| 摘要 |
The invention relates to an improved surfactant mixture which permits use of lower concentrations of polyphenolics including natural vegetable polyphenolic extracts and/or synthetic phenolic resins to produce stable anionic slow-setting asphalt-in-water emulsion compositions suitable for use as pavement sealers and coatings. The polyphenolics are selected from natural vegetable polyphenolic extracts including Chestnut A, Chestnut N and Sumac-K10; or from synthetic phenolic resins including phenol-formaldehyde, resorcinol-formaldehyde and novolak resins; or mixtures thereof; in amounts of about 0.1% to 10% polyphenolics in the final emulsion, to form and stabilize the emulsion. The emulsions employ a surfactant mixture comprising a nonionic surfactant with a hydrophilic/lipophilic balance index of from about 16 to about 20, and an anionic lignin sulfonate, in amounts of about 0.1% to 3.0% surfactant mixture in the final emulsion. Optionally 0.02% to 2.00% w/w of sodium borate decahydrate may be included. The pH may be adjusted from pH 4.5 to pH 12.5. The emulsions produced using these components dry and cure faster and yield residual asphalt having higher viscosity, high ionic headroom, a higher softening temperature, greater ductility, increased adhesion and increased cohesive strength as compared to existing asphalt-in-water emulsions. The phenolic elements of the composition act as universal emulsifiers in that they are effective over a wide range of pH values and are effective for use with a variety of particulate and fiber filler materials.
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