| 摘要 |
<p>A positively charged, stabilized emulsion of paraffin wax in water is made by melting the wax with a primary alkyl amine, bringing the temperature of the melt to about 20 DEG C. above the melting point of the wax and slowly adding hot water containing an amount of acetic acid equivalent to the amine, accompanied by vigorous stirring. The acetate of the primary alkyl amine which is formed functions as a cation-active emulsifying agent and can be decomposed, by heat, into a volatile portion and a solid hydrophobic portion. A change from a water-in-wax to a wax-in-water emulsion occurs. The emulsion is slowly stirred and cooled to 2 DEG to 3 DEG C. above the melting point of the wax. Water at 0 DEG C., e.g. ice water, is then added to lower the temperature of the emulsion, suddenly, to a value below the said melting point and the emulsion is allowed to cool to the ambient temperature. Emulsions of micro-crystalline waxes, vegetable waxes and polyethylene may be prepared by a similar method. The method may be modified so that a quaternary salt, such as tribenzyl alkyl ammonium chloride or cetyl pyridinium chloride, is utilized as the emulsifying agent.ALSO:A size, from which a waxy substance is precipitated on to paper-making &c. fibres when the size is added to an aqueous suspension thereof, comprises a stabilized emulsion of the waxy substance, e.g. paraffin, microcrystalline or vegetable wax or polyethylene, in water containing a cation-active emulsifying agent, which, for example, completely neutralizes the negative charge on the fibres. The fibres may be of unbleached cellulosic sulphate pulp, glass, asbestos or a plastic substance. The emulsifying agent may be a quaternary salt such as tribenzyl alkyl ammonium chloride or cetyl pyridinium chloride or the acetate of a primary alkyl amine which, for example, on being heated, decomposes into a volatile portion and a solid hydrophobic portion.</p> |
