GB326545A - Improvements in or relating to phenolic resins and to a process of making the same - Google Patents

Abstract

326,545. Wade, H., (Bakelite Corporation). Dec. 15, 1928. Phenol-aldehyde condensation products.-Non- reactive phenolic resins are prepared by heating a non-reactive phenol-methylene resin with furfural and a basic condensing agent for a time sufficient to convert the resin into a mass which is brittle when cold, but insufficient to destroy its non-reactive character. The initial resin may be made from phenol, cresol, or a mixture thereof, and formaldehyde, and may have incorporated with it another resin of still lower reactivity; for example, a cresol-formaldehyde or phenol-acetaldehyde resin may be added to an initial resin derived from phenol and formaldehyde, or a retarding agent such as rosin may be added thereto. In an example, the liquefied initial resin, to which stearic acid and hydrated lime are added, is maintained at a temperature of 130‹-150‹ C. for some time while stirring, furfural is then added, and the stirring is continued until a sample of the resin is brittle, when cold. The hydrated lime may be replaced wholly or in part by other basic condensing agents, for example, magnesia, or the hydroxides or carbonates of sodium or potassium. Moulding mixtures are prepared by incorporating the products with methylene-containing hardening agents and fillers. To lessen the time required for the final hardening, a small proportion of such hardening agent may also be added during the furfural treatment stage.