One of the condensation products of phenols or phenolic derivatives with aldehydes such as formaldehyde and furfural. The term phenoplasts is sometimes used to refer to the whole group of products. The phenol-formaldehyde resins, developed com- mercially between 1905 and 1910, were the first truly synthetic polymers and have found wide usage for electrical insulation, molded objects, shell molds for metals, laminates, adhesives, and many other applications. They are characterized by low cost, dimensional stability, high strength, and resistance to aging. The combination of low cost and good properties is reflected in the fact that phenolic resins are produced in greater volume than any other thermosetting resin.