Note: Descriptions are shown in the official language in which they were submitted.
~074937
The invention is concerned ~ith a process for the prepsration
o~ a mixture Or a chemical~r modified bitumen with aggregate and/or
filler and ~ith a surface coated ~ith 8 mixture so prepared.
It is knoun to coat surrace~ with mixtures of bituminous
binders and aggregate ~nd/or fillers, Such mixture~ may be applied
to B surrace ~such mixtures beine rererred to herein as pre-mixes)
or may be prepared on the surface itself (such mixtures being
referred to herein as surface-mixes); such procedures being particularly
useful in spplication~ such as paring (e.g. road-mdking), hydraulic
engineering, erosion control and building industry e,g. roofing,
flooring, pipe-sealing etc, Both pre-mixes and surrace-mixe~ are
usually prepared by mixing the components at elevated temperatures
; e.g, in the range of from 100 to 250C although lower temper~tures
e,g. ambient temperature may also be used. Insofar as hot pre-mixes
are concerned the components are usually pre-heated to a temperature
$ in this range before they are actively or intimately mixed whereas
insofar as hot surface-mixes are concerned usually only the bituminous
binder is pre-heated toia temperature in this range before it
} i8 mixed with the aggre8ate and/or filler on the surface. Pre-mix
2Q techniques are discussed in "Asf~lt" by Vereniging roor Bitumineuze
Werken, 1973.
Various types of bituminous binder have been mixed with aggregate
~ and/or filler to form pre-mi~es or surface-mixes, but in practice
', the choice is generally limited to those types ~hich have a sufficiently
low riscosity at the mixing temperature. In the case of pre-mixes,
this low viscosity is necessary both for spraying or pumping the
binder into the mixing zone or chamber of the mix spparatu~ and
for good intimate mixing therein with the aggregate or filler.
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]~n the case ol surface-rnixes, this low viscosity is necessary for pumping
or spraying the binder onto the surface. In general, binders may be regarded
as unsuitable or unhandleable if the viscosity thereof exceeds 400-500 cSt
at the mixing ternperature. Potentially very useful binders are those which
have been chemically modified but ~litherto such binders have not been used
on a large-scale because of their high viscosities.
The Applicants have now discovered that it is possible to pre-
pare mixtures of these high viscosity binders by carryir~ out at least a
part of the modification thereof in-situ i.e. by modifying such binders in
the presence of the aggregate and/or filler.
Accordingly, the present invention is concerned with a process
for the preparation of a mixture contairL~ng a chemically modified maleinized
bituminous binder having a viscosity of more than 400 cSt at a temperature
of from about ambient to about 250C, which process comprises chemically
modifying at least a part of a non-emulsified maleinized bituminous binder
c in-situ by means of reaction with from about 28% to about 500% of the stoi-
chiometric amount of a chemical modifier during the process of mixing the
~ rr leinized bituminous binder with the aggregate or filler, at a mixing
:~r temperature of from about ambient temperature to about 250C, wherein the
20 chemical modifier is at least one compound chosen from the group comprising
a metal compound capable of forming ionic groups with the maleinized bitum~
inous binder; an organic compound having at least two functional groups sel-
ected from hydroxyl, mercapto, amino, N-hydrocarbylamino, epoxy and iso-
cyanato and maleinizing compounds.
The invention is particularly useful for preparing pre-mixes,
particularly hot pre-mixes i.e. pre-mixes prepared at elevated temperatures
e.g. at temperatures in the range of from 100 to 250C. Insofar as pre-
parir~ the mlxture at ambient temperature is concerned, the bituminous
binder may be in the form of a cut-back bitumen, i.e. a bitumen which has
been diluted with a volatile solvent, although such binders are not widely
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applied, particularly in road-construction, because of their longer
curing times and the poorer physical properties of the mixture re-
maining after the solvent has evaporated. ~n addition such binders,
even when prepared from known chemically modified bitumens, do not
always produce handleability problems; however, by applying the
process of the present invention, i.e. by chemical modification in-
situ, even these known chemically modified bitumens can be improved,
since it bec~nes possible to use less solvent than would otherwise
have been used.
Bituminous binders prepared by reacting bitumens, such as
gilsonite, straight-run bitumens, propane bitumens or blown bitumens, or
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1074~ 7
mixtures thcreof with cxtcnders ag~llts and/or pol~ncrs, with say from 0.5
to 10 ~wt of olefinically unsaturated anhydrides, c.g. maleic anhydride,
or olefinically unsaturated acids, e.g. maleic acids, are also known. For
convenience, these types of bituminous binders are referred to herein as
maleinized bituminous binders. For example, maleinized bituminous binders
prepared from bitumen/polymer mixtures are described in our co-pending
Application Nos. 221,269 and 221,270. Suitable polymers are olefinically
unsaturated elastomeric materials of molecular weight in the range of from
loo,ooo to 500,000 such as styrene-butadiene copolymers e.g. type "Cariflex"
S 1712 or type "Cariflex" S 1500 (Cariflex is a registered Trade Mark).
Suitable amounts of polymers are below 10 %wt, based on bitumen, with from
0.1 to 7.0 %wt being preferred.
` Such maleinized bituminous binders to be modified in the process
suitably have acid values, determined by titration, of from 0.01 to 2.0
meq/g.
Such maleinized bituminous binders may be modified in the process
by the ionic or covalent coupling thereof by the use of the approprlate
chemical modifier. Suitable chemical modifiers capable of coupling malein-
ized bituminous binders are also described in the aforesaid co-pending
Applications as well as the coupling of emulsified maleinized bituminous
binaers in the presence of aggregate and, optionally, other coupling agents.
Suitable chemical modifiers for ionically coupling maleinized
bituminous binders are compounds of the metals of Group I to IV of the
Periodic Table, especially those of the Sub-Groups IA to IVA, e.g. lithium,
sodium, potassium, calcium, magnesium, barium,
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~7~937
aluminium ~nd lead. ~uit~le compound~ ~re the hydroxides, alkoxides
and leok acid salts o~ these metnls. Specific ex~mples include
the hydroxides o~ lithium, sodiu~, potossium snd bariu~, lead
II acetate, magnesium acetate, alun~nium isopropoxide ~nd aluminium
sec-butoxide and mixtures thereof. Preferably the modi~ier is
; added in aqueou3 solution or i~ in the liquid state at the mixing
temperature.
Suitable chemic~l modifiers which co-valently couple maleinized
bituminous binders are those which form (~hio)ester, amide or
imide groups. Such group6 are formed when organic compounds having
at least two runctional groups capable of reacting with the groups
f attached to the msleini~ed bituminous binder are used as chemical
modiriers. Suitable functional groups include: hydroxyl, mercapto,
amino and N-hydrocarbylamino, epoxy e.B. epoxyalkyl, snd isocyanato
groups. Thus examples Or Yuitable coupling agents are: ethylene
glycol; diethylene glycol; 1,4-butsnediol; glycerol; trimethylolpropane;
: the diglycidyl ester Or bisphenol A; methylenediphenyl-4,4'-di-isocyanate;
tolylene-di-isocyanates; triethylenetriamine; tetraethylene pentamine
and diethsnolamine.
,~ 20 The amount Or chemical modifier used to couple the maleinized
~ituminous binders is from 28 to 500 %w Or that needed stoichiometricslly
to react with, e.g. to neutralize, the binder. Amounts ranging
~ro~ 50 to to 300 %w, particulsrly from 75 to 200 %w Or the theoretical
a~ount are prererred however. m e ~aleinized bituminous binder
msy be blended with extenders and/or polymers before they are
modified in the proce3s.
As stated above, the present invention i~ particular~Y suitable
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for preparing mlxtures of chemically moclified n~leinized bituminous
binders with aggregate and/or filler. The reason for this is that although
maleinized bitum~lous blnders, especial~y those prepared with less than
10% w maleic anhydride, have vlscosities of below 400-500 cSt at the
usual mixing temperatures and therefore are handleable, the chemically
dified maleinized bituminous binders have viscosities well in excess
of 400-500 cSt, usually in excess of 1000 cSt, at the usual mixing
I temperatures and therefore are not handleable and are difficult to mix.
However, the present invention is not restricted to the
preparation of mixtures of chemically modified bituminous binders of
the above types. For example, it n~y be used to prepare maleinized
bituminous binders having a high acid content. As stated hereinbefore
maleinized bituminous binders prepared from below 10% w of maleic
anhydride may have viscosities below 500 cSt at the mixing temperature
but if the amount of maleic anhydride is increased say to about 20% w
then the resultant binder ma~ have a viscosity which is too high to be
handleable. Hence the present invention may be used to maleinize a
bitumen such as a straight-run bitumen or to further maleinize an
already maleinized bituminous binder.
The aggregate and/or filler to be used in the process may
be any conventional aggregate of filler. Examples of suitable aggregates
include gravel, bauxite, granite, gritstones, basalt, porphyry,
dolomite, slags and limestone whereas limestone, sand, asbestos and
glass fibre are examples of suitable fillers. In general, aggregates
may be described as particles which do not
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10749137
pQss through a 75 micron ~ieve wherea~ fillers sre psrticleu which
do pas~ through a 75 micron sieve, In general the ~mount of aggregate
in the mixture i~ ~rom 10% to 5,000 %w based on weight Or homogeneous
bituminous binder.
In the case of preparing pre-mixes, the three components
used in the process i.e. the bituminou~ binder, the aBeregate
and/or filler and the chemical modifier may be fed as separate
streams to the mixing zone but it is also possible to prior mix
the aggregate and/or filler with the chemical modifier or binder.
It is desirable to add, the chemical modifier to the mixing zone
srter some mixing of bitu~inous binder and sggregate and/or filler
~, has already taken pl~ce.
m e in~ention will now be illustrated with reference to the
, following Examples. In the Examples the ~iscosities were determined
by the capillary ~iscosimeter (ASTM D-2170). The penetrations
are the ASTM-D5 penetrations (25C, 0,1 mm) and the ~oftening
'- points the Rin8 and B~ll softening points (C). m e Marshall test
was carried out according to ASTM D-1559, after compaction at
160 C.
~, EXAMPLE I
:~: Preparation of a maleinized bituminous binder
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A Kuwait fully blown bitumen (penetration 40; sortening point
85 C; 1000 g) was extended with 200 8 Or an aromatic oil extract
~, (Dutrex 729 HP), The mixture was then heated to 175C, maleic
J anhydride added (24g, 2 %w) and the mixture maintained at 170-180C
for 2 hours with continual ~tirrinB. m e ~isco~ity Or the homogeneous
'' 25 product w~s about 175 cSt at 190C and the product h~d an ~cid
~ol~e Or 0.23 ~eq/g,
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1t)7~937
EXAMPLE 2 (Comparati~e)
The maleinized bituminous binder (1200 e) prepared according
to Example 1 wa8 heated to 160-180C and ~0~ (15 e) added with
stirring. The temperature was maintained at 160-180C for from
0,5 to 2.0 hour~. The viscosity of the product wss too high to
determine and it was not possible to use the product in ~tandard
hot-mix apparatus.
EXAMPLE 3
Maleinized bituminous binder (66g) prepsred according to
Example 1 ~as pumped at 175-180C into the mixing zone of a laboratory
hot-mix apparatus simultan~ously with the separate addition of
'; 10 1200e of normal road building aggregate (55 %w stone (0.2-l,ôcm),:
35% sand (2mm) and 10% filler (~64~)) at 175-180C. KOH (1.0 g)
was added as an aqueous ~olution to the mixture and ~ixing continued
for 1 minute. The pre-mix of chemically coupled bituminous binder
and aggregate had excellent properties including good compactability.
The Marshall test data for the product are given in Table 1,
EXAMPLE 4
Preparation of a maleinized bituminous binder
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Example 1 was repeated using Kuwait semi-blown bitumen (penetration
80-100; for Marshall test data, see Table 1) and 48g of maleic
anhydride (4 %w), The homogeneou~ product had a viscosity of about
j 109 cSt at 190C and an acid value Or about 0.40 meq/g.
EXAMPLE 5 (comparative)
; 20 Ex~mple 2 ~as repeated using the maleinized bitu~inous binder
(1200 g) prepared according to Example 4 and 34g of the diglycidyl
ether of bisphenol A. The viscosity of the product ~as lôOO cSt
at 190C and it was not possible to use the product in 6tandard
S hot-mix appsratus,
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~XAMPLE 6
Exa~ple 3 wa~ repeated using the maleinized bituminous binder
(66 g) prepared according to ~x~mple 4 and 1.9 g of the di~lycidyl
ether of bisphenol A. ~,le hot-mix of chemically coupled bituminous
binder and aggregate had excellent properties including good compactability.
The Marshall test d~ta for the product are given in Table 1. Similar
results were obtained using KOH instead of the diglycidyl ether
of bisphenol A.
EXAMPLE 7
Preparation of a maleini~ed bitu3inous binder
Ex~mple 1 was repeated using a bitumen (penetration 80-100)
prepared by fluxing (565g) an Irsnian propane bitumen with 635g
Or an Iranian short residue, to which was added 4 %w Or a ~tyrene-bu-
t6diene rubber ("Cariflex" S 1500). The amount of msleic anhydride
used ~as 24g (2 %w). The visco~ity Or the homogeneous product
wa~ about 200 cSt at 190O' and it had an acid value Or 0.17 meq/g.
EXAMPLES 8 snd 9 (Comparative)
Example 2 was repeated using the maleinized bituminou~ binder
(1200 g) prepared according to Example 7 and 26,9 g of ~OH (Example
8) or 39,3 g of aluminium sec-butoxide (Example 93. The viscositie~
of the products were too high to determine and it wa8 not po-~sible
to use the products in standard hot-mix appars,tus.
EXAMPLES 10 snd _11
Example 3 was repeated using the maleinized bituminous binder
(66 g) prepared according to Example 7 and 1.5g o~ ~OH (Example
10) and 2.2g of aluminium sec-butoxide (Example 11). Thc pre-mixes
of chemically coupled bitu~inous binder and ag~regate h~d excellent
properties including good compactabili'y. The Marshell test dsta
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~ 0749371
for the products are glven in Table 1.
Table 1
Example 1* 2*
PM(kN) FM(~) QM(PM/FM)
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Kuwait 80/100 3* 6.7 4.8 1.4
3. 11.3 2.1 6.3
6. 14.2 4.1 3.5
' 10. 11.5 3.9 3.
11. 12.2 3.3 3-7
l* stability
2* flow value
3~ see E~:mple 4
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