PFbinder

PFbinder is a class of binding agents based on phenol-formaldehyde (PF) resins used to bind granular materials in industrial processes, most notably silica sand in metal casting. The term is used for commercial PF resin binders marketed to the foundry industry and, more broadly, to describe PF binder chemistries employed in molding and refractory applications.

Chemistry and forms: PF binders are thermosetting polymers formed by the condensation of phenol with formaldehyde. They are formulated with additives to adjust viscosity, cure rate, and water tolerance and can be supplied as liquid resins or aqueous emulsions. Curing is achieved by heat or by catalysts, depending on the system.

Applications: The primary use is in the foundry sector, where PF binders join silica sand to form molds and cores for metal casting. They are also employed in ceramic processing and in some abrasive products. Key performance attributes include adhesion, hot strength, and resistance to metal penetration.

Processing and curing: The binder is mixed with sand and a hardener or catalyst is added. The mold or core is formed and then cured according to the formulation, typically by heating in a controlled oven or by room-temperature chemical curing.

Environmental and safety: Emissions of formaldehyde during curing are a concern, prompting engineering controls such as ventilation, capture systems, and exposure monitoring. Handling, storage, and waste disposal are subject to occupational safety and environmental regulations.

See also: Phenol-formaldehyde resin; Foundry sand; No-bake molding; Shell molding.