Chapter 1 Classification of Thermal Insulation Materials
Insulation material is the general term of heat preservation material and heat insulation material. Usually, the one that prevents indoor heat from flowing out is called heat preservation material, and the one that prevents outdoor heat from entering is called heat insulation material. Generally, it is a material with a guiding thermal coefficient≤0.12W/(m·K).
According to the form, it can be divided into fibrous, microporous, bubble-like and layered. According to the material composition, it can be divided into two categories: organic and inorganic.
Chapter 2 Inorganic Materials
, Foamed cement
, Calcium silicate products
, Aluminum silicate cotton
, Foam glass
, Vitrified beads
, Foamed ceramics
, Vacuum insulation board
Advantages: fireproof and flame retardant, low deformation coefficient, stable and environmentally friendly performance, low construction difficulty and low cost.
Disadvantages: large bulk density, poor compactness and workability, and poor thermal insulation performance.
☆The following parameters are for reference only☆
1. Foam cement
Thermal conductivity 0.08-0.28 W/(m·K)
Dry bulk density 300-1600 Kg/m³
Compressive strength 0.6-4.5 MPA
Foamed cement is also called thermal insulation concrete, foamed concrete, aerated concrete, and foamed concrete.
The foam and cement slurry are uniformly mixed, and then cast in place or molded into a mold to form an insulation material with a large number of closed pores.
Belongs to bubble-like thermal insulation material. It has a wide range of applications in building insulation.
2. Calcium silicate products (CaSiO₃)
1. Diatomite insulation brick
Density around 700Kg/m³
Thermal conductivity 0.13-0.20W/(m.k)
Operating temperature ≤1250℃
It is made by adding some combustible materials with diatomite as the main raw material, and then mixing, forming and sintering. Mainly used for heat insulation of industrial kilns and other thermal equipment and thermal pipelines.
2. Calcium silicate insulation material
Thermal conductivity 0.058-0.075 W/(m·k)
Use temperature ≤1000℃
It is made of diatomaceous earth or silica and lime through batching mixing, forming and hydrothermal treatment. Mainly used for fire protection and heat insulation in electric power, metallurgy, petrochemical, construction, shipbuilding and other fields.
3. Aluminum silicate cotton (Al₂O₃·SiO₂)
Dry density ≤220kg/m³
Thermal conductivity ≤ 0.07W/(m·k)
Compressive strength ≥100kpa
Paste density ≤ 1000kg/m³
Volume shrinkage ≤20.0%
Operating temperature ＞1000℃
Aluminum silicate is also called refractory fiber. Use raw materials such as scorch gemstone, high-purity alumina, silicon dioxide and other materials to melt and spray into fiber at high temperature, and then press into shape.
4. Expanded perlite
Low temperature thermal conductivity 0.028～0.038W/(m·K)
Thermal conductivity at room temperature 0.0245～0.048W/(m·K)
High temperature thermal conductivity 0.058～0.175W/(m·K)
The highest operating temperature is about 800℃
It is a kind of natural acidic vitreous volcanic lava. Because it expands 4 to 30 times in volume at a high temperature of 1000 to 1300 ℃, it is collectively referred to as expanded perlite.
Including perlite, turpentine and obsidian. As a high-efficiency heat preservation and cold preservation filling material, it is widely used in construction, metallurgy, petroleum, machinery, light industry, hydropower, casting, medicine, food, agriculture, forestry and gardening.
5. Stone wool
Thermal conductivity 0.030-0.047 W/(m·K)
Density around 180kg/m³
Compressive strength 40-100Kpa
Rock wool originated from a volcanic eruption in Hawaii. The production process is to simulate the natural process of volcanic eruption. Using basalt, dolomite, etc. as the main raw materials, after being melted at a high temperature of 1450 ℃, the fiber is centrifuged at a high speed, and then solidified and cut into rock wool products of different specifications and uses.
6. Mineral wool
Raw cotton bulk density 50～100kg/m³
Felt bulk density 40～200kg/m³
Board density 70～500kg/m³
Thermal conductivity 0.041～0.07 W/(m·K)
The cotton-like short fibers made from the silicate melt are called slag wool when metallurgical slag or fly ash is the main raw material.
There are three types of cotton-forming processes: injection, centrifugal and centrifugal injection. The mineral wool and adhesive can be formed into various mineral wool products after forming, drying, curing and other processes.
Seven, asbestos (asbestos)
Withstand temperature around 1400℃
Thermal conductivity 0.13～0.15 W/(m·K)
The general term for natural fibrous silicate minerals. There are serpentine asbestos, hornblende asbestos, actinolite asbestos, anthophyllite asbestos, amosite asbestos, tremolite asbestos, etc.
Because asbestos fibers can cause asbestos lung, pleural mesothelioma and other diseases, many countries list them as carcinogens and prohibit their use.
Common asbestos cement products include asbestos cement pipes, asbestos cement tiles, and asbestos cement boards.
8. Glass wool
Bulk density 10-120kg/m³
Thermal conductivity is about 0.042 W/(m·K)
The chemical composition of glass wool is glass, which is a kind of man-made inorganic fiber. Glass wool is a material that fiberizes molten glass into a cotton shape.
It has the characteristics of good molding, low bulk density, thermal conductivity, good sound absorption, corrosion resistance, and stable chemical properties.
It must be used concealed because of the sprinkling of fibers. Common surface treatment methods: sticking plastic paper and spraying on the surface.
9. Foam glass
Thermal conductivity: about 0.058W/(m·K)
Bubble diameter 1-2mm
Inorganic non-metallic glass material made of cullet, foaming agent, modified additive and foaming accelerator, etc., after pulverization, mixing, high-temperature melting, foaming, and annealing.
Sound-absorbing foam glass has more than 50% open-cell bubbles, and thermal insulation foam glass has more than 75% closed-cell bubbles.
10. Vitrified beads
Light bulk density 80～120kg/m³
Thermal conductivity 0.043-0.070W/(m·K)
Expanded vitrified microbeads are an inorganic glassy mineral material that is processed through multi-stage silicon carbide electric heating tube production technology.
Irregular spherical particles, internal porous cavity structure, vitrified closed surface, smooth luster.
It can replace the application of many traditional lightweight aggregates such as fly ash float beads, glass beads, expanded perlite, polystyrene particles, etc. in different products.
11. Foamed ceramics
Thermal conductivity 0.08~0.1W/(m·K)
It is a closed-cell ceramic material roasted at high temperature with clay tailings, ceramic fragments, and river sludge as the main raw materials.
There is no cracking, deformation, or shrinkage under thermal expansion and cold shrinkage, and the tensile bonding strength with cement mortar can reach more than 0.2MPa after the double-faced flour is brushed with the inorganic interface agent.
12. Ceramic fiber
Fiber diameter 2-5um
Ordinary ceramic fiber is also called aluminum silicate fiber. Generally, ceramic fiber blanket is divided into two types, one is spinning blanket and the other is spinning blanket.
Ceramic fiber products are an excellent refractory material. It has the advantages of light weight, high temperature resistance, small heat capacity, good thermal insulation performance, good high temperature thermal insulation performance, and non-toxicity.
Density around 3kg/m³
Thermal conductivity 0.013-0.03W/(m·K)
Aerogel, also known as xerogel, solid smoke, blue smoke. The gel removes most of the solvent, so that the liquid is much less than the solid, or the medium filled with the gel is gas and the appearance is solid. This is an aerogel.
Common aerogels are silicon aerogels. At present, the lightest aerogel is only 0.16mg/cm³, which is slightly less dense than air, and is the lightest solid in the world.
14. Vacuum Insulation Panel
The thermal conductivity is about 0.003W/(m·K)
Vacuum insulation board (VIP board) is a kind of vacuum insulation material, which is composed of filling core material and vacuum protection surface layer. It is the most advanced high-efficiency insulation material in the world.
VIP is mainly used for thermal insulation, such as household refrigerators, yacht refrigerators, mini refrigerators, car refrigerators, cryogenic freezers, electric water heaters, vending machines, freezers, refrigerated containers, building wall insulation, and LNG storage and transportation.
Chapter III Organic Materials
, Molded polystyrene
, Extruded polystyrene board
, Rubber sponge
, Composite insulation mortar
Advantages: light weight, good processability, high compactness, and good thermal insulation effect.
Disadvantages: easy to burn, high engineering cost, difficult to recycle.
1. Molded polystyrene (EPS)
Thermal conductivity 0.030-0.045W/(m·K)
Use temperature <70℃
It is a rigid closed-cell structure foamed plastic that is formed by heating and forming expandable polystyrene beads containing a foaming agent in a mold.
Graphite polystyrene board (SEPS) adds graphite on the original basis, which has lower thermal conductivity and better fire resistance.
The real gold board uses the polymer fireproof isolation and separation granular technology to improve the fire rating, and the other properties are basically the same.
2. Extruded polystyrene (XPS)
Thermal conductivity 0.026-0.035W/(m·K)
Strength coefficient 150-1000kpa
Water absorption ＜1%
It is made of polystyrene resin and other additives through an extrusion process with a continuous and uniform surface layer and a closed-cell honeycomb structure.
Building roof insulation, steel structure roofing, building wall insulation, building ground moisturizing, square ground, ground frost heave control, central air conditioning and ventilation ducts, airport runway insulation, high-speed railway subgrades, etc.
Graphite extruded board adds graphite to the original extruded board, which can effectively reduce thermal conductivity and enhance fire resistance.
3. Polyurethane (PU)
When the density is 35～40kg/m³
Thermal conductivity 0.018-0.024W/(m·K)
Compressive strength 200-300KPA
Polymers containing urethane groups in the main chain of macromolecules are called polyurethanes. Polyurethane is divided into two types: polyester polyurethane and polyether polyurethane.
Rigid polyurethane insulation panels can be widely used in color steel sandwich panels, central air conditioners, building wall materials, cold storage, cold storage rooms, incubators, chemical tanks and other fields.
4. Phenolic Foam
Thermal conductivity 0.023-0.030W/(m·k)
Bulk density 30-80Kg/m³
Phenolic is a foam of phenol and formaldehyde. Modified products are composite modified phenolic board, which is composited with interface agent or grid cloth mortar on the surface of phenolic board.
Vulcanized rubber with a sponge-like porous structure. There are open pores, closed pores, mixed pores and micro pores. Can be made into soft rubber or hard rubber products.
It is widely used in many aspects such as sealing, shock absorption, noise reduction, heat insulation, clothing, shoemaking, home appliances, printing and dyeing, fitness equipment and ion exchange.
Six, thermal insulation mortar
Insulation mortar is a kind of ready-mixed dry powder mortar made by mixing various lightweight materials as aggregate, cement as cementitious material, adding some modified additives, and mixing.
There are two main types of thermal insulation mortar: 1. Inorganic thermal insulation mortar (vitrified microbead fireproof thermal insulation mortar, composite aluminum silicate thermal insulation mortar, perlite thermal insulation mortar, etc.). 2. Organic thermal insulation mortar (polystyrene particle thermal insulation mortar, etc.).