| 摘要 |
Emulsifier compositions comprising a mixture of quebracho, a surfactant, water, and a pH adjusting reagent for dry and aqueous anionic emulsifiers for producing universal bitumen-in-water emulsions. These emulsifiers are particularly useful in producing stable, anionic asphalt-in-water emulsions that are universal, i.e., they can be used as is or with a wide variety of fillers, additives, pigments and the like, including fine particulate materials, without premature breaking. In the preferred emulsifier, crude, spray-dried quebracho is mixed with an alpha olefin sulfonate containing 10 to 20 carbon atoms, and the pH is preferably adjusted to pH 10 producing an anionic emulsifying agent. The pH may be adjusted from pH 4.5 to pH 11.5. Asphaltic emulsions made with the quebracho emulsifier exhibit enhanced stability, increased viscosity, high ionic headroom and decreased drying times. The residual asphalt coat modified with quebracho exhibits increased adhesion, cohesion, hardness, viscosity and ductility and increased softening temperature as compared to base asphalt in water emulsions not having quebracho in the emulsifier. The emulsifier composition of this invention can be prepared in dry, powdered form or in aqueous solution form. Direct addition of quebracho to asphalt prior to emulsification is taught.
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