Fire-resistant materials are made of fire-resistant, flame-retardant, self-extinguishing, and smokeless phenolic resins to make fire-resistant boards, fire-resistant walls, fire-resistant doors, etc.
Viscosity (25°C) Free Phenol Free Formaldehyde Moisture Solid Content Use Phenolic resin contains a large number of phenol rings, it is a good free radical absorbent, the free radical energy formed by the broken methyl group (-CH2-) during high temperature decomposition are rapidly absorbed by these reactive functional groups. The test shows that the phenolic foam does not need to add any flame retardant, and the oxygen index can be as high as 40, which is a B1-level flame-retardant material. The oxygen index of high-density phenolic foam with inorganic fillers can reach 60, and the flame retardant grade is A11 according to the GB/T8625-1988 standard, so it is used in refractory boards.
The proportion of carbon atoms in the molecular structure of phenolic resin is high. When the foam encounters fire, a graphite layer of structural carbon can be formed on the surface, which effectively protects the internal structure of the foam, and the temperature of the other side will not rise when one side of the material catches fire. High, do not spread, when the flame is removed the fire automatically extinguishes. When the foam is exposed to flame, due to the existence of the graphite layer, the surface has no dripping, no curling and no melting phenomenon, and the smoke density is less than 3% and almost no smoke when burning. It has been determined that the flame resistance of phenolic foam can reach 120min at a flame temperature of 1000°C. It can be used to make phenolic foam firewalls and fire doors. Generally, the molding of foam plastics can be roughly divided into three stages, namely foam formation, Growth of foam and stable curing of foam. The heat released by the reaction is the basis for foaming, and for room temperature foaming systems, the type and amount of catalyst is extremely important to obtain stable foams with suitable properties. In the molding process, the cross-linking speed should match the gasification and expansion speed of the blowing agent to prepare foam with good stability. A typical formulation is as follows: Phenolic Resin 100 Surfactant. Usually a strong inorganic or organic acid plus hydrochloric acid and formaldehyde foaming parameters are used, and different phenol/aldehyde ratios are used in industry according to different uses, usually phenol/formaldehyde=1:1.5~2.5 (molar mass ratio) Under the catalysis of alkali metal or alkaline earth metal solution, phenolic resin with different performance indexes can be obtained in 50 condensation-neutralization-decompression dehydration-cooling. The curing agent firstly mixes the resin, surfactant and foaming agent evenly. After adding the curing agent and stirring quickly, it is injected into a model of a specific size and kept at a constant temperature of 50~90°C for a period of time. When the foam is completely cured, it is taken out. Use a band saw to cut into slices or casings to the specified thickness and size. According to different uses, by adjusting the ratio of raw materials, phenolic foam products with different properties can be obtained.
Judging from the research progress, it is expected that high-quality and inexpensive modified phenolic foam will be produced in the near future, which will replace the existing polyurethane and polystyrene foam.
Conclusion Most of my country's oil pipelines and urban heating pipelines use rock wool and polyurethane foam. Rock wool easily absorbs water, corrodes the pipeline, affects the heat insulation effect, wastes energy, and is difficult to construct and labor-intensive. Polyurethane foam is expensive, has poor temperature resistance and is easy to burn. If these two materials are replaced by phenolic resin foam, its economic and social benefits will be very considerable.
With the development of my country's construction industry, building materials tend to be prefabricated, lightweight, high-strength and multi-functional. Chemical building materials have become an important part of building materials. In recent years, many companies have introduced phenolic foam continuous foaming production lines, and a small amount of phenolic foam has entered the building materials market. At present, countries in Europe and Southeast Asia have legally stipulated that civil building foam materials must be fireproof materials. If phenolic foam can be solved in terms of price and brittleness, its application range and usage will be further developed.
It is worth mentioning that with the improvement of people's living standards in my country, the prosperity of the flower market will also open up a larger application field for the development of phenolic foam. As a planting material for flowers, flower mud will have a potential large market.
