Process for the production of polymer-modified asphalts and asphalts emulsions

Disclosed is a polymer-modified asphalt composition which comprises a mixture of (a) a blend of from about 10 to 75 weight-percent of one or more of a thermoplastic rubber polymer and from about 90 to 25 weight-percent of one or more of a fatty dialkyl amide, and (b) an asphalt cement. Also disclosed is a method of preparing such compositions, which requires gentle stirring only.

BACKGROUND OF THE INVENTION 
The present invention relates to a process for the production of 
polymer-modified asphalts and asphalt emulsions for use in road 
construction and repair. 
The use of polymer-modified asphalt has received considerable attention in 
the past few years. Almost everyone in the road building and maintenance 
industry, including state highway departments, asphalt suppliers, and 
polymer suppliers, has performed some type of research and development 
activity or built a trial road with polymer-modified asphalts. The reason 
for such intense interest in the field is that polymers have been shown to 
substantially change certain of the physical properties of the asphalt and 
therefore produce better and longer lasting roads. Some of the properties 
of asphalt which are affected by the addition of polymers are viscosity, 
flow, temperature susceptibility, flexibility, and adhesion of aggregates. 
Viscosity, flow, and temperature susceptibility are related properties. In 
general, the addition of polymers to asphalt increases viscosity and flow, 
and decreases temperature susceptibility. In hot climates, this serves to 
minimize rutting and deformation of the road surface. Most of these 
polymers contain butadiene-type monomers imparting "rubber band"-like 
properties of flexibility and recovery after stretching. This is extremely 
beneficial in cold climates where cracking presents a problem. In 
addition, the adhesion of aggregates in chip seals is greatly improved. 
Virtually all asphalts used in the United States are products of the 
distillation of crude petroleum. Asphalt is produced in a variety of types 
and grades ranging from hard and brittle solids to almost water-thin 
liquids. Asphalt cement is the basis of all of these products. It can be 
made fluid for construction uses by heating, by adding a solvent, or by 
emulsifying it. Hot mix asphalts are used extensively on main highway 
construction where greater durability is required. When a petroleum 
solvent, such as naphtha or kerosene, is added to the base asphalt to make 
it fluid, the product is called a cutback. When asphalt is broken into 
minute particles and dispersed in water with an emulsifier, it becomes an 
asphalt emulsion. The tiny droplets of asphalt remain uniformly suspended 
until the emulsion is used for its intended purpose. 
When combined with an appropriate hydrocarbon solvent, the asphalt cement 
in a cutback is in solution. In an emulsion, the chemical emulsifier is 
oriented in and around droplets of asphalt cement, thus influencing their 
dispersion and stable suspension in water. When either a cutback or an 
emulsion is used in the field, evaporation of the asphalt carrier (i.e., 
the cutback hydroccarbon solvent or the emulsion water) causes the cutback 
or emulsion to revert to asphalt cement. In the case of the emulsion, the 
chemical emulsifier is retained with the deposited asphalt. Because 
environmental considerations militate against the use of cutback asphalts, 
due to the necessary solvent expulsion from these applied asphaltic 
compositions, asphalt emulsions are greatly preferred. These may be 
divided into three general categories: cationic, anionic, and nonionic 
emulsions. 
Cationic and anionic emulsions are those more commonly used in roadway 
construction and maintenance. As their names imply, such emulsions utilize 
anionic or cationic emulsifiers to form an oil-in-water emulsion which can 
be used alone or combined with aggregate for use in the road construction 
and maintenance industry. 
Emulsions are further classified on the basis of how quickly the asphalt 
will coalesce, i.e., revert to asphalt cement. The terms RS, MS, and SS 
have been adopted to simplyfy and standardize this classification. They 
are relative terms only and mean rapid-setting, medium-setting, and 
slow-setting, in reference to anionic emulsions. Corresponding rapid-, 
medium, and slow-setting cationic emulsions are termed CRS, CMS and CSS, 
respectively. The tendency to coalesce is closely related to the mixing of 
an emulsion. An RS/CRS emulsion has little or no ability to mix with an 
aggregate, an MS/CMS emulsion is expected to mix with coarse but not fine 
aggregate, and an SS/CSS emulsion is designed to mix with fine aggregate. 
Chemically, asphalts are complex aggregations of rather large aliphatic and 
cyclic hydrocarbon molecules. Besides the obvious hydrocarbon content, 
additional constituents in asphalts may include oxygen, sulfur, and 
nitrogen (often in substantial quantities) and iron, nickel, and vanadium 
(present usually in trace quantities). Asphaltic mixtures composed of 
mineral aggregate and bituminous constituents are used widely in the road 
construction industry. 
Aggregate used in road construction can be hydrophilic or hydrophobic 
depending upon the nature of the material. While the aggregate can include 
various mineral materials such as cinders or slags, typically the 
aggregate is of natural origin such as sand, rock, or the like, typically 
to the localities where the roads are being built. For example, limestone, 
dolomite, silica, sedimentary, metamorphic, or igneous rocks of various 
other kinds are regularly used in road building. 
There are three general types of polymers that are currently being used in 
the asphalt and road building industries, viz., latex polymers, solid 
polymers, and ground-up automobile tire rubber. The most commonly used 
latex polymers are neoprene, SBR (styrene-butadiene-rubber), and natural 
rubber. The most commonly used solid polymers are SBR, EVA (ethylene-vinyl 
acetate), SBS (syrene-butadiene-styrene), and SIS 
(styrene-isoprene-styrene). 
One of two methods is commonly employed to incorporate polymers into 
asphalt. One method involves adding latex polymer to an asphalt emulsion 
either by addition to the emulsifier solution prior to emulsification or 
to the emulsion following emulsification. Either way, this method is 
relatively easy and trouble-free. The second method involves adding solid 
polymer to the asphalt. This method normally requires substantial mixing 
and shearing in order to uniformly disperse the polymers, particularly 
when SBS or SIS block copolymers are used. 
Two other methods are utilized less frequently to incorporate polymers into 
asphalt. 
Two other methods are utilized less frequently to incorporate polymers into 
asphalt. One method involves addition of a latex polymer to hot asphalt, 
whereby the latex is slowly added and the water flashed off. The other 
method involves addition of solid polymers to asphalt with heating, 
stirring, and addition of monomers such as styrene or methyl methacrylate. 
This mixture reacts to yield a chemically crosslinked polymer which is 
also chemically attached to the asphalt molecules. Thereafter the asphalt 
is either emulsified or used "as is" in hot applications. 
The addition of polymers to asphalt using latex addition either to the 
emulsifier solution or post emulsification has been used successfully for 
many years. Initial problems with latex "creaming," floating to the top of 
the emulsion, and a severe loss in emulsion viscosity have essentially 
been solved. 
The addition of solid polymers to asphalt has not been as successful as 
latex addition to emulsions. The major reason for this lack of success has 
been the extreme difficulty encountered in uniformly dispersing the neat 
polymers in asphalt. Furher, the emulsions produced from the modified 
asphalt very often possess lower viscosities. 
Styrene-butadiene-styrene, styrene-ethylene/butylene-styrene, and 
styrene-isoprene-styrene block copolymers are being investigated by many 
asphalt emulsion manufacturers because of the desirable physical 
properties they impart to asphalt. The very high tensile strength of these 
block copolymers is caused by the physical crosslinking that occurs when 
the blocks of styrene orient themselves in rigid domains forming network 
similar to chemical crosslinking. The rubber mid-block (butadiene, 
ethylene/butylene, isoprene) gives the polymers their elasticity. Heat, 
shear and/or solvent will soften the styrene domains and allow flow which 
facilitates dispersion in asphalt. However, uniform dispersion of the 
polymers in asphalt requires high-speed, high-shear mixers. 
In an attempt to overcome the difficulties of dispersion, manufacturers of 
the SBS and SIS block copolymers have begun to plasticize various grades 
of the polymers with aliphatic, aromatic, or naphthenic oils. These oils 
are intended to separate or pre-dissolve or pre-disperse the styrene 
domains in order that the resulting mixture of polymer and oil might 
disperse readily in the asphalt. However, it has been the experience of 
those skilled in the art that vigorous stirring is nevertheless nearly 
always required in order to achieve uniform dispersion. Oil-extended 
blends are now being used in an attempt to alleviate the necessity for 
such stirring, but have in general resulted in a deterioration of emulsion 
quality: storage stability is often unacceptable, and emulsion viscosity 
can be extremely low (i.e., less than 100 SSF at residues as high as 
71+%). 
Accordingly, there exists a need for a polymer-modified asphalt which can 
be conveniently and economically prepared without high-speed, high-shear 
mixing equipment, and for asphalt emulsions prepared from the same 
polymer-modified asphalt which possess both excellent viscosity and 
storage stability. 
BROAD STATEMENT OF THE INVENTION 
The present invention relates to a process for preparing polymer-modified 
asphalts which comprises first blending one or more thermoplastic rubber 
polymers and one or more fatty dialkyl amides, with heating and gentle 
stirring, and then dispersing the resultant polymer blend into asphalt 
cement with simple recirculation or paddle stirring. Fatty dialkyl amides 
efficaciously employed in the invention may be represented by the 
following general structure: 
##STR1## 
wherein: R.sub.1 and R.sub.2 are the same or different moieties and are 
selected from C.sub.1 -C.sub.8 alkyl groups; and 
R.sub.3 is a C.sub.6 -C.sub.22 alkyl group. 
Asphalts so prepared can be used in hot applications or can be further 
processed into emulsions. Such emulsions are of very good quality, possess 
excellent stability, and exhibit good viscosities at relatively low 
asphalt residue levels.

DETAILED DESCRIPTION OF THE INVENTION 
Polymers which may be utilized in the present invention are well-known, 
commercially available thermoplastic rubber polymers. A rubber is defined 
as an elastic, resilient cohesive solid made from the juice of certain 
tropical trees or similar synthetic materials. Such rubbers are readily 
prepared as is widely described in patents and the published literature by 
polymerizing such monomers as styrene, butadiene, ethylene, butylene, and 
isoprene and other alpha olefins. A thermoplastic polymer is one that 
softens and flows when exposed to heat, and returns to its original 
consistency when cooled. 
These polymers may posses a linear, diblock, triblock or radial structure. 
Preferred for use in the present invention are triblock copolymers. A 
copolymer is defined as a polymer produced by the simultaneous 
polymerization of two or more dissimilar monomers, a block copolymer as 
one whose structure is composed of alternating sections of one monomer 
separated by sections of a different monomer or a coupling group of low 
molecular weight, and a triblock thermoplastic rubber copolymer as one 
having an elastomeric block in the center and a thermoplastic block on 
each end. The thermoplastic block has a glass transition temperature well 
above room temperature whereas the elastomeric block has a glass 
transition temperature well below room temperature. Thus, these two blocks 
are thermodynamically incompatible. It is this incompatibility that 
imparts to these polymers the useful properties described herein. 
The preferred polymer will have a molecular structure comprising block 
segments of styrene monomer units and rubber monomer units. Each such 
block segment may consist of 100 monomer units or more. The resultant 
polymer is thus composed of two phases, a first phase consisting of 
polystyrene end blocks and a second phase consisting of a rubbery 
midblock, usually polyisoprene, poly(ethylene-butylene), polybutadiene, or 
the like. The physical crosslinking and reinforcing properties of the 
polystyrene domains provide these polymers with high tensile strength, 
whereas the rubber midblock provides elasticity. This particular structure 
allows the polymers to soften and flow under shear when heated, yet 
recover their strength and elastomeric properties upon cooling. 
Some polymers which have been found to work well in the practice of the 
present invention are Kraton thermoplastic rubbers (available from Shell 
Chemical Company). These include the triblock copolymers of the Kraton D 
series, wherein the elastomeric midblock of the molecule is an unsaturated 
rubber, and of the Kraton G series, wherein the elastomeric midblock is a 
saturated olefin rubber. 
Another type of thermoplastic copolymer which works well in the practice of 
this invention is an ethylene-vinyl acetate polymer. In particular, Elvax 
resins (available from DuPont Company) have been utilized with good 
results. 
The polymer structure most preferred for use in the present invention is 
the linear A-B-A block type, exemplified by the SBS and SIS polymers. In 
addition to A-B-A type polymers, specialized polymers of the radial 
(A-B).sub.n or diblock (A-B) types may be used. 
The fatty dialkyl amide, constituting the crux of the present invention, 
may be any such amide capable of dissolving the specific polymer selected. 
Combinations of polymers and/or amides may also be utilized in order to 
obtain specific desired properties, as will become apparent to those 
skilled in the art. The fatty dialkyl amides preferred for use in the 
present invention may be represented by the following general structure: 
##STR2## 
wherein: R.sub.1 and R.sub.2 are the same or different moieties and are 
selected from C.sub.1 -C.sub.8 alkyl groups; and 
R.sub.3 is a C.sub.6 -C.sub.22 alkyl group. 
The blend of dialkyl amide and polymer is prepared by mixing the two 
ingredients together and heating, with occasional stirring, until blended 
and homogeneous. Ordinarily these blends are too viscous to prepare in a 
standard roundbottom flask with a normal stirring apparatus. A Kitchen Aid 
mixer (Hobart) with heated bowl is an ideal device for preparation of 
these blends. 
Once the polymer-amide blend reaches homogeneity, it is spread onto a hard 
surface and allowed to cool. The cooled blend can then be easily handled. 
The consistency of the blend will range from a viscous liquid to a waxy 
solid, depending on alkyl chain length and the amount of unsaturation in 
the alkyl chain. 
Further processing of the polymer-amide blend is optional, and a wide range 
of possibilities should be apparent to those of skill in the art. For 
instance, it might be advantageous to pulverize, granulate, extrude, 
powder, or otherwise change the form of solid blends, depending on such 
factors as intended use, storage, transportation, and the like. 
Although it is preferred that the polymer be dissolved in the fatty dialkyl 
amide, it has also been found in conjunction with the present invention 
that the addition of fatty dialkyl amides alone to asphalt serves to 
facilitate dissolution of polymer added independently of the fatty dialkyl 
amide. 
The polymer-amide blend will ordinarily contain from about 10% to about 75% 
by weight of polymer and from about 90% to about 25% by weight of one or 
more fatty dialkyl amides. Preferably, the blend will contain from about 
40% to about 60% by weight of polymer and from about 60% to about 40% by 
weight of dialkyl amide. Most preferred is a 50:50 blend of polymer and 
amide. 
The fatty dimethyl amides most preferred for use in the present invention 
are dimethyl hard tallow amide (DMHTA) and dimethyl stearyl amide (DMSA). 
When incorporated into 50:50 blends with block copolymers, DMHTA and DMSA 
form waxy solids which are easily handled. In addition, both DMHTA and 
DMSA are readily available commercially. DMHTA is the dimethyl amide of 
choice. 
Bitumen used in accordance with the invention may be derived from domestic 
or foreign crude oil, plastic residues from coal tar distillation, 
petroleum pitch, asphalts diluted from solvents (cutback asphalts), 
mineral waxes, and the like. Practically any viscosity- or 
penetration-graded asphalt cement for use in pavement construction, as 
described in ASTM designation D-3381 and D-946, may be used in the present 
invention. The polymer-modified asphalt compositions of the present 
invention will ordinarily contain from about 1% to about 50% by weight of 
polymer-amide blend and from about 99% to about 50% by weight of asphalt 
cement. Preferably, the compositions will contain from about 2% to about 
10% by weight of polymer-amide blend and from about 98% to about 90% by 
weight of asphalt cement. 
The polymer-modified asphalt compositions of the present invention may be 
incorporated into cationic asphalt emulsions by heating and maintaining 
the polymer-modified asphalt composition at 250.degree.-300.degree. F., 
preferably at 285.degree.-295.degree. F. The emulsifier and other 
additives are added to the continuous water phase and neutralized to a pH 
of about 1.5 to about 4.5, preferably about 2.0 to about 3.0 , by the 
addition of acid, preferably hydrochloric acid. Preferred emulsifiers are 
Arosurf AA-28 and AA-78 (available from Sherex Chemical Company, Dublin, 
Ohio), widely used and commercially accepted cationic emulsifiers known to 
generally produce emulsions with good/high viscosities at relatively low 
residues, using a variety of asphalts. The emulsifier solution is 
maintained at 80.degree.-160.degree. F., preferably 
100.degree.-125.degree. F. The asphalt and the emulsifier solution are 
then blended together, preferably with a colloid mill or homogenizer, to 
obtain the desired emulsion. 
The polymer-modified asphalt compositions of the present invention may be 
incorporated into anionic asphalt emulsions by heating and maintaining the 
polymer-modified asphalt compositions at 250.degree.-300.degree. F., 
preferably 285.degree.-295.degree. F. The emulsifier and other additives 
are added to the continuous water phase and neutralized to a pH of about 8 
to about 12 by the addition of caustic, preferably sodium hydroxide. This 
solution is maintained at 80.degree.-160.degree. F., preferably at 
100.degree.-125.degree. F. The modified asphalt and the emulsifier 
solution are then blended together to obtain the desired emulsion. 
If an asphalt emulsion is to be prepared, the preferred bituminous binder 
material is asphalt of paving grade having a penetration of between 30 and 
300 as determined by ASTM test number D5-73 (Penetration of Bituminous 
Materials). The production, selection and properties of suitable 
petroleum-derived asphalts for use in accordance with the present 
invention are commonly known and are described in the literature. 
The amount of bituminous binder material used in asphalt emulsions will 
generally range between about 20% and about 80%, based on the weight of 
the asphalt emulsion composition, and preferably from about 50% to about 
70% by weight. 
Additives commonly used in aqueous asphalt emulsions may also be employed 
in the practice of the present invention. For example, and inorganic salt, 
e.g., calcium chloride, ammonium chloride, ammonium acetate, ammonium 
sulfate, sodium sulfate and the like, can be added to cationic asphalt 
emulsions prepared pursuant to the invention in an amount of up to about 2 
% by weight, in order to prolong the emulsion stability and to improve 
storage stability. Such inorganic or organic salt additives should be 
water-soluble. 
The particle size of the emulsions which may be utilized in the practice of 
this invention is not particularly critical. Generally, particle size will 
range from between 0.5 micron to 100 microns in diameter. It is preferred 
to use an emulsion having a particle size of less than 10 microns. 
The pH of cationic emulsions prepared in accordance with the invention may 
range from about 1 to about 10, with a range of from about 2 to about 7 
being preferred. The emulsions will generally be somewhat more stable and 
possess better viscosity characteristics when the pH is on the acidic 
side. Nevertheless, neutral or alkaline emulsions may also be used. 
Although cationic emulsions were the emulsions of choice for the 
experimentation conducted in connection with the present invention, it 
will be apparent to those skilled in the art that anionic emulsions having 
equivalent efficacy could be prepared by utilizing anionic surfactants and 
emulsifiers in accordance with procedures known in the art. 
In order to qualify as a "good quality emulsion," a cationic emulsion must 
meet ASTM D-2397 specifications or similar local specifications. Typical 
cationic rapid-set emulsions (CRS-2) have a critical minimum viscosity and 
minimum residue specification. There exists a direct correlation between 
emulsion viscosity and the weight-percent asphalt content in the emulsion. 
As a general rule, the greater the asphalt content (i.e., the higher the 
percentage of residue), the higher the viscosity. In an emulsion does not 
meet the minimum viscosity specification, a typical solution to the 
problem is to increase the amount of asphalt in the formulation. From a 
financial standpoint, an emulsion manufacturer attempts to produce a CRS-2 
emulsion as close to the minimum residue specification as possible but 
still meeting the minimum viscosity specification. The reason for this, of 
course, is that asphalt is the raw material ordinarily contributing the 
greatest cost to an emulsion. Most emulsions are purchased by government 
agencies on a low-bid basis; thus, the lower the cost of raw materials, 
the lower a producer can bid on an agency's requirements. It will be seen 
in the examples that the residue/viscosity results obtained with the 
dialkyl amides of the present invention are far superior to those obtained 
with standard polymers alone, which in many cases fail to meet minimum 
viscosity specifications. This ability of the dialkyl amides to impart 
excellent viscosity values at relatively low residue percentages makes the 
resultant asphalt emulsions enormously attractive from the standpoint of 
economics as well as performance. 
While the preferred use for the asphalt cement compositions of the present 
invention is in conjunction with aggregate to form road paving materials, 
they may also be advantageously employed in many other applications, e.g., 
asphalt roofing cements, mastics, moisture barriers, joint and crack 
fillers, sheeting, and so forth. 
IN THE EXAMPLES 
It is believed that one skilled in the art can, using the preceding 
description and without further elaboration, utilize the present invention 
to its fullest extent. The following preferred specific embodiments are, 
therefore, to be construed as merely illustrative and not as limiting the 
remainder of the disclosure in any way whatsoever. 
For convenience several abbreviations are used in the examples. A list of 
these abbreviations and the terms for which they stand are given below: 
DMF=dimethyl formamide 
DMODA=dimethyl octadecyl amide 
DMCOA=dimethyl cocoamide 
DMTA=dimethyl tallow amide 
DMHTA=dimethyl hard tallow amide 
DMOA=dimethyl oleyl amide 
DMCAA=dimethyl canola amide 
DMSA=dimethyl stearyl amide 
DEHTA=diethyl hard tallow amide 
DBHTA=dibutyl hard tallow amide 
Temperatures are set forth in degrees Fahrenheit. Unless otherwise 
indicated, all parts and percentages are by weight. 
It should be noted that for convenience rapid-set cationic emulsions were 
evaluated in the examples. Cationic medium-set and slow-set emulsions 
could be prepared using similar procedures. It is also believed that all 
three types of anionic emulsions (rapid-, medium- and slow-set) could be 
equally readily prepared. 
EXAMPLE 1 
The method employed for preparation of all dialkyl amide-polymer blends 
tested in accordance with the present invention was as follows: Small 
sample blends of 100 grams of dialkyl amide, 50 grams of Kraton 1101 SBS 
block copolymer (Shell Chemical Company), and 50 grams of Kraton 1118 
styrene-butadiene branched copolymer (Shell Chemical Company) were 
prepared by weighing all ingredients into a pint can and then heating the 
can and contents on a hot plate to 250.degree.-325.degree. F. Contents of 
the can were stirred occasionally with a metal stirring rod during the 
first 30 minutes, then continuously until homogeneous and very viscous. 
The blend was then spread onto a hard surface and allowed to cool. 
The specific dialkyl amide-polymer blends prepared and their physical forms 
are listed in Table 1. 
TABLE 1 
______________________________________ 
Dialkyl Amide 
Amide at 77.degree. F. 
50:50 Blend at 77.degree. F. 
______________________________________ 
DMODA Liquid Very viscous liquid 
DMCOA Liquid Very viscous liquid 
DMTA Soft solid Very viscous liquid 
DMHTA Solid Waxy solid 
DMCAA Liquid Very viscous liquid 
DMSA Solid Waxy solid 
DEHTA Soft solid Rubbery solid 
DBHTA Soft solid Rubbery solid 
______________________________________ 
An attempt was made to prepare amide-polymer blends utilizing amides which 
lacked C.sub.1 -C.sub.8 dialkyl groups. The same procedure was followed 
with three such amides: monobutyl hard tallow amide, oleyl diethanol 
amide, and eurcylamide. It was not possible to dissolve the 
styrene-butadiene copolymers in these amides, and thus blends could not be 
prepared. 
EXAMPLE 2 
An amount of dialkyl amide/polymer blend (prepared in Example 1) equal to 
6% by weight of the asphalt to be used was weighed into a container and 
preheated to about 300.degree. F. To facilitate handling, the heated blend 
was then added to the asphalt, which was also heated to 
290.degree.-300.degree. F. The entire blend was then subjected to simple 
hand stirring and circulating, which resulted in a uniformly dispersed 
polymer-asphalt blend. 
Two grades of asphalt were selected for use in this example: AC-20, having 
penetration values of 60-90, and AC-5, having penetration values of 
160-200 (both available from Ashland Oil, Inc.). AC-20 is preferred over 
softer grades of asphalt because the dimethyl amide remains in the asphalt 
after the emulsion breaks and exerts a softening effect. This effect must 
be taken into consideration, as polymer-modified asphalt emulsion residues 
typically must meet normal emulsion residue specifications of 100-250 
penetration. Incorporation of 6% of the polymer-amide blend softened AC-20 
from 60-90 pen to 130-150 pen, the range desired, whereas AC-5 was 
softened from 160-200 pen to 210-280 pen. 
When the dialkyl amide used was dimethyl hard tallow amide or dimethyl 
stearyl amide, the dimethyl amide/polymer blend was a waxy solid and no 
preheating was necessary. 
Whereas uniform dispersions were achieved in this example with simple 
hand-stirring, dispersing the original neat polymers at this same 
percentage (3% by weight) in the same asphalt required 30 minutes of 
mixing at 350.degree. F. using a high-speed, high-shear Ross mixer. 
EXAMPLE 3 
Various asphalt emulsions were prepared by heating and maintaining 
polymerdialkyl amide-asphalt blends prepared in Example 2 at 
250.degree.-300.degree. F., preferably at 285.degree.-295.degree. F. 
Arosurf AA-28 or AA-78 emulsifier (Sherex Chemical Company) at 1.0% by 
weight and other additives were added to the continuous water phase and 
neutralized to a pH of 2.0-3.0 by the addition of hydrochloric acid. This 
solution was maintained at a temperature of 100.degree.-125.degree. F. The 
asphalt and the emulsifier solution were then blended together with a 
colloid mill to yield the desired emulsion. 
Specific dialkyl amides tested were dimethyl formamide, dimethyl octadecyl 
amide, dimethyl cocoamide, dimethyl tallow amide, dimethyl hard tallow 
amide, dimethyl oleyl amide, dimethyl canola amide, dimethyl stearyl 
amide, diethyl hard tallow amide, and dibutyl hard tallow amide. 
All emulsifier solutions were adjusted to pH 2.0 by addition of 
hydrochloric acid. All emulsions were tested in accordance with ASTM 
D-2397, and the test results are shown in Table 2. The polymer content, 
for those emulsions containing polymers, was 3.0% by weight polymer in 
asphalt. All emulsions tested passed maximum sieve test specifications of 
0.10% as required for CRS-2. Emulsion viscosities were measured using a 
Saybolt Furol viscometer at 122.degree. F. in accordance with ASTM D-2397. 
Starting and ending asphalt penetrations were determined prior to and 
following incorporation of additives and/or polymers, per ASTM D-5. All 
emulsions were stored at approximately 140.degree. F. 
TABLE 2 
__________________________________________________________________________ 
Weight % Viscosity, SSF 
Penetration 
Formulation 
Emulsifier 
Aqueous 
Residue 
1 Day 
7 Day 
Asphalt 
Start 
End 
Polymer 
__________________________________________________________________________ 
263-31-1 
AA-78 0.85 70.4 27 -- AC-5 160 
-- 4455X.sup.3 
263-32-2 
AA-28 0.85 71.3 50 62 AC-5 160 
-- 4463X.sup.4 
263-94-1 
AA-28 1.00 80 107 AC-5 
160 -- 4455X 
263-95-1 
AA-28 1.00 70.1 34 31 AC-5 160 
-- 4463X 
263-94-5 
AA-78 1.00 70.5 57 55 AC-5 160 
-4455X 
263-124-1 
AA-28 1.03 70.4 616 -- AC-5 160 
--Blend 1.sup.5 
263-130-3 
AA-28 a.03 69.4 317 311 AC-5 
187 -- -- 
263-136-2 
AA-28 1.03 68.3 226 261 AC-20 
75 
-- -- 
263-138-2 
AA-28 1.03 69.6 386 386 AC-20 
75 
134 
Blend 1 
263-150-3 
AA-28 1.03 67.5 230 201 AC-20.sup.1 
75 
111 
-- 
263-151-3 
AA-28 1.03 68.8 476 403 AC-20.sup.2 
75 
116 
-- 
263-154-3 
AA-28 1.00 67.7 236 241 AC-20 
75 
-- -- 
263-178-3 
AA-28 1.00 70.4 273 291 AC-20 
82 
135 
Blend 2.sup.6 
263-179-2 
AA-28 1.00 68.5 387 369 AC-20 
82 
135 
Blend 3.sup.7 
263-180-2 
AA-28 1.00 66.5 160 127 AC-20 
82 
130 
Blend 4.sup.8 
263-183-3 
AA-28 1.00 70.7 439 507 AC-20 
82 
132 
Blend 5.sup.9 
263-189-1 
AA-28 1.00 71.9 187 -- AC-20 
82 
-- 4463X 
__________________________________________________________________________ 
.sup.1 3% by weight DMOA added to asphalt. 
.sup.2 3% bt weight Dutrex extended oil (Shell Chemical Company) added to 
asphalt. 
.sup.3 4455X = Kraton D4455X, linear SB copolymer 
.sup.4 4463X = Kraton D4463X, linear SBS coploymer. 
.sup.5 Blend 1 = 25% Kraton D1101G linear SBS copolymer (11011G), 25% 
Kraton D1118 GX diblock SB copolymer (1118 GX), and 50% DMOA. 
.sup.6 Blend 2 = 25% 1101 G, 25% 1118 GX, and 59% DMTA. 
.sup.7 Blend 3 = 25% 1101G, 25% 1118GX, and 50% DMHTA. 
.sup.8 Blend 4 = 25% 1101G, 25% 1118GX, and 50% DMCOA. 
.sup.9 Blend 5 = 25% 1101 G, 25% 1118GX, and 50% DMSA. 
From the foregoing description, one skilled in the art can easily ascertain 
the assential characteristics of this invention and, without departing 
from the spirit and scope thereof, can make various changes and 
modifications of the invention to adapt it to various usages and 
conditions.