GB1149257A - Emulsions - Google Patents

Abstract

1,149,257. Running tracks and tennis courts. I.B.E. Ltd. 24 Oct., 1966 [22 July, 1965], No. 47352/66. Heading A6D [Also in Divisions B1, B2 and C3] In a process for coating surfaces such as roads, running tracks by a slurry coating process particulate material is mixed with an aqueous alkaline bituminous emulsion having a concentration of 50-75% bitumen, free of clay-type stabilisers, containing a soap formed by reaction of a naphthenic acid and alkali and containing up to 5% of a surface active agent, and a demulsifying agent in an amount in excess of that required to demulsify the emulsion, the surface active agent comprising an organic sulphonate containing an ether linkage and the amounts of surface active agent and water being such that the emulsion breaks quickly on mixing, the particles of the particulate material being coated individually with bituminous material while the particles remain within the aqueous medium of the emulsion, and the mixture is spread over the surface. Other surface active agents may be present e.g. non-ionic surface active agents such as ethylene oxide condensates with phenols, alcohols, acids and amines containing a fatty group, and long chain fatty acid amides, long chain esters and ethers from polyhydric alcohols, protective colloid stabilisers such as a water soluble protein, polyvinyl alcohol, gelatin containing materials such as glue, resin soaps. The preferred emulsions comprise 50 to 75% bituminous material dispersed in dilute alkali, 0.1 to 5% organic sulphonates, 0 to 1% of a non-ionic surface active agent, 0 to 1% of a higher aliphatic amine oxide, 0 to 5% of a resin soap, 0 to 5% of a soluble protein. The bituminous material is generally bitumen of specified grade and penetration value and may be a bondable bitumen such that the coated particles adhere together. Preferred demulsifying agents are lime, baryta, calcium salts. Other agents mentioned include hydroxides, chlorides, sulphates of magnesium, aluminium, zinc, and double salts such as alums quaternary ammonium compounds and higher fatty acids. The agents may be formed in situ. Effective demulsification is said to be produced with 0.5% calcium hydroxide. The particulate material may be fibrous, cellular e.g. vermiculite, sisal, glass, polypropylene fibres. Continued mixing after the emulsion breaks results in a foam structure which remains workable for as long as the structure of the foam remains. The particulate aggregate, demulsifying agent, water and aqueous bituminous emulsion are charged separately into separate hoppers on a travelling mixer fitted with at least one mixer and continuous flow meters. The mixture is fed to a spreading box towed behind the travelling mixture. The surface is rolled to squeeze the water out of the finish. It is said that traffic can run over the surface within 2 to 3 minutes of spreading the mixture. In the Examples a mixture for surfacing hard tennis courts which when spread over a seed bed sown with grass seed allows good growth of grass through the surfacing comprises sisal cuttings, granite, cork hydrated lime, red iron oxide and a bitumen emulsion and 5) a mixture for surfacing indoor running tracks comprises rubber crumb, hydrated lime, glass fibre and a bituminous emulsion.