Asphalt amine functionalized polymer composition

A bituminous composition comprising a bituminous component, a polymer which comprises at least one block of a conjugated diolefin and at least one block of an acrylic monomer such as an alkyl methacrylate and from 0.001 parts to 1 part by weight of a polyfunctional amine having at least two amino groups. An acid or anhydride functionalized conjugated diene block copolymer may be used in place of the acrylic monomer polymer.

BACKGROUND OF THE INVENTION 
Asphalt is a common material utilized for the preparation of paving and 
roofing materials and also for coatings such as pipe coatings and tank 
liners. While the material is suitable in many respects, it inherently is 
deficient in some physical properties which it would be highly desirable 
to improve. Efforts have been made in this direction by addition of 
certain conjugated diene rubbers, ethylene containing plastics like EVA 
and polyethylene, neoprene, resins, frillers and other materials for the 
modification of one or more of the physical properties of the asphalt. 
Each of these added materials modifies the asphalt in one respect or 
another but certain deficiencies can be noted in all modifiers proposed. 
For example, some of them have excellent weather resistance, sealing and 
bonding properties but are often deficient with respect to warm tack, 
modulus, hardness and other physical properties; and some of them improve 
only the high temperature performance- of asphalt, some only improve the 
low temperature performance of asphalt, while some lack thermal stability 
or mixing stability with asphalt. 
Since the late 1960s, diene polymer rubbers such as styrene-butadiene 
rubber and styrene-rubber block copolymers such as 
styrene-butadiene-styrene and styrene-isoprene-styrene block copolymers 
have been used to dramatically improve the thermal and mechanical 
properties of asphalts. Practical application of the rubber addition 
approach requires that the blended product retain improved properties and 
homogeneity during transportation, storage and processing. Long term 
performance of elastomer-modified asphalts also depends on the ability of 
the blend to maintain thermal and chemical stability. 
To be suitable for paving materials, the asphalt polymer mixtures should 
meet the following requirements: 
(a) The polymer must be mixable in asphalt and stay mixed during subsequent 
processing--compatibility. In a modified asphalt composition, 
compatibility is important. The polar asphaltene fraction of the asphalt 
is generally incompatible with the polymer and phase separates over time. 
This phase separation leads to a serious deterioration in physical 
properties. 
(b) The mixture must have the right rheological (flow) properties to 
prevent rutting which is the permanent deformation of a road caused by 
repetitive traffic loads. Viscosity is important but elasticity is the 
most important aspect since the material must be able to recover rather 
than just resist deformation. This characteristic is most important in 
warm climates. 
(c) The mixture must have good low temperature properties, i.e. resistance 
to cracking. As a road cools, stresses develop because it cannot shrink 
uniformly and eventually this will cause cracking. Traffic-caused stresses 
also contribute. The polymer will lower the temperature at which cracking 
will occur. This characteristic is more important in cold climates. 
(d) Temperature susceptibility of a polymer modified asphalt is a major 
consideration. Ideally, one would want a binder (asphalt and polymer) 
which would be "hard" and elastic at elevated temperatures to resist 
permanent deformation. 
To be suitable for synthetic roofing materials, the asphalt polymer 
mixtures should meet the following requirements: 
(a) sufficient resistance to flow at high temperatures, 
(b) sufficient flexibility at low temperatures, 
(c) workability according to the conventional methods used in the roofing 
technique, 
(d) adequate hot storage stability, 
(e) adequate hardness to prevent deformation during walking on the roof, 
and 
(f) if it is to be used as an adhesive, sufficient adhesion. 
British Patent 1,584,504 made bituminous emulsions which were made with an 
aqueous solution of a polyamine. The emulsion optionally contained a 
functionalized polymer but the bitumen was modified by functionalizing it 
with carboxylic acid anhydride groups. The functionalization of asphalt is 
a difficult and impractical step and is not used commercially. 
At the present time, unfunctionalized polymers are being used in paving and 
roofing applications. Unfunctionalized polymers have certain disadvantages 
which can cause problems when used in applications such as these. Such 
disadvantages include undesirably low adhesion to polar materials such as 
some asphalts, fillers, aggregates, substrates, reinforcing mats, and the 
like. 
SUMMARY OF THE INVENTION 
This invention relates to a bituminous composition with improved properties 
over neat asphalt. The invention is a polymer modified bituminous 
composition which exhibits better compatibility than previous polymer 
modified bituminous compositions. The bituminous composition comprises a 
bituminous component and a functionalized polymer containing at least one 
conjugated diolefin block and, optionally, a vinyl aromatic hydrocarbon 
block and, finally, a polyfunctional amine having at least two amino 
groups. Specific applications of this composition include roofing 
materials, coatings, hot melt asphalt concrete and sealant compositions. 
The polymer may be functionalized by incorporating therein at least one 
acrylic monomer block or the polymer may be functionalized by grafting 
onto the polymer backbone acid or anhydride groups. Preferred acid or 
anhydride groups are those of carboxylic acids. Preferred acrylic monomers 
are alkyl methacrylates and acrylates. Preferred is a composition 
comprising from 1 to 45 parts by weight per 100 parts of the bituminous 
composition of a functionalized block polymer. To this is added from 0.001 
to 1 parts by weight of the bituminous composition of the polyfunctional 
amine. 
In one preferred embodiment of the present invention, the bituminous 
composition contains a block polymer of at least one conjugated diene and 
at least one acrylic monomer with the structure: 
##STR1## 
where R.sub.1 is hydrogen, phenyl or an alkyl radical which is linear or 
branched and has from 1 to 10 carbon atoms and R.sub.2 is an alkyl radical 
which has from 1 to 14 carbon atoms, may contain a tertiary amine or an 
ether linkage and may be a cyclic hydrocarbon. 
These polymers are functionalized in that they contain, in the polymer 
backbone, acrylic, especially methacrylate or acrylate, functionality. 
This provides the polymer with strongly reactive and interactive chemical 
groups. An example is t-butyl which has the formula:

DETAILED DESCRIPTION OF THE INVENTION 
The bituminous component in the bituminous-polymer compositions according 
to the present invention may be a naturally occurring bitumen or derived 
from a mineral oil . Also, petroleum derivatives obtained by a cracking 
process, pitch and coal tar can be used as the bituminous component as 
well as blends of various bituminous materials. Any asphalt may be used 
but the invention is generally more useful for asphalts with high 
asphaltene contents, i.e. greater than 12%, because such asphalts are 
generally incompatible with the polymer component. Asphaltenes are known 
to those skilled in the art. For purposes of this application, asphaltenes 
make up the n-heptane insoluble fraction of asphalt. 
Examples of suitable components include distillation or "straight-run 
bitumens", precipitation bitumens, e.g. propane bitumens, blown bitumens 
and mixtures thereof. Other suitable bituminous components include 
mixtures of one or more of these bitumens with extenders such as petroleum 
extracts, e.g. aromatic extracts, distillates or residues, or with oils. 
Acid functionalized block copolymers which can be used in the present 
invention are hydrogenated and unhydrogenated block copolymers as 
described below which have been reacted with various acid functional 
group-containing molecules. The acid functional group containing molecules 
which may be reacted with such block copolymers to produce a 
functionalized block copolymer useful in the present invention include 
acid or anhydride groups or derivatives thereof. Functionalized polymers 
containing carboxyl groups reacted onto the vinyl aromatic hydrocarbon 
block are described in U.S. Pat. No. 4,868,245 which is herein 
incorporated by reference. The preferred acid monomers for functionalizing 
the polymers of the present invention are those which can be grafted onto 
the diene block of the polymer in free radical initiated reactions. Such 
preferred monomers include acids or anhydrides or derivatives thereof such 
as carboxylic acid groups and their salts, anhydrides, esters, imide 
groups, acid chlorides and the like. Such monomers and functionalized 
polymers incorporating them are described in U.S. Pat. No. 4,578,429 which 
is herein incorporated by reference. The preferred modifying monomers are 
unsaturated mono- and polycarboxylic-containing acids and anhydrides and 
other derivatives thereof. Examples of such monomers include maleic acid, 
maleic anhydride, fumaric acid and the other materials mentioned in the 
above-referenced patent. Sulfonic acid functionalized polymers, such as 
described in U.S. Pat. No. 4,086,171, herein incorporated by reference, 
may also be used. 
The acid functionalized block copolymers utilized should contain from at 
least 0.2% of the functional groups because this ensures the desired 
improvement is obtained. Preferably, from 0.5% to 3% of the acid 
functional groups should be present in the polymer. 
Polymers containing backbone functionality which may be used according to 
the present invention are polymers of conjugated dienes and acrylic 
monomers of the formula described above such as alkyl methacrylates or 
derivatives of alkyl methacrylates such as hydrolyzed alkyl methacrylates 
or anhydride derivatives thereof. Other suitable acrylic monomers include 
acrylates, such as t-butyl acrylate; cyclic alkyl methacrylates, such as 
2,6-dimethylcyclohexyl methacrylate; and acrylates in which the alkyl 
group contains an ether linkage, such as tetrahydrofuran acrylate. 
Copolymers containing two or more conjugated dienes are useful herein. 
Copolymers of conjugated dienes and acrylic monomers with vinyl aromatic 
monomers are preferred and both random and block copolymers thereof are 
useful herein. The description which follows is described in terms of 
block copolymers of conjugated dienes, alkyl methacrylates and vinyl 
aromatic hydrocarbons but it is applicable also to the other polymers 
described in this paragraph. This means that this invention encompasses 
functionalized polymers which are not block copolymers but which 
incorporate the functionality as described below. 
The present invention encompasses polymers which are both high and low in 
molecular weight, as well as in between. High molecular weight polymers 
include those up to several million molecular weight as defined by gel 
permeation chromatography (GPC) peak molecular weight of the main species. 
Low molecular weight polymers include those of only 1000 molecular weight 
or even less. In all cases these polymers contain both conjugated dienes 
and acrylic monomers (alkyl methacrylates). These polymers may have two or 
more vinyl aromatic hydrocarbon blocks, i.e. polystyrene blocks. These 
polymers should have a vinyl aromatic hydrocarbon content of less than 60% 
so that they are more compatible with asphalt and greater than 10% so that 
they will provide flow resistance at reasonable molecular weight. They 
should have molecular weights greater than 30,000 so that they improve 
flow resistance at low use levels and less than 1,000,000 so that they are 
compatible and readily mixable with asphalt. The 1,000,000 molecular 
weight limit refers to linear structures. Radial or star polymer with from 
three to fifty arms are also envisioned. Their uncoupled precursor should 
have a molecular weight below 500,000. After coupling, they could have a 
molecular weight of up to 50 times 500,000, or 25,000,000. 
One class of preferred base polymers of the present invention are block 
copolymers of conjugated dienes, acrylic monomers such as alkyl 
methacrylates or their derivatives and vinyl aromatic hydrocarbons. Such 
block copolymers may be multiblock copolymers of varying structures 
containing various ratios of the monomers including those containing up to 
weight of vinyl aromatic hydrocarbon. At higher vinyl aromatic hydrocarbon 
contents, the polymers are not very compatible with bitumens. Thus, 
multiblock copolymers may be utilized which are linear or radial, 
symmetric or asymmetric, and which have structures represented by the 
formulae, ABAC, ABC, BC, BAC, CABAC, CBC, (CB).sub.n X, (BC).sub.n X, 
(CB).sub.n XA.sub.m, (BC).sub.n XA.sub.m,(CB).sub.n XB.sub.m, (BC).sub.n 
XB.sub.m, etc. where A is the vinyl aromatic hydrocarbon, B is the diene, 
C is the acrylic monomer, X is a coupling agent and n and m are integers 
from 1 to 50. These are just some of the structures possible. Their finite 
number is not meant to limit the scope of the invention. It is not 
necessary but B can be a polymer block of a conjugated diene that has been 
hydrogenated. As can be seen in the examples, hydrogenation of the diene 
is sometimes preferred. 
It may be desirable to acid functionalize these block copolymers of 
methacrylate and rubber. However, the routes to acid functionalizing 
involve exposing the polymer to: (1) heat which eliminates isobutylene to 
form methacrylic acid, or (2), hydrolysis of the ester group by heating 
(70.degree.-90.degree. C.) a polymer solution in the presence of an acid 
or acid catalyst. Both routes can degrade and/or crosslink unsaturated 
rubber. To circumvent this problem the rubber block may be hydrogenated. 
An alternate route to acid functionalization of styrene-rubber copolymers 
is possible by sequentially polymerizing a segment of polymethacrylate 
onto one end of the styrene-rubber to make an "ABC" type polymer. The acid 
functionality can then be made in situ during the acid wash stage of 
catalyst removal. 
Preferred polymers for use herein are block copolymers which contain a 
block of conjugated diene and a block of alkyl methacrylate because such 
polymers are more compatible in asphalt and improve the low temperature 
properties of asphalt as well as offering improved adhesion, reactivity, 
crosslinkability, etc. 
The block copolymers may be produced by any well known block polymerization 
or copolymerization procedures including the well-known sequential 
addition of monomer techniques, incremental addition of monomer technique 
or coupling technique. As is well known in the block copolymer art, 
tapered copolymer blocks can be incorporated in the multiblock copolymer 
by copolymerizing a mixture of conjugated diene and vinyl aromatic 
hydrocarbon monomers utilizing the difference in their copolymerization 
reactivity rates. The manufacture of such polymers containing alkyl 
methacrylates is described in U.S. Pat. No. 5,002,676 and copending 
commonly assigned application Ser. No. 525,812, filed May 21, 1990, both 
of which are herein incorporated by reference. 
Conjugated dienes which may be utilized to prepare the polymers and 
copolymers include those having from 4 to 8 carbon atoms and also include 
1,3-butadiene, 2-methyl-1,3-butadiene(isoprene), 2,3-dimethyl-1, 
3-butadiene, 1,3-pentadiene, 1,3-hexadiene and the like. Mixtures of such 
conjugated dienes may also be used. The preferred conjugated dienes are 
1,3-butadiene and isoprene. 
Vinyl aromatic hydrocarbons which may be utilized to prepare copolymers 
include styrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 
2,4-dimethylstyrene, alpha-methylstyrene, vinylnapthal vinylanthracene and 
the like. The preferred vinyl aromatic hydrocarbon is styrene. 
Alkyl methacrylates are preferred for use herein and those employed herein 
include methacrylates wherein the alkyl group has up to 14 carbon atoms 
inclusive. Derivatives of these polymers are also included herein, such 
as, for example, polymers with partially or completely acidified 
methacrylate groups, their anhydrides, their ionomers, their reaction 
products with alcohols and the like. Derivatives of alkyl methacrylates 
include methacrylic acid, methacrylic acid salts (for example, zinc, 
sodium and quaternary ammonium salts) and anhydrides formed between 
adjacent acid units by heating. It should be noted that derivatization of 
the methacrylate group can be carried out prior to adding the polymer to 
bitumen or in situ after the polymer is added to bitumen. Catalysts such 
as acids and bases can be added to aid the in situ conversion in asphalt. 
Illustrative of such methacrylate esters are methyl methacrylate, ethyl 
methacrylate, sec-butyl methacrylate, t-butyl methacrylate, i-amyl 
methacrylate, hexyl methacrylate, decyl methacrylate and dodecyl 
methacrylate. Largely because of ease of polymerization, the preferred 
alkyl methacrylates are branched-butyl methacrylates, i.e., iso-butyl 
methacrylate and t-butyl methacrylate. The desired poly(alkyl 
methacrylate) block is produced by directly polymerizing the corresponding 
alkyl methacrylate monomer or alternatively the desired block is obtained 
by polymerizing a more easily polymerizable methacrylate and subsequently 
transesterifying the product to introduce the desired alkyl group. It is 
also possible to copolymerize randomly or by sequential addition two or 
more different acrylic monomers in the acrylic monomer block. Tertiary 
butyl methacrylate (TBMA) is preferred because of ease of purification and 
polymerization, and because it undergoes thermolysis at temperatures as 
low as about 180.degree. C. 
High acrylic monomer content polymers and high molecular weight acrylic 
monomer blocks are also contemplated herein. Acrylic monomer contents of 
up to 80% or even as high as 99% and acrylic monomer block molecular 
weights up to 300,000 are envisioned. However, some acrylic monomers, such 
as TBMA, are presently expensive compared to monomers typically used 
commercially. Lower acrylic monomer contents, such as 1 to 30%, preferably 
1 to 10%, and block molecular weights are advantageous at the present 
time, at least from a cost standpoint. As little as 0.1% of the acrylic 
monomer will provide the advantages of the invention but the results are 
better as the amount of acrylic monomer used is increased. 
Acrylic monomer-containing polymers which do not improve the flow 
resistance of bitumen dramatically are of interest when combined with 
bitumen, or when combined with bitumen and other polymers (which provide 
the flow resistance; e.g., block copolymers of conjugated dienes and 
styrene which contain two or more styrene blocks, provided that they are 
effective at providing interfacial properties, or provided that they are 
crosslinked or reacted. Polymers which are easily crosslinked in asphalt 
are typically of high molecular weight so that less crosslinks per volume 
or weight of polymer are required. Furthermore, polymers which are easily 
crosslinked in asphalt and contain an acrylic monomer (or derivative) 
block include ones with many arms so that less crosslinks per volume or 
weight of polymer are required. Crosslinking can be carried out by 
conventional approaches such as sulfur or free radical or by reacting 
through methacrylate or methacrylate derivative groups. 
Low molecular weight (less than 30,000 molecular weight) acrylic 
monomer-containing polymers are of interest for blending with asphalt when 
they are active at interfaces or when they are cured or reacted to form 
higher molecular weight polymers. Low molecular weight acrylic 
monomer-containing polymers are easily mixed into asphalt. 
The present invention works with both unhydrogenated and hydrogenated 
polymers. Hydrogenated ones are useful in certain circumstances. While 
unhydrogenated diene polymers have a number of outstanding technical 
advantages, one of their principal limitations lies in their sensitivity 
to oxidation. This can be minimized by hydrogenating the copolymers, 
especially in the diene blocks. The hydrogenation of these polymers and 
copolymers may be carried out by a variety of well established processes 
including hydrogenation in the presence of such catalysts as Raney Nickel, 
noble metals such as platinum, palladium and the like and soluble 
transition metal catalysts. Titanium biscyclopentadienyl catalysts may 
also be used. Suitable hydrogenation processes which can be used are ones 
wherein the diene-containing polymer or copolymer is dissolved in an inert 
hydrocarbon diluent such as cyclohexane and hydrogenated by reaction with 
hydrogen in the presence of a soluble hydrogenation catalyst. Such 
processes are disclosed in U.S. Pat. Nos. 3,113,986, 4,226,952 and Reissue 
27,145, the disclosures of which are herein incorporated by reference. The 
polymers are hydrogenated in such a manner as to produce hydrogenated 
polymers having a residual unsaturation content in the polydiene block of 
less than about 20%, and preferably as close to zero percent as possible, 
of their original unsaturation content prior to hydrogenation. 
For purposes of achieving the most useful crosslinking, it is preferred 
that the functionality in the polymer be localized. One example of a 
polymer with localized functionality is a vinyl aromatic 
hydrocarbon/diene/ vinyl aromatic hydrocarbon/acrylic monomer block 
copolymer--all the functionality is at one end of the polymer (a specific 
example is the polymer used in Example 2 below). The localization of the 
functionality allows the production, by crosslinking, of a well defined 
star structure which will still be thermoplastic and processable. Randomly 
dispersed functionality, such as that of the polymer of Example 1 below, 
will, when crosslinked at the same levels, lead to a completely 
crosslinked system which is a thermoset. 
A highly preferred polymer for use herein is a vinyl aromatic 
hydrocarbon/diene/acrylic monomer triblock copolymer. Crosslinking this 
polymer with a polyfunctional amine produces a radial structure with 
greatly enhanced properties--increased softening, decreased penetration 
and improved fatigue resistance. 
The composition of the present invention generally comprises 100 parts by 
weight of a bituminous component and from 1 to 45 parts by weight per 100 
parts of the composition of the polymer described above. If less than I 
part of the polymer of the invention is used, then the composition does 
not exhibit enhanced properties (increased softening point, decreased 
penetration and improved fatigue resistance). If more than 45 parts are 
used, the composition may be too high in viscosity depending upon the 
specific polymer structure. If more than 25 parts are used, the 
compositions may be too costly. However, the range of 25-40 parts polymer 
is of interest because often master batches are prepared at a 
manufacturing site and let down with additional bitumen later in the 
field. 
The bituminous compositions of the present invention must contain from 
about 0.001 to about 1 part by weight of the composition of a 
polyfunctional amine having at least two amino groups. If less than 0.001 
parts is used, then there is no benefit in enhancing compatibility and if 
more than 1 part is used, then the composition will be viscous to process. 
It is theorized that the amine reacts with both the functional groups on 
the polymer and the carboxyl groups on the asphaltenes, thereby linking 
the two phases together and making the mixture more stable. Thus, the 
bitumen and the polymer are made more compatible than they normally would 
be without the presence of the amine. Amine compounds which can be used 
herein include but are not limited to aromatic amines such as 
p-phenylenediamine, 2,4-diaminotoluene, benzidine, diaminonaphthalene, 
2,7-diaminofluore methylenedianiline, aminophenylsulfone and 
dianilineether; aliphatic amines such as ethylenediamine, 
1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 
1,5-diaminopentane, hexanediamine, diaminooctane, 1,9-diaminononane, 
1,10-diaminodecane, 1,12-diaminododecane, 1,2-diaminocyclohexane, 
1,4-diaminocyclohexane, 1,8-diamino-p-menthane, isophoronediamine, 
1,3-cyclohexanebis(methylamine), m-xylylenediamine, 
1,3-diamino-2-hydroxypropane, 3,3'-iminobispr methyldipropylamine, 
diethylenetriamine, triethylenetetrameine, tetraethylenepentamine, 
N,N'-bis(2-aminoethyl)-1,3-propanediamine, 
N,N'-bis(3-aminopropyl)ethylenediamine and 1,4polyamines such as 
tris(2-aminoethyl)amine. Secondary amines are acceptable but primary 
amines are preferred because they are more reactive and will form very 
stable imides. Aromatic amines are also acceptable but aliphatic amines 
are preferred because they are more reactive. Unhindered amines are 
preferred with CH.sub.2 NH.sub.2 most preferred because they are more 
reactive. Other functionality can be present as long as it does not 
interfere with the grafting reaction. Acceptable groups are amines, 
amides, esters, hydroxyls, halogens, ethers, sulfones, aromatic rings, 
olefins, acetylenes, sulfides. These are exemplary, not limiting. High 
boiling (BP&gt;160.degree. C.) amines are preferred for ease of addition and 
mixing. They may be liquid or solid at room temperature. 
The compositions of the present invention may optionally include other 
ingredients like fillers such as ground tires or inorganic fillers like 
talc, calcium carbonate and carbon black. The composition may also include 
resins and oils and other components such as stabilizers. It may also 
include other polymers, for example, other polymers of conjugated 
diolefins. 
Hot melt asphalt concrete compositions according to the present invention 
are especially advantageous. Hot melt asphalt concrete compositions 
according to the present invention will normally contain from 80 parts to 
99 parts by weight of aggregate and from 1 part to 20 parts of a 
bituminous composition which is generally comprised of 85 to 99 parts by 
weight per 100 parts of the bituminous composition of a bituminous 
component and from 1 part to 15 parts by weight per 100 parts of the 
bituminous composition of one of the polymers discussed above. The same 
amount of amine is used to provide the advantages discussed above. If less 
than 1 part of the polymer is used, then improved adhesion between bitumen 
and aggregate is not obtained and if more than 15 parts of the polymer is 
used, then the composition is too costly and high in viscosity. Asphalts 
with good flow resistance prior to polymer addition are preferred at very 
low polymer concentrations because at very low polymer concentrations the 
polymer does not contribute strongly to other properties such as 
deformation resistance, i.e. rutting resistance. In other words, at low 
polymer concentrations, asphalts with good rutting resistance on their own 
are preferred. The bituminous composition may optionally include other 
ingredients such as fillers, such as ground tires or inorganic fillers. 
The composition may also include resins and oils and stabilizers. It may 
also include other polymers, for example, non-functionalized polymers of 
conjugated diolefins. 
Aggregate is basically rocks and sand. It is intended to be mixed with the 
bituminous composition to form the hot mix asphalt concrete. The 
bituminous composition is the binder which holds the aggregate together. 
In using the bituminous composition of the present invention in hot melt 
asphalt concrete, it is preferred that these polymers comprise from 1 to 8 
parts by weight per hundred parts by weight of the bituminous composition. 
However, if it is desired to achieve the maximum anti-stripping results in 
the most cost effective manner, it is most preferred that the polymers 
comprise from 1 to 4 parts by weight per hundred parts by weight of the 
bituminous composition. 
Roofing compositions according to the present invention are also especially 
advantageous. In roofing compositions designed for roll roofing membranes 
a composition of 85-92 parts asphalt and 8-15 parts polymer is preferred. 
A composition of 87-90 parts asphalt and 10-13 parts polymer is most 
preferred. As with HMAC compositions other additives such as inorganic 
fillers, resins, oils, and stabilizers may be added. 
Similar compositions may be used for laminating adhesives and tab 
adhesives. For laminating or tab adhesives a composition of 90-96 parts 
asphalt and 4-10 parts polymer is preferred. 
EXAMPLE 1 
Anhydride Modified Polymer 
Four bitumen/polymer blends were made. The blends contained 88% asphalt, 
10% unfunctionalized unhydrogenated polymer (KRATON.RTM.D1101 rubber which 
is a commercially available unhydrogenated linear 
styrene-butadiene-styrene block copolymer) and 2% KRATONOG1901X rubber (a 
commercially available selectively hydrogenated styrene-butadiene-styrene 
block copolymer containing approximately 1.8% weight grafted maleic 
anhydride). Two of the blends were made with WR AC20, an asphalt made by 
Shell Oil Company at its Deer Park, Texas Refinery, and the other two 
blends were made with DS AC20, an asphalt made by Diamond Shamrock. For 
each asphalt, 0.07 parts of m-xylylene diamine was added to only one of 
the two blends. 
The compatibility of the blends were then compared by determining the 
percent separation. This was carried out by aging samples under nitrogen 
at 1600.degree. C. for five days. After cooling, a clear phase separation 
into a soft, rubbery polymer-rich phase and a hard, glassy asphaltene 
phase was typically observed. 
When the WRC AC20 blend without the amine was tested, the asphaltene phase 
comprised approximately 45% of the total but when the amine was added, the 
asphaltene phase comprised only about 1-2% of the total. Similarly, for 
the DS AC20 asphalt, without the amine the asphaltene phase was 
approximately 45% and with the amine, the asphaltene phase was only about 
15%. Thus, it can be seen that the amine does have a substantial impact 
upon the compatibility of the bitumen/polymer blend. 
EXAMPLE 2 
Tertiary Butyl Methacrylate Polymer 
The asphalt used in this experiment was WRC AC20. The tertiary butyl 
methacrylate (TBMA) polymer used herein was a linear styrene (15,000 
molecular weight)--butadiene (70,000 MW)--styrene (7500 MW)--TBMA (5,000 
MW) block copolymer. 
Four blends, all containing 12 parts by weight polymer, were prepared. The 
first contained KRATON.RTM. D1101 rubber as described above. The second 
contained the above-described TBMA block copolymer. The third contained 
the above TBMA polymer to which 0.08 parts of m-xylenediamine was added. 
In the fourth blend, the amine was added to the asphalt before the TBMA 
polymer was added. 
The physical properties of the four blends were determined and are compared 
in the table set forth below. Compatibility was determined as described 
above. Pen was determined by ASTM D-5 and is a measure of the hardness of 
the blend. The 1600.degree. C. viscosity was measured on a Brookfield 
viscometer (ASTM D-4402) and is important because this is a typical 
processing temperature and an appropriate viscosity is required. R&B is 
ring and ball softening point (ASTM D-36). 
______________________________________ 
tBMA POLYMERS 
##STR3## 
R&B pen Compat 160.degree. C. vis 
______________________________________ 
D1101 230 28 57 4350 
tBMA 210 32 100 5300 
tBMA than amine 
221 30 100 5700 
amine then tBMA 
219 32 93 4800 
______________________________________ 
It can be seen that all of the TBMA blends are far superior in 
compatibility to the unhydrogenated unfunctionalized polymer. Also, it can 
be seen that, while the pen and 1600 viscosities are comparable, the two 
TBMA samples including the amine had a higher R&B than the TBMA sample 
without the amine.