Thermal insulation lightweight material and method for manufacturing the same
By precisely controlling the composition of melamine, formaldehyde aqueous solution and epoxy resin solution, lightweight thermal insulation materials are prepared, which solves the problems of flame retardancy, high density and construction pollution of existing building thermal insulation materials, and achieves efficient and environmentally friendly thermal insulation effect and stable construction adaptability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 马鞍山万盛化工有限公司
- Filing Date
- 2026-01-22
- Publication Date
- 2026-05-29
AI Technical Summary
Existing building insulation materials suffer from problems such as poor flame retardancy, high density, construction pollution, insufficient coating compatibility, and poor production stability. Moreover, their production processes are complex and costly, making it difficult to meet the requirements of environmental protection and construction adaptability.
Using melamine, formaldehyde aqueous solution, epoxy resin solution and curing agent solution as core components, and through precise control of reaction temperature, time and washing process, a lightweight powder with a particle size of 50-200μm is prepared, with a bulk density of ≤80kg/m³, a thermal conductivity of ≤0.035W/(m·K), and good compatibility with coating systems, and a crosslinking degree of ≥85%.
It achieves lightweight, efficient, and environmentally friendly thermal insulation, with the coating improving thermal insulation performance by 30%-40%. It maintains stable performance in complex environments, reduces energy consumption and construction costs, and is suitable for large-scale production.
Smart Images
Figure CN122103807A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of thermal insulation material preparation technology, specifically to a thermal insulation lightweight material and its preparation method. Background Technology
[0002] With the increasing demand for building energy conservation and industrial insulation, the performance, environmental friendliness, and construction compatibility of insulation materials have become the core focus of the industry. Currently, commonly used building insulation materials on the market mainly include polystyrene foam boards, rock wool, glass wool, and traditional insulation coatings and fillers, but all have significant technical shortcomings: polystyrene foam boards have poor flame retardant properties, easily release toxic gases at high temperatures, and have insufficient aging resistance; inorganic insulation materials such as rock wool and glass wool have high density, easily generating dust pollution during construction, and their thermal conductivity increases significantly after absorbing moisture, resulting in a substantial decrease in insulation effect; the fillers added to traditional insulation coatings are mostly ordinary inorganic powders, which have poor dispersibility and insufficient compatibility with the coating system, leading to low durability of the coating's insulation performance, and some materials, due to unscientific raw material ratios, pose environmental hazards such as excessive free formaldehyde.
[0003] Meanwhile, the existing production processes of thermal insulation materials often suffer from problems such as complex formulations, difficulty in parameter control, and insufficient stability in large-scale production: some composite thermal insulation materials require the addition of multiple additives, which not only increases production costs but also easily leads to poor synergy among the components; unreasonable matching of parameters such as temperature and time during the curing process can easily result in insufficient cross-linking of the product, leading to low strength and easy powdering.
[0004] Therefore, developing a thermal insulation material that is simple in formulation, lightweight and efficient, flame-retardant and environmentally friendly, compatible with coating systems, and easy to control in production process has become a key requirement to solve the pain points of existing technologies. Summary of the Invention
[0005] To solve the above-mentioned technical problems, a heat-insulating lightweight material and its preparation method are provided. This technical solution solves the above-mentioned problems.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A thermal insulation lightweight material and its preparation method are disclosed. The material comprises 20-30 parts of melamine, 20-30 parts of formaldehyde aqueous solution, 20-30 parts of epoxy resin solution, and 20-30 parts of curing agent solution, with the total weight of the four components being 100 parts.
[0007] Preferably, the formaldehyde aqueous solution has a mass concentration of 37%–40%; the epoxy resin solution is an aqueous solution of E-44 or E-51 type epoxy resin with a solid content of 40%–60%; and the curing agent solution is an aqueous solution of an amine curing agent with a solid content of 30%–50%.
[0008] Preferably, the optimal formulation of the material is: 25 parts melamine, 25 parts 37% formaldehyde aqueous solution, 25 parts E-44 type epoxy resin aqueous solution (solid content 50%), and 25 parts ethylenediamine aqueous solution (solid content 40%). The product is a lightweight powder with a particle size of 50-200μm, a bulk density ≤80kg / m³, and a thermal conductivity ≤0.035W / (m・K). When added to the coating at a dosage of 10%-15%, the thermal insulation effect of the coating is improved by 30%-40% compared with the system without addition, and the performance degradation rate after 12 months of storage at room temperature is ≤3%.
[0009] A method for preparing a thermal insulation lightweight material, comprising the following steps: S1. Raw material pretreatment: Melamine is sieved through an 80-mesh vibrating screen to ensure that more than 95% pass through; the moisture content of melamine is tested using a Karl Fischer moisture analyzer to ensure that it is ≤3.0%. If it exceeds the limit, it is placed in a vacuum drying oven at 50-60℃ for 1-2 hours and then cooled to 25-30℃ for later use. S2. Preparation of formaldehyde-melamine pre-reaction solution: Melamine and formaldehyde aqueous solution are added to the reaction vessel in proportion, the temperature is raised to 70-80℃, the pH value is adjusted to 8.0-9.0 with triethanolamine, and the reaction is stirred at 100-120 rpm for 60-90 minutes to obtain the pre-reaction solution; S3. Preparation of curing agent-epoxy resin aqueous solution: Mix epoxy resin solution and curing agent solution with solvent in proportion, add deionized water to adjust the solid content of the system to 35%-45%, stir at 80-100 rpm for 20-30 minutes to obtain a uniform aqueous solution; S4. Dropping reaction and curing: Slowly add the aqueous solution prepared in step S3 to the pre-reaction solution in step S2 at a dropping rate of 5-10 mL / min, while maintaining a reaction temperature of 120-150℃ and a stirring rate of 120-150 rpm, and continue the reaction for 3-5 hours. S5. Filtration and Drying: After the reaction is complete, cool the reaction system to 40-50℃ and filter using a vacuum filtration device. Wash the filter cake 2-3 times with deionized water to remove unreacted monomers. Place the filter cake in a 105-110℃ forced-air drying oven for 2-3 hours to ensure the moisture content is ≤3.0%. S6. Crushing and Sieving: The dried solid is crushed in a high-speed crusher and sieved through a 100-mesh vibrating screen to collect particles of 50-200μm, thus obtaining the finished thermal insulation lightweight material.
[0010] 5. The method for preparing a heat-insulating lightweight material according to claim 4, characterized in that: in step S1, the vibration frequency of the vibrating screen is 25-35Hz, and the screen is cleaned every 10 minutes to avoid clogging of the screen holes and resulting in a decrease in screening efficiency; the melamine particles after screening are detected by a laser particle size analyzer to ensure that the proportion of particles with a particle size ≤100μm is ≥95%, and the coarse particles that do not pass through the screen can be ground and re-screened for reuse.
[0011] Preferably, in step S2, the temperature of the reaction vessel is controlled by a water bath during stirring, with temperature fluctuations ≤ ±2℃, to avoid sudden temperature rises and falls affecting the stability of the pre-reaction liquid; the viscosity of the pre-reaction liquid is controlled between 300 and 800 mPa·s, and the viscosity is measured using a rotational viscometer (NDJ-5S type) at a test temperature of 25℃ and a rotation speed of 60 rpm; samples are taken every 15 minutes during the reaction to measure the free formaldehyde content, ensuring that the free formaldehyde content is ≤ 0.5% at the end of the reaction.
[0012] Preferably, in step S4, the dripping process employs a constant flow pump to precisely control the dripping rate. The dripping rate can be dynamically adjusted according to the viscosity of the pre-reaction liquid. When the viscosity is too high, the dripping rate is set to the lower limit; when the viscosity is too low, the dripping rate is set to the upper limit. During dripping, the infusion tube is inserted 5-8 cm below the surface of the pre-reaction liquid to prevent splashing and uneven local reaction. After dripping, the mixture is kept at 120-150℃ and stirred for 30-60 minutes to ensure that the epoxy resin and curing agent are fully crosslinked and react completely with the melamine-formaldehyde prepolymer. The curing temperature is preferably 120℃, corresponding to a reaction time of 4 hours. Under these conditions, the product crosslinking degree is ≥85%. During the reaction, the temperature of the reactor is maintained stable using a heat transfer oil furnace, with temperature fluctuations ≤±3℃. Simultaneously, the pressure of the reaction system is monitored in real time and controlled between 0.1-0.15 MPa to prevent excessive pressure from causing the system to boil over.
[0013] Preferably, in step S5, the vacuum filtration device uses a combination of a Buchner funnel and a circulating water vacuum pump, with the vacuum level stably controlled at -0.08 to -0.09 MPa. The filter cloth is made of polytetrafluoroethylene with a pore size of 5 to 10 μm to ensure effective filter cake retention and prevent sticking. The filter cake is washed in small batches, with 50 to 80 mL of deionized water added to every 100 g of filter cake. After soaking for 5 to 10 minutes, the cake is filtered, and this process is repeated 2 to 3 times. After washing, the amount of unreacted monomers remaining in the filter cake is ≤0.3%. The washed filter cake is first placed on a tray and spread out to a thickness ≤2 cm, then placed in a 105 to 110°C forced-air drying oven. During drying, the forced-air velocity is 1.5 to 2.0 m / s, and the filter cake is turned over every 30 minutes to ensure uniform drying. The drying endpoint is determined by the difference in moisture content between two consecutive samples being ≤0.2%, with the final filter cake moisture content ≤3.0%.
[0014] Preferably, in step S6, the high-speed pulverizer is a claw-type high-speed pulverizer (FS-100 type). The feeding rate during pulverization is controlled at 5-10 kg / h to avoid insufficient pulverization or equipment overload due to excessively fast feeding. The pulverizer speed is 3000-4000 rpm, and the pulverization time is 5-10 minutes. The pulverization time can be adjusted according to the particle size distribution after pulverization; if the particle size exceeds the standard, the pulverization time can be extended by 1-2 minutes. Screening uses a double-layer vibrating screen, with the upper layer being a 100-mesh screen (retaining particle sizes > 100 mm). The first layer consists of 150μm particles, with a 200-mesh sieve at the bottom (retaining particles with a diameter of 50-150μm). The vibration frequency is 30-40Hz, and the sieving time is 15-20 minutes. After sieving, fine powder with a diameter <50μm and coarse particles with a diameter >200μm are collected and combined. Before re-pulverizing, the moisture content must be tested to ensure it is ≤3.0%. If it exceeds this limit, it must be dried to the qualified level before pulverizing. The finished particles after sieving are collected using a closed collection device to prevent dust from flying and causing raw material loss and environmental pollution.
[0015] Preferably, the bulk density of the finished product is determined according to GB / T16913-2008 "Test Method for Physical Properties of Dust". During the test, the finished product particles are naturally poured into a 100mL graduated cylinder, leveled, and weighed. Three parallel samples are made for each test group, and the average value is taken. The relative deviation is ≤2.0%. The thermal conductivity is determined according to GB / T10294 "Determination of Steady-State Thermal Resistance and Related Properties of Thermal Insulation Materials - Protective Hot Plate Method". The test sample needs to be pressed into a circular disc with a diameter of 50mm and a thickness of 10mm. The moisture content of the sample is ≤3%. 0%, test temperature 25℃, relative humidity 50%; particle size distribution was determined using a laser particle size analyzer (Malvern Mastersizer 3000), the dispersion medium was deionized water, 0.1% sodium dodecyl sulfate was added as a dispersant, and the particles were ultrasonically dispersed for 10 minutes before testing. The test range was 0.1-1000μm, and the particle size distribution was expressed as D10, D50, and D90. All performance test data must be recorded in the test report. Finished products that fail the test must be re-crushed or sieved.
[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention is proposed. Attached Figure Description
[0017] Figure 1 This is a flowchart illustrating the preparation process of the present invention. Detailed Implementation
[0018] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.
[0019] Example 1 (Optimal Formula Thermal Insulation Lightweight Material) Raw material composition (based on a total mass of 100 parts) 25 parts of melamine, 25 parts of 37% formaldehyde aqueous solution, 25 parts of E-44 type epoxy resin aqueous solution (solid content 50%), and 25 parts of ethylenediamine aqueous solution (solid content 40%).
[0020] Preparation steps: S1: Raw material pretreatment: Melamine is put into an 80-mesh vibrating screen (vibration frequency 30Hz), and the screen is cleaned every 10 minutes. After screening, the proportion of particles with a particle size ≤100μm is 98%; the moisture content is measured by a Karl Fischer moisture analyzer and is ≤2.2% to 3.0%. It can be used directly. S2: Preparation of formaldehyde-melamine pre-reaction solution: Add to the reaction vessel according to the ratio, heat to 75℃, adjust the pH value to 8.5 with triethanolamine, stir at 110 rpm for 75 minutes; control the temperature in a water bath to ensure temperature fluctuation ±1.5℃, measure the viscosity of the pre-reaction solution with a rotational viscometer (NDJ-5S type) to be 550 mPa·s, and the free formaldehyde content at the reaction endpoint is ≤0.3%-0.5%; S3: Preparation of curing agent-epoxy resin aqueous solution: Mix epoxy resin solution and curing agent solution, add deionized water to adjust the solid content of the system to 40%, stir at 90 rpm for 25 minutes to obtain a uniform aqueous solution; S4: Dropping reaction and curing: A constant flow pump was used to control the dropping rate at 8 mL / min, and the infusion tube was inserted 6 cm below the surface of the pre-reaction liquid; the reaction temperature was maintained at 120℃, and the reaction was stirred at 130 rpm for 4 hours. After the dropping was completed, the mixture was kept at the temperature and stirred for another 45 minutes; the temperature was controlled by a heat transfer oil furnace during the reaction, with temperature fluctuations of ±2℃, and the system pressure was kept stable at 0.12 MPa. The product crosslinking degree was ≥85% (88%). S5: Filtration and Drying: The reaction system was cooled to 45℃ and filtered using a Buchner funnel and a circulating water vacuum pump (vacuum degree -0.085MPa). The filter cloth was made of polytetrafluoroethylene (8μm pore size). For every 100g of filter cake, 60mL of deionized water was added for 8 minutes each time, followed by 3 washes. The unreacted monomer residue was 0.2% ≤ 0.3%. The filter cake was spread out to a thickness of 1.5cm ≤ 2cm and placed in a 108℃ forced-air drying oven (wind speed 1.8m / s) for 2.5 hours, turning it over every 30 minutes. The final moisture content was 2.1% ≤ 3.0%. S6: Crushing and Screening: FS-100 claw-type high-speed crusher is selected, crushing for 8 minutes at 3500 rpm, with a feeding rate of 8 kg / h; a double-layer vibrating screen (upper layer 100 mesh, lower layer 200 mesh, vibration frequency 35 Hz) is used for screening for 18 minutes to collect 50-200 μm particles, and a closed collection device is used to prevent dust from flying.
[0021] Product performance particle size distribution: D10=65μm, D50=120μm, D90=185μm; bulk density 72kg / m³≤80kg / m³; thermal conductivity 0.032W / (m·K)≤0.035W / (m·K); when added to building insulation coatings at a ratio of 12%, the insulation effect is improved by 36% compared to the system without addition; the performance degradation rate after 12 months of storage at room temperature is 2.1%≤3%, suitable for high-precision insulation scenarios such as building walls and industrial equipment surfaces.
[0022] Example 2 (High-melamine type thermal insulation lightweight material) Raw material composition (based on a total mass of 100 parts) 30 parts melamine, 20 parts 40% formaldehyde aqueous solution, 25 parts E-44 type epoxy resin aqueous solution (60% solid content), and 25 parts ethylenediamine aqueous solution (50% solid content).
[0023] Preparation steps: S1: Raw material pretreatment: After melamine screening, the moisture content is 2.8% ≤ 3.0%, and the proportion of particles with a particle size ≤ 100μm is 96%, which can be used directly; S2: Preparation of formaldehyde-melamine pre-reaction solution: Heat to 80℃, pH 8.8, stir at 120 rpm for 90 minutes, the viscosity of the pre-reaction solution is 720 mPa·s, and the free formaldehyde content is 0.4% ≤ 0.5%; S3: Preparation of curing agent-epoxy resin aqueous solution: Adjust the solid content of the system to 45%, stir at 100 rpm for 30 minutes, and mix evenly; S4: Dropping reaction and curing: Due to the high viscosity of the pre-reaction solution, the dropping rate was adjusted to 10 mL / min, the reaction temperature was 130℃, the stirring speed was 150 rpm for 3.5 hours, and the stirring was maintained at this temperature for 60 minutes; the system pressure was 0.14 MPa, and the product crosslinking degree was ≥85% (86%). S5: Filtration and drying: Cool to 50℃, vacuum degree -0.09MPa, wash the filter cake twice, unreacted monomer residue 0.25%; dry in a 110℃ forced-air drying oven for 2 hours, moisture content 2.5% ≤ 3.0%; S6: Crushing and sieving: High-speed crusher at 4000 rpm for 10 minutes, feed rate 10 kg / h, and collect finished particles of 50-200 μm after sieving.
[0024] Product performance: bulk density 78kg / m³≤80kg / m³; thermal conductivity 0.034W / (m·K)≤0.035W / (m·K); when added to coatings at a ratio of 15%, the thermal insulation effect is improved by 38% compared to the system without addition; the performance degradation rate after 12 months of storage at room temperature is 2.8%≤3%, and the flame retardant performance is better (oxygen index 33%), making it suitable for industrial thermal insulation scenarios in high-temperature environments.
[0025] Example 3 (Lightweight Insulation Materials with Different Curing Agents) Raw material composition (total mass of 100 parts): 28 parts melamine, 22 parts 38% formaldehyde aqueous solution, 25 parts E-51 type epoxy resin aqueous solution (solid content 45%), and 25 parts diethylenetriamine aqueous solution (solid content 35%).
[0026] Preparation steps: S1: Raw material pretreatment: Melamine moisture content 2.5% ≤ 3.0%, particle size ≤ 100μm particles account for 97%, ready for immediate use; S2: Preparation of formaldehyde-melamine pre-reaction solution: Heat to 70℃, pH 8.2, stir at 100 rpm for 60 minutes, pre-reaction solution viscosity 420 mPa·s, free formaldehyde content 0.35% ≤ 0.5%; S3: Preparation of curing agent-epoxy resin aqueous solution: Adjust the solid content of the system to 38%, stir at 85 rpm for 22 minutes, and mix evenly.
[0027] S4: Dropping reaction and curing: Due to the low viscosity of the pre-reaction solution, the dropping rate was adjusted to 5 mL / min, the reaction temperature was 140℃, the stirring speed was 120 rpm for 5 hours, and the stirring was maintained at this temperature for 30 minutes; the system pressure was 0.13 MPa, and the product crosslinking degree was ≥85%; S5: Filtration and drying: Cool to 42℃, vacuum degree -0.08MPa, wash filter cake 3 times, unreacted monomer residue 0.22%; dry in a 106℃ forced-air drying oven for 2.2 hours, moisture content 2.3% ≤ 3.0%; S6: Crushing and sieving: High-speed crusher at 3200 rpm for 9 minutes, feed rate 7 kg / h, and collect 50-200 μm finished particles after sieving; Product performance: Bulk density 75kg / m³≤80kg / m³; Thermal conductivity 0.033W / (m·K)≤0.035W / (m·K); When added to coatings at a ratio of 13%, the thermal insulation effect is improved by 35% compared to the system without addition; The performance degradation rate after 12 months of storage at room temperature is 2.5%≤3%, with excellent crosslinking stability, making it suitable for building thermal insulation scenarios in humid environments.
[0028] Comparative example (talc filler used in traditional thermal insulation coatings) Raw material composition: Commercially available traditional thermal insulation talc powder (particle size 50-200μm, no specific formula ratio).
[0029] Preparation steps: Finished talc powder is purchased directly, without raw material pretreatment, pre-reaction, or precise curing steps; it is only sieved through a standard 100-mesh sieve, without moisture control, cross-linking reaction, or precise pulverization processes; it is directly packaged after sieving without any airtight collection measures. ##Product performance: Bulk density 135 kg / m³ (1.88 times that of Example 1); Thermal conductivity 0.068 W / (m·K) (2.13 times that of Example 1); When added at a 12% ratio to the same coating system, the insulation effect is only 12% higher than the system without addition (far lower than the 36% of Example 1); After 12 months of storage at room temperature, due to the lack of cross-linking structure and poor dispersibility, the insulation performance decay rate is 15% (7.14 times that of Example 1); it easily clumps after absorbing moisture, leading to coating cracking and peeling, and can only meet low-precision basic insulation requirements.
[0030] The table below compares the performance of the examples and comparative examples. Performance Comparison Table of Examples and Comparative Examples In summary, the advantages of this invention are as follows: This thermal insulation lightweight material uses only melamine, formaldehyde aqueous solution, epoxy resin solution, and curing agent solution as its core components. The weight ratio of each component is 20-30 parts (the optimal ratio is 25 parts each). The formula is simple and has no redundant additives. The raw materials are widely available and the cost is controllable. The components have strong synergistic reaction, and stable production can be achieved without complex control. The performance deviation between batches is ≤2%, making it suitable for large-scale mass production. The product is a lightweight powder with a particle size of 50-200μm and a bulk density of ≤80kg / m³, which is much lower than that of traditional inorganic thermal insulation fillers (100-150kg / m³), and can significantly reduce the self-weight of thermal insulation coatings or structures; the thermal conductivity is ≤0.035W / (m・K). When added to coatings at a ratio of 10%-15%, the thermal insulation effect of the coating is improved by 30%-40% compared with the system without the addition, which can effectively reduce the energy consumption loss of buildings or industrial equipment and meet the requirements of energy conservation and emission reduction policies. The core component, melamine, has excellent flame-retardant properties. Combined with the cross-linking and curing effect of epoxy resin, the product has an oxygen index of ≥32%, achieving a flame-retardant level and does not release toxic gases at high temperatures. During the production process, the reaction temperature, time, and washing process are precisely controlled to ensure that the product's free formaldehyde residue is ≤0.3%, meeting environmental protection standards, avoiding pollution during use, and ensuring the safety of the construction and use environment. The product consists of uniform, fine powder particles. Its surface-active groups have good compatibility with coating systems. After addition, it is easy to disperse and does not affect the leveling or film-forming properties of the coating. No major adjustments to existing coating formulations or application processes are required. Its lightweight nature means that there is no additional load during coating application, and it can be widely used for thermal insulation and protection in various scenarios such as building walls and industrial equipment surfaces. Through the process design of pre-reaction, drop-addition crosslinking and gradient curing, the product has a crosslinking degree of ≥85%, good mechanical strength, and is not easy to pulverize or crack. The performance degradation rate is ≤3% after 12 months of storage at room temperature. It can still maintain stable thermal insulation performance in complex environments such as humidity and alternating high and low temperatures. Its service life is far longer than that of traditional thermal insulation fillers, reducing the cost of later maintenance and replacement. The production process requires no complex equipment and can be completed through basic steps such as raw material pretreatment, pre-reaction, dripping and curing, filtration and drying, crushing and sieving. The key parameters, curing temperature of 120-150℃ and reaction time of 3-5 hours, are easy to control and have a low operating threshold. No additional foaming agents, flame retardants or other additives are required, which reduces raw material costs by 15%-20% and reduces subsequent environmental treatment costs, resulting in significant economic advantages.
[0031] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.
Claims
1. A thermal insulation lightweight material, characterized in that: The material comprises 100 parts by weight, including: 20-30 parts of melamine, 20-30 parts of formaldehyde aqueous solution, 20-30 parts of epoxy resin solution, and 20-30 parts of curing agent solution, with the total weight of the four components being 100 parts.
2. The thermal insulation lightweight material according to claim 1, characterized in that: The formaldehyde aqueous solution has a mass concentration of 37%–40%; the epoxy resin solution is an aqueous solution of E-44 or E-51 type epoxy resin with a solid content of 40%–60%; and the curing agent solution is an aqueous solution of amine curing agent with a solid content of 30%–50%.
3. The thermal insulation lightweight material according to claim 1, characterized in that: The optimal formulation of the material is: 25 parts melamine, 25 parts 37% formaldehyde aqueous solution, 25 parts E-44 type epoxy resin aqueous solution, and 25 parts ethylenediamine aqueous solution. The product is a lightweight powder with a particle size of 50-200μm, a bulk density of ≤80kg / m³, and a thermal conductivity of ≤0.035W / (m・K). When added to the coating at a dosage of 10%-15%, the thermal insulation effect of the coating is improved by 30%-40% compared with the system without the addition, and the performance degradation rate after 12 months of storage at room temperature is ≤3%.
4. A method for preparing a thermally insulating lightweight material, characterized in that, The preparation steps are as follows: S1. Raw material pretreatment: Melamine is sieved through an 80-mesh vibrating screen to ensure that more than 95% pass through; the moisture content of melamine is tested using a Karl Fischer moisture analyzer to ensure that it is ≤3.0%. If it exceeds the limit, it is placed in a vacuum drying oven at 50-60℃ for 1-2 hours and then cooled to 25-30℃ for later use. S2. Preparation of formaldehyde-melamine pre-reaction solution: Melamine and formaldehyde aqueous solution are added to the reaction vessel in proportion, the temperature is raised to 70-80℃, the pH value is adjusted to 8.0-9.0 with triethanolamine, and the reaction is stirred at 100-120 rpm for 60-90 minutes to obtain the pre-reaction solution; S3. Preparation of curing agent-epoxy resin aqueous solution: Mix epoxy resin solution and curing agent solution with solvent in proportion, add deionized water to adjust the solid content of the system to 35%-45%, stir at 80-100 rpm for 20-30 minutes to obtain a uniform aqueous solution; S4. Dropping reaction and curing: Slowly add the aqueous solution prepared in step S3 to the pre-reaction solution in step S2 at a dropping rate of 5-10 mL / min, while maintaining a reaction temperature of 120-150℃ and a stirring rate of 120-150 rpm, and continue the reaction for 3-5 hours. S5. Filtration and Drying: After the reaction is complete, cool the reaction system to 40-50℃ and filter using a vacuum filtration device. Wash the filter cake 2-3 times with deionized water to remove unreacted monomers. Place the filter cake in a 105-110℃ forced-air drying oven for 2-3 hours to ensure the moisture content is ≤3.0%. S6. Crushing and Sieving: The dried solid is crushed in a high-speed crusher and sieved through a 100-mesh vibrating screen to collect particles of 50-200μm, thus obtaining the finished thermal insulation lightweight material.
5. The method for preparing a thermal insulation lightweight material according to claim 4, characterized in that: In step S1, the vibration frequency of the vibrating screen is 25-35Hz, and the screen is cleaned every 10 minutes to avoid clogging of the screen holes and a decrease in screening efficiency. The melamine particles after screening are detected by a laser particle size analyzer to ensure that the proportion of particles with a diameter ≤100μm is ≥95%. The coarse particles that do not pass through the screen can be ground and screened again for reuse.
6. The method for preparing a thermal insulation lightweight material according to claim 4, characterized in that: In step S2, the temperature of the reaction vessel is controlled by a water bath during stirring, with temperature fluctuations ≤ ±2℃, to avoid sudden temperature rises and falls affecting the stability of the pre-reaction liquid; the viscosity of the pre-reaction liquid is controlled between 300 and 800 mPa·s, and the viscosity is measured using a rotational viscometer at a test temperature of 25℃ and a rotation speed of 60 rpm; during the reaction, samples are taken every 15 minutes to test the free formaldehyde content, ensuring that the free formaldehyde content is ≤ 0.5% at the end of the reaction.
7. The method for preparing a thermal insulation lightweight material according to claim 4, characterized in that: In step S4, the dripping process employs a constant flow pump to precisely control the dripping rate. The dripping rate can be dynamically adjusted according to the viscosity of the pre-reaction liquid. When the viscosity is too high, the dripping rate is set to the lower limit; when the viscosity is too low, the dripping rate is set to the upper limit. During dripping, the infusion tube is inserted 5-8 cm below the surface of the pre-reaction liquid to prevent splashing and uneven local reaction. After dripping, the mixture is kept at 120-150℃ and stirred for 30-60 minutes to ensure that the epoxy resin and curing agent are fully crosslinked and react completely with the melamine-formaldehyde prepolymer. The curing temperature is preferably 120℃, corresponding to a reaction time of 4 hours. Under these conditions, the product crosslinking degree is ≥85%. During the reaction, the temperature of the reactor is maintained stable using a heat transfer oil furnace, with temperature fluctuations ≤±3℃. Simultaneously, the pressure of the reaction system is monitored in real time and controlled between 0.1-0.15 MPa to prevent excessive pressure from causing the system to boil over.
8. The method for preparing a thermal insulation lightweight material according to claim 4, characterized in that: In step S5, the vacuum filtration device uses a combination of a Buchner funnel and a circulating water vacuum pump, with the vacuum level stably controlled at -0.08 to -0.09 MPa. The filter cloth is made of polytetrafluoroethylene with a pore size of 5 to 10 μm to ensure effective filter cake retention and prevent sticking. The filter cake is washed in small batches, with 50 to 80 mL of deionized water added for every 100 g of filter cake. After soaking for 5 to 10 minutes, the cake is filtered, and this process is repeated 2 to 3 times. After washing, the amount of unreacted monomers remaining in the filter cake is ≤0.3%. The washed filter cake is first placed on a tray and spread out to a thickness ≤2 cm, then placed in a 105 to 110°C forced-air drying oven. During drying, the forced-air velocity is 1.5 to 2.0 m / s, and the filter cake is turned over every 30 minutes to ensure uniform drying. The drying endpoint is determined by the difference in moisture content between two consecutive samples being ≤0.2%, with the final filter cake moisture content ≤3.0%.
9. The method for preparing a thermal insulation lightweight material according to claim 4, characterized in that: In S6, a claw-type high-speed pulverizer is selected. The feeding rate during pulverization is controlled at 5-10 kg / h to avoid insufficient pulverization or equipment overload caused by excessive feeding. The pulverizer speed is 3000-4000 rpm, and the pulverization time is 5-10 minutes. The pulverization time can be adjusted according to the particle size distribution after pulverization. If the particle size exceeds the standard, the pulverization time is extended by 1-2 minutes. Screening adopts a double-layer vibrating screen, with a 100-mesh screen on the upper layer and a 200-mesh screen on the lower layer. The vibration frequency is 30-40 Hz, and the screening time is 15-20 minutes. After screening, fine powder with a particle size <50μm and coarse particles with a particle size >200μm are collected and combined. Before re-pulverization, the moisture content needs to be tested to ensure ≤3.0%. If it exceeds the standard, it should be dried to meet the requirements before pulverization. The finished particles after screening are collected by a closed collection device.
10. The method for preparing a thermal insulation lightweight material according to claim 4, characterized in that: The bulk density of the finished product was determined according to the standard test method for physical properties of dust. During the test, the finished product particles were naturally poured into a 100mL graduated cylinder, leveled, and weighed. Three parallel samples were made for each test group, and the average value of the results was taken. The relative deviation was ≤2.0%. Thermal conductivity was determined according to the standard of the protective hot plate method for determining the steady-state thermal resistance and related properties of insulation materials. The test sample should be pressed into a disc with a diameter of 50 mm and a thickness of 10 mm. The moisture content of the sample should be ≤3.0%, and the test temperature should be 25℃ with a relative humidity of 50%. The particle size distribution was determined using a laser particle size analyzer. The dispersion medium was deionized water with 0.1% sodium dodecyl sulfate added as a dispersant. The sample was ultrasonically dispersed for 10 minutes before testing. The test range was 0.1-1000 μm, and the particle size distribution was expressed as D10, D50, and D90. All performance test data should be recorded in the test report. Finished products that fail the test should be re-crushed or sieved.