Residol is a very viscous, dark substance. It is partially polymerized CNSL (Cashew Nut Shell Liquid) obtained in the distillation process of technical CNSL (TCNSL), after separation of the monohydroxyl derivative of phenol (Cardanol).

The active constituent of CNSL is a meta substituted phenol with long hydrocarbon side chain which on account of its unique molecular structure
imparts to CNSL many useful properties leading to its manifold uses in the manufacture of oil soluble resins, varnishes and paints, friction dusts and chemical resistant linings, rubber compounds, bonding resins, adhesives etc.,

For most of the above applications, CNSL has to be partially polymerized to a thick viscous liquid consistency which generally is a time consuming and laborious process. We are preparing Residol, the bodied material from CNSL, through the action of heat only without using any catalyst. This avoids contamination with other chemicals which may interfere with its ultimate use.

Residol contains a natural phenol derivative, which allows easy condensation. A layer of varnishes, enamels and paints made of Residol, dries and hardens both in ambient and baking conditions. Such surfaces have a high gloss, good hardness and elasticity, resistance to water, diluted alkalis, acids, common organic solvents and have particularly good corrosion resistance.

Residol is a relatively cheap material and can partially or completely replace linseed oil and other drying oils and resins in protective coating compositions that do not require bright surfaces.
Residol is used for brake pads in the form of friction dust and in core casting as an oil binder.