The invention relates to a tackifier dispersion comprising a resinous material and an emulsifier, the emulsifier being obtainable by a method comprising providing an ester of one or more fatty acids containing at least two conjugated double bonds, reacting the ester with a dienophile containing an acid or anhydride group, to form an intermediate product A, and, reacting the intermediate product A with one or more polyalkylene glycols. The invention also relates to a method for the production of a tackifier dispersion, its use as a tackifier, and an adhesive composition comprising the tackifier dispersion. The invention further relates to an emulsifier, a method of producing the same and its use for emulsifying resinous materials.