G. Ostberg et al., INFLUENCE OF EMULSIFIER ON THE FORMATION OF ALKYD EMULSIONS, Colloids and surfaces. A, Physicochemical and engineering aspects, 94(2-3), 1995, pp. 161-171
In traditional alkyd paints, the alkyd is dissolved in an organic solv
ent such as mineral spirit. For health and environmental reasons there
is an increasing interest in water-borne alkyd paints. Alkyd emulsion
s are therefore an interesting alternative. The alkyd emulsion should
have a good colloidal stability at a low concentration of surfactant.
A high concentration of surfactant gives undesired properties of the p
aint film, such as water sensitivity. In this paper the influence of e
mulsification temperature and emulsifier concentration on the formatio
n of alkyd emulsions has been investigated. The temperature dependence
observed with both anionic and non-ionic emulsifiers is related to th
e change in viscosity of the alkyd with temperature. In the case of no
n-ionic emulsifiers, an additional effect is seen due to the change in
hydrophilic-lipophilic balance (HLB) of the surfactant with temperatu
re. A concentration corresponding to a close packing of the non-ionic
surfactant on the surface of the droplets is needed to obtain a stable
emulsion when non-ionic surfactants are used. In the case of anionic
emulsifiers, stable emulsions can be obtained at low concentrations gi
ving a very low packing density at the surface.