Patent GB-727701-A (GB)
Title: A method of preventing adhesion between blocks of bituminous substances and compositions therefor
Inventor: DEMPSTER JOHN
IPC: C08L95/00
Filed: 1953-03-06
Abstract: An aqueous solution containing at least 40 per cent. by weight based on the total weight of the composition of a deliquescent salt and at least 1 per cent. of a wetting agent, the salt and wetting agent being mutually non-reactive, is applied to the surfaces of blocks of bituminous substances to inhibit adhesion between them.  The deliquescent salt may be an organic compound, e.g. a hydrochloride of an aliphatic or cycloaliphatic amine, or an inorganic salt such as lithium chloride, potassium carbonate, calcium chloride, calcium nitrate, magnesium chloride, magnesium nitrate, zinc chloride, zinc nitrate, cupric chloride, cupric nitrate, ferric chloride or aluminium chloride; mixtures of salts may be used.  The wetting agent may be any water-soluble anionic, cationic or non-ionic surface-active agent.  Suitable cationic agents are the quaternary ammonium salts containing a hydrophobic group attached to the nitrogen atom, e.g. cetyl pyridinium chloride and trimethyl cetyl ammonium chloride.  Preferred anionic wetting agents are the water-soluble salts of compounds having at least 7 carbon atoms in the molecule and having the general formula RSO3H or RXSO3H, wherein R represents an alkyl or substituted alkyl and X an oxygen atom or a carbocyclic radical, the SO3H group being attached to the carbocyclic radical either directly or through a hydrocarbon side chain substituent.  The wetting agent may be separated from sodium sulphate and other inorganic salts which are ordinarily present and might react with the deliquescent salt, by extracting the wetting agent with alcohol and recovering it therefrom.  Preferred non-ionic wetting agents are obtained by reacting a water-insoluble compound containing at least one amino, hydroxyl or carboxylic acid group with polyethylene glycols containing a chain of at least four ethenoxy groups or with a corresponding quantity of ethylene oxide; or analogous compounds in which some or all of the ethenoxy groups are replaced by propenoxy groups. Examples quoted are the polyoxyethylene esters of oleic, stearic or naphthenic acid containing from 6 to 15 ethenoxy groups in the molecule; products obtained by condensing oleyl alcohol with from 6 to 15 molecular proportions of ethylene oxide; condensation products of alkyl phenols containing at least 4 carbon atoms in the alkyl groups with alkylene oxides or polyethylene glycols, e.g. the product obtained by condensing p-isooctyl phenol with 10 molecular proportions of ethylene oxide; and higher fatty acid partial esters of polyhydric alcohols and the ethylene oxide condensation products thereof.  A minor proportion of finely divided inert material such as powdered chalk, clay, graphite, charcoal or starch may be added.  In examples, blocks of bitumen are wetted with aqueous solutions containing calcium chloride and the wetting agent sold under the Registered Trade Mark "Teepol" and containing sodium secondary alkyl sulphates of 10 to 18 carbon atoms in the alkyl radical, together with a small quantity of sodium sulphate.  Some of the compositions also contain china clay.