveness and acoustic functionality while maintaining the workability and stability of the system. Through the construction of the above structural design and preparation strategy, the composite filler proposed by the present invention establishes an effective connection between the microscopic configuration and macroscopic performance of the material, providing key technical support for the functionalization of flexible sound insulation tile adhesive.

[0010] Further, the leveling agent is BYK-306 leveling agent; The defoaming agent is BYK-024 defoaming agent; The dispersant is DISPERBYK-2013 dispersant; The anti-settling agent is Bentone® SD-2 anti-settling agent; The thickening agent is hydroxyethyl cellulose.

[0011] The present invention also discloses a preparation method of a flexible sound insulation tile adhesive, comprising the following steps: S1. Mix the boron nitride nanotube / silica hollow microsphere composite filler, talc powder, mica powder, quartz powder and deionized water in proportion and place them in a planetary mixer, and perform pre-dispersion at a stirring speed of 300-500 rpm, control the temperature at 20-35 °C, and the duration is 15-30 min to form a uniform suspension slurry; S2. Add the aqueous polyurethane emulsion and the dispersant to the premix, switch to a high-speed disperser and perform shear dispersion at a rotational speed of 800 - 1200 rpm for 20 - 40 min, maintain the system temperature at 20 - 35 °C to ensure that the filler is evenly embedded in the emulsion matrix and a stable colloidal dispersion is formed; S3. Add the defoamer to the dispersion system, adjust the stirring speed to 200 - 400 rpm for low-speed defoaming for 10 - 20 min, simultaneously apply a vacuum degree of 0.08 - 0.1 MPa to accelerate the escape of bubbles, and control the temperature not exceeding 35 °C; S4. After injecting the leveling agent, adjust the stirring speed to 400 - 600 rpm and maintain for 10 - 15 min, then add the thickener in batches, and stir for 5 - 10 min to stabilize the viscosity within the range of 5000 - 8000 mPa·s; S5. After adding the anti-settling agent, use an anchor agitator to perform low-speed homogenization at a rotational speed of 200 - 400 rpm for 5 - 10 min, control the system temperature at 25 - 40 °C to ensure that the thixotropic properties of the colloid meet the requirements of vertical coating; S6. Transfer the colloid to a vacuum degassing tank, apply a vacuum degree of 0.09 - 0.1 MPa and let it stand for 15 - 30 min, simultaneously monitor the colloid density to be 1.2 - 1.5 g / cm³, adjust the temperature to 20 - 30 °C after degassing to stabilize the rheological properties, transfer the degassed colloid to a sealed container, seal the bag after vacuum packaging or inert gas protection, control the packaging environment temperature at 15 - 30 °C, relative humidity ≤ 60%, and store in the dark.

[0012] The present invention uses a composite filler of boron nitride nanotubes / silica hollow microspheres and a waterborne polyurethane emulsion to synergistically construct a flexible sound-insulating tile adhesive system, aiming to achieve a dual improvement in the flexible adaptability and sound-insulating performance of the material, while ensuring the workability and stability of the system. The composite filler consists of silica microspheres with a hollow structure and boron nitride nanotubes distributed on their surface. This structure simultaneously exerts a mechanical buffering and acoustic wave scattering effect in the colloidal system through precise control of the filler morphology and interfacial state. The hollow microspheres provide a lightweight and highly elastic structural support, which is beneficial for relieving stress concentration in the base layer and improving the flexible response ability of the material. The boron nitride nanotubes distributed on their surface have good rigidity and interfacial adhesion, which can enhance the cohesion and structural stability of the system. In addition, the high aspect ratio of the boron nitride nanotubes enables them to form a certain degree of network structure in the colloid, further enhancing the interference and energy absorption ability of the composite material in the acoustic wave propagation path, thus significantly improving the sound-insulating effect. On this basis, the present invention uses DISPERBYK-2013 dispersant to achieve stable dispersion of the filler in the waterborne polyurethane emulsion, ensuring the uniformity of the system; uses BYK-024 defoamer to effectively control the foam problem during the dispersion process; introduces BYK-306 leveling agent to optimize the surface spreading performance of the colloid; uses hydroxyethyl cellulose as a thickener to regulate the viscosity of the system, endowing it with excellent rheological behavior; and adds Bentone® SD-2 anti-settling agent to enhance the thixotropy and storage stability of the colloid. During the entire preparation process, each component is introduced sequentially according to steps, and dynamic homogenization and stable defoaming of the system are achieved through different shear rates, vacuum treatment, and temperature control. Finally, a flexible sound-insulating tile adhesive with good workability and environmental adaptability is obtained. The above-mentioned multi-components form complementary synergy at the structural and functional levels, significantly superior to the additive effect of single components, not only improving the application reliability of the material in complex building environments, but also providing a new solution for the functional design of high-performance building adhesives.

[0013] (3) Beneficial technical effects: 1. By constructing a synergistic composite structure of boron nitride nanotubes and silica hollow microspheres, the present invention realizes the synchronous improvement of the flexibility and sound-insulating performance of the material, solves the problems of poor compatibility and weak acoustic attenuation of existing tile adhesives, and is applicable to complex scenarios such as high-rise buildings and lightweight walls. The interface integrated design significantly enhances the component synergy, and the performance is superior to that of a single-functional filler system.

[0014] 2. The present invention synergistically constructs the main system through the combination of boron nitride nanotube / silica hollow microsphere composite filler and aqueous polyurethane emulsion, and successively and precisely adds DISPERBYK-2013 dispersant, BYK-024 defoamer, BYK-306 leveling agent, Bentone® SD-2 anti-settling agent and hydroxyethyl cellulose thickener, and controls the shear rate and degassing process, so as to achieve an overall performance improvement in terms of flexibility, sound insulation, workability and storage stability, demonstrating a synergistic advantage superior to the prior art and broad application potential. Description of the Drawings

[0015] Figure 1 It is a scanning electron microscope morphology diagram of the boron nitride nanotube / silica hollow microsphere composite filler prepared in Example 1 of the present invention.

[0016] Figure 2 It is a transmission electron microscope morphology diagram of the boron nitride nanotube / silica hollow microsphere composite filler prepared in Example 1 of the present invention. Detailed Embodiments

[0017] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0018] Example 1: A flexible sound-insulating tile adhesive, comprising the following raw materials in parts by weight: 10.0 parts of boron nitride nanotube / silica hollow microsphere composite filler, 80.0 parts of aqueous polyurethane emulsion, 5.0 parts of talc powder, 5.0 parts of mica powder, 3.0 parts of quartz powder, 2.0 parts of leveling agent, 1.0 part of defoamer, 2.0 parts of dispersant, 1.0 part of anti-settling agent, 2.0 parts of thickener, and 8.0 parts of deionized water; The boron nitride nanotube / silica hollow microsphere composite filler in this example is composed of silica hollow microspheres and boron nitride nanotubes distributed in a divergent manner on the surface of the silica hollow microspheres; the mass ratio of the silica hollow microspheres to the boron nitride nanotubes is: 5:0.5. The average diameter of the silica hollow microspheres is 10 µm; the average diameter of the boron nitride nanotubes is 50 nm, and the average length is 2.0 µm; The preparation method of the boron nitride nanotube / silica hollow microsphere composite filler in this embodiment is as follows: By weight, 1.0 part of yttrium nitrate and 0.5 part of lithium nitrate are dry-ground in an agate mortar for 15 min to form a uniform catalyst mixture, which is then added to a planetary ball mill together with 10.0 parts of amorphous boron nitride powder and 50.0 parts of silica hollow microspheres. Wet ball milling is carried out at a speed of 300 rpm for 60 min to obtain a premix. The ball milling medium is anhydrous ethanol and the ratio of material to liquid is 1:3. The premix is transferred to an alumina crucible and placed in a tube furnace. It is heated to 800 °C at a heating rate of 5 °C / min in a flowing ammonia atmosphere, the holding time is 60 min, the ammonia flow rate is 5 mL / min, and the system pressure is 0.1 MPa. During this period, yttrium nitrate and lithium nitrate decompose into a composite catalyst and promote the gas-solid phase growth of amorphous boron powder on the surface of silica microspheres to form boron nitride nanotubes. After the reaction, the temperature is programmed to decrease at a rate of 2 °C / min to below 200 °C and the product is taken out. It is washed 3 times with 0.1 mol / L hydrochloric acid solution, deionized water and anhydrous ethanol in sequence to remove residual catalyst and unreacted boron powder. Finally, it is treated in a vacuum drying oven at 80 °C for 120 min to obtain the boron nitride nanotube / silica hollow microsphere composite filler.

[0019] The preparation method of the silica hollow microspheres in this embodiment is as follows: By weight, 1.0 part of polystyrene microspheres are dispersed in a mixed solvent of 30.0 parts of anhydrous ethanol and 20.0 parts of deionized water. 0.5 part of surfactant CTAB is added and mechanically stirred at 200 rpm for 10 min to form a uniform dispersion. Then 3.0 parts of tetraethyl orthosilicate are added and the system temperature is controlled at 25 °C. 0.5 part of ammonia water catalyst is injected drop by drop to make the pH value 9.0. The stirring rate is maintained at 300 rpm for hydrolysis and condensation reaction for 1 h. After the reaction is completed, the core-shell microspheres coated with a silica shell layer are collected by centrifugal separation and washed 3 times with anhydrous ethanol and deionized water in sequence to remove unreacted silicon source and surfactant. The above product is placed in a muffle furnace and heated to 500 °C at a heating rate of 2 °C / min. The calcination time is 2 h to completely remove the polystyrene template to form a cavity structure, or the solvent extraction method is used to immerse the core-shell microspheres in 10.0 parts of tetrahydrofuran and ultrasonically treat them at 50 °C for 6 h to dissolve the template. Then centrifugal separation is carried out and pickling is carried out with 0.5 mol / L hydrochloric acid solution at 30 °C for 1 h to remove residual metal ions. Finally, it is washed with deionized water to neutrality and vacuum dried at 60 °C for 4 h to obtain monodisperse silica hollow microspheres.

[0020] The preparation method of the amorphous boron nitride powder in this example is as follows: by weight, 10.0 parts of crystalline boron powder and stainless steel grinding balls are loaded into a high-energy ball milling tank at a material-to-ball ratio of 1:5. After evacuating the air, ammonia gas is filled until the pressure in the tank is 0.1 MPa, and dry ball milling is carried out at a ball milling speed of 200 rpm for 30 min. During this period, a mechanical chemical reaction occurs between ammonia gas and boron powder to generate an amorphous boron nitride precursor. The ball milling product is transferred to a tubular furnace and heated to 500°C at a heating rate of 5°C / min under a flowing nitrogen atmosphere, with a holding time of 60 min and a nitrogen flow rate of 5 mL / min, so that the unreacted boron powder is completely nitrided and the crystallization process is inhibited. After cooling to room temperature, the product is taken out, ultrasonically treated with 0.1 mol / L hydrochloric acid solution for 10 min to remove metal impurities, then washed with deionized water until neutral, and finally treated in a vacuum drying oven at 60°C for 120 min to obtain amorphous boron nitride powder.

[0021] The leveling agent in this example is BYK-306 leveling agent; the defoaming agent is BYK-024 defoaming agent; the dispersant is DISPERBYK-2013 dispersant; the anti-settling agent is Bentone® SD-2 anti-settling agent; the thickening agent is hydroxyethyl cellulose.

[0022] The preparation method of a flexible sound-insulating tile adhesive in this example includes the following steps: S1. Mix the boron nitride nanotube / silica hollow microsphere composite filler, talc powder, mica powder, quartz powder and deionized water in proportion and place them in a planetary mixer. Carry out pre-dispersion at a stirring speed of 300 rpm, control the temperature at 20°C, and the duration is 15 min to form a uniform suspension slurry. S2. Add the aqueous polyurethane emulsion and the dispersant to the premix, switch to a high-speed disperser and carry out shear dispersion at a speed of 800 rpm for 20 min, maintaining the system temperature at 20°C to ensure that the filler is evenly embedded in the emulsion matrix and a stable colloidal dispersion is formed. S3. Add the defoaming agent to the dispersion system, adjust the stirring speed to 200 rpm for low-speed defoaming, the defoaming time is 10 min, and simultaneously apply a vacuum degree of 0.08 MPa to accelerate the escape of bubbles, controlling the temperature not to exceed 35°C. S4. After injecting the leveling agent, adjust the stirring speed to 400 rpm and maintain it for 10 min, then add the thickening agent in batches, and the stirring time is 5 min to make the viscosity stable within the range of 5000 mPa·s. S5. After adding the anti-settling agent, use an anchor stirrer to carry out low-speed homogenization at a speed of 200 rpm for 5 min, control the system temperature at 25°C, and ensure that the thixotropic performance of the colloid meets the requirements of vertical coating. S6. Transfer the colloid to a vacuum degassing tank, apply a vacuum degree of 0.09 MPa and let it stand for 15 min. Synchronously monitor the colloid density to be 1.2 g / cm³. After degassing, adjust the temperature to 20°C to stabilize the rheological properties. Transfer the degassed colloid to a sealed container, seal the bag after vacuum packaging or inert gas protection, control the packaging environment temperature to be 15°C, and the relative humidity ≤60%, and store it away from light.

[0023] It can be seen from Figure 1 and Figure 2 that the boron nitride nanotube / silica hollow microsphere composite filler prepared in Example 1 exhibits a good composite structure morphology. The scanning electron microscope image shows that the nanotubes are uniformly coated or wound on the surface of the hollow microspheres, forming a three-dimensional network structure, effectively increasing the interfacial contact area between the filler and the polymer matrix; the transmission electron microscope further confirms that the boron nitride nanotubes are densely distributed on the surface of the microspheres, with a complete structure, clear orientation, thin nanotube diameter, large length, and a tight interface with the hollow microspheres, and no obvious peeling or agglomeration phenomenon is observed, fully indicating that the wet ball milling and gas-solid phase in-situ growth process adopted in the present invention can achieve the uniform in-situ construction of boron nitride nanotubes on the surface of hollow microspheres. This composite structure provides a structural basis for enhancing the sound insulation performance, mechanical strength and flexibility in the follow-up, verifying the rationality and feasibility of the design of the composite filler system of the present invention.

[0024] Example 2: A flexible sound insulation tile adhesive, comprising the following raw materials in parts by weight: 15 parts of boron nitride nanotube / silica hollow microsphere composite filler, 95 parts of aqueous polyurethane emulsion, 7 parts of talc powder, 7 parts of mica powder, 4 parts of quartz powder, 3 parts of leveling agent, 1 part of defoaming agent, 3 parts of dispersant, 1 part of anti-settling agent, 3 parts of thickening agent, and 12 parts of deionized water; The boron nitride nanotube / silica hollow microsphere composite filler in this example is composed of silica hollow microspheres and boron nitride nanotubes distributed in a divergent manner on the surface of the silica hollow microspheres; the mass ratio of the silica hollow microspheres to the boron nitride nanotubes is: 5:0.7. The average diameter of the silica hollow microspheres is 16 µm; the average diameter of the boron nitride nanotubes is 65 nm, and the average length is 2.5 µm; The preparation method of the boron nitride nanotube / silica hollow microsphere composite filler in this example is as follows: by weight, 1.8 parts of yttrium nitrate and 0.9 part of lithium nitrate are dry-ground in an agate mortar for 20 min to form a uniform catalyst mixture, which is then jointly added to a planetary ball mill together with 15 parts of amorphous boron nitride powder and 59 parts of silica hollow microspheres. Wet ball milling is carried out at a speed of 360 rpm for 78 min to obtain a premix. The ball milling medium is anhydrous ethanol and the ratio of material to liquid is 1:3.6. The premix is transferred to an alumina crucible and placed in a tube furnace. It is heated to 860°C at a heating rate of 7°C / min in a flowing ammonia atmosphere. The holding time is 96 min, the ammonia flow rate is 8 mL / min, and the system pressure is 0.2 MPa. During this period, yttrium nitrate and lithium nitrate decompose into a composite catalyst and promote the gas-solid phase growth of amorphous boron powder on the surface of silica microspheres to form boron nitride nanotubes. After the reaction is completed, the product is taken out after cooling to below 200°C at a rate of 3°C / min. It is washed 4 times each with 0.2 mol / L hydrochloric acid solution, deionized water, and anhydrous ethanol to remove residual catalyst and unreacted boron powder. Finally, it is treated in a vacuum drying oven at 92°C for 156 min to obtain the boron nitride nanotube / silica hollow microsphere composite filler.

[0025] The preparation method of the silica hollow microspheres in this example is as follows: by weight, 1.6 parts of polystyrene microspheres are dispersed in a mixed solvent of 36 parts of anhydrous ethanol and 26 parts of deionized water. 0.9 part of surfactant CTAB is added and mechanically stirred at 260 rpm for 13 min to form a uniform dispersion. Then, 4.5 parts of tetraethyl orthosilicate are added and the system temperature is controlled at 30°C. 0.8 part of ammonia water catalyst is injected dropwise to make the pH value 9.5. The stirring rate is maintained at 360 rpm for hydrolysis and condensation reaction for 1.6 h. After the reaction is completed, the core-shell microspheres coated with a silica shell are collected by centrifugal separation and washed 4 times each with anhydrous ethanol and deionized water to remove unreacted silicon source and surfactant. The above product is placed in a muffle furnace and heated to 545°C at a heating rate of 3°C / min. The calcination time is 3 h to completely remove the polystyrene template to form a cavity structure, or the solvent extraction method is used to immerse the core-shell microspheres in 13 parts of tetrahydrofuran and ultrasonically treat them at 56°C for 8 h to dissolve the template. Then, centrifugal separation is carried out and pickling is carried out with 0.9 mol / L hydrochloric acid solution at 36°C for 1.6 h to remove residual metal ions. Finally, it is washed with deionized water until neutral and vacuum dried at 69°C for 5 h to obtain monodisperse silica hollow microspheres.

[0026] The preparation method of the amorphous boron nitride powder in this embodiment is as follows: By weight, 16 parts of crystalline boron powder and stainless steel grinding balls are loaded into a high-energy ball milling tank at a material-to-ball ratio of 1:7. After evacuating the air, ammonia gas is filled until the pressure in the tank is 0.2 MPa, and dry ball milling is carried out at a ball milling speed of 290 rpm for 57 min. During this period, a mechanical chemical reaction occurs between ammonia gas and boron powder to generate an amorphous boron nitride precursor. The ball milling product is transferred to a tubular furnace and heated to 590°C at a heating rate of 7°C / min under a flowing nitrogen atmosphere. The holding time is 96 min, and the nitrogen flow rate is 8 mL / min to completely nitride the unreacted boron powder and inhibit the crystallization process. After cooling to room temperature, the product is taken out, ultrasonically treated with a 0.2 mol / L hydrochloric acid solution for 16 min to remove metal impurities, then washed with deionized water until neutral, and finally treated in a vacuum drying oven at 69°C for 192 min to obtain the amorphous boron nitride powder.

[0027] The leveling agent in this embodiment is BYK-306 leveling agent; the defoaming agent is BYK-024 defoaming agent; the dispersant is DISPERBYK-2013 dispersant; the anti-settling agent is Bentone® SD-2 anti-settling agent; the thickening agent is hydroxyethyl cellulose.

[0028] The preparation method of a flexible sound-insulating tile adhesive in this embodiment includes the following steps: S1. Mix the boron nitride nanotube / silica hollow microsphere composite filler, talc powder, mica powder, quartz powder and deionized water in proportion and place them in a planetary mixer. Perform pre-dispersion at a stirring speed of 360 rpm, control the temperature at 24°C, and the duration is 20 min to form a uniform suspension slurry. S2. Add the aqueous polyurethane emulsion and the dispersant to the premix, switch to a high-speed disperser and perform shear dispersion at a rotation speed of 920 rpm. The dispersion time is 26 min, and maintain the system temperature at 24°C to ensure that the filler is evenly embedded in the emulsion matrix and a stable colloidal dispersion is formed. S3. Add the defoaming agent to the dispersion system, adjust the stirring speed to 260 rpm for low-speed defoaming. The defoaming time is 13 min, and simultaneously apply a vacuum degree of 0.09 MPa to accelerate the escape of bubbles, and control the temperature not to exceed 35°C. S4. After injecting the leveling agent, adjust the stirring speed to 460 rpm and maintain it for 11 min, then add the thickening agent in batches, and the stirring time is 7 min to stabilize the viscosity within the range of 5900 mPa·s. S5. After adding the anti-settling agent, use an anchor stirrer to perform low-speed homogenization at a rotation speed of 260 rpm for 7 min, control the system temperature at 30°C, and ensure that the thixotropic performance of the colloid meets the requirements of vertical coating. S6. Transfer the colloid to a vacuum degassing tank, apply a vacuum degree of 0.09 MPa and let it stand for 20 min. Synchronously monitor the colloid density to be 1.3 g / cm³. After degassing, adjust the temperature to 23°C to stabilize the rheological properties. Transfer the degassed colloid to a sealed container, seal the bag after vacuum packaging or inert gas protection, control the packaging environment temperature to be 20°C, relative humidity ≤ 60%, and store it in the dark.

[0029] Example 3: A flexible sound-insulating ceramic tile adhesive, comprising the following raw materials in parts by weight: 25.0 parts of boron nitride nanotube / silica hollow microsphere composite filler, 130.0 parts of aqueous polyurethane emulsion, 12.0 parts of talc powder, 10.0 parts of mica powder, 6.0 parts of quartz powder, 5.0 parts of leveling agent, 3.0 parts of defoaming agent, 5.0 parts of dispersant, 3.0 parts of anti-settling agent, 5.5 parts of thickening agent, and 20.0 parts of deionized water; The boron nitride nanotube / silica hollow microsphere composite filler of this example consists of silica hollow microspheres and boron nitride nanotubes distributed in a divergent manner on the surface of the silica hollow microspheres; the mass ratio of silica hollow microspheres to boron nitride nanotubes is: 5:1.2. The average diameter of the silica hollow microspheres is 30 µm; the average diameter of the boron nitride nanotubes is 100 nm, and the average length is 3.5 µm; The preparation method of the boron nitride nanotube / silica hollow microsphere composite filler of this example is as follows: in parts by weight, grind 3.5 parts of yttrium nitrate and 2.0 parts of lithium nitrate dry in an agate mortar for 30 min to form a uniform catalyst mixture, and then add it together with 25.0 parts of amorphous boron nitride powder and 80.0 parts of silica hollow microspheres to a planetary ball mill, and wet ball mill at a speed of 500 rpm for 120 min to obtain a premix. The ball milling medium is anhydrous ethanol and the ratio of material to liquid is 1:5; transfer the premix to an alumina crucible and place it in a tube furnace, heat it to 1000°C at a heating rate of 10°C / min in a flowing ammonia atmosphere, keep the temperature for 180 min, the ammonia flow rate is 15 mL / min, and the system pressure is 0.5 MPa. During this period, yttrium nitrate and lithium nitrate decompose into a composite catalyst and promote the gas-solid phase growth of amorphous boron powder on the surface of silica microspheres to form boron nitride nanotubes; after the reaction, cool it down to below 200°C at a rate of 5°C / min and take out the product, wash it 5 times with 0.5 mol / L hydrochloric acid solution, deionized water and anhydrous ethanol in sequence to remove residual catalysts and unreacted boron powder, and finally treat it in a 120°C vacuum drying oven for 240 min to obtain the boron nitride nanotube / silica hollow microsphere composite filler.

[0030] The preparation method of the silica hollow microspheres in this embodiment is as follows: by weight, disperse 3.0 parts of polystyrene microspheres in a mixed solvent of 50.0 parts of absolute ethanol and 40.0 parts of deionized water, add 2.0 parts of surfactant CTAB and mechanically stir at 400 rpm for 20 min to form a homogeneous dispersion. Subsequently, add 8.0 parts of tetraethyl orthosilicate and control the system temperature at 40°C, inject 1.5 parts of ammonia catalyst dropwise to make the pH value 10.5, and maintain the stirring rate at 500 rpm for hydrolysis and condensation reaction for 3 h. After the reaction is completed, collect the core-shell microspheres coated with a silica shell layer by centrifugation, and wash them 5 times with absolute ethanol and deionized water respectively to remove the unreacted silicon source and surfactant; place the above product in a muffle furnace and heat it to 650°C at a heating rate of 5°C / min, and the calcination time is 5 h to completely remove the polystyrene template to form a cavity structure, or use the solvent extraction method to immerse the core-shell microspheres in 20.0 parts of tetrahydrofuran, ultrasonically treat them at 70°C for 12 h to dissolve the template, then centrifuge and pickle them with 2.0 mol / L hydrochloric acid solution at 50°C for 3 h to remove residual metal ions, and finally wash them with deionized water to neutrality and dry them in a vacuum at 90°C for 8 h to obtain monodisperse silica hollow microspheres.

[0031] The preparation method of the amorphous boron nitride powder in this embodiment is as follows: by weight, put 30.0 parts of crystalline boron powder and stainless steel grinding balls into a high-energy ball milling tank according to a material-ball ratio of 1:10, evacuate and then fill with ammonia gas until the pressure in the tank is 0.3 MPa, and carry out dry ball milling at a ball milling speed of 500 rpm for 120 min. During this period, a mechanical chemical reaction occurs between ammonia gas and boron powder to generate an amorphous boron nitride precursor; transfer the ball milling product to a tubular furnace, heat it to 800°C at a heating rate of 10°C / min in a flowing nitrogen atmosphere, keep the temperature for 180 min, and the nitrogen flow rate is 15 mL / min to completely nitride the unreacted boron powder and inhibit the crystallization process; take out the product after cooling to room temperature, ultrasonically treat it with 0.5 mol / L hydrochloric acid solution for 30 min to remove metal impurities, then wash it with deionized water to neutrality, and finally treat it in a vacuum drying oven at 90°C for 360 min to obtain amorphous boron nitride powder.

[0032] The leveling agent in this embodiment is BYK-306 leveling agent; the defoaming agent is BYK-024 defoaming agent; the dispersant is DISPERBYK-2013 dispersant; the anti-settling agent is Bentone® SD-2 anti-settling agent; the thickening agent is hydroxyethyl cellulose.

[0033] The preparation method of a flexible sound-insulating tile adhesive in this embodiment includes the following steps: S1. Mix the boron nitride nanotube / silica hollow microsphere composite filler, talc powder, mica powder, quartz powder and deionized water in proportion, place them in a planetary mixer, and perform pre-dispersion at a stirring speed of 420 rpm, control the temperature at 29 °C, and the duration is 24 min to form a uniform suspension slurry; S2. Add the aqueous polyurethane emulsion and the dispersant to the premix, switch to a high-speed disperser and perform shear dispersion at a rotation speed of 1040 rpm, the dispersion time is 32 min, and maintain the system temperature at 29 °C to ensure that the filler is evenly embedded in the emulsion matrix and forms a stable colloidal dispersion; S3. Add an antifoaming agent to the dispersion system, adjust the stirring speed to 320 rpm for low-speed defoaming, the defoaming time is 16 min, simultaneously apply a vacuum degree of 0.09 MPa to accelerate the escape of bubbles, and control the temperature not to exceed 35 °C; S4. After injecting the leveling agent, adjust the stirring speed to 520 rpm and maintain it for 13 min, then add the thickener in batches, and the stirring time is 8 min to make the viscosity stable within the range of 6800 mPa·s; S5. After adding the anti-settling agent, use an anchor agitator to perform low-speed homogenization at a rotation speed of 320 rpm, the duration is 8 min, control the system temperature at 34 °C, and ensure that the thixotropic performance of the colloid meets the requirements of vertical coating; S6. Transfer the colloid to a vacuum degassing tank, apply a vacuum degree of 0.10 MPa and let it stand for 24 min, simultaneously monitor the colloid density at 1.4 g / cm³, adjust the temperature to 26 °C after degassing to stabilize the rheological properties, transfer the degassed colloid to a sealed container, use vacuum packaging or inert gas protection and then seal the bag, control the packaging environment temperature at 24 °C, relative humidity ≤ 60%, and store in the dark.

[0034] Example 4: A flexible sound-insulating tile adhesive, comprising the following raw materials in parts by weight: 19 parts of boron nitride nanotube / silica hollow microsphere composite filler, 110 parts of aqueous polyurethane emulsion, 9 parts of talc powder, 8 parts of mica powder, 5 parts of quartz powder, 4 parts of leveling agent, 2 parts of antifoaming agent, 4 parts of dispersant, 2 parts of anti-settling agent, 4 parts of thickener, and 15 parts of deionized water; The boron nitride nanotube / silica hollow microsphere composite filler in this example consists of silica hollow microspheres and boron nitride nanotubes distributed in a divergent manner on the surface of the silica hollow microspheres; the mass ratio of the silica hollow microspheres to the boron nitride nanotubes is: 5:0.9. The average diameter of the silica hollow microspheres is 22 µm; the average diameter of the boron nitride nanotubes is 80 nm, and the average length is 2.9 µm; The preparation method of the boron nitride nanotube / silica hollow microsphere composite filler in this embodiment is as follows: by weight, 2.5 parts of yttrium nitrate and 1.4 parts of lithium nitrate are dry-ground in an agate mortar for 24 min to form a uniform catalyst mixture, which is then added together with 19 parts of amorphous boron nitride powder and 68 parts of silica hollow microspheres into a planetary ball mill, and wet-milled at a speed of 420 rpm for 96 min to obtain a premix. The ball-milling medium is anhydrous ethanol and the ratio of material to liquid is 1:4.2. The premix is transferred to an alumina crucible and placed in a tube furnace. Under a flowing ammonia atmosphere, it is heated to 920°C at a heating rate of 8°C / min, the holding time is 132 min, the ammonia flow rate is 11 mL / min, and the system pressure is 0.3 MPa. During this period, yttrium nitrate and lithium nitrate decompose into a composite catalyst and promote the gas-solid phase growth of amorphous boron powder on the surface of silica microspheres to form boron nitride nanotubes. After the reaction, the product is taken out by cooling at a rate of 4°C / min to below 200°C, and washed 4 times each with 0.3 mol / L hydrochloric acid solution, deionized water, and anhydrous ethanol to remove residual catalyst and unreacted boron powder. Finally, it is treated in a vacuum drying oven at 104°C for 192 min to obtain the boron nitride nanotube / silica hollow microsphere composite filler.

[0035] The preparation method of the silica hollow microspheres in this embodiment is as follows: by weight, 2.2 parts of polystyrene microspheres are dispersed in a mixed solvent of 42 parts of anhydrous ethanol and 32 parts of deionized water, 1.4 parts of surfactant CTAB is added, and mechanical stirring is carried out at 320 rpm for 16 min to form a uniform dispersion. Then 6.0 parts of tetraethyl orthosilicate is added, the system temperature is controlled at 34°C, and 1.1 parts of ammonia water catalyst is injected dropwise to make the pH value 10.0. The stirring rate is maintained at 420 rpm for a hydrolysis and condensation reaction for 2.2 h. After the reaction is completed, the core-shell microspheres coated with a silica shell layer are collected by centrifugal separation, and washed 4 times each with anhydrous ethanol and deionized water to remove unreacted silicon source and surfactant. The above product is placed in a muffle furnace and heated to 590°C at a heating rate of 4°C / min, and the calcination time is 4 h to completely remove the polystyrene template to form a cavity structure, or the solvent extraction method is used to immerse the core-shell microspheres in 16 parts of tetrahydrofuran, ultrasonically treated at 62°C for 10 h to dissolve the template, then centrifugally separated and pickled with 1.4 mol / L hydrochloric acid solution at 42°C for 2.2 h to remove residual metal ions, and finally washed with deionized water to neutrality and dried in vacuum at 78°C for 6 h to obtain monodisperse silica hollow microspheres.

[0036] The preparation method of the amorphous boron nitride powder in this embodiment is as follows: By weight, 22 parts of crystalline boron powder and stainless steel grinding balls are loaded into a high-energy ball milling tank at a material-to-ball ratio of 1:8. After vacuum pumping, ammonia gas is filled until the pressure in the tank is 0.2 MPa, and dry ball milling is carried out at a ball milling speed of 380 rpm for 84 min. During this period, a mechanical chemical reaction occurs between ammonia gas and boron powder to generate an amorphous boron nitride precursor; the ball milling product is transferred to a tubular furnace, heated to 680°C at a heating rate of 8°C / min under a flowing nitrogen atmosphere, with a holding time of 132 min and a nitrogen flow rate of 11 mL / min, to completely nitride the unreacted boron powder and inhibit the crystallization process; after cooling to room temperature, the product is taken out, ultrasonically treated with a 0.3 mol / L hydrochloric acid solution for 22 min to remove metal impurities, then washed with deionized water until neutral, and finally treated in a vacuum drying oven at 78°C for 264 min to obtain amorphous boron nitride powder.

[0037] The leveling agent in this embodiment is BYK-306 leveling agent; the defoaming agent is BYK-024 defoaming agent; the dispersant is DISPERBYK-2013 dispersant; the anti-settling agent is Bentone® SD-2 anti-settling agent; the thickening agent is hydroxyethyl cellulose.

[0038] The preparation method of a flexible sound-insulating tile adhesive in this embodiment includes the following steps: S1. Mix the boron nitride nanotube / silica hollow microsphere composite filler, talc powder, mica powder, quartz powder and deionized water in proportion and place them in a planetary mixer, and carry out pre-dispersion at a stirring speed of 500 rpm, control the temperature at 35°C, and the duration is 30 min to form a uniform suspension slurry; S2. Add the aqueous polyurethane emulsion and the dispersant to the premix, switch to a high-speed disperser and carry out shear dispersion at a rotation speed of 1200 rpm, the dispersion time is 40 min, and maintain the system temperature at 35°C to ensure that the filler is evenly embedded in the emulsion matrix and form a stable colloidal dispersion; S3. Add the defoaming agent to the dispersion system, adjust the stirring speed to 400 rpm for low-speed defoaming, the defoaming time is 20 min, and simultaneously apply a vacuum degree of 0.1 MPa to accelerate the escape of bubbles, and control the temperature not to exceed 35°C; S4. After injecting the leveling agent, adjust the stirring speed to 600 rpm and maintain it for 15 min, then add the thickening agent in batches, and the stirring time is 10 min to make the viscosity stable within the range of 8000 mPa·s; S5. After adding the anti-settling agent, use an anchor stirrer to carry out low-speed homogenization at a rotation speed of 400 rpm, the duration is 10 min, and control the system temperature at 40°C to ensure that the thixotropic performance of the colloid meets the requirements of vertical coating; S6. Transfer the colloid to a vacuum degassing tank, apply a vacuum of 0.1 MPa and let it stand for 30 min. Synchronously monitor the colloid density to be 1.5 g / cm³. After degassing, adjust the temperature to 30°C to stabilize the rheological properties. Transfer the degassed colloid to a sealed container, seal the bag after vacuum packaging or inert gas protection, control the packaging environment temperature at 30°C, relative humidity ≤60%, and store it in the dark.

[0039] Comparative Example 1: It is basically the same as Example 1, except that the addition amount of boron nitride nanotube / silica hollow microsphere composite filler is less than 10.0 parts, resulting in a decrease in sound insulation performance and insufficient flexibility.

[0040] Comparative Example 2: It is basically the same as Example 1, except that the mass ratio of silica hollow microspheres to boron nitride nanotubes is 5:0.2, the composite structure is incomplete, and the synergistic effect is significantly weakened.

[0041] Comparative Example 3: It is basically the same as Example 1, except that the average particle size of silica hollow microspheres is 6 µm, the elasticity of the system is insufficient, and the sound absorption performance decreases.

[0042] Comparative Example 4: It is basically the same as Example 1, except that the average diameter of the boron nitride nanotubes is 200 nm.

[0043] Comparative Example 5: It is basically the same as Example 1, except that the dosage of yttrium nitrate is 0.5 part.

[0044] Comparative Example 6: It is basically the same as Example 1, except that the wet ball milling speed is 200 rpm.

[0045] Comparative Example 7: It is basically the same as Example 1, except that the temperature of the gas-solid phase growth reaction is 750°C.

[0046] Comparative Example 8: It is basically the same as Example 1, except that the calcination temperature of the silica hollow microspheres is 450°C.

[0047] Comparative Example 9: It is basically the same as Example 1, except that the pressure in the high-energy ball milling tank is 0.05 MPa.

[0048] Comparative Example 10: It is basically the same as Example 1, except that the nitridation temperature of the amorphous boron nitride powder is 900°C.

[0049] Comparative Example 11: It is basically the same as Example 1, except that: the stirring speed in the pre-dispersion step is 600 rpm.

[0050] Comparative Example 12: It is basically the same as Example 1, except that: the vacuum degree in the high-speed dispersion step is 0.05 MPa.

[0051] Comparative Example 13: It is basically the same as Example 1, except that the heating rate in the curing step is 10 °C / min.

[0052] Comparative Example 14: It is basically the same as Example 1, except that boron nitride nanotubes are not prepared on the surface of the silica hollow microspheres.

[0053] Performance test: Experiment 1: Sound insulation performance test (according to ASTM E1050 standard): The noise reduction coefficient (NRC) and sound transmission loss (STL) of the material are tested by the impedance tube method. The sample is prepared into a disc with a diameter of 100 mm and a thickness of 2 mm, placed in a two-channel impedance tube. Under the excitation of sound waves in the frequency range of 100 - 6300 Hz, the incident sound pressure and transmitted sound pressure are collected by a microphone array, and the absorption coefficient and sound transmission loss curve under normal incidence are calculated. And the noise reduction coefficient is calculated according to ISO 354 standard (NRC≥0.75 is qualified), and the influence of different schemes on the sound insulation performance is compared.

[0054] Experiment 2: Flexibility and elongation at break test (according to ASTM D638 standard): The cured colloid is prepared into dumbbell-shaped specimens (thickness 2 mm, gauge length 25 mm), and unidirectional tension is carried out using a universal material testing machine at a tensile rate of 50 mm / min. The stress-strain curve is recorded until fracture, the elongation at break and elastic modulus are calculated, and the fracture surface morphology is observed simultaneously to analyze the interfacial bonding strength between the filler and the matrix.

[0055] Experiment 3: Mechanical strength test (according to ASTM D638 / D1002 standard): The bonding performance between the colloid and the ceramic tile substrate is evaluated through the shear strength test. The colloid is coated on the surface of a standard ceramic tile (coating thickness 1.5 mm), and after curing, it is adhesively bonded with another ceramic tile. Shear test is carried out using a universal testing machine at a loading rate of 1 mm / min, the maximum shear strength is recorded, and the interfacial failure mode is analyzed.

[0056] Experiment 4: Weather resistance test (according to ASTM G154 standard): Simulate the ultraviolet aging environment, place the sample in a QUV accelerated aging test chamber, use UVA-340 lamps, and the cycle conditions are: ultraviolet irradiation (0.76 W / m²@340 nm, 60 °C, 8 h) → condensation (50 °C, 4 h). After 1000 h of cycling, the appearance change of the colloid, the retention rate of mechanical strength and the attenuation rate of sound insulation performance (≤10%) are tested to evaluate the reliability of long-term outdoor use.

[0057] The performances of the tile adhesives of Examples 1 - 4 and Comparative Examples 1 - 14 are summarized in Table 1.

[0058] Table 1: Summary of the performances of the tile adhesives of Examples 1 - 4 and Comparative Examples 1 - 14

[0059] As can be seen from Table 1, the dosage of boron nitride nanotube / silica hollow microsphere composite filler directly affects the sound insulation performance and flexibility. Insufficient filler (<10.0 parts) will lead to weakened sound wave scattering and energy dissipation capabilities, and an incomplete composite skeleton structure, resulting in a significant decrease in the noise reduction coefficient (NRC). At the same time, insufficient flexible support is likely to cause stress concentration and a decrease in the elongation at break; a low mass ratio of silica hollow microspheres to boron nitride nanotubes (such as 5:0.2) will make the nanotubes sparsely distributed and unable to fully form a synergistic toughening and multi-scale energy dissipation structure, leading to a double decline in the interfacial bonding force and sound insulation performance; when the particle size of silica hollow microspheres is too small (such as 6 μm), its cavity structure is likely to fail due to shell layer collapse, reducing the cavity resonance frequency and sound absorption capacity. At the same time, the increase in connection points between particles causes stress concentration and reduces the flexibility of the material; the diameter of boron nitride nanotubes exceeding the reasonable range (such as >100 nm to 200 nm) will reduce the specific surface area and interfacial reaction activity, resulting in poor bonding between the filler and the matrix, and a decrease in flexibility and bonding strength; insufficient dosage of the catalyst yttrium nitrate (such as 0.5 parts) will inhibit the effective growth amount of nanotubes, the composite structure is sparse, affecting the overall sound insulation performance and mechanical strength; too low wet ball milling speed (such as 200 rpm) results in uneven dispersion of the filler and incomplete composite reaction, a decrease in the nanotube loading rate, and an increase in interfacial defects, leading to an overall decline in performance; if the gas-solid phase growth temperature is too low (such as 750°C), it cannot effectively drive the growth of boron nitride nanotubes, and the filler surface lacks the support of a synergistic structure, resulting in a decrease in flexibility and shear strength; insufficient calcination temperature of silica hollow microspheres (<500°C, such as 450°C) will lead to incomplete removal of the polystyrene template, insufficient shell layer density, and unstable microsphere structure, affecting the weather resistance and sound absorption effect; too low high-energy ball milling pressure (such as 0.05 MPa) will result in incomplete mechanochemical reactions, a small amount of amorphous boron nitride with poor activity, affecting the nucleation efficiency of nanotubes and the formation of subsequent composite structures; too high nitriding temperature (such as 900~1000°C) will cause crystallization of boron nitride, and the interface between crystalline BN and the polyurethane matrix is mismatched, resulting in stress concentration and a decrease in bonding strength. The XRD can show the characteristic peaks of hexagonal BN; if the pre-dispersion stirring speed is too high during the composite glue-making process (such as 600 rpm), it may cause local agglomeration or air bubbles to be introduced, affecting the dispersion uniformity and subsequent mechanical properties; insufficient high-speed dispersion vacuum degree (such as <0.08 MPa) will cause residual air bubbles in the system to not escape in time, forming micropore defects, reducing the shear strength and sound insulation performance; too fast curing heating rate (such as 10°C / min) will lead to uneven release of internal stress, forming microcracks, affecting the weather resistance and flexibility; if the silica hollow microspheres are not loaded with boron nitride nanotubes, there will be a lack of multi-scale energy dissipation paths and synergistic interfacial structures, resulting in a significant decrease in sound insulation performance (NRC<0.70), both the shear strength and the elongation at break are significantly deteriorated; in addition, although an excessive amount of polyurethane emulsion (such as >130 parts) enhances the flexibility of the matrix, it will lead to a decrease in the storage modulus, a decrease in the elastic modulus, and a significant decrease in the shear strength of the bonding interface. The DMA test can verify the attenuation of its dynamic mechanical properties; the above factors, acting alone or in combination, determine the final sound insulation performance, flexibility, bonding strength and weather resistance stability of the composite system of the present invention. Ensuring that the parameters are controlled within a reasonable range is the key to achieving high-performance flexible sound insulation tile adhesive.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that any equivalent structural transformation made under the concept of the present invention by using the content of the specification and drawings of the present invention should be covered by the protection scope of the claims of the present invention.

Claims

1. A flexible soundproof tile adhesive, characterized in that, It includes raw materials in the following parts by weight: 10.0 - 25.0 parts of boron nitride nanotube / silica hollow microsphere composite filler, 80.0 - 130.0 parts of aqueous polyurethane emulsion, 5.0 - 12.0 parts of talcum powder, 5.0 - 10.0 parts of mica powder, 3.0 - 6.0 parts of quartz powder, 2.0 - 5.0 parts of leveling agent, 1.0 - 3.0 parts of defoaming agent, 2.0 - 5.0 parts of dispersant, 1.0 - 3.0 parts of anti-settling agent, 2.0 - 5.5 parts of thickener, and 8.0 - 20.0 parts of deionized water; The described boron nitride nanotube / silica hollow microsphere composite filler is composed of silica hollow microspheres and boron nitride nanotubes distributed in a divergent manner on the surface of the silica hollow microspheres.

2. The flexible sound-insulating tile adhesive according to claim 1, characterized in that, The mass ratio of the described silica hollow microspheres to boron nitride nanotubes is: 5:(0.5 - 1.2).

3. The flexible sound-insulating tile adhesive according to claim 1, wherein The average diameter of the described silica hollow microspheres is 10 - 30 µm.

4. The flexible sound-insulating tile adhesive according to claim 1, characterized in that, The average diameter of the described boron nitride nanotubes is 50 - 100 nm, and the average length is 2.0 - 3.5 µm.

5. A flexible sound-insulating tile adhesive as claimed in claim 1, wherein The preparation method of the described boron nitride nanotube / silica hollow microsphere composite filler is as follows: by weight, 1.0 - 3.5 parts of yttrium nitrate and 0.5 - 2.0 parts of lithium nitrate are dry-ground in an agate mortar for 15 - 30 min to form a uniform catalyst mixture, and then 10.0 - 25.0 parts of amorphous boron nitride powder and 50.0 - 80.0 parts of silica hollow microspheres are jointly added to a planetary ball mill, and wet-milled at a speed of 300 - 500 rpm for 60 - 120 min to obtain a premix. The ball-milling medium is anhydrous ethanol and the ratio of material to liquid is 1:3 - 1:5; the premix is transferred to an alumina crucible and placed in a tubular furnace, heated to 800 - 1000°C at a heating rate of 5 - 10°C / min in a flowing ammonia atmosphere, the holding time is 60 - 180 min, the ammonia flow rate is 5 - 15 mL / min, and the system pressure is 0.1 - 0.5 MPa. During this period, yttrium nitrate and lithium nitrate decompose into a composite catalyst and promote the gas-solid phase growth of amorphous boron powder on the surface of silica microspheres to form boron nitride nanotubes; after the reaction ends, the product is taken out after being cooled to below 200°C at a rate of 2 - 5°C / min, washed 3 - 5 times with 0.1 - 0.5 mol / L hydrochloric acid solution, deionized water and anhydrous ethanol in sequence to remove residual catalyst and unreacted boron powder, and finally treated in a vacuum drying oven at 80 - 120°C for 120 - 240 min to obtain the boron nitride nanotube / silica hollow microsphere composite filler.

6. The flexible sound-insulating tile adhesive according to claim 5, wherein, The preparation method of the described silica hollow microspheres is as follows: by weight, disperse 1.0 - 3.0 parts of polystyrene microspheres in a mixed solvent of 30.0 - 50.0 parts of absolute ethanol and 20.0 - 40.0 parts of deionized water, add 0.5 - 2.0 parts of surfactant CTAB and mechanically stir at 200 - 400 rpm for 10 - 20 min to form a homogeneous dispersion. Subsequently, add 3.0 - 8.0 parts of tetraethyl orthosilicate and control the system temperature at 25 - 40 °C, and inject 0.5 - 1.5 parts of ammonia catalyst dropwise to make the pH value 9.0 - 10.

5. Maintain the stirring rate at 300 - 500 rpm for hydrolysis and condensation reaction for 1 - 3 h. After the reaction is completed, collect the core-shell microspheres coated with a silica shell layer by centrifugation, and wash them 3 - 5 times each with absolute ethanol and deionized water to remove unreacted silicon source and surfactant; place the above product in a muffle furnace and heat it to 500 - 650 °C at a heating rate of 2 - 5 °C / min, and the calcination time is 2 - 5 h to completely remove the polystyrene template to form a cavity structure, or use the solvent extraction method to immerse the core-shell microspheres in 10.0 - 20.0 parts of tetrahydrofuran, and ultrasonically treat them at 50 - 70 °C for 6 - 12 h to dissolve the template. Subsequently, centrifuge and pickle with 0.5 - 2.0 mol / L hydrochloric acid solution at 30 - 50 °C for 1 - 3 h to remove residual metal ions, and finally wash with deionized water until neutral and vacuum dry at 60 - 90 °C for 4 - 8 h to obtain monodisperse silica hollow microspheres.

7. The flexible sound-insulating tile adhesive according to claim 5, characterized in that, The preparation method of the described amorphous boron nitride powder is as follows: by weight, load 10.0 - 30.0 parts of crystalline boron powder and stainless steel grinding balls into a high-energy ball milling tank according to a material-to-ball ratio of 1:5 - 1:10, evacuate and then fill with ammonia until the pressure in the tank is 0.1 - 0.3 MPa, and perform dry ball milling at a ball milling speed of 200 - 500 rpm for 30 - 120 min. During this period, a mechanochemical reaction occurs between ammonia and boron powder to generate an amorphous boron nitride precursor; Transfer the ball milling product to a tubular furnace, heat it to 500 - 800 °C at a heating rate of 5 - 10 °C / min in a flowing nitrogen atmosphere, keep the temperature for 60 - 180 min, and the nitrogen flow rate is 5 - 15 mL / min to completely nitride the unreacted boron powder and inhibit the crystallization process; after cooling to room temperature, take out the product, ultrasonically treat it with 0.1 - 0.5 mol / L hydrochloric acid solution for 10 - 30 min to remove metal impurities, then wash with deionized water until neutral, and finally treat it in a vacuum drying oven at 60 - 90 °C for 120 - 360 min to obtain amorphous boron nitride powder.

8. The flexible sound-insulating tile adhesive according to claim 1, wherein, The described leveling agent is BYK-306 leveling agent; The described defoaming agent is BYK-024 defoaming agent; The described dispersant is DISPERBYK-2013 dispersant; The described anti-settling agent is Bentone® SD-2 anti-settling agent; The described thickener is hydroxyethyl cellulose.

9. The preparation method of a flexible sound insulation tile adhesive according to claim 1, characterized in that, It includes the following steps: S1. Mix the boron nitride nanotube / silica hollow microsphere composite filler, talcum powder, mica powder, quartz powder and deionized water in proportion and place them in a planetary mixer. Perform pre-dispersion at a stirring speed of 300 - 500 rpm, control the temperature at 20 - 35 °C, and the duration at 15 - 30 min to form a uniform suspension slurry. S2. Add the aqueous polyurethane emulsion and the dispersant to the premix, switch to a high-speed disperser and perform shear dispersion at a rotational speed of 800 - 1200 rpm for 20 - 40 min, maintain the system temperature at 20 - 35 °C to ensure that the filler is uniformly embedded in the emulsion matrix and form a stable colloidal dispersion. S3. Add an antifoaming agent to the dispersion system, adjust the stirring speed to 200 - 400 rpm for low-speed defoaming for 10 - 20 min, simultaneously apply a vacuum degree of 0.08 - 0.1 MPa to accelerate the escape of bubbles, and control the temperature not exceeding 35 °C. S4. After injecting the leveling agent, adjust the stirring speed to 400 - 600 rpm and maintain it for 10 - 15 min, then add the thickener in batches and stir for 5 - 10 min to stabilize the viscosity within the range of 5000 - 8000 mPa·s. S5. After adding the anti-settling agent, use an anchor agitator to perform low-speed homogenization at a rotational speed of 200 - 400 rpm for 5 - 10 min, control the system temperature at 25 - 40 °C to ensure that the thixotropic properties of the colloid meet the requirements of vertical coating.

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