Use of Novel Amines as Bases for the Preparation of Emulsions of Hydrocarbon Binders

The present invention relates to novel amines which are especially interesting as bases of emulsifiers for hydrocarbon binders.

Hydrocarbon binders (asphalts or tars which may contain various known additives) are used for surfacings, particularly in the form of emulsions. The emulsifying agents which may be used for making these emulsions are for example fatty diamines having from 8 to 22 carbon atoms.

These fatty diamines of industrial nature are, in fact, known to be mixtures containing not only diamines but also by-products such as primary monoamines, triamines. These fatty diamines are products with a relatively high melting point. It has been thought to use them in liquid form either by converting them (Leuckart-Wallasch process which produces numerous novel by products), by adding thereto liquid alkoxylated amines, or by dissolving them in a solvent. Each of these techniques presents certain difficulties in execution.

It has been found that in the industrial mixtures based on fatty diamines as mentioned above, the replacement of the fatty diamines by methylated diamines of formula: ##STR2## in which:

R is a saturated or non-saturated alkyl radical having from 8 to 22 carbon atoms and 2.ltoreq.n.ltoreq.6 had, compared with the corresponding non-methylated products, lower melting points and consequently presented interesting properties as base of emulsifying products for hydrocarbon binders.

The products in which n is equal to 3 may be mentioned among the especially interesting diamines.

The melting temperatures of certain diamines according to the invention are given hereinafter:

These diamines according to the invention may therefore be stored at ambient temperature in the liquid state.

To produce the surface active agents which may be used with the hydrocarbon binders, an emulsifying soap is made by reaction of the diamine (or a mixture of these diamines) with an acid, such as hydrochloric acid, the reaction being carried out in aqueous medium.

With conventional diamines, it is advisable, to carry out this reaction, in melting the diamine previously and dispersing it in hot water before adding the hydrochloric acid.

With the monomethylated amines according to the invention, it will always be possible to disperse the diamine directly in water, at ambient temperature, and to carry out the reaction with hydrochloric acid without heating.

The surface active agents thus produced may be used with hydrocarbon binders, and particularly asphalts, such as those obtained from non-methylated amines. An example of such a use with asphalts is given hereinafter.

A cationic emulsion of a road asphalt of normal quality is prepared with the assistance of a colloid mill under conventional temperature conditions (binder at 285.degree. F. aqueous phase at 130.degree. C.) with three formulae of composition (by weight): kg

In the three cases, the N-tallow propylene diamine I and the N-methyl N-tallow propylene diamine (II) product of the invention, have been compared.

The results are given in Table I hereinafter.

The breakdown time is measured by proceeding, at ambient temperature, with the coating of chippings and the formation of a continous film of asphalt is assessed by taking a coated chipping at regular intervals and subjecting it to the jet of water of a washing bottle; the breakdown time is the period after which the film of asphalt is no longer displaced by the water jet.

The adhesiveness is measured by immersing, under determined conditions of duration and temperature, chippings coated with the binder and by observing the variation in percentage of surface coated for the binder.

Emulsions A correspond to coating emulsions. Emulsions B and C correspond to distribution emulsions for making surface dressings.

As shown in the Table, there is no significant difference between the properties of the emulsions made with the N-tallow propylene diamine (I) and N-methyl N-tallow propylene diamine (II).

However, N-methyl N-tallow propylene diamine (II) has a melting point of +48.degree. F. whilst N-tallow propylene diamine (I) has a melting point of +95.degree. F.

The mixtures based on methylated diamines according to the invention may be used in the crude state or be mixed with liquid alkoxylated amines with a view to reducing their melting point or be dissolved in suitable solvents.