ISO 4320:1977

Non-ionic surface active agents — Determination of cloud point index — Volumetric method

Publication date:   Feb 1, 1977

General information

90.93 Standard confirmed   May 25, 2019


ISO/TC 91 Surface active agents

International Standard

71.100.40   Surface active agents



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The determination is carried out by adding, at 30 degree Celsius, of distilled water to a propanol solution to the surface active agent until the appearance of cloudiness. The determination of the cloud point index provided a way of characterizing weakly alkoxylated derivates and their hydrocarbon hydrophobic groups. This simple and rapid measurement is a valuable means for checking the level of alkoxylation of non-ionic derivatives intended, for example, for sulphonation.

Life cycle


ISO 4320:1977
90.93 Standard confirmed
May 25, 2019