Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Patent
1986-10-14
1988-09-20
Lieberman, Allan M.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
2523115, 524 55, 524 60, 524 68, 524123, C08K 517, C08K 553, C08L 500, C08L 9500
Patent
active
047726482
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to cationic emulsions of bituminous binders of the bitumen/polymer type. In one aspect, the invention relates to a cationic emulsifying system preferably utilizable for obtaining these emulsions.
BACKGROUND OF THE INVENTION
Converting bituminous binders in cationic or anionic emulsions is a well-known technique. The emulsion consists of a dispersion of fine bitumen globules in a continuous aqueous phase. The emulsion is called anionic or cationic according to the total electrical charge surrounding the globule which can be negative or positive. In the presence of a continuous electric current, the micellae of bitumen of an emulsion settle on the anode if the emulsion is anionic or on the cathode if the emulsion is cationic.
The conversion of bituminous binders to emulsion makes use of emulsifying agents that favor the dispersion of the globules of binder in the aqueous phase by forming a charged protective shell that prevents their agglomeration.
In the case of anionic emulsions, the emulsifying agent is of the anionic type and preferably consists of a fatty acid alkaline salt. This emulsifying agent is generally mixed with the bituminous binder in a quantity of from 0.05 to 2% by weight. The binder containing the emulsifying agent is then dispersed in an alkaline aqueous phase by passing into an emulsifier.
Cationic emulsions are obtained by using cationic emulsifying agents, which generally consist of nitrogenized organic compounds such as fatty amines, fatty amidoamines, fatty imidoazolines, fatty mono and diquaternary ammonium compounds and reaction products of one or more of said products with ethylene or propylene oxide. The fatty radical of the emulsifying compounds can possess a very diversified chemical structure and the raw materials for the preparation of the emulsifying compounds can originate from different sources such as animal fats, refined petroleum products, vegetable oils and liquid resins. The cationic emulsifying agent is generally dispersed in water to which hydrochloric acid is added. The hydrochloride formed is soluble. The homogeneous solution thus obtained, having a pH generally comprised between 1 and 5, is then put into contact with the bituminous binder in an emulsifier in order to form the emulsion.
Regardless of whether it is anionic or cationic, the emulsion is considered to be a means that allows lowering the viscosity of bituminous binders. The emulsion restores, after rupture, the bituminous binder to which has been added the emulsifying agent used for producing the emulsion. The presence of this emulsifying agent in the bituminous binder is regarded as exerting a favorable effect on the adhesiveness of the binder in the presence of mineral surface, provided it is within a narrow range of pH comprised between 1 and 6.
The largest sale of bituminous emulsions is mainly in the area of building and repair of roads, and essentially in the form of cationic emulsions. Experience in this field shows that cationic emulsions are easier to apply and prevent the numerous inconveniences of anionic emulsions such as the possibility of restoration to emulsion in the presence of water, of unforeseeable rupture in storage and of weak adhesiveness of the binder to the surface of the aggregate.
Cationic bituminous emulsions are mainly used according to two type of technique, namely, coating and encasing.
Coating consists in gluing layers of fine gravel on the surface of the road by means of the bituminous emulsion in order to produce roughness and make the surface impervious. This technique contributes to the creation of a new runway layer.
In encasement, the bituminous emulsion allows the use of layers having a thickness of from 0.4 cm to more than 20 cm, which integrate in all levels of a road structure.
At present, due to the general reduction of budgets for repair and building of roads, the use of the bitumen emulsion is particularly limited to the repair of the surface of roads. However, due to the extreme mechanical demands to which ar
REFERENCES:
patent: 2862831 (1958-12-01), Mertens
patent: 4171295 (1979-10-01), Frese et al.
patent: 4370170 (1983-01-01), Tolonen et al.
patent: 4494992 (1985-01-01), Schilling et al.
patent: 4576648 (1986-03-01), Denangeon et al.
Demangeon Francis
Lopez Emile
ELF France
Lieberman Allan M.
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