Phenolic foam is known as "the king of heat preservation", which was used in the insulation of missiles and rocket heads early. In recent years, due to high building, transportation, ship, aviation, space technology and other aspects of synthetic foam plastics, thermal stability and fire resistance have been put forward strict requirements, so that phenolic foam has developed more rapidly. As a new type of multi-purpose foam material, phenolic resin foam has attracted wide attention due to its advantages such as heat resistance, flame resistance, self extinguishing, flame resistance penetration, and no drop in fire.
Phenolic foam is based on phenolic resin as the main raw material, adding curing agent, foaming agent and other auxiliary components. When the resin is cross-linked and solidified, the foaming agent dispersing the gas and forming the foamed plastic is formed. It has many excellent properties. 1, first of all, the heat-resistant phenolic foam is composed of several phenol rings linked by methylene bridge. Thermodynamics shows that the methylene bridge is one of the small and stable connections in the organic matter connection, which makes the phenolic foam have excellent thermal stability. It can be used for a long time at 150 C and its instantaneous working temperature can reach over 200 - 300. Its high temperature resistance is obviously better than that of other foam plastics. 2 "Flammability" is also prominent. Phenol molecules are good free radical absorbents. The free radicals produced by the broken methylene bridge during high temperature decomposition are rapidly absorbed by phenol molecules, which prevents the reaction from continuing. This phenomenon makes the phenolic foam extremely hard to burn, and the phenolic foam oxygen index is 50, without adding any flame retardant additives. The flame retardant grade is B1. Class. The high density phenol formaldehyde foam index with inorganic filler can reach 70, and its combustion performance can meet the requirements of German DIN4102 building materials A2 class. Resistance to flame penetration. According to experts, phenolic foam has direct carbon dioxide, no dripping, no curl and no melting phenomenon. After flame burning, foam remains basically. Only a layer of "graphite foam" is formed on the surface, which effectively protects the foam structure in the layer. It is also "low toxic and low smoke" - only carbon, hydrogen and oxygen atoms in phenolic molecules can only produce these 3 products when decomposing at high temperature. There is no other toxic gas except a small amount of CO. The smoke density of phenolic foam is 5%, and that of high density phenolic foam is only 2.3%, which is quite low compared with the smoke density of 74% PU foam. 3 insulation: phenolic foam has a uniform micro closed cell structure, low thermal conductivity, its adiabatic performance is similar to that of PU foam, superior to PS foam, and its thermal insulation performance is about twice as high as that of mineral wool, light cork, perlite, glass wool, and other traditional thermal insulation materials. The temperature range is wide. The strength of phenolic foam is not affected obviously by temperature. At low temperatures (even -196 degrees), the cold shrinkage and cold brittleness do not occur. The mechanical strength of phenolic foam is basically unchanged. 90% of the room temperature strength can be maintained at 130 C continuously. Usually the temperature range is - 150 - 150 C. Corrosion resistance and aging: in addition to being attacked by strong alkali, phenolic foam is almost resistant to all inorganic acids, organic acids and salts.
Phenolic foam is one of the most promising insulation materials in the world. Because this new material is essentially different from the material obtained by adding flame retardant in common macromolecule resin. It does not burn, melt or emit toxic smoke in fire. It also has the advantages of light weight, non-toxic, non-corrosive, heat preservation, energy saving, sound insulation and low price. It does not need Freon foaming, and has no environmental pollution. Its comprehensive performance is incomparable with all kinds of insulation materials at present. It is widely used in the heat preservation of the central air-conditioning system of high rise and high-rise buildings such as hotels, apartments, hospitals and so on. The central air conditioning system of Hongkong's advanced buildings has been mostly converted to phenolic foam in recent years. There are indisputable comprehensive advantages for refrigeration, cold storage, thermal insulation of industrial pipelines and equipment used in petrochemical industry, building partition wall, exterior wall composite board, ceiling, sound absorption board and so on. It solves the problem of unsatisfactory fire protection performance of other organic materials, while inorganic materials have high water absorption, easy dew and skin during construction. The itching problem is the third generation insulation material of air conditioning system and various electrical appliances.