Phase change thermal insulation coating

Abstract

The application belongs to the field of thermal insulation coatings, and particularly relates to a phase change thermal insulation coating, wherein the raw materials of the coating include pure water 10-40 parts, film-forming resin 15-45 parts, phase change microcapsules 10-20 parts, pigment and filler 15-25 parts, auxiliary agent 2 parts and heat insulation filler 40-60 parts. The preparation method of the phase change thermal insulation coating is also disclosed. The phase change thermal insulation coating has a low thermal conductivity coefficient, and the thermal conductivity thereof is only 0.021 W / mK at normal temperature. The phase change thermal insulation coating has a certain heat storage capacity, can inhibit the temperature rise of the coating itself, and reduce the heat dissipation of the thermal insulation layer. The phase change thermal insulation coating can be widely used in the outer surface of industrial storage tanks, pipelines and civil high-temperature equipment, can inhibit heat loss, and can realize significant energy saving and consumption reduction benefits.

Description

Technical Field

[0001] This invention relates to a phase change thermal insulation coating and its preparation method, which is particularly suitable for thermal insulation of high-temperature equipment, pipelines, chemical storage tanks and buildings. Background Technology

[0002] With the rapid development of the national economy, the demand for thermal insulation products in both industrial and civilian sectors has grown rapidly. my country's thermal insulation material production capacity has increased from 3.36 million tons in 2007 to approximately 7 million tons recently, with a market size exceeding 100 billion yuan. The main thermal insulation materials are traditional ones, such as rock wool, rubber-plastic composites, aluminum silicate, and aerogel felt. While these materials have low thermal conductivity and good insulation effects, they are all solid, rigid materials. The construction process is relatively complex, requiring wire fixing and wrapping, often resulting in a significant gap between the insulation effect and expectations. Construction is particularly difficult on narrow pipes and irregularly shaped equipment surfaces, such as valves and flanges. Exposing these areas leads to thermal bridging, causing significant heat waste. Therefore, developing a liquid thermal insulation coating is of great significance, as it is not limited by the shape of equipment and facilities, is easy to apply, and avoids thermal bridging.

[0003] This invention discloses a phase change thermal insulation coating with a low thermal conductivity of only 0.021 W / mK at room temperature. It also possesses a certain heat storage capacity, suppressing the temperature rise of the coating itself and reducing heat loss from the insulation layer. It can be widely used on the outer surfaces of industrial storage tanks, pipelines, and high-temperature equipment in civil applications to inhibit heat loss and achieve significant energy-saving and consumption-reducing benefits. Furthermore, this coating formulation does not contain organic solvents, harmful volatile gases such as benzene and formaldehyde, or heavy metals, making it friendly to humans and the environment. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: based on the above problem, the present invention provides a phase change thermal insulation coating and its preparation method.

[0005] One technical solution adopted by the present invention to solve the above-mentioned technical problems is: the raw materials of the phase change thermal insulation coating include 10-40 parts of pure water, 15-45 parts of film-forming resin, 10-20 parts of phase change microcapsules, 40-60 parts of thermal insulation filler, 15-25 parts of other fillers, and 1.5-2.5 parts of additives.

[0006] The phase change thermal insulation coating of this invention uses an inorganic silicone resin as the film-forming resin, with a solid content of 48±2% and a glass transition temperature of 10℃. It exhibits excellent high-temperature resistance, hydrophobicity, and chemical stability. The inorganic silicone resin is used as the adhesive primarily because it can withstand temperatures up to 500℃ while maintaining good adhesion during the insulation process, preventing cracking and peeling. Furthermore, the inorganic silicone resin has excellent hydrophobicity, with a contact angle of approximately 110°, preventing moisture from corroding the internal metal insulation materials and extending the equipment's service life. The inorganic silicone resin was purchased from BASF.

[0007] The phase change microcapsules in the phase change thermal insulation coating of this invention have a core-shell structure, wherein the shell is made of silica and the core is n-hexadecane. The phase change temperature is 96℃. The microcapsule size is 10-20 micrometers. Before use, the microcapsules are activated in dilute hydrochloric acid (5% by mass) for 4 hours (activation aims to increase the surface active sites of the silica shell material, improving its dispersibility in water and resin). The main functions of adding phase change microcapsules are threefold: First, they maintain the stability of their own temperature, delaying the rise in the temperature of the thermal insulation coating itself, reducing the surface temperature of the coating directly in contact with air, and significantly reducing heat loss and improving the insulation effect under the same surface area. Second, they inhibit the rise in the coating's own temperature, thus also inhibiting the increase in the thermal conductivity of the coating. Finally, when the temperature rises to the phase change temperature, hollow parts also appear inside the microcapsules; that is, the microcapsules not only inhibit the temperature rise but also act as hollow insulating fillers, further inhibiting heat conduction. Silica was chosen for the shell material due to its excellent heat resistance and low thermal conductivity. The core material is hexadecane, with a phase change temperature of 96℃, lower than the temperature of most equipment requiring insulation. This ensures phase change occurs during insulation, suppressing the coating's own temperature rise. Furthermore, the 10-20 micrometer size of the phase change microcapsules was chosen to create a size gradient with other hollow insulating fillers, thus achieving better insulation performance. The phase change microcapsules were purchased from Chuangke Yuntu Energy-Saving New Materials Technology (Changzhou) Co., Ltd.

[0008] The thermal insulation filler in the phase change thermal insulation coating of this invention comprises hollow ceramic microspheres, hollow glass microspheres, and expanded perlite. The porous thermal insulation fillers have a certain size gradient, with hollow ceramic microspheres measuring 20-40 micrometers, hollow glass microspheres 50-100 micrometers, and expanded perlite 200-400 micrometers. The ratio of the three thermal insulation fillers is 2:1:1. The purpose of using multiple hollow thermal insulation fillers is to address the contact thermal resistance between different materials. Heat transfer in a solid can be viewed as the transfer of quasi-particles—phonons—through the overall movement of the crystal lattice. Phonons encounter interfacial thermal resistance when transferring at the interfaces between different materials. Although the thermal insulation effect of hollow ceramic microspheres is better than that of hollow glass microspheres and expanded perlite, the effect of using multiple hollow thermal insulation fillers is higher than that of using a single filler. Furthermore, the certain size gradient of the three hollow thermal insulation fillers also helps to suppress heat transfer; the different internal pore sizes have a positive effect on suppressing phonon transfer.

[0009] The other fillers in the phase change thermal insulation coating of this invention are several selected from rutile titanium dioxide (3000 mesh), silicon dioxide (6000 mesh), alumina (3000 mesh), and barium sulfate (3000 mesh). The additives are dispersants, defoamers, preservatives, and film-forming agents in a ratio of 2:1:1:1. Smaller fillers are used to achieve the largest possible contact area between the filler and the resin, providing more material interfaces. More material interfaces result in greater thermal resistance, reduced thermal conductivity, and inhibited heat transfer. Titanium dioxide, alumina, and barium sulfate were purchased from Liyang Industrial (Shanghai) Co., Ltd., and silicon dioxide was purchased from Guangdong Chuangguo High-Tech Materials Co., Ltd.

[0010] The production process of the phase change thermal insulation coating of this invention is as follows: A dispersant is added to purified water and stirred for 30 minutes at a stirring speed of 1100 rpm. Then, thermal insulation filler, other fillers, and defoamer are added, and stirring continues for 50 minutes. Phase change microcapsules and film-forming resin are added and stirred for 60 minutes. The stirring speed is reduced to 500 rpm, and preservatives and film-forming agents are added. Stirring continues for 10 minutes to obtain the phase change thermal insulation coating. The product can be applied by spraying, rolling, or brushing.

[0011] The beneficial effects of this invention are: (1) Unlike traditional solid thermal insulation materials, this phase change thermal insulation coating has a paste-like form, which can be applied to the surface of equipment of any shape, making construction convenient and reducing costs; (2) The thermal conductivity of this phase change thermal insulation coating at room temperature is only 0.021 W / mK, which is only half that of rock wool material; (3) This thermal insulation coating has good water repellency, which can avoid the problem of significant reduction in thermal insulation effect due to the absorption of moisture by traditional thermal insulation materials; (4) This thermal insulation coating has a long service life and does not contain volatile organic gases, making it friendly to human body and environment. In summary, this thermal insulation coating can simultaneously achieve thermal insulation, heat insulation, waterproofing and anti-corrosion performance of equipment, pipelines and buildings, extend equipment life, improve safety factor, and achieve significant energy saving and emission reduction benefits. Detailed Implementation

[0012] The present invention will now be further described with reference to specific embodiments. The following embodiments are intended to illustrate the present invention and not to further limit the present invention.

[0013] Example 1

[0014] Add 10g of dispersant to 250g of purified water and stir for 30 minutes at a stirring speed of 1100 rpm. Then add 50g of rutile titanium dioxide (3000 mesh), 50g of silica (6000 mesh), 30g of alumina (3000 mesh), 70g of barium sulfate (3000 mesh), 240g of hollow ceramic microspheres (20-40 microns), 120g of hollow glass microspheres (50-100 microns), 120g of expanded perlite (200-400 microns), and 5g of defoamer, and continue stirring for 50 minutes. Add 160g of phase change microcapsules and 300g of film-forming resin (inorganic silicone resin, with a solid content of 48±2%) and stir for 60 minutes. Reduce the stirring speed to 500 rpm, add 5g of preservative and 5g of film-forming agent, and continue stirring for 10 minutes to obtain the phase change thermal insulation coating. The phase change microcapsules have a core-shell structure, with a shell made of silica and a core of n-hexadecane. Their phase change temperature is 96℃. The microcapsule size is 10-20 micrometers. Before use, the microcapsules are activated in dilute hydrochloric acid (5% by mass) for 4 hours.

[0015] Comparative Example 1

[0016] Based on the phase change thermal insulation coating of Example 1, the film-forming resin was changed to 140 grams, while other conditions remained unchanged.

[0017] Comparative Example 2

[0018] Based on the phase change thermal insulation coating in Example 1, the deionized water was replaced with 480 grams, while other conditions remained unchanged.

[0019] Comparative Example 3

[0020] Based on the phase change thermal insulation coating in Example 1, the phase change microcapsules were changed to 80 grams, while other conditions remained unchanged.

[0021] Comparative Example 4

[0022] Based on the phase change thermal insulation coating in Example 1, the phase change microcapsules were changed to 220 grams, while other conditions remained unchanged.

[0023] Comparative Example 5

[0024] Based on the phase change thermal insulation coating of Example 1, the total amount of thermal insulation filler was changed to 360 grams, while the proportions of the three components remained unchanged: 180 grams of hollow ceramic microspheres, 90 grams of hollow glass microspheres, and 90 grams of expanded perlite. Other conditions remained unchanged.

[0025] Comparative Example 6

[0026] Based on the phase change thermal insulation coating of Example 1, the total amount of thermal insulation filler was changed to 520 grams, while the proportions of the three components remained unchanged: 260 grams of hollow ceramic microspheres, 130 grams of hollow glass microspheres, and 130 grams of expanded perlite, with other conditions remaining the same.

[0027] Comparative Example 7

[0028] Based on the phase change thermal insulation coating of Example 1, the phase change microcapsules used are not activated, and other conditions remain unchanged.

[0029] Comparative Example 8

[0030] Based on the phase change thermal insulation coating of Example 1, the size of the phase change microcapsules was changed to 60-100 micrometers, while other conditions remained unchanged.

[0031] Comparative Example 9

[0032] Based on the phase change thermal insulation coating of Example 1, the size of titanium dioxide, silicon dioxide, aluminum oxide and barium sulfate were all changed to 1000 mesh, while other conditions remained unchanged.

[0033] Example 2

[0034] Add 10g of dispersant to 250g of purified water and stir for 30 minutes at a stirring speed of 1100 rpm. Then add 50g of rutile titanium dioxide (3000 mesh), 50g of silica (6000 mesh), 30g of alumina (3000 mesh), 70g of barium sulfate (3000 mesh), 120g of hollow ceramic microspheres (20-40 microns), 180g of hollow glass microspheres (50-100 microns), 180g of expanded perlite (200-400 microns), and 5g of defoamer and continue stirring for 50 minutes. Add 160g of phase change microcapsules and 300g of film-forming resin (inorganic silicone resin, with a solid content of 48±2%) and stir for 60 minutes. Reduce the stirring speed to 500 rpm, add 5g of preservative and 5g of film-forming agent, and continue stirring for 10 minutes to obtain the phase change thermal insulation coating. The phase change microcapsules have a core-shell structure, with a shell made of silica and a core of n-hexadecane. Their phase change temperature is 96℃. The microcapsule size is 10-20 micrometers. Before use, the microcapsules are activated in dilute hydrochloric acid (5% by mass) for 4 hours.

[0035] Example 3

[0036] Add 10g of dispersant to 250g of purified water and stir for 30 minutes at a stirring speed of 1100 rpm. Then add 50g of rutile titanium dioxide (3000 mesh), 50g of silica (6000 mesh), 30g of alumina (3000 mesh), 70g of barium sulfate (3000 mesh), 300g of hollow ceramic microspheres (20-40 microns), 180g of hollow glass microspheres (50-100 microns), and 5g of defoamer, and continue stirring for 50 minutes. Add 160g of phase change microcapsules and 300g of film-forming resin (inorganic silicone resin, emulsion solid content 48±2%) and stir for 60 minutes. Reduce the stirring speed to 500 rpm, add 5g of preservative and 5g of film-forming agent, and continue stirring for 10 minutes to obtain the phase change thermal insulation coating. The phase change microcapsules have a core-shell structure, with the shell made of silica and the core being n-hexadecane. Its phase transition temperature is 96℃. The phase transition microcapsules have a size of 10-20 micrometers. The phase transition microcapsules are activated in dilute hydrochloric acid (5% by mass) for 4 hours before use.

[0037] Example 4

[0038] Add 10g of dispersant to 250g of purified water and stir for 30 minutes at a stirring speed of 1100 rpm. Then add 50g of rutile titanium dioxide (3000 mesh), 50g of silica (6000 mesh), 30g of alumina (3000 mesh), 70g of barium sulfate (3000 mesh), 300g of hollow ceramic microspheres (20-40 microns), 180g of expanded perlite (200-400 microns), and 5g of defoamer, and continue stirring for 50 minutes. Add 160g of phase change microcapsules and 300g of film-forming resin (inorganic silicone resin, emulsion solid content 48±2%) and stir for 60 minutes. Reduce the stirring speed to 500 rpm, add 5g of preservative and 5g of film-forming agent, and continue stirring for 10 minutes to obtain the phase change thermal insulation coating. The phase change microcapsules have a core-shell structure, with the shell made of silica and the core being n-hexadecane. Its phase transition temperature is 96℃. The phase transition microcapsules have a size of 10-20 micrometers. The phase transition microcapsules are activated in dilute hydrochloric acid (5% by mass) for 4 hours before use.

[0039] Example 5

[0040] Add 10g of dispersant to 250g of purified water and stir for 30 minutes at a stirring speed of 1100 rpm. Then add 50g of rutile titanium dioxide (3000 mesh), 50g of silica (6000 mesh), 30g of alumina (3000 mesh), 70g of barium sulfate (3000 mesh), 300g of hollow ceramic microspheres (20-40 microns), 180g of hollow glass microspheres (50-100 microns), 180g of expanded perlite (200-400 microns), and 5g of defoamer, and continue stirring for 50 minutes. Add 300g of film-forming resin (inorganic silicone resin, with a solid content of 48±2%) and stir for 60 minutes. Reduce the stirring speed to 500 rpm, add 5g of preservative and 5g of film-forming agent, and continue stirring for 10 minutes to obtain the thermal insulation coating.

[0041] Table 1 shows the thermal conductivity, surface temperature (1 cm thickness, equipment temperature below 300℃), adhesion, and dispersibility of various fillers in the phase change insulating coating samples prepared for each comparative example (three samples were prepared for each type of sample, and the average value was taken). The test standards for thermal conductivity are GB / T 10295-2008, adhesion is GB / T 9286-1998, dispersibility is HG / T 5182-2017, and surface temperature was tested using an infrared thermometer.

[0042] Example 1 0.021 Uniform temperature 122±4℃ Level 0 very good Comparative Example 1 0.022 Uneven temperature 127±11℃ Level 2 Poor quality, with lumps Comparative Example 2 0.045 Uniform temperature 168±4℃ Level 0 very good Comparative Example 3 0.035 Uniform temperature 150±4℃ Level 0 very good Comparative Example 4 0.020 Uniform temperature 119±5℃ Level 0 very good Comparative Example 5 0.044 Uniform temperature 166±4℃ Level 0 very good Comparative Example 6 0.020 Uneven temperature 120±13℃ Level 0 Poor quality, with a large number of clusters. Comparative Example 7 0.030 Uneven temperature 144±9℃ 0 Slightly poor, with a small amount of clumping. Comparative Example 8 0.025 Uniform temperature 132±4℃ 0 very good Comparative Example 9 0.030 A relatively uniform temperature of 142±7℃ 0 Slightly poor, with a small amount of clumping.

[0043] The table above shows that the thermal conductivity of the coating is closely related to the amount of phase change microcapsules and insulating fillers added. Although phase change microcapsules do not directly act as insulating fillers, their addition amount has a significant impact on the coating, indicating their three main functions. Furthermore, reducing the amount of water and resin added, and increasing the amount of insulating fillers can lower the thermal conductivity of the coating, but the effect is not significant; the proportions in Example 1 have already achieved near-optimization. Moreover, the above measures lead to anisotropy in the thermal insulation performance of the coating, with large surface temperature differences. This is because the fillers are poorly dispersed in the system, resulting in agglomeration. Further increasing the content of phase change microcapsules also cannot significantly reduce the thermal conductivity, indicating that the proportions in Example 1 have achieved the synergistic effect of phase change microcapsules and various insulating fillers. If the phase change microcapsules are not activated, their dispersibility in the coating is affected, leading to a decrease in thermal insulation performance. Additionally, adjusting their size to be similar to other hollow insulating fillers will also lead to an increase in thermal conductivity; the surface size gradient is crucial for achieving good thermal insulation performance in phase change insulating coatings.

[0044] Table 2 shows the thermal conductivity, surface temperature (1 cm thickness, equipment temperature below 300℃), adhesion, and dispersibility of various fillers in the phase change thermal insulation coating samples prepared in each embodiment (three samples were prepared for each type of sample, and the average value was taken). The test standards for thermal conductivity are GB / T 10295-2008, adhesion is GB / T 9286-1998, dispersibility is HG / T 5182-2017, and surface temperature was tested using an infrared thermometer.

[0045] Example 1 0.021 Uniform temperature 122±4℃ Level 0 very good Example 2 0.028 Uniform temperature 138±5℃ Level 0 very good Example 3 0.024 Uniform temperature 129±3℃ Level 0 very good Example 4 0.027 Uniform temperature 134±5℃ Level 2 very good Example 5 0.022 Uneven temperature 123±14℃ Level 0 Very bad, unable to disperse

[0046] The table above shows that changing the proportions of the three hollow insulating fillers increases the thermal conductivity of the coating, indicating that a suitable proportion of the three insulating fillers can achieve a synergistic effect in their insulating properties. If the phase change microcapsules are not added, but the amount of the three hollow insulating fillers is increased, the thermal conductivity of the sample decreases slightly. Furthermore, due to excessive filler addition, the powder dispersion in the coating is very poor, affecting the quality.

[0047] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A phase change thermal insulation coating, characterized in that: Add 10g of dispersant to 250g of purified water and stir for 30 minutes at a stirring speed of 1100 rpm. Then add 50g of 3000-mesh rutile titanium dioxide, 50g of 6000-mesh silica, 30g of 3000-mesh alumina, 70g of 3000-mesh barium sulfate, 240g of 20-40 micron hollow ceramic microspheres, 120g of 50-100 micron hollow glass microspheres, 120g of 200-400 micron expanded perlite, and 5g of defoamer. Continue stirring for 50 minutes. Add 160g of phase change microcapsules and 300g of film-forming resin (inorganic silicone resin) with a solid content of 48±2% in the emulsion and stir for 60 minutes. Reduce the stirring speed to 500 rpm, add 5g of preservative and 5g of film-forming agent, and continue stirring for 10 minutes to obtain the phase change thermal insulation coating. The phase change microcapsules have a core-shell structure, with the shell made of silicon dioxide and the core being n-hexadecane; the phase change temperature is 96℃, the size of the phase change microcapsules is 10-20 micrometers, and the phase change microcapsules are activated in 5% dilute hydrochloric acid for 4 hours before use.