Current situation and future development direction

Current situation and future development direction of aerogel gel thermal insulation coating

current situation and future development direction of aerogel gel thermal insulation coating

May 26, 2020

aerogel gel is a porous material with gas filled internal network structure and extremely low solid density on the surface. Its complex structure is generally composed of cross-linked nanoparticles, in which the pores inside the particles are mainly micropores, and the pores between particles are mostly mesopores or macropores at 2 nm. Because of its extremely low density (3kg/m3), it has won the title of "the lightest solid in the world" in the Guinness Book of records. As a new solid material with nano porous structure, aerogel has excellent characteristics such as ultra light, heat insulation, transparency, heat preservation, fire prevention and so on

classification from component composition is the most common way to distinguish aerogel gel, which is divided into single component and composite component. Single component aerogels include oxide aerogels gel (silica and non silica), organic aerogels gel (resin based and fiber based), carbon aerogels gel (carbonized plastics, carbon nanotubes and graphene), sulfide aerogels gel and other kinds of aerogels (single elements, carbides); Composite aerogels include multi-component gel, gradient aerogels and micro/nano aerogel gel composites. Among them, silicon aerogel, carbon aerogel and silicon dioxide aerogel gel are the most common

silica aerogel has the characteristics of low density, high specific surface area and high porosity due to its unique micro nano structure. These characteristics make it have unique excellent properties in thermal, optical, electrical, acoustic and other aspects. It can be used as high-efficiency heat insulation materials, acoustic impedance coupling materials, low dielectric insulation materials, catalysts and catalyst carriers, among which high-efficiency heat insulation materials are widely used. There are four main application forms of silica aerogel in the field of thermal insulation: aerogel gel powder/particle; Aerogel gel felt; Aerogel plate; Aerogel gel glass, in which the coating industry mainly prepares aerogel coatings on the basis of aerogel gel powder

composition and performance

for example, the cleaning room aerogel thermal insulation coating is prepared with the self crosslinking acrylic lotion as the film-forming material, SiO2 aerogel gel, hollow glass beads, potassium hexatitanate whiskers and other fillers in the cooperation of a variety of additives. The coating has the advantages of thin-layer spraying construction, nano hole insulation, safety and fire prevention, environmental protection and energy saving, excellent cost performance, and no risk of falling off. The test results show that 1mm thick aerogel gel thermal insulation coating has better thermal insulation performance than 8cm thick polystyrene foam board

heat preservation principle

heat conduction is always transferred from high temperature area to low temperature. There are three ways of heat conduction: solid heat conduction, air convection heat conduction and radiation heat conduction. The characteristic of aerogel gel thermal insulation coating is that it can effectively block or shield the above three heat conduction pathways. Among the coating components, nano SiO2 aerogel plays a key role in heat insulation, followed by potassium hexatitanate whiskers and hollow glass beads. Nano SiO2 aerogel is a light nano porous amorphous solid material with excellent thermal insulation performance. Its porosity is as high as 80% ~ 99%. The typical size of the hole is 2 ~ Fu Mingke, senior senior senior minister of the China Mining Federation, believes that 50nm, the average pore diameter is 20nm, the specific surface area is 600 ~ 1000m2/g, the apparent density is 0.003 ~ 0.35g/cm3, and the thermal conductivity at room temperature can be as low as 0.013w/(m k). Even at 800 ℃ high temperature, Its thermal conductivity is only 0.043w/(m k), and it does not decompose under high temperature, without harmful gas emission. It is a pure green environmental protection material. Its disadvantages are low strength, brittleness and difficult to use alone. Mixing nano SiO2 aerogel with aluminum silicate fiber and hollow glass beads can greatly improve the physical and mechanical properties of the coating under the cross-linking effect of elastic film-forming material

current status of standards

01 refer to the national standard

there is no current industry standard for aerogel gel thermal insulation paint. At present, most enterprises refer to the national standard of thermal insulation paint GB/T reflective thermal insulation paint for buildings

02 group standard

at present, some standards for aerogel gel insulation coating 25 days that have been released and are being prepared are as follows:

1) group standard t/scda 032-2019 technical standard for application of aerogel modified insulation paste external wall internal insulation system edited by Shanghai kaibiao Engineering Construction Consulting Co., Ltd

2) technical specification for building application of aerogel gel thermal insulation coating organized and prepared by Hunan Construction Technology and building energy conservation association

3) standards of China Association for engineering construction standardization "aerogel gel thermal insulation thick coating system" and "technical specification for application of aerogel gel thermal insulation thick coating system" led by China building standards design and Research Institute Co., Ltd. and Shanghai Zhongnan building materials Co., Ltd

4) standards of aerogel gel new building materials system and technical specification for application of aerogel gel new building materials system mainly drafted by China building standards design and Research Institute Co., Ltd., Shenzhen Zhongning Technology Co., Ltd. and Shanxi Yangzhong new materials Co., Ltd. Aerogel gel new building materials system is the application of aerogel gel thick insulation coating system, aerogel gel felt, aerogel gel self insulation wall and other special processes to the construction field, meeting the national energy-saving requirements in the construction field. The technical specification for the application of aerogel gel new building materials system aims to solve the technical problems of real-time data transmission and data comparison during the experiment, such as the design, construction and acceptance of the new building materials

development direction

at present, the main application field of aerogel gel coating products is building thermal insulation, because this field is relatively the easiest to promote and the lowest technical difficulty, while the thermal insulation of metal equipment is relatively difficult. The main reason is that at present, the adhesion of aerogel gel thermal insulation coating is not high, and heat resistance needs to continue to be optimized

in addition to silica aerogel, other types of aerogel gel powders, such as ceramic aerogel and graphene aerogel gel, are also promising to be gradually applied to aerogel coatings to improve the current heat resistance and strength deficiencies of silica aerogel gel. In the future, the R & D direction of products should be developed like products with comprehensive properties. For example, architectural aerogel gel thermal insulation coatings should have the ability of heat preservation, water resistance and aging resistance, It can be directly applied to the external wall external insulation system without finish paint; For example, products used in the field of equipment insulation need to have comprehensive functions of insulation, corrosion prevention and fire prevention, and such products also have more technical content