Cationic Chemically Modified Asphalts

The present application is related to application U.S. Ser. No. 329,901 and U.S. Ser. No. 329,897, all of which are concurrently being filed.

The present invention relates to asphalt compositions, and more particularly it relates to chemically modified asphalt compositions. Even yet more particularly, the present invention relates to amine modified asphalts.

Asphalt has been employed for numerous and wide variety of applications for many years. One of the problems encountered with asphalt is that its adhesion to various substrates and especially to aggregate needs to be improved. Such aggregate is represented, for example, by gravel, crushed rock, slag, sand and crushed limestone. Additionally, the adhesion of asphalt needs to be improved with respect to other material such as, for example, cementitious materials, metals, glass and the like.

Thus, in accordance with the present invention improved chemically modified asphalts are provided with the asphalt being the product produced by reacting asphalt with a vinyl aromatic monomer and an amine of an acyclic unsaturated hydrocarbon, and a rubbery polymer.

Some of the desirable properties of the present compositions include improved coatability and adhesion, less stripping, self-emulsifiability, flexibility, strength, reduced high temperature flow, durability, homogeneity and increased compatibility with polymers.

These compositions will find utility for a wide variety of purposes. They, for example, will find application in the highway and bridge construction, repair and maintenance areas as, for example, crack and pothole fillers, joint sealers, and water resistant membranes, as well as cut-backs with the compositions being used alone or as blends with conventional asphalts. These compositions can be formed into emulsions either with or without emulsifiers to form a rapid set emulsion, having utility for chip and seal applications, or as a cold overlay. Generally, these compositions are self-emulsifying, but if desired conventional emulsifiers may be employed, preferably non-ionic surfactants. The compositions may also be employed as corrosion resistant and/or water resistant coatings for metals and as coatings and/or impregnants for glass, especially glass fibers. Such coated or impregnated glass fibers will show outstanding compatibility with conventional asphalt and consequently will serve as outstanding reinforcements for such asphalts.

The compositions of this invention are produced by reacting the above-indicated ingredients by heating at an elevated temperature for several hours. Suitably, the heating is done at a temperature of at least about 120.degree. C. for 10 hours, and most desirably, at about 160.degree. C. to about 180.degree. C. for about 20 hours.

The amines employed in the present invention are amines of unsaturated, acyclic hydrocarbons. The unsaturation in these compounds provides reactive sites for chemically integrating the amines into the compositions and the amine functionality provides the desired polarity, or functionality, so as to form cationic compositions which will exhibit tenacious bonding to aggregate commonly employed in the highway maintenance and repair industry, as well as cementitious and other substrates. Preferably, the hydrocarbon portion of the amine will contain 8 to 25 carbon atoms. Thus, the hydrocarbon can include such groups as alkenyl, alkadienyl, alkatrienyl, alkatetraenyl, and alkapentaenyl radicals. The preferred hydrocarbon radicals will be found to be octadecenyl radicals, for example a 9 octadecenyl radical or octadecadienyl radicals, for example a 9,12 octadecadienyl radical or octadecatrienyl radicals, for example the 9,12,15 octadecatrienyl radical. Representative of other suitable amines include: the decenyl amines, for example 9 decenyl amine; decadienyl amines, for example 2,4 decadienyl amine; dodecenyl amine, for example 9 dodecenyl amine; hexadecenyl amine, for example 9 hexadecenyl amine; 9,11,13,15 octadecatetraenyl amine; 6,9,12,15 octadecatetraenyl amine; 9,11,13 octadecatrienyl amine; 9,12,15 octadecatrienyl amine; 6 octadecenyl amine; 11 octadecenyl amine; eicosenyl amines, for example 9 eicosenyl amine and 11 eicosenyl amine; eicosatetraenyl amines, for example 8,11,14,17 eicosatetraenyl amine and 5,8,11,14 eicosatetraenyl amine; eicosapentaenyl amines like 5,8,11,14,17 eicosapentaenyl amine; docosenyl amines, for example 11,13 docosenyl amine; docasapentaenyl amines, for example 7,10,13,16,19 docasapentaenyl amine; and tetracosenyl amines, for example, 15 tetracosenyl amine. Of course, it will be appreciated that mixtures of such unsaturated acyclic hydrocarbon primary amines may be employed, and in fact in a preferred mode of practicing the present invention, such a mixture is employed.

The above-indicated amines are commercially available. One suitable source for such amines is Humko Chemical division of Witco Chemical Company, which supplies these amines under the trade name Kemamine. Those amines are manufactured by coverting fatty acids to nitriles followed by reduction, for example, by hydrogenation, to the amines. Thus, as will be apparent, these amines may also be viewed upon as derivatives of fatty acids. Thus, the preferred amines as indicated above may be viewed upon as oleyl amine, linoleyl amine, and linolenyl amine, or mixtures thereof. Suitable amines which are commercially available are represented by Kemamine P-997, P-997D, and P-999. These amines generally have melting point ranges varying between about 10.degree. C. to about 60.degree. C., with the preferred amines indicated above having melting point ranges between about 15.degree. C. to about 26.degree. C. If desired, saturated acyclic hydrocarbon amines may also be employed, for example, those having 8 to 25 carbon atoms in the hydrocarbon chain. In fact, the preferred amines, namely P-997, P997D and P-999, are mixtures of several unsaturated acyclic hydrocarbon amines and saturated acyclic hydrocarbon amines. For example, P-999 amine contains approximately 57% by weight of oleyl amine, 15% by weight linoleyl amine, 7% by weight of linolenyl amine, about 2% by weight of gadoleyl amine, 15% by weight of palmityl amine, and 4% by weight of stearyl amine. The P-997 and P-997D amines contain about 45% by weight of oleyl amine, 30% by weight linoleyl amine, about 15% by weight of palmityl amine, and about 10% by weight of stearyl amine. The above-indicated commercially available amines are typically about 93% to about 97% amine by weight.

Asphalt materials which are suitable preferably are those which are typically used for road paving, repair and maintenance purposes. Thus, asphalt includes natural asphalt, petroleum asphalt and petroleum tar. The natural asphalts include, for example, asphaltite, such as Gilsonite, grahamite and glancepitch, lake asphalt, such as Trinidad asphalt, and rock asphalt. The petroleum asphalt that may be used includes straight asphalt obtained by distillation of a crude oil, blown asphalt, produced by blowing an oxygen-containing gas into straight asphalt, and solvent extracted asphalt. The petroleum tar that may be used includes coal tar and oil gas tar. Tar pitch is equally suitable. Additionally, the asphalts can be those that have been blown with steam, ammonia, or amines of the type set forth in U.S. Pat. No. 4,166,752. Preferably, the asphalt which will be employed is an asphalt cement of the type typically used for road paving, repair and maintenance purposes, such as for example, the AC-5, AC-10, AC-20 grades. Such asphalts typically have penetrations ranging between about 20 to about 200.

As the polymerizable vinyl monomer, use is preferably made of a monofunctional vinyl aromatic monomer having a general formula: ##STR1## wherein R.sub.1 is an aromatic group containing 6 to 12 carbon atoms, including a phenyl group, a substituted phenyl group wherein the substituent is any one of an amino group, a cyano group, a halogen group, a C.sub.1 to C.sub.3 alkoxy group, a C.sub.1 to C.sub.3 alkyl group, a hydroxy group, a nitro group, etc. R.sub.2 is preferably hydrogen or lower alkyl e.g., a C.sub.1 to C.sub.5 alkyl and R.sub.3 is hydrogen, lower alkyl or one of the following groups: ##STR2## wherein X is halogen, and preferably chlorine or bromine. Styrene is preferred. In conjunction with the vinyl aromatic monomer as described above, a polyfunctional vinyl aromatic monomer containing 6 to 12 carbon atoms in the aromatic ring and two or more polymerizable vinyl groups chemically bonded to the aromatic ring can be employed. Preferred polyfunctional monomers are those having the general formula: ##STR3## wherein R.sub.4 is a divalent aromatic group containing 6 to 12 carbon atoms, and preferably a phenylene group; and, R.sub.5 and R.sub.6 have the same meaning as is described above with respect to R.sub.2 and R.sub.3, respectively for the monofunctional vinyl aromatic monomer. Illustrative of a suitable polyfunctional vinyl aromatic monomer is divinyl benzene. When use is made of a polyfunctional vinyl aromatic monomer in combination with a monofunctional vinyl aromatic monomer such as styrene, generally the monofunctional vinyl aromatic is present in a weight ratio of about 1:1 to 40:1 based on the weight of the polyfunctional vinyl aromatic monomer.

As the rubbery polymer, use can be made of a number of vulcanizable elastomeric materials well known to those skilled in the art. Included are natural rubbers as well as synthetic rubbers. Suitable are synthetic rubbers which are homopolymers of a conjugated diene (e.g., butadiene, isoprene, chloroprene, etc.) as well as various polymers which are substituted with a functional group containing a labile hydrogen atom. For example, various hydroxy, amino and like substituted homopolymers of conjugated dienes may likewise be used in the practice of this invention. Substituted butadienes are commercially available from, for example, Atlantic-Richfield under the trademark "Poly B-D", a series of hydroxy-terminated butadiene polymers; for example, use can be made of hydroxy-terminated butadiene homopolymers like Poly B-D R-15M which has a hydroxy number of 42 of Poly B-D R-45M.

Preferably, the rubber polymer is an elastomeric material formed by copolymerization of one or more conjugated dienes with one or more ethylenic monomers, such as styrene as well as hydroxy, amino and mercapto-substituted derivatives thereof, acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid, etc. Included are butadiene-styrene rubbers, butadiene-acrylonitrile rubbers, etc. Hydroxy-terminated copolymers are likewise useful in the practice of this invention, including the hydroxy-terminated butadiene-styrene copolymer designated "Poly B-D CS-15" and hydroxy-terminated butadiene-acrylonitrile copolymers like Poly B-D CN-15 having a hydroxyl number of 39. Preferred are butadiene-styrene rubbers like SOLPRENE 1205C available from Phillips Petroleum.

The above ingredients may be varied over wide ranges. Preferably, however, the amine will be employed in an amount of about 0.5 to about 10% based on the weight of asphalt, the vinyl aromatic will be employed in an amount of about 0.5 to about 20% based on the weight of asphalt, and the rubbery polymer will be employed in an amount of about 0.5 to about 35% by weight based on the weight of asphalt. Most desirably, however, the amine will be used in an amount of about 1 to about 7%, the vinyl aromatic in an amount of about 0.5 to about 7.5% and the rubbery polymer in an amount of about 0.5 to about 17%.

While the foregoing describes the present invention so as to enable one skilled in the art to make and use same, nonetheless there follows further exemplification.

A chemically modified asphalt in accordance with this invention is prepared from a charge of about 85.4% by weight of AC-20 asphalt, about 5.9% by weight styrene, about 5.0% by weight Solprene 1205C rubber, and about 3.8% by weight of Kemamine P-999. The asphalt is charged into a reactor equipped with a reflux condenser and an agitator and heated to approximately 110.degree. C., at which time the styrene is added and the reactor is then heated to approximately 160.degree. C. during which time the amine and rubber are added. Under reflux and agitation, the ingredients are then heated at 160.degree. C. for about 20-24 hours, the product then cooled and recovered. This product is suitable for any of the numerous uses previously set forth.

While the above describes the present invention, it will, of course, be apparent that modifications are possible which pursuant to the patent statutes and laws do not depart from the spirit and scope thereof.