Tool-wear effects of anionic components of urea-formaldehyde resins used as particleboard binders

Tool-wear effects of chloride, sulfate, and a few other components of catal ysts normally added to particleboard (PB) binder urea-formaldehyde (UF) res ins were evaluated by bonding PBs and testing them with a tungsten carbide (C2) knife. At the normal 0.4 and 0.8 percent addition levels, ammonium chl oride showed the highest tool-wear effect and ammonium sulfate the lowest. Both sodium chloride and sodium sulfate showed mild tool-wear effects at th e 2.0 percent level, but showed high tool-wear effects at the 5.0 percent l evel, with the former having a greater effect than the latter. Sodium salts of oxalic and nitric acid in UF resins and sodium hydroxide in phenol-form aldehyde (PF) resin also showed increased tool-wear effects. Both the acidi ty and basicity of catalyst additives and the active involvement of certain additive elements in corrosion/oxidation wearing processes of tool metals appear to cause the excess tool-wear effects observed.