Heat insulation coating fabric is a fabric that has a heat-insulating coating applied to its surface. By blocking, reflecting or radiating solar energy, it aims to lower the temperature inside the covered area of the fabric and reduce energy consumption. It has broad application prospects in the textile industry. 

The fabric insulation coating is classified into three types based on its insulation mechanism: barrier type, reflection type, and radiation type. The barrier type insulation coating is a passive cooling coating that achieves insulation through the impedance effect of heat transfer. Its insulation mechanism is relatively simple. Generally, low thermal conductivity compositions are used or air with extremely low thermal conductivity is introduced into the coating to achieve good insulation effects. It usually has the characteristics of a relatively small bulk density, low thermal conductivity, and small dielectric constant. The reflection type insulation coating isolates solar energy through reflection. Common reflection materials include ceramic micro-powders, aluminum powder, titanium dioxide, and ATO (selenium doped tin oxide) powders. 

The common barrier-type fabric insulation coating agents, based on their chemical structures, mainly include polyvinyl chloride (PVC), polyacrylate (PA), polyurethane (PU), organosilicon, rubber emulsion, and polytetrafluoroethylene (PTFE), among others. Among them, PA and PU types are more commonly used; according to the medium they are used with, they can be divided into solvent-based and water-dispersible types. 
SiO2 aerogel, as an amorphous nano-porous material, has a controllable structure and a continuous three-dimensional network structure. Its density can be adjusted within the range of 3 to 500 mg/cm³, making it the material with the lowest density in the world. The porosity can reach 80% to 99.8%, and the pore size ranges from 1 to 100 nm. The specific surface area can be as high as 1000 m²/g. Due to its unique nano-porous structure, its thermal conductivity is extremely low. At room temperature and normal pressure, the thermal conductivity is as low as 0.017 W/(m·K), making it the material with the lowest thermal conductivity known so far. Because the structural units that form the aerogel framework are smaller than the visible light wavelength, it also has good light transmission performance. Moreover, it is an inorganic material and has non-flammable or flame-retardant properties, which makes it have broad application prospects in the field of heat insulation and preservation. 

According to statistics, the global market for aerogels has experienced a compound annual growth rate of 36.4% in recent years, while the compound annual growth rate of the domestic aerogel market has reached as high as 61.1%. Its application in thermal insulation fabrics not only reduces the weight of thermal protection clothing, making it lighter and thinner, but also significantly reduces the working wear and tear during use. 

For example, SiO2 aerogel can be added to PA or PU type adhesives in a certain proportion to prepare a thermal insulation coating agent. This agent can be directly applied to cotton fabrics, and then through processes such as drying and baking, the SiO2 aerogel thermal insulation coated fabric can be produced. Compared with the original fabric, the thermal insulation performance of the coated fabric with SiO2 aerogel is significantly improved. Moreover, when the amount of aerogel added to the coating agent is less than 10%, the thermal insulation effect of the fabric gradually improves as the amount of SiO2 aerogel added increases. 
In addition, glass fiber SiO2 aerogel sheets can also be selected as the insulation layer material for the fabric. Its thermal protection performance exceeds 60, and it can withstand a 450℃ high-temperature flame for 50 seconds, significantly enhancing the thermal protection performance of the fabric and enabling it to withstand sudden high temperatures encountered in firefighting and emergency rescue operations. 

SiO2 aerogel possesses characteristics such as high porosity and low thermal conductivity, making it a new type of super-insulating material. However, the flexibility and integrity of SiO2 aerogel are poor, and the aerogel prepared by drying at room temperature often shows a rapid increase in thermal conductivity when heated, which significantly limits the application of SiO2 aerogel. In recent years, SiO2 aerogel composite insulation materials prepared by in-situ sol-gel method and compression molding have improved its toughness, integrity and high-temperature insulation performance to a certain extent, making it possible to use SiO2 aerogel as a standalone block insulation material.