Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INVENTION
Asphalt primers are asphalt-containing liquids which do
not contain aggregate or other solid fillers, and which find use as
rapidly applied surfacing agents for sand, gravel, or dirt roadways.
Asphalt primers are valued for their ability to penetrate the
substrate of particulate matter and rapidly cure to bind the
particles of the substrate into a wind and water resistant surface
of some depth.
Asphalt primers are typically emulsions, cutback asphalts,
or road oils. By cutback asphalt is meant an asphalt containing a
hydrocarbon diluent, comprising roughly one-half the total product,
to reduce the asphalt to spraying viscosity. The light hydrocarbon
distillate which is employed as diluent, being flammable, poses
safety hazards during manufacture and use. Furthermore, as the
primer cures part of the diluent evaporates into the atmosphere
causing air pollution and wasting hydrocarbons. Asphalt emulsions
are of either the oil-in-water type, or of the water-in-oil (invert
emulsion) type. Oil-in-water emulsions are normally of the cationic
or anionic variety depending on the choice of a cationic or anionic
emulsifier. Tall oil, a complex mixture of rosin and fatty acids,
is saponified by reaction with metallic hydroxides or metallic oxides
to produce a soap. The tall oil soap is a known anionic emulsifying
agent for asphalt. Invert emulsions, on the other hand, depend on
the dlspersing agent to disperse a small amount of water (usually 2-
15 weight percent water) in a much larger amount of asphalt. Oil-
soluble soaps are the most common agents used to form invert
emulsions although inorganic powders are also used.
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SUMMARY OF THE INVENTION
An invert water-in-oil asphalt emulsion finding use on
roadways composed of particulate materials, such as sand, gravel,
or dirt, consisting of a dispersion of paving asphalt, medium-light
petroleum distillate dispersing agents and water wherein the
dispersing agent comprises an effective amount of unsaponified tall
oil. The asphalt emulsion comprises about 50 to 70 weight percent
of liquid asphalt, about
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001 -2-
002 48-28 weight percent water and about 0.5-4 weight percent of
003 tall oil.
004 DETAILED D~SCRIPTIO~I OF PREFERRED EMBODI~IEI`~TS
. . _ .
005 The asphalt primer of the present invention comprises
006 a water-in-oil emulsion of a liquid asphalt and water dispersed
007 by a small amount of tall oil. The asphalt primer penetrates
008 quickly and deeply into the particulate materials normally
009 found in rural roadways, such as sand, dirt and gravel. Sur-
010 prisingly, the asphalt primer penetrates quickly into either
011 wet or dry gravel and does not tend to run off. It is storage
012 stable, i.e., no visible separation of the emulsion occurs even
013 over a five day period, it is safe to use and handle, i.e., has
014 a high flash point, preferably greater than about 48C, and has
015 less hydrocarbon to pollute the atmosphere and be wasted.
016 The liquid asphalt finding use within the scope of
017 the present invention is composed of a cutback asphalt, i.e.,
018 an asphalt diluted by addition of a hydrocarbon oil. The
019 liquid asphalt is composed of about 60-80 weight percent, more
020 preferably about 67 weight percent, of an asphalt having
021 penetration of about 85-100 at 25C, 5S, as measured by ASTM
022 D-5, and containing about 40-20 weight percent, and most
023 preferably about 33 weight percent of a hydrocarbon oil. The
024 liquid asphalt preferably has an ~STM D-2170 viscosity less
025 than about 75 cs and an ASTM D-1310 flash point greater than
026 about 100F. The hydrocarbon oil may be 100~ paraffinic but is
027 preferably a paraffinic-naphthenic oil containing only a minor
028 amount of aromatics. The hydrocarbon oil has a specific
029~ gravity of about 0.6~0.9 (15.5C/15.5C), ASTM D-287, more
030 preferably about 0.8.
031 Tall oil is af by-product of the sulfate pulping
032 process. It is a mixture of rosin and fatty acids with a minor
033 amount of unsaponifiable material. For the chemistry, process-
034 ing and other information about tall oil see Kirk-Othmer,
035 Encyclopedia of Chemical Technology, 2nd edition, Volume 19
036 from page 614. The tall oil finding use within the scope of
037 the present invention will contain about 30-90 weight percent
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001 -3~
002 fatty acids, and preferably more than 50 weight percent fatty
003 acids the balance being mainly rosin acids in admixture with
004 minor amounts of unsaponifiable materials of unknown chemical
OOS composition. The fatty acids in tall oil consist mainly of
006 oleic, linoleic, conjugated linoleic, palmitic, stearic,
007 palmitoleic, arachidic, and behenic acids. Commercially avail-
008 able tall oils include those of the following compositions:
009 palmitic (0.1-5.3%); palmitoleic (0.1-2.1%); stearic (2.1-
010 2.6~); oleic (39.3-49.5%); linoleic (38.1-41.4~); eicosanoic
011 (1.2-1.9~); eicosadionic (0.5-3.2%); eicosatrienoic (0.4-2.9~);
012 and behenic (0.4-0.9%) acids, with the balance being rosin
013 acids, unidentified acids and unsaponifiable materials.
014 In the making of the asphalt primer of the present
OlS invention one normally adds about 0.5-4 weight percent tall oil
016 based on the final composition, preferably about 1-3 weight
017 percent tall oil to the liquid asphalt which itself will com-
018 prise about 50-7Q weight percent of the final composition, pref-
019 erably about 55-65 weight percent. The asphalt-tall oil mix-
020 ture is then added with about 48-28 weight percent water based
021 on final composition to a mixing vessel and the materials are
022 mixed to homogeneity, e.g., by a high speed propeller stirrer.
023 The mixture is agitated periodically and heat is kept to a
024 minimum, e.g., 90-100F (32-38C). The asphalt primer has a
025 viscosity of about 80-175 sec. (saybolt viscosity at 50C).
026 The asphalt is normally applied for purposes of
027 priming roadways composed of particulate material, at a
028 concentration of approximately 0.1-0.5 gallons of asphalt
029 primer per square yard of surface.
030 Exemplification
031 A liquid asphalt having the properties listed in
032 Table I, and consisting of 33 weight percent of solvent having
033 the properties listed in Table II and 67~ of an asphalt having
034 a penetration of 85-100, was used as base stock for an asphalt
035 primer of the present invention.
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001 -4-
002 - TABLE I
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004 LIQUID ASPE~ALT
_
005 Gravity, Specific, 60F ASTM D-1250 0.94
006 (15.56C)
008 Viscosity at 140F (60C), CS ASTM D-2170 75 (Max.)
010 Flash Point, Tag, OC, F ASTM D-1370 100 (Min.)
011 (38C)
013 Distillation, IBP, F ASTM D-402 360 (Min.)
014 (182C)
016 % at 500F (260C) of T~ 80 (Min.)
017 to 680F (360C)
019 % at 600F (315.3C) of TD 95 (Min.)
020 to 680F (360C)
022 % Residue at 680F (360C) 66-68
023 (by weight)
025 Distillation Residue:
027 Softening Point, F ASTM D-35107 (Max.)
028 (42C)
030 Pen, 77F, 100 g. 5s ASTM D-5120 (Max.)
032 Ductility, 77F (25C), cm ASTM D-113 150 (Min.)
:
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001 -5-
002 TABLI. II
004 CHARACTERIS~IC METHOD REFERENCE TYPICAL RESULT
_ _
005 Appearance Visual Inspection Light & Clear,
006 no residue
007 Color, Saybolt ASTM D-156 +30
008 Gravity, API ASTM D-287 43.0
009 Specific Gravity ASTM D-287 0.788
010 60/60F (15.5/15.5C)
011 ~lash Point, Tag C.C. ASTM D-56 110F (43.5C)
012 Distillation Range ASTM D-86
013 IBP 311F (155C)
014 10% Vol. 325F (162.5C)
015 50% Vol. 336F (169C)
016 90% Vol. 359F ~181.5C)
017 DP 376F (191C)
013 Aniline Point ASTM D-1012 130F (54C)
019 Kauri Butanol Value ASTM D-1133 38
020 Doctor Test GCM 132 Nesgative
021 Sulfur ppm GCM 217 1.2
022 Copper Corrosion ASTM 130
023 3 hr at 212F (100C)
024 Compositional Analysis GCM 170
025 % vol~
026 Paraffins 44.7
027 Olefins 0.1
028 Naphthenes 40.2
029 Aromatics (total) 15.1
030 Benzene 0.1
031 Aromatics C8 & higher 14.8
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002 In the manufacture of the asphalt primer, a small
003 amount of tall oil was blended into the base stock and water
004 was added in a dispersion tank~ A typical analysis of the
005 asphalt primer was shown in Table III and the product formula
006 is shown in Table IV.
007 T~BLE III
009 Typical product analysis of Asphalt Primer
011 Flash Point (Open Tag) C -------------------------55
012 Viscosity (SF) 50C S ------------------------130
013 Residue by distillation, % mass. --------------------------42
014 Oil portion of distillate, % volume ----------------------24
01S Settlement in 5 days ------------------no visible separation
016 Test on residue from distillation to 360C
017 Penetration, 25C, 100 g, 5S --------------~-------------140
u19 TABLE IV
021 ~ilograms Percent
022 Per Liter by Weight
023 Liquid Asphalt 0.5770 60.5
024 Tall Oill 0.0143 1.5
u25 Water 0.3624 38.0
026 0.9537 100
027 1. Typically a tall oil containing about 50% or more fatty
028 acids (typically, oleic and linoleic acids).
029 The asphalt primer of Tables I-IV was studied in
030 penetration and water resistance in comparison to an asphalt
031 primer which was merely a cutback asphalt containing light
032 hydrocarbon distillate.,~ One-half inch gravel and screenings
033 were used for these tests. The gradations of the gravel are
034 shown in Table V.
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002 -' TA~L~ V
003 Gradation of 12" Grà'vel
004 ( 1/2" 98
005 ( 3/8" 89
006 ( #4 69
007 ( #~, 61
008 Gradation ~ Passing ~ ( #16 53
009 ( #30 42
010 ( #50 26
011 ( ~100 11
012 ( #200 6
013 In these tests the relative rapidity of penetration
014 of the asphalt primer into the particulate matter was measured
015 as well as the depth and uniformity of penetration. It was
016 observed that the asphalt primer of the present invention
017 penetrates as quickly and as deeply as an asphalt primer solely
018 composed of cutback asphalt into either wet or dry gravel, but
019 penetrates faster into the wet highly compacted dense surface
020 of the screenings. We also observed in all specimens that the
021 cutback asphalt primer tended to spread on the surface indicat-
022 ing, potential runoff, whereas the asphalt primer of the present
023 invention penetrated straight down. In order to compare the
024 early water resistance of the asphalt primers the specimens
025 were placed under gentle tap water for 5 minutes. Close
026 examination shows that the asphalt primer of the present inven-
027 tion performs as well as the cutback asphalt primer without re-
028 emulsification or wash off.
029 In another experiment the asphalt primer of the
030 present invention was field tes-ted by spraying the primer on a
031 dirt roadway at the rat,e~of 0.3 gallons per square yard and
032 then sanding the surface with 20 pounds per square yard of
033 sand. Penetration of the asphalt primer was observed to be
03~ excellent (estimated at 1/2") with penetration of the gravel
035 substrate in 10-20 minutes.
