OIL-IN-WATER EMULSIONS

The invention relates to an oil-in-water emulsion comprising an oil phase and an aqueous phase, and a primary surfactant, wherein the oil phase is dispersed in the aqueous phase, and wherein the oil-in-water emulsion has: an average droplet size distribution (D[4,3]) in the range of from 3 to 15 µmand less than 3wt% of the droplets have a particle size of greater than 125 µm;a viscosity of greater than 100 and up to 700 mPas at 50oC ±10% and 20 s-1 ±10%;and a static stability of less than 5% residue after centrifugation at 50oC ±10% and 2000g ±10% for 30 minutes±10%. A process for preparing such an oil-in-water emulsion comprises preparing an aqueous phase comprising a primary surfactant, heating a hydrocarbon-containing oil-phase, and blending the hydrocarbon-containing oil and the aqueous phase under conditions sufficient to form an oil-in-water emulsion. The invention also relates to methods for determining the static and dynamic stability of oil-in-water emulsions. Static stability can be determined by a method comprising the steps of: providing an oil-in-water emulsion;centrifuging the oil-in-water emulsion under predetermined conditions for a predetermined period of time; determining the amount of residue deposited from the oil-in-water emulsion after the predetermined period of time; and determining the oil-in-water emulsion's static stability. A method for determining the dynamic stability of an oil-in-water emulsion comprises the steps of: providing an oil-in-water emulsion;analysing the oil-in-water emulsion at a first time; recirculating the oil-in-water emulsion in a recirculation loop; and analysing the oil-in- water emulsion at second time after recirculation has started; in which the oil-in-water emulsion's dynamic stability is determined based on the analysis at the first and second times. L'invention concerne une émulsion huile dans l'eau comprenant une phase huileuse et une phase aqueuse et un tensioactif primaire, ladite phase huileuse étant dispersée dans la phase aqueuse, et ladite émulsion huile dans l'eau présentant : une répartition de la taille moyenne des gouttelettes (D[4,3]) située dans la plage allant de 3 à 15 µm et moins de 3 % en poids des gouttelettes ayant une taille de particule supérieure à 125 µm ; une viscosité supérieure à 100 et pouvant aller jusqu'à 700 mPas à 50 °C ± 10 % et à 20 s-1 ± 10 % ; et une stabilité statique inférieure à 5 % de résidus après centrifugation à 50 °C ± 10 % et à 2000 g ± 10 % pendant 30 minu