Partial acid number in unsaturated polyester resin in accordance with DIN EN ISO 2114

The partial acid number, e.g., in an unsaturated polyester resin, is defined as the amount of potassium hydroxide that is required for the neutralization of all carbonyl end groups, free acids and half of all anhydride groups. This Application Note describes the determination of the partial acid number in accordance with DIN EN ISO 2114 with the aid of potentiometric titration and KOH in ethanol as titrant.