Application of Hydrogen containing Silicone Oil in Dry Powder Fire Extinguishing Agent
In case of fire, the normal operation of the fire extinguisher is very important. For the dry powder fire extinguisher, it means that in the long-term storage, the internal materials need to be able to maintain fluidization, to ensure that the powder can be evenly ejected during use, so that the fire extinguisher can work normally and put out the fire quickly. The challenge of dry powder is that its internal components are hygroscopic, easy to absorb water in the storage process, easy to agglomerate and block after moisture absorption, resulting in poor fire-extinguishing performance. Therefore, in order to ensure its long-term fluidity, it is necessary to add hydrophobic agent and flow aid to the powder to reduce its agglomeration trend.
I. composition of dry powder fire extinguishing agent
The fire extinguishing dry powder is composed of inorganic salt with fire extinguishing effect and a small amount of additives, which are dried, crushed and mixed into a fine solid powder. The dry powder extinguishing agent is generally divided into BC dry powder extinguishing agent and ABC dry powder extinguishing agent. The dry powder extinguishing agent is mainly composed of extinguishing component, hydrophobic component and inert filler. The hydrophobic component includes silicone oil and hydrophobic white carbon black, forming a superimposed water repellent field around the extinguishing agent particles, so that the dry powder can keep good water repellency and moisture resistance.
Silicone powder processing and curing process
II. Application of Hydrogen containing Silicone Oil in dry powder fire extinguishing agent
The silicone oil used for dry powder fire extinguishing agent consists of methyl silicone oil, ethyl silicone oil, methyl hydrosilicone oil and ethyl hydrosilicone oil, among which methyl Hydrogen containing Silicone Oil (202) is the most commonly used. There are some active Si-H bonds in methyl Hydrogen containing Silicone Oil molecules, which are easy to cross-linking reaction. Because of its highly hydrophobic hydrophobic group -CH3, the liquid film can not form a film shape in the formation process, but shrink into a sphere, thus reducing the contact area between particles, significantly weakening the tendency of agglomeration, thus giving dry powder water repellency.
In the process of grinding the dry powder, the fire extinguishing powder is usually coated with Hydrogen containing Silicone Oil, and then heat cured. Some of the silicone oil is cured by catalyst at room temperature. The solidified silicone oil coating forms a hydrophobic film, which makes the particle surface hydrophobic and prevents moisture.
Hydrophobic silica is formed by hydrophobic treatment of silica with silicone oil. There is alcohol hydroxyl on the surface of silica, which is bonded with hydrogenated silicone oil. In addition, the adsorbed water in the pores of silica also dehydrogenated with hydrogen silicone oil, and the physical adsorption of silicone oil polymer on the surface of silica is the main one.