A silicone thermal barrier coating and a method of making the same

Abstract

The application discloses a kind of organic silicon heat insulation coatings, including A component and B component;By mass parts, A component includes: 20-40 parts vinyl silicone oil, 10-20 parts phenyl vinyl silicone rubber, 5-15 parts of wollastonite, 2-8 parts of mica powder, 5-10 parts of glass powder, 0.5-2 parts of nano expanded graphite, 1-15 parts of hollow glass microsphere, 1-10 parts of hydrogen-containing silicone oil, 0.1-1 parts of inhibitor, 1-10 parts of PCL phase change material;By mass parts, B component includes: 20-50 parts vinyl silicone oil, 10-15 parts phenyl vinyl silicone rubber, 5-15 parts of wollastonite, 2-8 parts of mica powder, 5-10 parts of glass powder, 0.5-2 parts of nano expanded graphite, 1-15 parts of hollow glass microsphere, 0.1-1 parts of catalyst, 1-10 parts of PCL phase change material;Wherein, the surface of nano expanded graphite in A component and B component has insulating layer;PCL phase change material is one or several of high-grade aliphatic hydrocarbons, fatty acids and fatty acid esters.The application also discloses a preparation method thereof.The coating of the application has high temperature resistance and heat insulation performance, and has good insulation, and can be used in battery field.

Description

Technical Field

[0001] This invention relates to the field of coatings for batteries, and particularly to an organosilicon heat-insulating coating and its preparation method. Background Technology

[0002] Paint is a coating applied to the surface of an object to be protected or decorated, forming a continuous, firmly adhered film. In other words, paint is a material that can be applied to the surface of an object using different application techniques to form a strong, continuous solid film.

[0003] In particular, coatings play a crucial role in the battery field, with wide-ranging applications such as serving as carriers for electrochemical active materials, coatings for insulating materials, and protecting battery casings and managing thermal stress. By enhancing the battery's conductivity, insulation, and corrosion resistance, they significantly improve the overall performance and reliability of the battery. In recent years, with the rise of emerging industries such as renewable energy and electric vehicles, the requirements for battery performance and safety have become increasingly stringent, driving further innovation in battery coating technology. New types of coatings, such as smart coatings and high-temperature resistant coatings, are constantly emerging, providing protection for batteries in extreme environments.

[0004] However, existing coatings are either heat-resistant but not insulating, or insulating but not heat-resistant. Heat-resistant but not insulating coatings achieve their heat-resistance by adding heat-resistant fillers to the formula, but these materials lack insulation properties. The lack of insulation in these coatings can lead to excessively high battery temperatures, potentially increasing the risk of battery overheating. Insulating but not heat-resistant coatings may be damaged by excessively high temperatures, such as melting, softening, or decomposing, thus losing their protective function for the battery. For example, polyurethane coatings work by thermally decomposing at high temperatures to provide insulation. However, this thermal decomposition causes them to lose their insulating properties and become conductive. For coatings applied to the battery casing, this conductivity can lead to battery leakage, short circuits, and other safety hazards. Therefore, there is a need for a coating that combines high-temperature resistance and insulation properties with good insulation, suitable for application to battery casings.

[0005] Currently, thermal insulation coatings are mainly divided into two categories: intumescent and non-intumescent. Intumescent coatings include polyurethane, epoxy, polyurea, and acrylic types. The characteristic of intumescent thermal insulation coatings is that, at high temperatures, the carbon source and gas source in the coating work synergistically to foam at a ratio of 10-30 times, forming a thick foamed carbon layer. This layer blocks oxygen and heat transfer, thus providing fireproofing and thermal insulation. The advantages of this type of coating are good thermal insulation performance and low cost. The disadvantages are that it requires space for foaming and expansion to form the foamed carbon layer to function, and the strength of the foamed carbon layer is not high, making it susceptible to damage from flames and airflow. Non-intumescent thermal insulation coatings include silicate, organosilicon, silica sol, organic-inorganic hybrid, and aerogel water-based fireproof and thermal insulation coatings. Among them, silicate and silica sol-based thermal insulation coatings suffer from high brittleness, hardness, and poor thermal insulation performance, making them unsuitable for the pressure-sensitive and resilience requirements of power batteries. Aerogel waterborne coatings offer better thermal insulation but have poor mechanical properties. Existing technologies attempt to improve mechanical properties by increasing the organic phase ratio, but this significantly impacts thermal insulation performance. Organosilicon thermal insulation coatings, on the other hand, benefit from the inherent high temperature resistance and excellent resilience of organosilicon. However, current organosilicon thermal insulation coatings generally have a high-temperature resistance range of around 200℃, undergoing thermal decomposition at 500–600℃, failing to meet the battery industry's requirement of a high-temperature resistance range of 600–1500℃. Therefore, it is necessary to conduct in-depth research on organosilicon thermal insulation coatings to achieve a high-temperature resistance range suitable for the battery industry while also possessing good thermal insulation performance and excellent electrical insulation properties. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention proposes an organosilicon heat-insulating coating and its preparation method.

[0007] In a first aspect, embodiments of the present invention disclose an organosilicon heat-insulating coating, comprising component A and component B;

[0008] By weight, component A comprises: 20-40 parts vinyl silicone oil, 10-20 parts phenyl vinyl silicone rubber, 5-15 parts wollastonite, 2-8 parts mica powder, 5-10 parts glass powder, 0.5-2 parts nano-expanded graphite, 1-15 parts hollow glass microspheres, 1-10 parts hydrogen-containing silicone oil, 0.1-1 parts inhibitor, and 1-10 parts PCL phase change material;

[0009] By weight, component B comprises: 20-50 parts vinyl silicone oil, 10-15 parts phenyl vinyl silicone rubber, 5-15 parts wollastonite, 2-8 parts mica powder, 5-10 parts glass powder, 0.5-2 parts nano-expanded graphite, 1-15 parts hollow glass microspheres, 0.1-1 parts catalyst, and 1-10 parts PCL phase change material.

[0010] The surface of the nano-expanded graphite in component A and component B has an insulating layer; the PCL phase change material is one or more of higher aliphatic hydrocarbons, fatty acids and fatty acid esters.

[0011] By employing the above technical solution, the combination of vinyl silicone oil and phenyl vinyl silicone rubber firstly improves the thermal insulation capacity of the coating while also providing good mechanical properties. The use of other functional powders further enhances the coating's high residual carbon content and dense surface state at high temperatures, resulting in excellent thermal insulation performance. Due to the volume collapse caused by the melting of glass powder and hollow glass microspheres at high temperatures, nano-expanded graphite can undergo 2-5 times volume expansion under high temperatures, forming a micron-scale loose porous structure. This effectively fills the collapsed volume and increases the cavity ratio of the ceramicized coating. Simultaneously, the formed carbon layer further reduces the thermal conductivity, improving both thermal insulation and flame retardancy. This yields a thermal insulation coating suitable for the battery field, possessing both high-temperature resistance and thermal insulation properties, as well as good flame retardancy. The insulating layer on the surface of the expanded graphite ensures the insulation properties of the silicone thermal insulation coating. Furthermore, the silicone thermal insulation coating of this invention comprises components A and B, facilitating the control of the viscosity of components A and B during preparation. This improves the curing and film-forming performance of the silicone thermal insulation coating, facilitates storage, and provides excellent processability.

[0012] Optionally, by weight, component A further includes 5-15 parts of nano-titanium dioxide and 5-15 parts of nano-aluminum hydroxide, and component B further includes 5-15 parts of nano-titanium dioxide and 5-15 parts of nano-aluminum hydroxide.

[0013] Optionally, by weight, component A further includes 0.1 to 1.5 parts of silane coupling agent and 0.05 to 1 part of iron oxide red; component B further includes 0.1 to 1.5 parts of silane coupling agent.

[0014] Optionally, component A and component B shall satisfy at least one of the following conditions:

[0015] The wollastonite has a particle size of 5–20 μm and an aspect ratio of 10:1–30:1.

[0016] The mica powder includes mica powder 1 and mica powder 2, the mass ratio of mica powder 1 to mica powder 2 is 1:1 to 3:1, the particle size of mica powder 1 is 15 to 30 μm, and the particle size of mica powder 2 is 1 to 10 μm.

[0017] The glass powder includes glass powder 1 and glass powder 2, the mass ratio of glass powder 1 to glass powder 2 is 3:1 to 6:1, the particle size of glass powder 1 is 1 to 5 μm, and the particle size of glass powder 2 is 15 to 30 μm.

[0018] The hollow glass microspheres include hollow glass microsphere 1 and hollow glass microsphere 2, with a mass ratio of 3:1 to 6:1. The particle size of hollow glass microsphere 1 is 30 to 60 μm, and the particle size of hollow glass microsphere 2 is 5 to 20 μm.

[0019] Optionally, in component A, the particle size of the expanded nano-graphite is 600–900 nm; in component B, the particle size of the expanded nano-graphite is 600–900 nm; and the particle sizes of the expanded nano-graphite in components A and B are equal.

[0020] Optionally, in components A and B, the melting point of glass powder 1 is 380–450°C, and the melting point of glass powder 2 is 500–600°C.

[0021] Optionally, in component A and component B,

[0022] The vinyl silicone oil comprises vinyl silicone oil 1 and vinyl silicone oil 2, wherein the viscosity of vinyl silicone oil 1 is 2000-5000 mPa·s, and the viscosity of vinyl silicone oil 2 is 8000-200000 mPa·s; the vinyl content of the vinyl silicone oil is 0.03%-2.3% by mass; by mass, component A comprises 10-20 parts of vinyl silicone oil 1 and 10-20 parts of vinyl silicone oil 2, and component B comprises 10-30 parts of vinyl silicone oil 1 and 10-20 parts of vinyl silicone oil 2;

[0023] The viscosity of the phenyl vinyl silicone rubber is 6000-200000 mPa·s, the mass content of vinyl in the phenyl vinyl silicone rubber is 0.1%-0.75%, the molar content of phenyl is 3%-25%, and the mass content of the phenyl vinyl silicone rubber in component A and / or component B is 10%-15%.

[0024] The hydrogen content in the hydrogen-containing silicone oil is 0.5wt% to 2.5wt%.

[0025] Secondly, embodiments of the present invention disclose a method for preparing an organosilicon heat-insulating coating, used to prepare an organosilicon heat-insulating coating as described in any embodiment of the first aspect, comprising the following steps:

[0026] Preparation of Component A: By weight, 20-40 parts of vinyl silicone oil powder, 10-20 parts of phenyl vinyl silicone rubber, 5-15 parts of wollastonite, 2-8 parts of mica powder, 5-10 parts of glass powder, 0.5-2 parts of nano-expanded graphite, 1-15 parts of hollow glass microspheres, 1-10 parts of hydrogen-containing silicone oil, 0.1-1 parts of inhibitor and 1-10 parts of PCL phase change material are mixed to obtain Component A;

[0027] Preparation of Component B: By weight, 20-50 parts of vinyl silicone oil powder, 10-15 parts of phenyl vinyl silicone rubber, 5-15 parts of wollastonite, 2-8 parts of mica powder, 5-10 parts of glass powder, 0.5-2 parts of nano-expanded graphite, 1-15 parts of hollow glass microspheres, 0.1-1 parts of catalyst and 1-10 parts of PCL phase change material are mixed to obtain Component B;

[0028] Preparation of silicone thermal insulation coating: The A component and the B component are mixed and cured to obtain the target silicone thermal insulation coating;

[0029] In the preparation steps of component A and component B, the nano-expanded graphite is further subjected to an insulating coating treatment before the preparation steps of component A and component B; the PCL phase change material is one or more of higher aliphatic hydrocarbons, fatty acids and fatty acid esters.

[0030] The above-mentioned technical solution has good processability, and the preparation process is simple and efficient, making it easy to prepare organosilicon heat insulation coatings that have both high temperature resistance and heat insulation properties, as well as good flame retardancy and insulation.

[0031] Optionally, at least one of the following conditions must be met in the steps of preparing component A and preparing component B:

[0032] The wollastonite has a particle size of 5–20 μm and an aspect ratio of 10:1–30:1.

[0033] The mica powder includes mica powder 1 and mica powder 2, the mass ratio of mica powder 1 to mica powder 2 is 1:1 to 3:1, the particle size of mica powder 1 is 15 to 30 μm, and the particle size of mica powder 2 is 1 to 10 μm.

[0034] The glass powder includes glass powder 1 and glass powder 2, with a mass ratio of glass powder 1 to glass powder 2 of 3:1 to 6:1. The particle size of glass powder 1 is 1 to 5 μm, the particle size of glass powder 2 is 15 to 30 μm, the melting point of glass powder 1 is 380 to 450°C, and the melting point of glass powder 2 is 500 to 600°C.

[0035] The hollow glass microspheres include hollow glass microsphere 1 and hollow glass microsphere 2, with a mass ratio of 3:1 to 6:1. The particle size of hollow glass microsphere 1 is 30 to 60 μm, and the particle size of hollow glass microsphere 2 is 5 to 20 μm.

[0036] Optionally, the preparation method of the organosilicon heat-insulating coating includes the following steps:

[0037] Powder modification: A mixture of silane coupling agent, water, ethanol, and 5 wt% ammonia is prepared. Then, by mass, 5-15 parts of wollastonite, 2-8 parts of mica powder 1, 1-4 parts of mica powder 2, 5-10 parts of glass powder 1, 1-4 parts of glass powder 2, 0.5-2 parts of nano-expanded graphite, 5-15 parts of nano-titanium dioxide, and 5-15 parts of nano-aluminum hydroxide are mixed and added to the mixture of silane coupling agent, water, ethanol, and 5 wt% ammonia. The mixture is then mixed using an air jet mill to obtain modified powder consisting of 5-15 parts wollastonite, 2-8 parts of mica powder 1, 1-4 parts of mica powder 2, 5-10 parts of glass powder 1, 1-4 parts of glass powder 2, 0.5-2 parts of nano-expanded graphite, 5-15 parts of nano-titanium dioxide, and 5-15 parts of nano-aluminum hydroxide.

[0038] Preparation of Component A: By mass, 10-20 parts of vinyl silicone oil 1, 10-20 parts of vinyl silicone oil 2 and 10-20 parts of phenyl vinyl silicone rubber were mixed, and then 5-15 parts of the modified wollastonite, 2-8 parts of mica powder 1, 1-4 parts of mica powder 2, 5-10 parts of glass powder 1, 1-4 parts of glass powder 2, 0.5-2 parts of nano-expanded graphite, 5-15 parts of nano-titanium dioxide and 5-15 parts of nano-aluminum hydroxide powder were added and mixed. The mixture was heated to dehydrate, and after cooling to stop dehydration, 1-10 parts of hydrogen-containing silicone oil and 0.1-1 parts of inhibitor were added and mixed at a constant temperature. Then, 5-10 parts of hollow glass microspheres 1, 1-5 parts of hollow glass microspheres 2, 0.05-1 parts of iron oxide red and 1-10 parts of PCL phase change material were added and mixed to obtain Component A.

[0039] Preparation of Component B: By mass, 10-30 parts of vinyl silicone oil 1, 10-20 parts of vinyl silicone oil 2 and 10-15 parts of phenyl vinyl silicone rubber were mixed, and then 5-15 parts of the modified wollastonite, 2-8 parts of mica powder 1, 1-4 parts of mica powder 2, 5-10 parts of glass powder 1, 1-4 parts of glass powder 2, 0.5-2 parts of nano-expanded graphite, 5-15 parts of nano-titanium dioxide and 5-15 parts of nano-aluminum hydroxide powder were added and mixed. Then 5-10 parts of hollow glass microspheres 1 and 1-5 parts of hollow glass microspheres 2 were added and mixed. The mixture was heated and dehydrated. After cooling and stopping the dehydration, 1-10 parts of PCL phase change material were added at a constant temperature and mixed. Finally, 0.1-1 parts of catalyst were added and mixed to obtain Component B.

[0040] Preparation of silicone thermal insulation coating: After mixing the components A and B, the mixture is sprayed onto the surface of the template and cured to obtain the target silicone thermal insulation coating;

[0041] In the preparation steps of component A and component B, the nano-expanded graphite is further subjected to an insulating coating treatment before the preparation steps of component A and component B; the PCL phase change material is one or more of higher aliphatic hydrocarbons, fatty acids and fatty acid esters. Attached Figure Description

[0042] Figure 1 The diagram shows the back surface temperature rise curves of a 1 mm coating at 900°C for Embodiments 1, 2, and Comparative Examples 1-4 of the present invention. Detailed Implementation

[0043] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention is presented in conjunction with preferred embodiments, this does not mean that the features of the invention are limited to these embodiments. On the contrary, the purpose of describing the invention in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of the present invention. To provide a deep understanding of the invention, many specific details will be included in the following description. The invention may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of the invention, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0044] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0045] The terms “first”, “second”, etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0046] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0047] While many coatings already exist in the prior art, the inventors have discovered that existing coatings are either heat-resistant but not insulating, or insulating but not heat-resistant. Some existing heat-insulating coatings even sacrifice their original insulation properties to achieve their insulating performance, leading to a series of safety accidents such as battery leakage and short circuits. In particular, silicone heat-insulating coatings are advantageous due to the good temperature resistance and resilience of silicone itself. However, current silicone heat-insulating coatings generally have a high-temperature resistance range of around 200℃, undergoing thermal decomposition at 500-600℃, which cannot meet the battery industry's requirement of a high-temperature resistance range of 600-1500℃. Therefore, the inventors aim to provide a silicone heat-insulating coating that combines high-temperature resistance and heat insulation properties, while also possessing good insulation properties, suitable for use in the battery industry, such as coating battery casings.

[0048] In a first aspect, embodiments of the present invention disclose an organosilicon heat-insulating coating, comprising component A and component B;

[0049] By weight, component A includes: 20-40 parts vinyl silicone oil, 10-20 parts phenyl vinyl silicone rubber, 5-15 parts wollastonite, 2-8 parts mica powder, 5-10 parts glass powder, 0.5-2 parts nano-expanded graphite, 1-15 parts hollow glass microspheres, 1-10 parts hydrogen-containing silicone oil, 0.1-1 parts inhibitor, and 1-10 parts PCL phase change material;

[0050] By weight, component B includes: 20-50 parts vinyl silicone oil, 10-15 parts phenyl vinyl silicone rubber, 5-15 parts wollastonite, 2-8 parts mica powder, 5-10 parts glass powder, 0.5-2 parts nano-expanded graphite, 1-15 parts hollow glass microspheres, 0.1-1 parts catalyst, and 1-10 parts PCL phase change material.

[0051] In this material, the surface of the nano-expanded graphite in components A and B has an insulating layer; the PCL phase change material is one or more of higher aliphatic hydrocarbons, fatty acids, and fatty acid esters. Specifically, higher aliphatic hydrocarbons include hexadecane, n-octadecane, microcrystalline wax, and polyethylene wax; fatty acids include stearic acid and palmitic acid. The PCL phase change material preferably has an externally coated spherical structure, maintaining closed pores even after the phase change material melts under endothermic heat. Furthermore, the mica powder includes one or more of muscovite, phlogopite, sericite, and fluorophlogopite; the glass powder is, for example, borosilicate glass.

[0052] This invention improves the thermal insulation capacity of an organosilicon thermal insulation coating by controlling the combination of vinyl silicone oil and phenyl vinyl silicone rubber in components A and B of the coating formulation, while also providing good mechanical properties. Furthermore, the use of other powders further controls the thermal insulation performance of the organosilicon thermal insulation coating. However, it was uncertain whether it could meet the high-temperature resistance requirements of the battery industry. Through various trials and experiments, the inventors determined the above-mentioned technical solution.

[0053] During their research, the inventors discovered that the combination of vinyl silicone oil and phenyl vinyl silicone rubber improved the temperature resistance of the coating, but still could not meet the high-temperature requirements of the battery industry. Furthermore, by controlling the curing rate with hydrogen-containing silicone oil in components A and B, and by adding powdered wollastonite, mica powder, and glass powder, the silicone thermal insulation coating could be ceramicized. Combined with the use of hollow glass microspheres as thermal insulation fillers, and the PCL phase change material melting at a temperature higher than its melting temperature to create pores, the PCL phase change material, on the one hand, absorbs energy, and on the other hand, the pores formed by its melting can form new sealed spaces with the ceramicized system, thereby further reducing heat conduction. This results in a silicone thermal insulation coating with a high residual carbon content and a dense surface at high temperatures, exhibiting excellent high-temperature resistance and thermal insulation capabilities.

[0054] During the experiment, the inventors also discovered that the glass powder and hollow glass microspheres in the above-mentioned powder melt at high temperatures, easily causing the volume of the coating to collapse. The inventors added nano-expanded graphite to components A and B. Under high temperatures, the nano-expanded graphite can undergo a 2-5 fold volume expansion, forming a loose, porous structure at the micron scale. The porous structure formed by the expansion effectively fills the aforementioned collapsed volume and increases the cavity ratio of the ceramicizable heat-insulating coating. Simultaneously, the formed carbon layer further reduces the thermal conductivity, improving heat insulation and flame retardancy. However, considering that expanded graphite itself is easily conductive, it must be treated before use to ensure that the surface of the nano-expanded graphite in components A and B has an insulating layer to avoid accidents such as battery leakage and short circuits caused by conductivity. Specifically, the surface of the nano-expanded graphite in components A and B is coated with an insulating layer. This insulating layer refers to a coating layer formed on its surface by the hydrolysis products of siloxanes, such as the insulating layer formed by the deposition of the product (silica) after the hydrolysis of tetraethyl orthosilicate on the surface of expanded graphite.

[0055] This invention obtains an organosilicon heat-insulating coating suitable for the battery field by combining components A and B in the above-mentioned formula, with the specific powder content ranges set as described above, and also possessing good flame retardancy and insulation properties.

[0056] Furthermore, the formulation of the silicone thermal insulation coating of the present invention includes component A and component B, which facilitates the separate control of the viscosity of components A and B during the preparation process, thereby improving the curing and film-forming performance of the silicone thermal insulation coating of the present invention. Component A includes a hydrogen-containing silicone oil as a curing agent and an inhibitor. The inhibitor refers to an alkyne inhibitor, such as butyrynethite or phenylacetylene, which is used to inhibit the silicon-hydroaddition reaction between the vinyl silicone oil and the hydrogen-containing silicone oil in component A, thus preventing cross-linking and curing. Component B includes a catalyst, specifically a platinum catalyst at a concentration of 5000 ppm. This ensures that the silicone thermal insulation coating of the present invention can only be prepared after components A and B are mixed and cured, facilitating storage and providing better processability.

[0057] Furthermore, by weight, component A further includes 5-15 parts of nano-titanium dioxide and 5-15 parts of nano-aluminum hydroxide, and component B further includes 5-15 parts of nano-titanium dioxide and 5-15 parts of nano-aluminum hydroxide. By adding radiation-resistant filler nano-titanium dioxide and flame-retardant nano-aluminum hydroxide to components A and B, and combining them with the other powders mentioned above, the inventors have further improved the fire resistance of the organosilicon heat-insulating coating, making it resistant to flame attack and enhancing its radiation resistance to improve its heat insulation capacity, thereby protecting adjacent batteries from the spread of thermal runaway due to the influence of individual thermal runaway cells.

[0058] Because the silicone thermal insulation coating of this invention is achieved through the synergistic combination of various powder fillers, and the powders are prone to agglomeration, etc., to avoid these problems, by weight, component A of this invention further includes: 0.1 to 1.5 parts of silane coupling agent; component B further includes: 0.1 to 1.5 parts of silane coupling agent. The silane coupling agent can reduce the tackifying and agglomerating effect of the powders and enhance the dispersibility of the powders in vinyl silicone oil and phenyl vinyl silicone rubber, thereby improving the adhesion of the silicone thermal insulation coating. Furthermore, by weight, component A of this invention further includes: 0.05 to 1 part of iron oxide red. Iron oxide red has good tinting strength; adding iron oxide red to component A allows users to distinguish component A and component B by color, facilitating use. The silane coupling agent, by mass, also includes 0-0.5 parts of silane coupling agent 1 and 0-0.5 parts of silane coupling agent 2. One end of silane coupling agent 1 can form a chemical bond with the groups on the surface of the powder, and the other end can react and bond with the resin. Silane coupling agent 2 can also undergo condensation crosslinking on the basis of the above, further improving the bonding strength between the powder and the resin matrix. At the same time, the hydrolysis products can further improve the hydrophobic properties of the powder.

[0059] Furthermore, in the above embodiments, components A and B satisfy at least one of the following conditions:

[0060] The grain size of wollastonite is 5–20 μm, and the aspect ratio of wollastonite is 10:1–30:1.

[0061] The mica powder includes mica powder 1 and mica powder 2, with a mass ratio of mica powder 1 to mica powder 2 of 1:1 to 3:1. The particle size of mica powder 1 is 15 to 30 μm, and the particle size of mica powder 2 is 1 to 10 μm.

[0062] The glass powder includes glass powder 1 and glass powder 2, with a mass ratio of glass powder 1 to glass powder 2 of 3:1 to 6:1. The particle size of glass powder 1 is 1 to 5 μm, and the particle size of glass powder 2 is 15 to 30 μm.

[0063] The hollow glass microspheres include hollow glass microsphere 1 and hollow glass microsphere 2, with a mass ratio of 3:1 to 6:1. The particle size of hollow glass microsphere 1 is 30 to 60 μm, and the particle size of hollow glass microsphere 2 is 5 to 20 μm.

[0064] Specifically, when only one condition is met by components A and B of the present invention, for example, components A and B satisfy the following conditions: the particle size of wollastonite is 5–20 μm, and the aspect ratio of wollastonite is 10:1–30:1. Through the above control, the low thermal conductivity of air can be effectively reduced to achieve thermal insulation.

[0065] When components A and B of this invention satisfy only two conditions, for example, components A and B satisfy the following: the particle size of wollastonite is 5–20 μm, and the aspect ratio of wollastonite is 10:1–30:1; and the mica powder includes mica powder 1 and mica powder 2, with a mass ratio of mica powder 1 to mica powder 2 of 1:1–3:1, the particle size of mica powder 1 being 15–30 μm, and the particle size of mica powder 2 being 1–10 μm. This invention, by controlling the particle size and aspect ratio of wollastonite and the combination of mica powders with different particle sizes, can optimize the pore structure and pore size distribution, making the heat conduction path in the material more tortuous, thereby reducing thermal conductivity.

[0066] When components A and B of this invention satisfy only three conditions, for example, components A and B satisfy the following: the particle size of wollastonite is 5–20 μm, and the aspect ratio of wollastonite is 10:1–30:1; the mica powder includes mica powder 1 and mica powder 2, the mass ratio of mica powder 1 to mica powder 2 is 1:1–3:1, the particle size of mica powder 1 is 15–30 μm, and the particle size of mica powder 2 is 1–10 μm; and the glass powder includes glass powder 1 and glass powder 2, the mass ratio of glass powder 1 to glass powder 2 is 3:1–6:1, the particle size of glass powder 1 is 1–5 μm, and the particle size of glass powder 2 is 15–30 μm. Through the synergistic effect of wollastonite, mica powder, and glass powder, a denser structure is formed, reducing air convection and heat conduction, effectively blocking heat conduction and convection, thereby giving the coating of this invention better thermal insulation performance.

[0067] When components A and B of this invention meet all four conditions (i.e., components A and B satisfy all the above conditions), components A and B satisfy the following: the particle size of wollastonite is 5–20 μm, and the aspect ratio of wollastonite is 10:1–30:1; the mica powder includes mica powder 1 and mica powder 2, the mass ratio of mica powder 1 to mica powder 2 is 1:1–3:1, the particle size of mica powder 1 is 15–30 μm, and the particle size of mica powder 2 is 1–10 μm; glass powder… The invention comprises glass powder 1 and glass powder 2, with a mass ratio of 3:1 to 6:1. Glass powder 1 has a particle size of 1–5 μm, and glass powder 2 has a particle size of 15–30 μm. Hollow glass microspheres also include hollow glass microspheres 1 and 2, with a mass ratio of 3:1 to 6:1. Hollow glass microspheres 1 have a particle size of 30–60 μm, and hollow glass microspheres 2 have a particle size of 5–20 μm. By controlling the combination of different particle sizes of the aforementioned powders, this invention achieves lower viscosity in components A and B at the same powder addition amount, further improving the process performance of subsequent preparation of organosilicon thermal insulation coatings. Simultaneously, due to the high filling rate in the spatial structure, the densest packing in three-dimensional space is formed, resulting in the longest heat insulation path formed by the heat insulation powder, maximizing the powder absorption of the film-forming silicone resin, enabling the prepared heat insulation coating to maintain good morphology at high temperatures, and also ensuring good ceramic integrity, forming a dense heat insulation layer, isolating convective heat transfer from external oxygen and the longest heat transfer path, reducing heat conduction, and maximizing the isolation of convective heat transfer.

[0068] During the experiment, the inventors discovered that traditional expanded graphite, characterized by its large particle size and high expansion ratio upon heating, while effectively improving flame retardant properties in ceramizable silicone thermal insulation coatings, suffers from significant damage to the overall ceramic integrity due to its excessive expansion ratio. This further exacerbates heat transfer via convection, thus reducing thermal insulation performance. Furthermore, the continuous structure formed by expanded graphite significantly reduces the electrical insulation properties of the coating. Therefore, through extensive experimental research, the inventors found that when the particle size of the nano-expanded graphite in component A and component B is 600–900 nm, and the particle sizes in components A and B are equal, the smaller particle size and lower layer structure retention result in a lower expansion ratio, preventing damage to the ceramic integrity after expansion. This also facilitates slight expansion when other components collapse, compensating for the lost volume, and the resulting carbon layer further reduces the thermal conductivity of the silicone thermal insulation coating.

[0069] Furthermore, in components A and B of this invention, glass powder 1 has a melting point of 380–450°C, and glass powder 2 has a melting point of 500–600°C. In this invention, both glass powder 1 and glass powder 2 serve as fluxes. Because glass powder 1 and glass powder 2 have different melting points, they can match the thermal decomposition of the silicone thermal insulation coating at high temperatures. That is, when the thermal insulation coating undergoes partial thermal decomposition, the flux also partially melts accordingly, fusing with the products of thermal decomposition to maintain the structure of the thermal insulation coating system. When the organic components of the thermal insulation coating rapidly decompose at even higher temperatures, the flux, with its higher melting point, also melts rapidly and in large quantities, fusing with the products of thermal decomposition to maintain the structure of the thermal insulation coating system, maintaining a dense outer insulating layer, improving the ceramic effect, further enhancing the thermal insulation capacity of the silicone thermal insulation coating of this invention, and also preventing powder shedding.

[0070] Furthermore, in the above embodiments, in components A and B,

[0071] The vinyl silicone oil includes vinyl silicone oil 1 and vinyl silicone oil 2. The viscosity of vinyl silicone oil 1 is 2000-5000 mPa·s, and the viscosity of vinyl silicone oil 2 is 8000-200000 mPa·s. The vinyl content of the vinyl silicone oil is 0.03%-2.3% by mass. Preferably, the vinyl content is between 0.1% and 1.0% by mass, and more preferably, the vinyl content is between 0.1% and 0.3% by mass.

[0072] By weight, component A contains 10-20 parts vinyl silicone oil 1 and 10-20 parts vinyl silicone oil 2, preferably 10-15 parts vinyl silicone oil 1 and 10-15 parts vinyl silicone oil 2; component B contains 10-30 parts vinyl silicone oil 1 and 10-20 parts vinyl silicone oil 2, preferably 20-30 parts vinyl silicone oil 1 and 10-15 parts vinyl silicone oil 2.

[0073] The viscosity of the phenyl vinyl silicone rubber is 6000–200000 mPa·s, preferably 6000–8000 mPa·s. The vinyl content of the phenyl vinyl silicone rubber is 0.1%–0.75% by mass, preferably 0.4%–0.6% by mass. The molar content of phenyl is 3%–25%, preferably 10%–13% by mass. The phenyl vinyl silicone rubber has a mass content of 10%–15% in component A and / or component B, meaning that 100 parts of component A contain 10%–15% phenyl vinyl silicone rubber by mass, and 100 parts of component B also contain 10%–15% phenyl vinyl silicone rubber by mass. Preferably, the phenyl vinyl silicone rubber has a mass content of 12–15% in component A and / or component B; preferably, by mass parts, component A contains 12–18 parts phenyl vinyl silicone rubber, and component B contains 10–13 parts phenyl vinyl silicone rubber. In addition, the hydrogen content in hydrogen-containing silicone oil is 0.5wt% to 2.5wt%, which refers to the mass content of hydrogen.

[0074] This invention controls the physical parameters of vinyl silicone oil, phenyl vinyl silicone rubber, and hydrogen-containing silicone oil, including viscosity, vinyl mass content, phenyl molar content, and hydrogen content in the hydrogen-containing silicone oil. This avoids the problem of excessively high viscosity of raw material powders, which could prevent spraying in subsequent processes or increase the difficulty of preparing the silicone thermal insulation coating. Furthermore, this invention ensures sufficient reaction of raw materials in the silicone thermal insulation coating formulation, facilitates process preparation, and results in a good cross-linked structure for the thermal insulation filler, while also possessing good mechanical strength and elasticity in addition to high-temperature resistance.

[0075] Secondly, the present invention provides a method for preparing an organosilicon heat-insulating coating, used to manufacture the organosilicon heat-insulating coatings of the above embodiments, comprising the following steps:

[0076] Preparation of Component A: By weight, 20-40 parts of vinyl silicone oil powder, 10-20 parts of phenyl vinyl silicone rubber, 5-15 parts of wollastonite, 2-8 parts of mica powder, 5-10 parts of glass powder, 0.5-2 parts of nano-expanded graphite, 1-15 parts of hollow glass microspheres, 1-10 parts of hydrogen-containing silicone oil, 0.1-1 parts of inhibitor and 1-10 parts of PCL phase change material are mixed to obtain Component A.

[0077] Preparation of Component B: By weight, 20-50 parts of vinyl silicone oil powder, 10-15 parts of phenyl vinyl silicone rubber, 5-15 parts of wollastonite, 2-8 parts of mica powder, 5-10 parts of glass powder, 0.5-2 parts of nano-expanded graphite, 1-15 parts of hollow glass microspheres, 0.1-1 parts of catalyst and 1-10 parts of PCL phase change material are mixed to obtain Component B.

[0078] Preparation of silicone thermal insulation coating: Component A and component B are mixed and cured to obtain the target silicone thermal insulation coating.

[0079] In the preparation steps of component A and component B, the nano-expanded graphite is further subjected to an insulating coating treatment before the preparation steps of component A and component B; the PCL phase change material is one or more of higher aliphatic hydrocarbons, fatty acids and fatty acid esters.

[0080] This invention simplifies the process and ensures the compatibility of components A and B by separately controlling the preparation steps of component A and component B in the formulation. Through these steps, the preparation process is simple and efficient, facilitating the production of silicone thermal insulation coatings that combine high-temperature resistance and thermal insulation properties, as well as good flame retardancy and electrical insulation.

[0081] The inventors also discovered through experimental comparison that the preparation steps of component A and component B must meet at least one of the following conditions:

[0082] The grain size of wollastonite is 5–20 μm, and the aspect ratio of wollastonite is 10:1–30:1.

[0083] The mica powder includes mica powder 1 and mica powder 2, with a mass ratio of mica powder 1 to mica powder 2 of 1:1 to 3:1. The particle size of mica powder 1 is 15 to 30 μm, and the particle size of mica powder 2 is 1 to 10 μm.

[0084] The glass powder includes glass powder 1 and glass powder 2, with a mass ratio of glass powder 1 to glass powder 2 of 3:1 to 6:1. The particle size of glass powder 1 is 1 to 5 μm, and the particle size of glass powder 2 is 15 to 30 μm. The melting point of glass powder 1 is 380 to 450℃, and the melting point of glass powder 2 is 500 to 600℃.

[0085] The hollow glass microspheres include hollow glass microsphere 1 and hollow glass microsphere 2, with a mass ratio of 3:1 to 6:1. The particle size of hollow glass microsphere 1 is 30 to 60 μm, and the particle size of hollow glass microsphere 2 is 5 to 20 μm.

[0086] Specifically, when the preparation steps of component A and component B of the present invention satisfy only one condition, for example, the preparation steps of component A and component B satisfy the following conditions: the particle size of wollastonite is 5 to 20 μm and the aspect ratio of wollastonite is 10:1 to 30:1.

[0087] When the preparation steps of component A and component B of the present invention satisfy only two conditions, for example, the preparation steps of component A and component B satisfy the following conditions: the particle size of wollastonite is 5-20 μm, the aspect ratio of wollastonite is 10:1-30:1; and the mica powder includes mica powder 1 and mica powder 2, the mass ratio of mica powder 1 and mica powder 2 is 1:1-3:1, the particle size of mica powder 1 is 15-30 μm, and the particle size of mica powder 2 is 1-10 μm.

[0088] When the preparation steps of component A and component B of the present invention satisfy only three conditions, for example, the preparation steps of component A and component B satisfy the following conditions: the particle size of wollastonite is 5-20 μm, and the aspect ratio of wollastonite is 10:1-30:1; and the mica powder includes mica powder 1 and mica powder 2, the mass ratio of mica powder 1 and mica powder 2 is 1:1-3:1, the particle size of mica powder 1 is 15-30 μm, and the particle size of mica powder 2 is 1-10 μm; and the glass powder includes glass powder 1 and glass powder 2, the mass ratio of glass powder 1 and glass powder 2 is 3:1-6:1, the particle size of glass powder 1 is 1-5 μm, the particle size of glass powder 2 is 15-30 μm, the melting point of glass powder 1 is 380-450℃, and the melting point of glass powder 2 is 500-600℃.

[0089] When the preparation steps of component A and component B of this invention meet four conditions, that is, when the preparation steps of component A and component B of this invention meet all the above conditions, the preparation steps of component A and component B satisfy the following: the particle size of wollastonite is 5-20 μm, and the aspect ratio of wollastonite is 10:1-30:1; the mica powder includes mica powder 1 and mica powder 2, the mass ratio of mica powder 1 and mica powder 2 is 1:1-3:1, the particle size of mica powder 1 is 15-30 μm, and the particle size of mica powder 2 is 15-30 μm. ~10μm; glass powder includes glass powder 1 and glass powder 2, with a mass ratio of glass powder 1 to glass powder 2 of 3:1 to 6:1, the particle size of glass powder 1 is 1 to 5μm, and the particle size of glass powder 2 is 15 to 30μm; hollow glass microspheres include hollow glass microspheres 1 and hollow glass microspheres 2, with a mass ratio of hollow glass microspheres 1 to hollow glass microspheres 2 of 3:1 to 6:1, the particle size of hollow glass microspheres 1 is 30 to 60μm, and the particle size of hollow glass microspheres 2 is 5 to 20μm.

[0090] By controlling the proportions of different particle sizes, structures, and melting points of wollastonite, mica powder, hollow glass microspheres, and glass powder in the preparation steps of component A and component B, the prepared heat-insulating coating exhibits a densely packed structure in three-dimensional space, forming a compact heat-insulating layer and significantly enhancing its heat insulation capacity. Simultaneously, with the same powder addition ratio, the preparation method of this invention yields components A and B with the lowest viscosity, facilitating spraying, mixing, and other processing operations to obtain the organosilicon heat-insulating coating. The preparation process is simple and improves production efficiency.

[0091] The inventors also discovered that the powder readily forms hydrogen bonds with vinyl silicone oil and phenyl vinyl silicone rubber, resulting in high viscosity of components A and B, making spraying impossible and increasing the difficulty of coating preparation. Therefore, the inventors controlled the modification of the powder before the preparation of components A and B, thereby reducing the viscosity of components A and B while improving the dispersibility of the powder in vinyl silicone oil and phenyl vinyl silicone rubber, and enhancing the adhesion between the powder and vinyl silicone oil and phenyl vinyl silicone rubber. Specifically, the modification of powdered wollastonite, mica powder 1, mica powder 2, glass powder 1, glass powder 2, nano-expanded graphite, nano-titanium dioxide, and nano-aluminum hydroxide includes the following steps:

[0092] (1) A mixture of silane coupling agent, water, ethanol, and 5 wt% ammonia in a mass ratio of 1:3:6:1 was obtained. Thus, by adjusting the pH of the hydrolysis environment to a weakly alkaline state with water and ammonia, ethanol accelerates the hydrolysis of the silane coupling agent to form silanol groups with active groups under the above hydrolysis environment.

[0093] (2) Mix 5-15 parts of wollastonite, 2-8 parts of mica powder 1, 1-4 parts of mica powder 2, 5-10 parts of glass powder 1, 1-4 parts of glass powder 2, 0.5-2 parts of nano-expanded graphite, 5-15 parts of nano-titanium dioxide, and 5-15 parts of nano-aluminum hydroxide. After mixing, add the powder to the barrel of an air jet mill and start the air jet mill. Specifically, mix at a speed of 300-600 rpm for 10-30 minutes. Using an air jet mill results in more uniform mixing and simplifies the process.

[0094] (3) The mixture from step (1) is added to the atomizer of the air jet mill for atomized feeding. After atomization feeding for 20-40 minutes, the powder and the mixture are mixed for 50-80 minutes at a temperature of 60-80°C. Then, the mixture is dried at a temperature of 90-120°C and cooled to obtain modified 5-15 parts of wollastonite, 2-8 parts of mica powder 1, 1-4 parts of mica powder 2, 5-10 parts of glass powder 1, 1-4 parts of glass powder 2, 0.5-2 parts of nano-expanded graphite, 5-15 parts of nano-titanium dioxide, and 5-15 parts of nano-aluminum hydroxide powder. Since the silane coupling agent in the mixture has been hydrolyzed, it can fully contact the powder through atomized feeding, maximizing the reaction with the exposed hydroxyl groups on the powder surface. This reduces the viscous effect of the powder and enhances the dispersibility of the powder in vinyl silicone oil and phenyl vinyl silicone rubber.

[0095] Furthermore, the modification of the powder through the above steps also improves the adhesion between the powder and vinyl silicone oil and phenyl vinyl silicone rubber.

[0096] Furthermore, the preparation method of the organosilicon heat-insulating coating includes the following steps:

[0097] Powder modification: A mixture of silane coupling agent, water, ethanol, and 5 wt% ammonia is prepared. By mass, 5-15 parts of wollastonite, 2-8 parts of mica powder 1, 1-4 parts of mica powder 2, 5-10 parts of glass powder 1, 1-4 parts of glass powder 2, 0.5-2 parts of nano-expanded graphite, 5-15 parts of nano-titanium dioxide, and 5-15 parts of nano-aluminum hydroxide are mixed and added to the mixture of silane coupling agent, water, ethanol, and 5 wt% ammonia. The mixture is then mixed using an air jet mill to obtain modified powder consisting of 5-15 parts wollastonite, 2-8 parts of mica powder 1, 1-4 parts of mica powder 2, 5-10 parts of glass powder 1, 1-4 parts of glass powder 2, 0.5-2 parts of nano-expanded graphite, 5-15 parts of nano-titanium dioxide, and 5-15 parts of nano-aluminum hydroxide.

[0098] Preparation of Component A: By mass, 10-20 parts of vinyl silicone oil 1, 10-20 parts of vinyl silicone oil 2 and 10-20 parts of phenyl vinyl silicone rubber were mixed, and then 5-15 parts of modified wollastonite, 2-8 parts of mica powder 1, 1-4 parts of mica powder 2, 5-10 parts of glass powder 1, 1-4 parts of glass powder 2, 0.5-2 parts of nano-expanded graphite, 5-15 parts of nano-titanium dioxide and 5-15 parts of nano-aluminum hydroxide powder were added and mixed. The mixture was heated to dehydrate, and after cooling to stop dehydration, 1-10 parts of hydrogen-containing silicone oil and 0.1-1 parts of inhibitor were added and mixed at a constant temperature. Then, 5-10 parts of hollow glass microspheres 1, 1-5 parts of hollow glass microspheres 2, 0.05-1 parts of iron oxide red and 1-10 parts of PCL phase change material were added and mixed to obtain Component A. The modified powder is mixed and then heated to 100-110℃ for dehydration. After cooling to 40-50℃ to stop dehydration, 1-10 parts of hydrogen-containing silicone oil and 0.1-1 parts of inhibitor are added at a constant temperature of 40-50℃. This process helps to improve the dispersibility of the powder and control the viscosity of component A.

[0099] Preparation of Component B: By mass, 10-30 parts of vinyl silicone oil 1, 10-20 parts of vinyl silicone oil 2 and 10-15 parts of phenyl vinyl silicone rubber were mixed, and then 5-15 parts of modified wollastonite, 2-8 parts of mica powder 1, 1-4 parts of mica powder 2, 5-10 parts of glass powder 1, 1-4 parts of glass powder 2, 0.5-2 parts of nano-expanded graphite, 5-15 parts of nano-titanium dioxide and 5-15 parts of nano-aluminum hydroxide powder were added and mixed. Then 5-10 parts of hollow glass microspheres 1 and 1-5 parts of hollow glass microspheres 2 were added and mixed. The mixture was heated and dehydrated. After cooling and stopping the dehydration, 1-10 parts of PCL phase change material were added and mixed at a constant temperature. Finally, 0.1-1 parts of catalyst were added and mixed to obtain Component B. Among them, heating and dehydration means heating to 100-110℃ for dehydration, cooling and stopping dehydration means cooling to 40-50℃ to stop dehydration, and then maintaining a constant temperature of 40-50℃.

[0100] Preparation of silicone thermal insulation coating: After mixing components A and B, the mixture is sprayed or scraped onto the surface of the template and cured to obtain the target silicone thermal insulation coating. Curing is performed by drying at room temperature for 22–26 hours, or by curing at a temperature of 60–70℃ for 3–5 hours.

[0101] In the preparation steps of component A and component B, the expanded graphite nanoparticles undergo an insulating coating process before the preparation steps of component A and component B; the PCL phase change material is one or more of higher aliphatic hydrocarbons, fatty acids, and fatty acid esters.

[0102] Specifically, in the preparation process of components A and B, the present invention first adds wollastonite, glass powder, mica powder, nano titanium dioxide, modified nano expanded graphite, and nano aluminum hydroxide powder to a modification device and mixes them evenly. Then, the modification is performed. Finally, a mixture of vinyl silicone oil and phenyl vinyl silicone rubber is added in batches. After good dispersion, the final hollow glass microspheres, PCL phase change material, and iron oxide red are added at a lower speed and dispersed. By adding the powders in batches, the present invention avoids the problem of uneven dispersion of powders when added all at once due to the high proportion of powders in components A and B. Secondly, the hollow glass microspheres in the powder have limited compressive strength, and their hollow structure will be destroyed at high speeds, leading to a rapid increase in the viscosity of the coating and a significant decrease in its heat insulation effect. Therefore, they are added last, and the speed is reduced for dispersion to ensure that the hollow structure is not destroyed. Furthermore, the invention avoids the problem of rapid temperature rise during stirring when adding all at once, which is not conducive to temperature control and easily leads to gelation.

[0103] The preparation method of this invention obtains an organosilicon heat-insulating coating with both high temperature resistance and heat insulation properties through the cooperation of the above steps, and has good insulation properties, which can be used in the battery field.

[0104] The preparation method of the organosilicon heat-insulating coating of the present invention will be described in further detail below.

[0105] Example 1

[0106] a. Powder modification

[0107] (1) Mix silane coupling agent XA-560, water, ethanol and 5wt% ammonia in a mass ratio of 1:3:6:1 and stir for 1 hour. The silane coupling agent is 1 part by mass. The mixture of silane coupling agent, water, ethanol and 5wt% ammonia is obtained.

[0108] (2) Add 10-12 parts of wollastonite, 5 parts of mica powder 1, 1.5 parts of mica powder 2, 6 parts of glass powder 1, 1.4 parts of glass powder 2, 0.8 parts of nano-expanded graphite, 5-15 parts of nano-titanium dioxide and 10 parts of nano-aluminum hydroxide to a high-speed disperser for mixing; mix at a speed of 500 rpm / min for 15 min, then add the mixed powder to the barrel of the air jet mill and start the air jet mill.

[0109] (3) Add the mixture from step (1) into the atomizer of the air jet mill for atomization feeding. After atomization feeding time of 30 min, mix the powder and the mixture for 60 min at a mixing temperature of 60-80℃. Then dry at a drying temperature of 100℃ and cool down to obtain 10-12 parts of modified wollastonite, 5 parts of mica powder 1, 1.5 parts of mica powder 2, 6 parts of glass powder 1, 1.4 parts of glass powder 2, 0.8 parts of nano-expanded graphite, 5-15 parts of nano-titanium dioxide and 10 parts of nano-aluminum hydroxide powder.

[0110] bA component preparation

[0111] By weight, 15 parts of vinyl silicone oil 1, 10 parts of vinyl silicone oil 2, and 15 parts of phenyl vinyl silicone rubber powder were mixed in a double-star mixer. The rotation speed was set to 2000 rpm and the revolution speed to 300 rpm, and the mixing time was 5 minutes. Then, 10 parts of modified wollastonite, 5 parts of mica powder 1, 1.5 parts of mica powder 2, 6 parts of glass powder 1, 1.4 parts of glass powder 2, 0.8 parts of nano-expanded graphite, 5-15 parts of nano-titanium dioxide, and 10 parts of nano-aluminum hydroxide powder were added to the double-star mixer in 4 batches, and the mixture was stirred for 10 minutes after each batch was added. After all the modified powders were added and stirring was maintained, the temperature was raised to 105°C, and vacuum was turned on for dehydration for 1 hour. While maintaining vacuum dehydration, the circulating cooling water was turned on to cool down the temperature to 40°C, and then the vacuum was turned off. Then, at a constant temperature of 40℃, add 7 parts of hydrogen-containing silicone oil (hydrogen content of 0.5% to 2.5%) and 0.2 parts of inhibitor and stir for 10 minutes. Then, add 7.5 parts of hollow glass microsphere 1, 2 parts of hollow glass microsphere 2, 0.1 parts of iron oxide red and 7.5 parts of PCL phase change material and stir for 10 minutes. Turn off the circulating cooling water and turn off the rotation and revolution stirring to obtain component A.

[0112] cB component preparation

[0113] By weight, 25 parts of vinyl silicone oil 1, 10 parts of vinyl silicone oil 2, and 10 parts of phenyl vinyl silicone rubber were mixed in a double-star mixer at a rotation speed of 2000 rpm and a revolution speed of 300 rpm for 5 minutes. Then, 12 parts of modified wollastonite, 5 parts of mica powder 1, 1.5 parts of mica powder 2, 6 parts of glass powder 1, 1.4 parts of glass powder 2, 0.8 parts of nano-expanded graphite, 5-15 parts of nano-titanium dioxide, and 10 parts of nano-aluminum hydroxide powder were added to the double-star mixer in four batches, mixing for 10 minutes after each batch. Next, 7.5 parts of hollow glass microspheres 1 and 2 parts of hollow glass microspheres 2 were added and mixed. The mixture was heated to 105°C, and vacuum dehydration was performed simultaneously for 1 hour. While maintaining vacuum dehydration, circulating cooling water was turned on to cool the mixture down to 40°C before turning off the vacuum. Then, 7.3 parts of PCL phase change material were added at a constant temperature of 40℃ and stirred for 10 min. Then, 0.5 parts of platinum catalyst with a concentration of 1000 ppm were added and stirred for 10 min to obtain component B.

[0114] d. Example 1: Preparation of Organosilicon Thermal Insulation Coating

[0115] Weigh 30g-50g of the prepared component A into a beaker, then add 30g-50g of component B to the beaker, with a mass ratio of component A to component B of 100:100. Stir and mix at 2000 rpm for 30 seconds. Apply the mixed components A and B to a 1mm thick aluminum plate by scraping or spraying, and dry at room temperature for 24 hours or at 60°C for 4 hours until fully cured to obtain the silicone thermal insulation coating of Example 1.

[0116] In the preparation steps of component A and component B, the vinyl silicone oil includes vinyl silicone oil 1 and vinyl silicone oil 2. The viscosity of vinyl silicone oil 1 is 2000-5000 mPa·s, and the viscosity of vinyl silicone oil 2 is 8000-200000 mPa·s. The vinyl content of the vinyl silicone oil is 0.03%-2.3% by mass. The viscosity of the phenyl vinyl silicone rubber is 6000-200000 mPa·s, and the vinyl content of the phenyl vinyl silicone rubber is 0.1%-0.75% by mass, and the molar content of phenyl is 3%-25%.

[0117] The formulation of the silicone thermal insulation coating in Example 1 is shown in Table 1.

[0118] Table 1. Formulation of the silicone thermal insulation coating in Example 1

[0119] Vinyl silicone oil 1 15 25 Vinyl silicone oil 2 10 10 Hydrogen-containing silicone oil 7 0 Phenyl vinyl silicone rubber 15 10 Hollow glass microspheres 1 7.5 7.5 Hollow glass microspheres 2 2 2 Nano-expanded graphite 0.8 0.8 Nano aluminum hydroxide 10 10 Nano titanium dioxide 10 10 Glass powder 1 6 6 Glass powder 2 1.4 1.4 Mica Powder 1 (Sericite) 5 5 Mica Powder 2 (Sericite) 1.5 1.5 Wollastonite 10 12 Iron oxide red 0.1 0 Silane coupling agent 1 0.5 0.5 Silane coupling agent 2 0.5 0.5 PCL phase change material 7.5 7.3 Inhibitors 0.2 0 catalyst 0 0.5 total 110 110

[0120] The formulation of the silicone thermal insulation coating in Example 2 is shown in Table 1.

[0121] The difference between Example 2 and Example 1 is that in the formulation of Example 2, both component A and component B contain only one type of glass powder 2, and glass powder 1 is not added. The formulation of Example 2 is shown in Table 2.

[0122] Table 2. Formulation of silicone thermal insulation coating in Example 2

[0123] Vinyl silicone oil 1 15 25 Vinyl silicone oil 2 10 10 Hydrogen-containing silicone oil 7 0 Phenyl vinyl silicone rubber 15 10 Hollow glass microspheres 1 7.5 7.5 Hollow glass microspheres 2 2 2 Nano-expanded graphite 0.8 0.8 Nano aluminum hydroxide 10 10 Nano titanium dioxide 10 10 Glass powder 1 0 0 Glass powder 2 7.4 7.4 Mica Powder 1 (Sericite) 5 5 Mica Powder 2 (Sericite) 1.5 1.5 Wollastonite 10 12 Iron oxide red 0.1 0 Silane coupling agent 1 0.5 0.5 Silane coupling agent 2 0.5 0.5 PCL phase change material 7.5 7.3 Inhibitors 0.2 0 catalyst 0 0.5 total 110 110

[0124] Comparative Example 1

[0125] The difference between Comparative Example 1 and Example 1 is that component A in the formulation of Comparative Example 1 does not contain hollow glass microspheres 2, mica powder 2, glass powder 2, and nano-expanded graphite, and component B does not contain hollow glass microspheres 2, mica powder 2, glass powder 2, and nano-expanded graphite. Therefore, Comparative Example 1 cannot control the different particle size combinations of different powders. The formulation of Comparative Example 1 is shown in Table 3.

[0126] Table 3. Formulation of silicone thermal insulation coating for Comparative Example 1

[0127] Vinyl silicone oil 1 15 25 Vinyl silicone oil 2 10 10 Hydrogen-containing silicone oil 7 0 Phenyl vinyl silicone rubber 15 10 Hollow glass microspheres 1 9.5 9.5 Nano aluminum hydroxide 10.8 10.8 Nano titanium dioxide 10 10 Glass powder 1 7.4 7.4 Mica Powder 1 (Sericite) 6.5 6.5 Wollastonite 10 12 Iron oxide red 0.1 0 Silane coupling agent 1 0.5 0.5 Silane coupling agent 2 0.5 0.5 PCL phase change material 7.5 7.3 Inhibitors 0.2 0 catalyst 0 0.5 total 110 110

[0128] Comparative Example 2

[0129] The difference between Comparative Example 2 and Example 1 is that component A and component B in the formulation of Comparative Example 2 do not contain PCL phase change material. The formulation of Comparative Example 2 is shown in Table 4.

[0130] Table 4. Formulation of silicone thermal insulation coating in Comparative Example 2

[0131] Vinyl silicone oil 1 15 25 Vinyl silicone oil 2 10 10 Hydrogen-containing silicone oil 7 0 Phenyl vinyl silicone rubber 15 10 Hollow glass microspheres 1 7.5 7.5 Hollow glass microspheres 2 2 2 Nano-expanded graphite 0.8 0.8 Nano aluminum hydroxide 10 10 Nano titanium dioxide 10 10 Glass powder 1 6 6 Glass powder 2 1.4 1.4 Mica Powder 1 (Sericite) 5 5 Mica Powder 2 (Sericite) 1.5 1.5 Wollastonite 10 12 Iron oxide red 0.1 0 Silane coupling agent 1 0.5 0.5 Silane coupling agent 2 0.5 0.5 Inhibitors 0.2 0 catalyst 0 0.5 total 102.5 102.5

[0132] Comparative Example 3

[0133] Purchased commercially available water-based epoxy fireproof coating for steel structures.

[0134] Comparative Example 4

[0135] Purchased commercially available aerogel thermal insulation coating.

[0136] Shear strength, density, thermal conductivity, volume shrinkage, ceramic formation, back surface temperature T1 and temperature rise curve, and insulation resistance were tested for different embodiments and comparative examples. Specific test methods and standards for different test items are shown in Table 5. The measurement results are shown in Table 6.

[0137] Table 5. Test methods and standards for different test items

[0138]

[0139] Table 6. Measurement results of the examples and comparative examples

[0140]

[0141] As shown in Table 6, the specifics are as follows:

[0142] The embodiments of the present invention exhibit good insulation properties, shear strength, and volume shrinkage rate, with a density of 1.0–1.50 g / cm³. 3Among them, compared with Examples 2, 1, 2, and 3, Example 1 has the lowest thermal conductivity. This is because in Example 1, the gaps between the raw materials are filled by small-diameter powder particles through the matching of particle sizes of hollow glass microspheres, mica powder, and glass powder. In Comparative Example 1, the gaps between the powder particles are filled with silicone resin, and the intrinsic thermal conductivity of silicone resin is about 0.1 W / m·K, which is much higher than the thermal conductivity of hollow glass microspheres (0.04 W / m·K). Therefore, the thermal conductivity of Comparative Example 1 is higher than that of Example 1. The formulations of Example 1 and Example 2 differ in the glass powder used. Because Example 1 uses glass powder 1 with a smaller particle size, the intrinsic thermal conductivity of glass powder 2 is slightly higher than that of glass powder 1. Therefore, Example 1 has a lower thermal conductivity and better thermal insulation performance than Example 2. Compared to Comparative Example 2, Example 1, due to the addition of PCL phase change material in its formulation, absorbed some heat during the thermal conductivity test, preventing a temperature increase in the test sample. Therefore, its measured thermal conductivity was lower than that of Comparative Example 2. Furthermore, Example 1, through the combination of different powder particle sizes and the addition of phase change heat-absorbing material, reduced the heat conduction path of the coating to a certain extent, resulting in better thermal insulation performance. In conjunction with... Figure 1 As shown, the blank iron plate serves as a blank control group. It can be seen that the thermal insulation temperature difference of Example 1 of the present invention is greater than that of Comparative Examples 1-4. In other words, Example 1 of the present invention has better thermal insulation performance than Comparative Examples 1-4.

[0143] Comparative Example 3 is a purchased water-based epoxy fireproof coating for steel structures. It involves adding powder fillers to an organosilicon resin system and then curing it onto fiberglass cloth. Since there's no need to consider the adhesion between the insulation pad and the substrate, it can be applied to the substrate surface via adhesive, allowing for a higher proportion of insulation fillers. Because it uses fiberglass cloth reinforcement, its tensile strength and other mechanical properties are higher than those of Example 1, Comparative Example 1, and Comparative Example 2. However, due to the high thermal conductivity of fiberglass itself, Comparative Example 3 has the highest overall thermal conductivity. Despite this, thanks to its good mechanical strength and the extremely high content of insulation fillers in the powder filler, and considering that the back surface temperature T1 of Comparative Example 2 is lower than that of Comparative Example 1 and the insulation temperature difference is higher, its overall insulation effect is better than Comparative Example 1, but still far inferior to Example 1 of this invention.

[0144] Comparative Example 4 is a purchased aerogel thermal insulation coating, which is currently a highly regarded thermal insulation coating on the market. Its composition consists of a large amount of aerogel powder in the film-forming layer, supplemented by a small amount of additives to disperse the aerogel powder. Water is generally added as a dispersant to reduce viscosity. Its film-forming substance is an inorganic silicate sol, which, after curing, is an inorganic phase, thus exhibiting good flame impact resistance. After high-temperature impact, it shows almost no change in morphology or size. Due to the large amount of aerogel powder added, it also possesses good thermal insulation performance. Compared with Example 1, its disadvantages are as follows:

[0145] (1) Comparative Example 4 is an inorganic system. After curing, it is hard and brittle, without toughness and resilience. When used between battery cells, the assembly force between the battery cells will cause the coating to crack. After cracking, a large amount of heat will be transferred from the cracks, affecting the heat insulation effect.

[0146] (2) Because water is added as a dispersant, the curing speed is slow, and surface cracking is likely to occur when curing at high temperature.

[0147] (3) The thermal conductivity of Comparative Example 4 is significantly smaller than that of Example 1, only 0.086 W / m·K. However, judging from the back temperature T1 measured in the experiment, its heat insulation effect is not as good as that of Example 1. The heat insulation temperature difference at 900℃ is only 739℃, which is lower than 758℃ of Example 1.

[0148] From the above three points, it can be seen that Example 1 and Example 2 have better performance than Comparative Example 4 under the condition of thermal insulation between battery cells.

[0149] While the present invention has been illustrated and described with reference to certain preferred embodiments, those skilled in the art should understand that the above description is a further detailed explanation of the invention in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of the invention to these descriptions. Various changes in form and detail can be made by those skilled in the art, including several simple deductions or substitutions, without departing from the spirit and scope of the invention.

Claims

1. An organosilicon heat-insulating coating, characterized in that, Includes component A and component B; By weight, component A comprises: 20-40 parts vinyl silicone oil, 10-20 parts phenyl vinyl silicone rubber, 5-15 parts wollastonite, 2-8 parts mica powder, 5-10 parts glass powder, 0.5-2 parts nano-expanded graphite, 1-15 parts hollow glass microspheres, 1-10 parts hydrogen-containing silicone oil, 0.1-1 parts inhibitor, and 1-10 parts phase change material; By weight, component B comprises: 20-50 parts vinyl silicone oil, 10-15 parts phenyl vinyl silicone rubber, 5-15 parts wollastonite, 2-8 parts mica powder, 5-10 parts glass powder, 0.5-2 parts nano-expanded graphite, 1-15 parts hollow glass microspheres, 0.1-1 parts catalyst, and 1-10 parts phase change material. The wollastonite has a particle size of 5~20 μm and an aspect ratio of 10:1~30:

1. The mica powder includes mica powder 1 and mica powder 2, the mass ratio of mica powder 1 to mica powder 2 is 1:1 to 3:1, the particle size of mica powder 1 is 15 to 30 μm, and the particle size of mica powder 2 is 1 to 10 μm. The glass powder includes glass powder 1 and glass powder 2, the mass ratio of glass powder 1 to glass powder 2 is 3:1 to 6:1, the particle size of glass powder 1 is 1 to 5 μm, and the particle size of glass powder 2 is 15 to 30 μm. The hollow glass microspheres include hollow glass microsphere 1 and hollow glass microsphere 2, the mass ratio of hollow glass microsphere 1 to hollow glass microsphere 2 is 3:1 to 6:1, the particle size of hollow glass microsphere 1 is 30 to 60 μm, and the particle size of hollow glass microsphere 2 is 5 to 20 μm. The nano-expanded graphite in components A and B has an insulating layer on its surface; the phase change material is one or more of higher aliphatic hydrocarbons, fatty acids and fatty acid esters.

2. The organosilicon heat-insulating coating as described in claim 1, characterized in that, By weight, component A further includes 5-15 parts of nano titanium dioxide and 5-15 parts of nano aluminum hydroxide, and component B further includes 5-15 parts of nano titanium dioxide and 5-15 parts of nano aluminum hydroxide.

3. The organosilicon heat-insulating coating as described in claim 2, characterized in that, By weight, component A further comprises: 0.1 to 1.5 parts of silane coupling agent and 0.05 to 1 part of iron oxide red; component B further comprises: 0.1 to 1.5 parts of silane coupling agent.

4. The organosilicon heat-insulating coating as described in claim 1, characterized in that, In component A, the particle size of the expanded nano-graphite is 600~900 nm; in component B, the particle size of the expanded nano-graphite is 600~900 nm; the particle sizes of the expanded nano-graphite in components A and B are equal.

5. The organosilicon heat-insulating coating as described in claim 1, characterized in that, Of components A and B, the melting point of glass powder 1 is 380~450℃, and the melting point of glass powder 2 is 500~600℃.

6. The organosilicon heat-insulating coating as described in claim 1, characterized in that, Of the components A and B The vinyl silicone oil comprises vinyl silicone oil 1 and vinyl silicone oil 2, wherein the viscosity of vinyl silicone oil 1 is 2000~5000 mPa·s, and the viscosity of vinyl silicone oil 2 is 8000~200000 mPa·s; the vinyl content of the vinyl silicone oil is 0.03%~2.3% by mass; by mass, component A comprises 10~20 parts of vinyl silicone oil 1 and 10~20 parts of vinyl silicone oil 2, and component B comprises 10~30 parts of vinyl silicone oil 1 and 10~20 parts of vinyl silicone oil 2; The viscosity of the phenyl vinyl silicone rubber is 6000~200000 mPa·s, the mass content of vinyl in the phenyl vinyl silicone rubber is 0.1%~0.75%, the molar content of phenyl is 3%~25%, and the mass content of the phenyl vinyl silicone rubber in component A and / or component B is 10%-15%. The hydrogen content in the hydrogen-containing silicone oil is 0.5wt%~2.5wt%.

7. The method for preparing the organosilicon heat-insulating coating according to any one of claims 1-6, characterized in that, Includes the following steps: Preparation of Component A: By weight, 20-40 parts of vinyl silicone oil powder, 10-20 parts of phenyl vinyl silicone rubber, 5-15 parts of wollastonite, 2-8 parts of mica powder, 5-10 parts of glass powder, 0.5-2 parts of nano-expanded graphite, 1-15 parts of hollow glass microspheres, 1-10 parts of hydrogen-containing silicone oil, 0.1-1 parts of inhibitor and 1-10 parts of phase change material are mixed to obtain Component A; Preparation of Component B: By weight, 20-50 parts of vinyl silicone oil powder, 10-15 parts of phenyl vinyl silicone rubber, 5-15 parts of wollastonite, 2-8 parts of mica powder, 5-10 parts of glass powder, 0.5-2 parts of nano-expanded graphite, 1-15 parts of hollow glass microspheres, 0.1-1 parts of catalyst and 1-10 parts of phase change material are mixed to obtain Component B; Preparation of silicone thermal insulation coating: The A component and the B component are mixed and cured to obtain the target silicone thermal insulation coating; In the preparation steps of component A and component B, the expanded graphite nanoparticles are further subjected to an insulating coating treatment before the preparation steps of component A and component B; the phase change material is one or more of higher aliphatic hydrocarbons, fatty acids and fatty acid esters.

8. The method for preparing the organosilicon heat-insulating coating as described in claim 7, characterized in that, The melting point of glass powder 1 is 380~450℃, and the melting point of glass powder 2 is 500~600℃.

9. The method for preparing the organosilicon heat-insulating coating as described in claim 8, characterized in that, Includes the following steps: Powder modification: A mixture of silane coupling agent, water, ethanol, and 5 wt% ammonia is prepared. Then, by mass, 5-15 parts of wollastonite, 2-8 parts of mica powder 1, 1-4 parts of mica powder 2, 5-10 parts of glass powder 1, 1-4 parts of glass powder 2, 0.5-2 parts of nano-expanded graphite, 5-15 parts of nano-titanium dioxide, and 5-15 parts of nano-aluminum hydroxide are mixed and added to the mixture of silane coupling agent, water, ethanol, and 5 wt% ammonia. The mixture is then mixed using an air jet mill to obtain modified powder consisting of 5-15 parts wollastonite, 2-8 parts of mica powder 1, 1-4 parts of mica powder 2, 5-10 parts of glass powder 1, 1-4 parts of glass powder 2, 0.5-2 parts of nano-expanded graphite, 5-15 parts of nano-titanium dioxide, and 5-15 parts of nano-aluminum hydroxide. Preparation of Component A: By mass, 10-20 parts of vinyl silicone oil 1, 10-20 parts of vinyl silicone oil 2 and 10-20 parts of phenyl vinyl silicone rubber were mixed, and then 5-15 parts of the modified wollastonite, 2-8 parts of mica powder 1, 1-4 parts of mica powder 2, 5-10 parts of glass powder 1, 1-4 parts of glass powder 2, 0.5-2 parts of nano-expanded graphite, 5-15 parts of nano-titanium dioxide and 5-15 parts of nano-aluminum hydroxide powder were added and mixed. The mixture was heated to dehydrate, and after cooling to stop dehydration, 1-10 parts of hydrogen-containing silicone oil and 0.1-1 parts of inhibitor were added and mixed at a constant temperature. Then, 5-10 parts of hollow glass microspheres 1, 1-5 parts of hollow glass microspheres 2, 0.05-1 parts of iron oxide red and 1-10 parts of phase change material were added and mixed to obtain Component A. Preparation of Component B: By mass, 10-30 parts of vinyl silicone oil 1, 10-20 parts of vinyl silicone oil 2 and 10-15 parts of phenyl vinyl silicone rubber were mixed, and then 5-15 parts of the modified wollastonite, 2-8 parts of mica powder 1, 1-4 parts of mica powder 2, 5-10 parts of glass powder 1, 1-4 parts of glass powder 2, 0.5-2 parts of nano-expanded graphite, 5-15 parts of nano-titanium dioxide and 5-15 parts of nano-aluminum hydroxide powder were added and mixed. Then 5-10 parts of hollow glass microspheres 1 and 1-5 parts of hollow glass microspheres 2 were added and mixed. The mixture was heated and dehydrated. After cooling and stopping the dehydration, 1-10 parts of phase change material were added at a constant temperature and mixed. Then 0.1-1 parts of catalyst were added and mixed to obtain Component B. Preparation of silicone thermal insulation coating: After mixing the components A and B, the mixture is sprayed onto the surface of the template and cured to obtain the target silicone thermal insulation coating; In the preparation steps of component A and component B, the expanded graphite nanoparticles are further subjected to an insulating coating treatment before the preparation steps of component A and component B; the phase change material is one or more of higher aliphatic hydrocarbons, fatty acids and fatty acid esters.

Images