Fatty phenolic resin is a non-aqueous organic binder for refractory materials. It is made by polycondensation of phenol C or cresol, or xylenol, or resorcinol) and formaldehyde (or sugar aldehyde) mixture under the action of a catalyst. Because phenolic resin has a high residual carbon rate comparable to asphalt, it can be kneaded and molded at room temperature, has good wettability to refractory aggregates and graphite, and has less environmental hazards, so phenolic resin is used as a binding agent and Carbon formers are increasingly replacing traditional carbon formers (such as pitch) for the production of shaped and amorphous products. Resin-bonded refractories have the following main characteristics:
a. Their production is harmless to the environment and saves energy for the mixing process.
b. They can be processed into a cured state or a non-cured state, and do not undergo a special plastic state during the curing and carbonization process, making them exceptionally resistant to deformation.
Can add more carbon (more graphite or carbon black), which can obtain the excellent wear resistance and slag resistance required for use on the converter.
Practice shows that carbon-bonded products using phenolic resin as carbon donor have excellent performance.
Phenolic resins include resole and novolac. Resole phenolic resin is accompanied by dehydration reaction in the temperature range of 100~150 degrees centigrade, about 10% dehydration, and can be cured by heating, and formic acid can also be cured at room temperature. It is customarily called a thermosetting resin.
Novolak itself has plasticity, but by using urotropine or solid resol phenolic resin in combination, no water is generated, and it heats and hardens with deamination. Due to its own thermal plasticity, novolac is difficult to change with time due to external temperature changes. Compared with resole phenolic resin, it is much better in terms of resin storage and ingredient storage. However, due to the reaction with urotropine to produce ammonia, it produces odor. Resole phenolic resin has a methyl alcohol group, so it can shorten the placing time from batching to molding, and the molded product is not easy to layer, but its wettability with aggregate is not as good as novolak. When the resol resin is cured, water is generated and ethylene glycol, which is a novolak solvent, is hygroscopic. Therefore, when using additives that react with metals, etc., and water, sufficient attention must be paid to the drying conditions.