ISO 1409:2020

This document specifies two methods for the determination of the surface tension of polymer dispersions and rubber latices (natural and synthetic).
— Method A is the ring method (Du Noüy ring method).
— Method B is the plate method (Wilhelmy plate method).
Method A is suitable valid for polymer dispersions and rubber latices with a viscosity less than 200 mPa·s.
Method B is not suitable for polymer dispersions and rubber latices containing cationic surfactants.
Methods A and B are also suitable for prevulcanized latices and compounded material.
In case of dispute, the preferred method is method A (the ring method).