Abstract

In this work, the effect of urea formaldehyde (UF) viscosity on a composite derived from reactive blend-ing of UF with natural rubber (NR) was investigated. Some physical properties of the urea formal-dehyde-natural rubber (UF-NR) obtained at different UF viscosities (2.1-256.3mPa^.s) were evaluated. The melting point, refractive index, density and formaldehyde emission were found to increase with increase in UF viscosity while the dry time, moisture uptake and elongation at break were found to decrease with increase in viscosity. UF viscosity below 30.55mPa.s was found to produce UF-NR blend soluble in water and beyond this value the composite became insoluble in water. Thus processing of UF-NR blend for emulsion paint formulation could be suggested below this viscosity level. The result obtained from this experiment will offer formulators different options and to control formulation processes towards developing a paint binder for emulsion paint formulation from UF-NR blend, which may be acceptable to the coating industry.

Key words: Paint binder, amino resins, urea formaldehyde, natural rubber, viscosity.