Types of foaming agent
2022-05-07
Chemical blowing agents are divided into inorganic blowing agents and organic blowing agents.
Organic foaming agents mainly include the following categories:
1. Azo compound
2. Sulfonyl hydrazide compounds
3. Nitroso compounds
Inorganic foaming agents mainly include the following categories:
Carbonate: An inorganic foaming agent, mainly calcium carbonate, magnesium carbonate, and sodium bicarbonate. Among them, sodium bicarbonate is a white powder with a specific gravity of 2.16. The decomposition temperature is about 100-140℃, and part of CO2 will be released, and all CO2 will be lost when it reaches 270℃. Soluble in water but not in alcohol.
Water glass: Sodium silicate, when mixed with glass powder and heated to about 850℃, it reacts with the glass and emits a large amount of gas. At the same time, it can strengthen the compressive and tensile strength of the material. It is mainly used as a foaming agent for preparing foam glass. .
Silicon carbide: The main foaming agent used in the current industrial production of foam glass, which emits a large amount of gas during sintering at 800-900°C.
Carbon black: It is also a very easy-to-use foaming agent. It emits CO2 when heated and has a good foaming effect, but the disadvantage is that the price is higher.
Commonly used physical blowing agents are low-boiling alkanes and fluorocarbons. The physical foaming agent is a compound physical foaming agent, which not only has the advantages of high foaming ratio, good foam stability, low bleeding, etc., but also has a certain modification effect on magnesite cement and reduces product halogenation. Probability of frost. Physical foaming agents have been widely used in the production of foamed magnesite products such as fireproof boards and lightweight partition boards, and in some products (magnesite fireproof door cores, etc.), they have a key role in success or failure.
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