phenolic resin is yellow, transparent, amorphous bulk material, due to containing free phenol was slightly red, the actual proportion of the average 1.7 or so, soluble in alcohol, insoluble in water, water, weak acid, weak alkaline solution stability. By phenol and formaldehyde in the catalyst conditions polycondensation, by neutralization, washing and made of resin. Depending on the choice of catalyst can be divided into two types of thermosetting and thermoplastic.
· Refractory:High carbon yield, wear resistance, and excellent particle wetting and bonding properties make phenolic resins ideal for refractory products. There are two general categories of refractory products: shaped and unshaped. Hydraulically pressed refractory bricks, slide gates, shrouds, nozzles, and crucibles are examples of shaped products. Examples of unshaped products are tap-hole compounds, tundish liners and ramming mixes used in steel making.
· Foundry:Many technologies are available to foundries for the production of dies for metal castings. Manufacturers using the shell molding process experience excellent dimensional accuracy, surface smoothness and high production rates using phenolic resin coated foundry sands. The shell molding process involves first creating mold cavities and cores by shaping sand coated with phenolic resin over a not metal form. Removed from the form and assembled, the mold and cores create the "negative" shape of the desired metal form. Hot metal is poured into the resin-sand mold and allowed to cool. Once hard, the excess resin-sand material is broken away revealing the metal part. Some recover the broken away sand for reuse. The careful selection of sand type, resin characteristics and coating method results in the desired mold and core properties such as strength, rigidity, flexibility, surface finish, part release and applicability to reuse.
· Coatings:Cured phenolic resins demonstrate exceptional chemical resistance. Railroad cars, storage tanks and heat transfer equipment are coated using phenolic resins as part of baked phenolic coating systems.
· Composites:Phenolic resins are the polymer matrix of choice in composite products especially when meeting high flame, smoke and toxicity (FST) properties. Phenolic resins provide for excellent strength at elevated temperatures in a variety of environments and are compatible with a multitude of composite fibers and fillers.
· Felt Bonding:Fiber felt manufacturers use phenolic resins with reclaimed or virgin fibers to produce thermal and acoustical insulation for the automotive and household appliance industries. Felt manufacturers achieve optimum rigidity, sound absorption and acoustical insulation performance by varying the density of the felt product.