US2673814A - Asphalt composition and method of making same - Google Patents

Description

drophilic to hydrophobic.

Patented Mar. 39, 1954 UNITED STATES PATENT OFFICE Frederick H. MacLaren, Munster,

to Standard Oil Company,

poration of Indiana Ind., assignor Chicago, 111., a cor- No Drawing. Application June 30, 1950, Serial No. 171,556

The present invention is directed to improvements in bitumen compositions, and particularly in mineral aggregate coating compositions, and

more particularly relates to bitumen compositions having improved adherence to damp or 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 effect of the oil and/or bitumen. This materially shortens the life of the road or pavement requiring frequent repairs and is, therefore. uneconomical.

Mineral aggregates employed in road or pavementconstruction range in character from hy- In general, siliceous and acidic minerals tend to be hydrophilic, while calcareous alkaline minerals tend to be hydrophobic. 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 difiicult 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 conjunction with a water-soluble salt of a polyvalent heavy metal 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 moles of soap per mole of activator. Use of larger amounts of soap than this diminishes the effect obtained and this diminution of effect increases with ex- .cess 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 of the reagents substantially disappears. I

The above method has the disadvantage that the relative amounts of soap and polyvalent 9 Claims. (Cl. 106269) heavy metal activator are critical and must be carefully adjusted for optimum results. Use of an excess of soap over the optimum amount diminishes rather than enhances the effect obtained; the use of excess heavy metal to avoid the danger of excess soap is not harmfulbut 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 eificient .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 sufiiciently 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 difiicult or impossible object of the present invention is to provide a coating composition for mineral aggregates which will not be stripped therefrom by aqueous liquids. Still another object of the invention is to provide a coating composition for mineral aggregate which can be applied 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 provide a method of preventing stripping of the coating composition from the mineral aggregate by water after the road and/0r pavement is constructed. A further object of the invention is to provide a method of promoting the adherence of oil bituminous materials to siliceous aggregates without thenecessity of drying the latter. Other objects and advantages of the invention will become apparent as description thereof proceeds.

In accordance with the present invention bitumens such as for example, road oils and asphalts having improved properties and adherence to wet mineral aggregates are obtained by incorporating in such bitumens from about 0.1% to about 30%, or more by weight, and preferably from about 3% to about by weight, of the propane insoluble fraction obtained in the propane extraction of crude fatty materials, such as animal, marine and vegetable fats, fatty oils or fatty acids split therefrom. This propane insoluble fraction, which is obtained as a residue, in amounts of the order of about .2 to 2 Weight percent, in the propane fractionation of such crude fatty materials contain most of the color bodies which were present in the crude fatty materials. Because of their very dark color they are referred to in commerce as ebony fats. The properties of representative samples of the propane insoluble residues obtained from animal fats and animal vegetable oils on a water-free basis, are approximately as follows:

Residue f1 cm from Animal Vegetable Fat Oil Residue Property Viscosity, Seconds Saybolt at 100 F 6, 500 930 Viscosity Seconds Saybolt at 130 F 1,860 430 Viscosity, Seconds Saybolt at 10 F 300 100 Ash, Weight Percent 1.3 06 A. P. I. Gravity, degrees... l0 l6 Acidity ASTM (D4304), mg. KOH/gui 41 63 Pentane Insoluble, Weight Percent 2. 6 4. 2 Benzene Insoluble, Weight Percent. .7 1.0 Saponification Number 190 170 Percent Fatty Acid. 31 Iodine Number 58 106 a suitable temperature, namely from about 100 F. to about 200 F., incorporating the desired amount of the herein-described residue and thoroughly mixing the two materials by suitable means until a homogeneous product is obtained. The grade of material, with respect to viscosity, determines the degree of heating prior to mixing with the bituminous material.

The effectiveness of the herein-described propane insoluble residues in enhancing the adherence of bitumens to damp or wet mineral aggregates can be readily determined by the following test:

Fifty grams of the mineral aggregate, which may be 20 or 30 mesh acidic aggregate, such as Ottawa sand, or calcareous aggregate, such as Bad Axe limestone, are covered with water and the excess drawn off. Two grams of the bitumen material to be tested are then added to the Wet aggregate in a beaker and the mixture stirred for about one minute. The coating is then visually observed to note whether or not the aggregate is adequately coated. Following this, the beaker is half-filled with water and the extent of stripping as evidenced by the amount of oil which leaves the aggregate and floats to the surface of the water is estimated. A reading of 0 to 10" is given based on a composite evaluation arrived from two observations in the test. A value of 10 indicates perfect coating and no stripping. The effectiveness of the propane insoluble residue from animal and fatty materials in improving the adherence of bitumens to both siliceous and calcareous mineral aggregates is demonstrated by the data in Table I which were obtained by subjecting the following samples to the foregoing test:

Sample 1.--Residual oil +no propane insoluble residue of the type herein described.

Sample 2.-Residual oil +no propane insoluble residue of the type herein described.

Sample 3.-Residual oil +3% propane insoluble residue from crude vegetable fatty oils.

Sample 4.Residual oil +5% propane insoluble residue from crude animal fats.

Sample 5.Residual oil +5% propane insoluble residue from crude animal fats.

The method of fractionating the animal, marine and vegetable fatty materials with propane is Well known to those skilled in the art and is commonly referred to as the Solexol process currently in commercial use and described in Industrial and Engineering Chemistry, February 1949, p. 280. A system for effecting such fractionation is described in considerable detail in U. S. 2,505,338. For most crude animal fats, marine oils and vegetable oils and similar fatty materials, including acids split from such fats, the fractionation conditions are employed which give a propane insoluble residue of about 1%, i. a, about 0.2 to 2%, although in some cases such residue may be as large as 5% or even 10%.

Bitumens containing the herein-described propane insoluble residue of crude fatty materials are readily prepared by heating the bitumen to Cracked residuum diluted with light aromatic stock to give a product of the following specifications:

Flash Not less than 150 F. Furol viscosity at 140 F -200 seconds.

Inspection of residue after distilling to 680 F.: AS'LM penetration at 77 IL- 120-300. ASTM ductility at 77 F Not less than 100. ASTM ductility at 60 F Not less than 100.

CC! solubility Not less than 99.5

about 150 F. on mixtures of asphalts and the propane-insoluble residue from crude fatty materials indicate good iompatibility of the additive with bituminous materials and substantially no loss in coating power after long periods of storage.

Th amount of the propane-insoluble residue from fatty materials employed in admixture with bitumens depends upon several factors, among which are the type of the bituminous material, the area of the aggregate-bitumen interface, the characteristics of the aggregate surface, and the severity of the conditions of use. For example, as is well known to those skilled in the art, bitumens of different types vary in what can be called inheren coating ability; some exhibit moderate ability to coat damp or wet aggregates while others exhibit little or no ability to coat such aggregates. This appears to be a character,- istic or property which cannot be predicted by analysis or from other properties. Accordingly, the amount of coating agent required for the same service conditions will vary with different bitumens. The area of the aggregate-bitumen interface also influences the amount of the coating agent to be used. It will be understood by those skilled in the art that this area depends upon the particle size distribution, particle shape and the degree of surface roughness and upon the properties of the aggregate and the bitumen. Furthermore, the surface characteristics of the aggregates vary extensively as regards the amount of the coating agent required to give a satisfactory coating since some aggregates are more hydrophilic than others and require a higher concentration of the coating agent per unit area of surface. Finally, the severity of the conditions under which it is desired to coat the aggregate, particularly as regards the amount of water upon the aggregate and the efliciency of the mixing facilities will affect the amount of coating agent required. Since the foregoing factors are interdependent to some extent, the amount of coating agent which can most advantageously be used should be determined for the individal combination of bitumen and aggregate. As aforesaid in general, the quantity of the propane insoluble residue of fatty materials required will vary from about 0.1% to about 30% or more by weight, and preferably from about 3% to about 10%, by weight, based upon the bitumen employed.

Another property of the herein-described propane-insoluble residues is that of increasing or raising the flash point of bitumen, such as asphalts to which it is added. The efiect of the addition of the herein-described additives on raising the flash point of bitumens to which they are added is illustrated by the data in Table II which were obtained with asphalts containing 5% of a propane-insoluble residue from crude animal fats:

6 It will be noted from the above data that both low flash and high flash bituminous materials are improved by the addition of the herein described additive.

While the present invention has been described with reference to its application of the coating of mineral aggregates with bituminous materials with special reference to highway and/or pavement surfacing, the invention is also applicable to the preparation of other products in which the water resistant bond between mineral substances and bituminous materials is advantageous or necessary. For example, the invention can be adapted for the preparation of bituminous grouts, mastic-s, caulking, or sealing compounds, enamels or for pipe dips; for the preparation of improved bituminous water-preventing agents for ma sonry; for the preparation of filled asphalt products comprising asphalt and very fine mineral fillers, such as are used in composition shingles or roofing; or for improving the adhesion of mineral granules to asphalt-surfaced roofing, etc.

The terms bituminous materials or bitumens as used herein refer to any mixtures of hydrocarbons of natural or pyrogenous origin or mixtures thereof and which may be liquid, semisolid or solid. Examples of such materials are road oils, cutbacks, asphalts, tars and pitches derived either from petroleum or coal. The definition also includes so-called native asphalts. The bitumens may be derived from straight run distillation of petroleum or from cracking processes, and may or may not be blown or oxidized. The oxidized or blown asphalts may be those obtained by blowing asphalt by air or oxygenated gases, or by the catalytic preparation of airblown asphalts using catalysts, such as phosphorus pentoxide, red phosphorus or phosphorus sulfide as described in U. S. 2,450,756, or halide salt catalysts as described in U. S. 2,421,421.

While the present invention has been described by reference to specific embodiments thereof, these are given by way of illustration only and the invention is not to be limited thereto but includes within its scope such modifications and variations as come within the spirit of the appended claims.

I claim:

1. A new composition of matter comprising a major proportion of bituminous material and from about 0.1% to about 30% of ebony fat which ebony fat is 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, and crude vegetable fats, fatty oils, and fatty acids, and mixtures thereof, with liquefied propane, said insoluble residue being insoluble in 6 to 30 volumes of propane at temperatures of from about F. and constituting from about 0.2% to about 10% of the crude fatty material from which said insoluble residue is extracted.

2. A new composition of matter as described in claim 1 in which the crude fatty material is a crude animal fat.

3. A new composition of matter as described in claim 1 in which the crude fatty material is a crude vegetable oil.

4. A roadway construction material resistant to water stripping comprising a mineral aggregate admixed with a bituminous material and from about 0.1% to about 30% by weight, based on said bituminous material, of ebony fat which ebony fat" is 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, and crude vegetable fats, fatty oils, and fatty acids, and mixtures thereof, with liquefied propane, said insoluble residue being insoluble in 6 to 30 volumes of propane at temperatures of from about 140 F. to about 190 F. and constituting from about 0.2% to about of the-crude fatty material from which said insoluble residue is extracted.

5. A roadway construction material as described in claim 4 in which the crude fatty material is crude animal fats.

'6. A roadway construction material described in claim 4 in which the crude fatty material is crude vegetable oils.

7. A roadway construction composition described in claim in which the bituminous material is a petroleum residuum.

8. A method of forming a water-resistant bond between mineral aggregates and a bituminous material comprising mixing said bituminous material with from about 0.1% to about 30% of ebony fat which ebony fat is the propaneinsoluble 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, and crude vegetable fats, fatty oils, and fatty acids, and mixtures thereof, with liquefied propane, said insoluble residue being insoluble in 6 to 30 volumes of propane at temperatures of from about 140 F. to about 190 F. and constituting from 0.2% to about 10% of the crude fatty material from which said insoluble resi- 8 due is extracted, and applying said mixture to said mineral aggregate.

9. In the construction of a bituminous pavement in which the bituminous coating material is applied to mineral aggregate, the improvement comprising mixing said mineral aggregate with said bituminous material and. incorporating in said mixture from about 0.1% to about 30% by weight, based on said bituminous material, of ebony fat which ebony fat is the propaneinsoluble 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, and crude vegetable fats, fatty oils, and fatty acids, and mixtures thereof, with liquefied propane, said insoluble residue being insoluble in 6 to 30 volumes of propane'at temperatures of from about 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.

FREDERICK H. MACLAREN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 835,113 Penny Nov. 6, 1906 1,905,376 Fischer Apr. 25, 1933 2,329,889 Ewing Sept. 21, 1943 2,383,097 Weetman Aug. 21, 1945 FOREIGN PATENTS Number Country Date 151,666 Great Britain Oct. '7, 1920

Claims (1)

1. A NEW COMPOSITION OF MATTER COMPRISING A MAJOR PROPORTION OF BITUMINOUS MATERIAL AND FROM ABOUT 0.1% TO ABOUT 30% OF "EBONY FAT" WHICH "EBONY FAT" IS 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, AND CRUDE VEGETABLE FATS, FATTY OILS, AND FATTY ACIDS, AND MIXTURES THEREOF, WITH LIQUEFIED PROPANE, SAID INSOLUBLE RESIDUE BEING INSOLUBLE IN 6 TO 30 VOLUMES OF PROPANE AT TEMPERATURES OF FROM ABOUT 140* F. AND CONSTITUTING FROM ABOUT 0.2% TO ABOUT 10% OF THE CRUDE FATTY MATERIAL FROM WHICH SAID INSOLUBLE RESIDUE IS EXTRACTED.