US 2772179 A
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United States Patent ASPHALT COMPOSITIONS Mathew L. Kalinowski, Chicago, and Lowell T. Crews, Homewood, 111., assignors to Standard Oil Company, Chicago, 111., a corporation of Indiana No Drawing. Application July 30, E54, Serial No. 446,964
Claims. (Cl. 106273) The present invention is directed to improvements in bitumen compositions, and particularly to improvements in mineral aggregate coating compositions, and more particularly relates to bitumen compositions having improved adherence to damp or wet mineral aggregates, and to improvements in the method of making such compositions.
Residual oils and/ or bituminous materials used in the preparation of pavements and roads do not coat and adhere well to mineral aggregates unless the aggregate is substantially dry, and for this reason, in conventional pavements or road construction practice, it is customary to dry the mineral aggregate by suitable well known methods. Furthermore, water entering the road or pavement during service may have a detrimental effect in that it may displace the oil or bitumen from the surface of the aggregate and thus diminish the bonding eifect of the oil and/or bitumen. This materially shortens the life of the road or pavement requiring frequent repairs and is,
Mineral aggregates employed in road or pavement con struction range in character from hydrophilic to hydrophobic. In general, siliceous and acidic minerals, such as sands and gravels, tend to be hydrophobic, while calcareous alkaline minerals, such as limestone, tend to be hydrophilic. It has been observed that the mineral aggregates appear to have a greater attraction for water than for oil or bitumens and that it is diflicult to obtain, by conventional methods, complete or satisfactory coating of aggregates by oil or bitumen when water is present. Furthermore, even though satisfactory coating is obtained by using dry aggregate, the oil or bitumen tends to be displaced if water enters the pavement or road.
It is known that the coating of damp or wet mineral aggregates by oil or bitumen may be effected and the resistance of the coating to displacement or stripping by water improved by treating the aggregate with small amounts of a water-soluble soap of a fatty acid in conmotion with a water-soluble salt of a polyvalent heavy etal or activator. For optimum results with these reagents, the relative amounts of the two reagents must be carefully adjusted. Thus, when a divalent heavy metal is used as activator, the amount of soap used should be substantially one mole per mole of activator; with a trivalent metal, between one and two mole of soap per mole of activator. Use of larger amounts of soap than this diminishes the effect obtained, and this diminution of eifect increases with excess of soap over the proportions given until, when the amount of soap becomes equivalent to the activator, i. e., two moles of soap per mole of divalent metal or three per mole of trivalent metal, the beneficial effect of the reagent substantially disappears.
The above method has the disadvantage that the relative amounts of soap and polyvalent heavy metal activator "ice of excess soap is not harmful but increases the cost. Furthermore the two reagents must be weighed or measured out and added to each batch, as neither is soluble in the oil or bitumen; while this disadvantage may be partially overcome under favorable conditions by using, in place of the soap, a fatty acid dissolved in the oil or bitumen, this expedient is effective only under favorable conditions of low moisture content of the aggregate, adequate and efficient mixing, etc. Under conditions which are not at all severe, such as appreciable amounts of water and/or facilities for only moderately eflicient mixing, fatty acids appear not to be sufficiently soluble in water to reach and react with the heavy metal ion to the required extent, and if added directly to the mixture or dissolved in the oil or bitumen, are practically without effect.
Another important disadvantage of the above method is that a heavy polyvalent metal salt must be used with the soap. Furthermore, it has been found that while some limestones appear capable of adsorbing or reacting with polyvalent heavy metal ions and accordingly respond to some degree to the above method, a great many others do not,and with these it is diflicult or impossible to obtain a good coating by the above method. Also, since the foregoing method is not in general satisfactory with limestone, a great many natural mixed aggregates such as gravels containing both siliceous and calcareous particles will have only a portion of the particles coated.
In addition to the use of polyvalent fatty acid soaps in bitumens as mineral aggregate coating agents, certain organic nitrogen compounds, such as those obtained by reacting a polyamine with a fatty acid under conditions to form essentially amides, have been used for this purpose. However, although amide-amine type asphalt additives are effective coating agents for acidic mineral aggregates complete amidation of arnine soaps of carboxylic acids such as that produced by high temperature treatment of a fatty acid affording material with an amine results in the production of a bitumen additive with reduced effectiveness for the coating of acidic mineral aggregates such as sand and gravel. It is a primary object of this invention to avoid the formation of amides in the preparation of the fatty acid-amine type additive for bitumens and thereby retain the effectiveness of the additive in fortifying the coating material for application to acidic aggregates. Another object of the present invention is to provide a coating composition for acidic and alkaline mineral aggregates which will not be stripped therefrom by aqueous liquids. Still another object of the invention is to provide a coating composition for acidic and alkaline mineral aggregates which can be supplied without the necessity of drying the mineral aggregate and which will adhere thereto even in a wet condition. Another object of the invention is to avoid the production of a preponderance of amido groups in the fabrication of fatty acidamine type bitumen additives. Still another object of the invention is to produce a heat-stable fatty acid-amine type bitumen additive. A further object is to produce a bitumen additive of sufficiently low viscosity to be pumpable at ambient temperatures, thus to facilitate transfer of the additive and to facilitate the incorporation thereof in bitumen materials.
In accordance with the present invention, bitumens,
such as for examples, road oils and asphalts having im- .the product obtained by reacting a mixture of aliphatic polyamines having from 2 to 6 amino groups and having from 2 to about 20 carbon atoms per molecule and consisting essentially of at least 75%, that is from 75% to about 95%, by weight of at least one alkylene polyamine having at least one primary amino group permolecule thereof and from about 5% to about 25% of an alkyl free of amido groups is obtained. Since amidation of amine soaps is brought about by the loss ofwater at high temperatures, the reaction of the aliphatic polyamine with the aforementioned propane-insoluble fraction is carried out at temperatures below about 240 F., that is, in the range of from about 180 F. to about 240 F., preferably from about 200 F. to about 230 F. for a period of time not longer than about 0.25 to 1.0 hour. An excess of the mixed polyamines over the stoichio'm'etric requirement for reaction with the propane-insoluble fraction is used. Thus, in general, from about 5% to about 50% excess of mixed polyamines is desirable.
. The reaction product of the propane-insoluble material With the mixed polyamines, when diluted with a hydrocarbonoil, preferably an aromatic. hydrocarbon-rich hydrocarbon oil in an amount of from about 10% to about 200% based on the weight of the reaction product, provides -a concentrate of the reaction product which is pumpable at ambient temperatures, thus making possible the transfer of'the additive product and dispersion thereof in bitumen coating material at ambient temperatures and thus avoiding the necessity of lowering the viscosity thereof by heating. Hence, amide formation is thereby minimized in handling the additive. On the other hand,
reaction products of the propane-insoluble fatty acid affording material with either the non-substituted alkylene polyamine alone or with the alkyl substituted alkylene I,
polyamine alone even when diluted with an aromatic hydrocarbon-rich hydrocarbon oil at a 1:1 ratio of diluent to reaction product is too viscous to pump and approaches a semi-solid with respect to consistency.
The propane-insoluble fraction obtained in the propane extraction of crude fatty materials of the type above described contains, in' addition to fats and fatty acids, esters of fatty acidsv and sterols; These propane-insoluble fractions which are obtained as residue of the order of about 0.2% to about 10%, by weight, contain most of the color bodies which are present in the crude fatty materials, and because of their very dark color, are referred to in commerce as Ebony Fats. The properties of representative samples'of the propane-insoluble residues obtained from animal fats and from vegetable oils, on a Water-free basis, are approximately as follows:
Residue Residue Property from from Animal Vegetable Fat Oil Viscosity, Seconds Saybolt at 100 F- 6, 500 930 Viscosity, Seconds Saybolt at 130 F 1, 860 430 Viscosity, Seconds Saybolt at 210 F 300 100 Ash. Weight Percent"; 1. 3 06 .A. P. I. Gravity degrees 10 16 Acidity A; S. T. M. (D-664) Mg. KOH/gm 41 ,63 Pentane Insoluble, Weight Percent. 2 6 2 Benzene Insoluble; Weight Percent 7 0 Saponification Number 190 I 170 Fatty Acid 20 31 Iodine Number- 58 0 The above properties are, of course, merely illustrative, and it should-be understood that both the amount and the property of the propane-insoluble residues depend upon the nature of the crude fatty material extracted and -pentaalkyl diethylene triamine.
.of alkyl-.substituted alkylene, polyamines containing no tation of a vegetable oil. The Hodag Fat #3 had an equivalent weight of 488. The term crude as used herein means that the color bodies and other materials, insoluble in 6 to 30 volumes of the propane at about F. to about F. have not been removed regardless of whether or not the fatty material has been destearinized.
The method of fractionating the animal, marine andvegetable fatty materials with propane to obtain Ebony Fat is well known to those skilled in the art and one example thereof is commonly referred to as the Solexol Process, currently and commercially used and'described in Industrial and Engineering Chemistry of February 1949, page 280. The system for effecting such extractive fractionation is described in detail in U. S. 2,505,338, and U. S. 2,521,234. For most crude animal fats,marine oils and vegetable oils, and similar fatty materials ineluding acids split from such fats, thefractionation conditions are employed which give a propane-insoluble residue of about 1%, i. e., about 0.2% to about 2%, although in somecases such residues may be as large as 5% or even 10%.
The major part, that is, at least 75% by weight, of
the polyamine reactant employed in preparing the additive of the present invention is an aliphatic polyamine, par
,ticularly an alkylen'e polyamine containing at least one ethylene propylene tetramine, tetraethylene pentamine, tetrabutylene pentamine, diethylene dipropylene penta-.
mine, butylenediamine, dihexylene triamine, and the like, or mixtures thereof. For example, a suitable polyamine product as the major polyaminecomponent of the polyamine mixed reactant is a crude diethylene triamine containingminor amounts of ethylene diamine and triethylene tetramine. :Other suitable polyamines include those having the general formula RNH(CH2)3NH2 in which R is preferably a C10 to CHIS aliphatic chain, and which are obtained by condensing the suitable amine with acrylonitrile. and hydrogenating to the corresponding diamine.
Commercially-available polyamines of this type are those marketed by Armour and Company as Duomeens, whichare prepared by the condensation 'of a dodecyl (coco) amine or an octadecyl (tallow) amine with acrylonitrile', followed by hydrogenation to the corresponding diamine product; these products are marketed as Duomeen C and Duomeen T, respectively. 7 V
The alkyl substituted alkylene polyamines are characterized by having no primary amino nitrogen atoms and as indicated above constitute the minor fraction of the total aminereactant mixture, that is, 5% to about 25% by Weight of the total polyamines. Examples 'of these, suitable for incorporation in the amine mixture are alkyl polyethylene polyamines containing no primary amino nitrogen, such asdialkyl, trialkyl, tetraalkyl and Another suitable class primary amino nitrogen atomsare the alkyl substituted ethylene diamines, such as dialkyl, trialkyl, and tetraalkyl ethylene diamine. Particularly suitable are the methyla substituted diamines such as tetramethyl ethylene diamme.
In the preparation of-the, Ebony Fat and polyamine reaction product, it is preferable, although not essential, that the Ebony Fat be firstdehydrated .to obtain an essentially Water-free product, or.a product having not more than about 0.5 %water. This can be readily ac- .complished by diluting the Ebony Fat with. from about 10% to about 200% of a suitable hydrocarbon solvent,
preferably a solvent rich in aromatic hydrocarbons, and by heating the'diluted mixture at a temperature of about 210 F. to 290 F. while stirring and/or blowing with air or other suitable gaseous medium until the water content has been reduced to the desired value. Following the dehydration step the Ebony Fat oil mixture is cooled to a temperature below about 150 F., preferably by the continued inert gas blow such as for example a passage therethrough of cold air. If the Ebony Fat contains an undesirable amount of contaminants, they can be removed by permitting the hot dehydrated solution to settle, and decanting the diluted solution of purified Ebony Fat. If desired, the diluent may be removed from the dehydrated Ebony Fat by suitable means, such as by distillation under vacuum; however, We prefer to react the diluted Ebony Fats with the polyamines.
Aromatic-rich hydrocarbon solvents suitable for this purpose are preferably those having boiling points above about 220 F. at atmospheric pressure, for example, from about 220 F. to about 600 F., and includes mononuclear aromatic hydrocarbons or condensed ring aromatics, such as naphthalenes and mixtures of the higher boiling mono-nuclear aromatic hydrocarbons and polynuclear aromatic hydrocarbons.
A preferred source of mixed aromatic hydrocarbons, suitable for the purpose, is a light catalytic cycle stock obtained from a powdered or a fluid-type catalytic-type hydrocarbon cracking operation in which gas oil or heavier hydrocarbons are cracked at a temperature of 800 F. to 1050 F. under a pressure of about atmosphere to 50 pounds per square inch, in the presence of suitable fluid or powdered catalyst, such as for example silica-alumina, silica magnesia, and other well-known cracking catalysts. A method of conducting a fluidized cracking operation is described in U. S. 2,341,193, issued to Fred W. Scheineman, February 8, 1944. Fractions from the process heavier than gasoline, depending upon their boiling range, are commonly referred to as light catalytic cycle stock, heavy catalytic cycle stock and catalytic recycle resid, which usually are cycled to cracking. A light catalytic cycle stock particularly well suited as .a diluent for the dehydration of the Ebony Fat is a fraction having an aromatic content of at least about 40% and a distillation range between about 425 F. and 560 F. A typical analysis of a suitable light catalytic cycle stock shows the material to be composed substantially of about 10% normal C12 to C20 parafi'ins, about 45% of other paraflins, and naphthenes, about mono-nuclear aromatics, which are mainly monoand hexa-alkylated benzenes, and about 40% polynuclear aromatics, which are mainly alkyl naphthalenes, largely methylated naphthalenes. While we prefer to use a light catalytic cycle stock of the type described, hydrocarbon fractions from other catalytic conversion processes or thermal hydrocarbon conversion processes are suitable, provided they have an aromatic content of at least about 20%, and a distillation range of above about 220 F. If desired, a part of .the bitumen coating material, if a road oil, may be used as diluent for the Ebony Fat for the dehydrating operation.
The dehydrated Ebony Fat, preferably but not necessarily in solution in the light catalytic cycle stock or other suitable diluent, is reacted with the polyamines in the ratio by weight of from about 20:1 to about 5:1, and preferably in a ratio of from about 12:1 to about 5:1 Ebony Fa to the mixture of polyamines, at a temperature below about 240 F. and preferably from about 200 F. to about 230 F., for not more than about one hour. If desired, the polyamines may be added to the Ebony Pat in the form of a dispersion in a hydrocarbon oil. By conducting the reaction in the manner herein described, an effective stable coating agent additive essentially free of amido groups is obtained.
The preparation of polyamine-Ebony Fat reaction products is illustrated by the folowing examples:
EXAMPLE I To a mixture containing 244 parts by weight of Ebony Fat, that is, Hodag (#3) Process Fat having an equivalent weight of 488 dispersed in 208 parts by weight of light catalytic cycle stock diluent was added 36 parts by weight of tetramethylethylened-iamine having an equivalent weight of 5 8. The reaction mixture was mixed by means of a mechanical stirrer at a temperature of 230 F. for a period of one hour after which additional light catalytic cracking cycle stock was added to the reaction mixture to adjust the finished additive to a 50% (by weight) active ingredient content.
EXAMPLE II A part of the reaction mixture prepared in Example I was stirred for an additional 45 minutes at 300 F. to determine the effect of higher temperature on the coating properties of the primary amino nitrogen-free reaction product with the Ebony Fat.
EXAMPLE III To a mixture of 244 parts by weight of the same Hodag #3 Process Fat used in Example I dispersed in 219 parts by weight of light catalytic cycle stock diluent was added 25 parts by weight of a 75% aqueous solution of ethylenediamine having an equivalent weight of 40, that is, 18.75 parts by Weight of polyarnine reactant. Contact of the reactants at a temperature of 230 F. was maintained for a period of one hour and diluent was added to provide a 50%50% mixture of active reaction product and diluent.
EXAMPLE IV A part of the 50% diluted reaction mixture of Example III was stirred and reheated for a period of 45 minutes at a temperature of 300 F.
EXAMPLE V To 244 parts by weight of Hodag (#3) Process Fat dispersed in 204 parts by weight of the light catalytic cycle oil diluent was added a mixture consisting of 27 parts by Weight of a 75% aqueous solution of ethylenediamine and 13 parts by weight of tetramethylethylene' diamine. The reaction mixture was processed in the same manner as Examples I and III.
EXAMPLE VI A part of the reaction product obtained in Example V was processed as Examples II and IV by heating for a period of 45 minutes, at 300 F.
The results of coating tests of samples of the above reaction product additives at 1.0% (by Weight) concentration of active Ebony Fat-polyamine soap, that is, 2.0% concentration of the diluted additive are given in the table below.
While we have not been able to determine definitely the composition of the Ebony Fat-polyamine reaction product, we believe the reaction product comprises essentially the amine soaps of the fatty acids contained in the Ebony Fat, together with unreacted esters and alcohols. i. e., sterols.
The asphalt component of the herein described composition may be any bitumen which is useful for the coating of mineral aggregates used in the making'of roads, hi hways, etc., or for the coating of other materials or surfaces Where a water-resistant bond between the surface and the asphalt is advantageous or necessary. The term asphalt as employed herein is intended to be synonymous with bitumen and to cover a liquid, semi-solid, or solid plastic bituminous material of the type employed in making or surfacing of highways and/o-r pavements, caulking agents, sealing compounds, water impervious paints, roofing materials, etc. Such asphalt or bituminous materials are mixtures of hydrocarbons of natural or pyrogenous origin, and are usually derived from petroleum or coal but may occur as such in nature. Asphalts may be derived as distillation resids or cracking resids with or without oxidation by air-blowing or by catalytic oxidation, A specific example of a liquid, asphalt of the type commonly em- Fat-polyarnine reaction products in enhancing the adployed in the preparation of highways, etc., is a petroleum residuum fluxed with a light aromatic diluent boiling in the range of 400 F. to 700 F. 'to give a cut-back product of the following specifications:
' Cutback asphalt Flash, F. (T. O. C.) NLT 150. Viscosity, Furol at 140 F 100-200.
. ASTM distillation:
1 Not less than. a Not more than.
-Normally solid paving asphalts of the m 200 pene- 'tration grades commonly used in road building fall within the following specification:
Penetration of residue at 77 F Not less than -75.
percent of original penetration.
The efiectiveness of the herein described Ebony hesion of asphalts to wet mineral aggregates is detera mined by subjecting blends of asphalts and the described reaction products to the following test.
In preparing the samples of asphalt for testing the coating efliciency of the fortified asphalt samples, diluted 40 additive prepared in the above examples sufficient to provide 1.0% (by weight) concentration of active Ebony -Fat-polyamine component in 'the asphalt was mixed thoroughly with the asphalt. Twenty grams of Ottawa sand and 20 grams of 20 to 35 mesh limestone were separately weighed into 2-ounce containers and covered with one-half inch of distilled water. One gram of the asphalt containing 1% of the additive was floated on the water. The mixture was shaken for 30 seconds and the extent of coating was determined by visual inspection. The asphalt used in these tests was a liquid medium curing asphalt of the above described type and is designated as MC-2 grade. This test is designated as the Modified Colorado Coating Test. A coating of 80% in this test is considered adequate coating efiiciency to satisfy the most severe service requirements for the coating of wet aggregates with bitumen material.
The results of the tests are tabulated below, The asphalt coating agent was a liquid asphalt, that is, a cutback asphalt of the above type designated as medium curing-2 grade.
1 Visual examination at ambient temperatures.
The results in the table show the superiority of the asphalt containing the mixed amines (Example V) Thus, this diluted additive was very fluid at ambient temperatures and submitting the additiveto secondary heating at a temperature of 300 F. indicated no deleterious eifect on the additive With respect'to its efliciency as an asphalt additive, i. e., the coverage was 95% before and after heating at 300 F. for 45 minutes when the asphalt fortified therewith was used for coating limestone; When this asphalt Was used to' coat sand the decrease in coating efliciency as .a result of 'thesecondary heating step was very small, i. e., from 95% coverage to coverage.
On the other hand, the additive prepared in Example I p and Example II, i. e., the reaction product of Hodag (#3) Process Fat with tetramethylethyle'ne diamine alone as the additive was not satisfactory even though heated only to a temperature of 230 F. in the preparation thereof and was not satisfactory when given secondary heating at- 300 F. Since the polyamine reactant contains no primary amino nitrogen, no amide was formed by the secondary heating. This is indicated by no change with respect to coating both sand and limestone as produced by secondary heating. The reaction product of the Hodag (#3) Process Fat with this polyamine showed a very high viscosity, i. e., that of a stiff liquid. The efiiciency of the asphalt fortified with ethylene diamine alone is shown in Examples III and IV. The sample of additive which had been subjected to a maximum temperature of 230 F. showed acoating efiiciency of for the two types of wet aggregate, Heating the additiveto .a temperatureof 300 F. before incorporation in the asphalt sample resulted in a decided reduction of the coating efiiciency of the asphalt with respect to coating sand, the percent coated decreasing from 95 to 50%. Likewise, there-was a slight decrease in the coating efliciency of the asphalt with respect to limestone when the additive was heated to 300 F. prior to incorporation in the asphalt. I
Having thus described our invention, we claim: 7
1. The proces of preparing an additive suitable for use in bitumen coating material, which process comprises reacting in a reaction zone for a period of time of from about A to about 1.0 hour. at a temperature within the range of from about 180 F. to about 240 F. a mixture Fat, which Ebony Fat is characterized as the pro-' pane-insoluble residue obtained in the solvent extraction of a crude fatty material selected fromthe class consisting of crude animal fats, fatty oils, and fatty1acids, crude vegetable fats, fatty oils, and fatty acids, andmixtures thereof with liquified propane, said insoluble residue being insoluble in 6 to 30 volumes of propane at a temperature of from about 140 F. to about F. and
constituting from about 0.2% to about 10% of the crude fatty material from which said insoluble residue is extracted, the total alkylene'polyamines in said reaction zone being in exces of the stoichiometric requirement for reaction with the Ebony Fat in said reaction zone.
2. The process as described in claim 1 wherein the Ebony Fat is dehydrated to a water content of not more than about 0.5% before contact with the alkylene polyamine components of the reaction mixture.
3. The process as described in claim 1 wherein the reaction of the Ebony Fat with alkylene polyamine mix ture is carried out in the presence of a hydrocarbon oil diluent.
4. The process as described in claim 1 wherein the primary amino group-containing alkylene polyamine is ethylene diamine. V V
5. The process as described in claim 1 wherein the alkyl substituted alkylene polyamine is tetramethylethylene diamine.
6. The method of preparing a hydrocarbon-oil diluted reaction product, essentially free of amido groups, suitable for use as a bitumen additive, which comprises forming a homogeneous mixture of Ebony Pat in an aromatic hydrocarbon-rich hydrocarbon solvent boiling in the range of from about 220 F. to about 600 F., dehydrating said mixture to a water content of less than about 0.5% based on the Ebony Eat content of said mixture, reacting in a reaction zone, a mixture of alkylene polyamines consisting essentially of at least 75% by weight of at least one alkylene polyamine having from 2 to 6 amino groups per molecule, at least one of which is a primary amino group and from about 5% to about 25% of at least one alkyl-substituted alkylene polyamine, none of the amino groups of which are primary amino groups, with the Ebony Fat in the dehydrated mixture of Ebony Fat and hydrocarbon oil at a temperature within the range of about 180 F. to about 240 F., for a period of from about hour to about 1.0 hour, the total alkylene polyamines in said reaction zone being in excess of the stoichiometric requirement for reaction With the Ebony Pat in said reaction zone, said Ebony Fat being the propane insoluble residue obtained in the solvent extraction of a crude fatty material selected from the class consisting of crude animal fats, fatty oils, and fatty acids, crude vegetable fats, fatty oils and fatty acids and mixtures thereof, with liquified propane, said insoluble residue being insoluble in 6 to 30 volumes of propane at a temperature of from about 140 F. to about 190 F., and constituting from about 0.2% to about 10% of the crude fatty material from Which said insoluble residue is extracted.
7. The bitumen additive consisting essentially of 10 Ebony Fat-alkylene polyamine reaction product produced as described in claim 1.
8. A bitumen composition comprising a major proportion'of a bitumen and from 0.25% to about 5% of 5 the bitumen active additive dispersed in hydrocarbon diluted reaction product obtained by the method described in claim 6.
9. A roadway construction material comprising mineral aggregates admixed with a coating composition con- 10 sisting essentially of a major proportion of a normally liquid bitumen and from about 0.25% to about 5.0% of a heat-stable reaction product obtained by reacting Ebony Fat with a mixture of alkylene polyamines having from 2 to about 6 amino groups per molecule and consisting essentially of at least one alkylene polyarnine having at least one primary amino group in an amount of at least 75% by weight of said mixture of alkylene polyamines and from about 5% to 25% by Weight of at least one alkyl-substituted alkylene polyamine containing no primary amino group, at a temperature within the range of from about 180 F. to about 240 F. for a period of time of from about one-quarter hour to about one hour. 10. The process as described in claim 1 wherein the primary amino group-containing alkylene polyamine is ethylene diamine and wherein the alkyl substituted a1- kylene polyamine is tetramethylethylene diamine.
References Cited in the file of this patent UNITED STATES PATENTS 2,049,467 Mnookin Aug. 4, 1936 2,201,041 Katz May 14, '1940 2,386,867 Johnson Oct. 16, 1945 2,438,318 Johnson Mar. 23, 1948 2,508,924 Mertens et a1 May 23, 1950 2,521,234 Leaders et a1. Sept. 5, 1950