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1. What is SASOFLEX ?
SASOFLEX is a unique combination of German and USA
technologies that meets many of the Customers needs efficiently,
effectively and economically in achieving target specifications
for Polymer Modified Asphalts.
2.Why SASOFLEX ?
In designing SASOFLEX the objective was to combine
the desired effects of a Plastomer (stiffness) plus an Elastomer
(flexibility) through a unique chemical linking mechanism
that enables the asphalt formulator to work with ease to modify
asphalts in a convenient manner and giving control over the
PG range. SASOFLEX incorporates a chemical linking
agent that effectively gets to work in the final modified
asphalt blend in forming a unique chemical linkage of Polymer
to asphalt and Plastomer to asphalt.
3. How does SASOFLEX work?
The Plastomer component of SASOFLEX (ie. Sasobit)
stiffens the asphalt and enhances the DSR or high temperature
rutting resistance /high traffic loading performance whilst
at the same time the Elastomer component of SASOFLEX (ie.
SBS) goes to work in maintaining flexibility at low temperatures.
Since the actual mechanism is through a chemical linkage,
lower quantities of Polymers are required produce the performance
effect and with considerable ease and without the need for
high shear mixing. The fluorescent microscope slides provided
below demonstrate he power of the SASOFLEX technology
in producing finer chemically linked dispersions of a more
consistent and reproducible quality.
4. Stretching the PG Box
It is the aim of every asphalt formulator to be able to take
the most economic source of asphalt and enhance the high temperature
properties (DSR value) and comply with low temperature requirements
(BBR/Direct Tension/Critical Cracking) in fulfilling PG targets.
SASOFLEX makes the achievement of this objective conveniently
and facilitates the accommodation of other additives to target
specific properties even in remote locations that do not have
high-tech equipment.
5. The Power of the Combined Technology includes:
(a) Convenient to handle free flowing powder form.
(b) Ease of dispersion - does not require high shear mixer.
(c) Dispersion time is dramatically reduced from many hours
(for SBS alone) to about 90 minutes.
(d) Since dispersion cycle times are minimized, Plant throughput
is increased by a factor of at least 4 times coupled with
significant labour and energy savings.
(e) Dispersion temperature is reduced by at least 50°
F because of the lower viscosity ie. lower equi-viscous temperture
of SASOFLEX.
(f) This drop in temperature and shorter batch cycle times
substantially reduces asphalt fume emissions.
(g) The viscosity of the modified asphalt is substantially
reduced such that it may be easily handled and transported
with consequent energy savings.
(h) The reduced viscosity of the modified asphalt means easier
mixing with aggregate, more even aggregate coating, easier
aggregate mix handling as well as easier paving at a temperature
reduction of at least 50° F with consequent energy savings.
(i) The compaction resistance of the aggregate mix is reduced
such that the target voids is achieved more easily with reduced
compaction cycles.
(j) Reduction of aggregate mixing temperature also means reduced
asphalt fume emissions and safer working conditions for the
paving workforce.
(k) An anti-oxidant property is imparted to the binder and
asphalt mix. Firstly, the double bonds in the asphalt and
elastomer are broken chemically to form the chemical linkages
so that the number of such bonds for attack by UV light are
reduced. Secondly, the plastomer component shields the remaining
double bonds from UV attack. Thirdly, the substantial reduction
in mixing temperature means that the oxidation of the binder
and aggregate mix is correspondingly reduced in the first
instance (Note that for every 50°F above 210°F that
asphalt is heated, the rate of oxidation is doubled).
(l) The reduction in the viscosity of the asphalt mix and
reduction in compaction resistance means that the paving window
is widened such that paving may be extended into early Fall
and commence again earlier in Spring. This is an important
benefit in completing urgent contracts in cold climates.
(m) The reduced viscosity of the binder coupled with the overall
reduction in surface energy of the binder results in more
effective coating of the aggregate and enhanced adhesive and
cohesive strength thereby reducing need for anti-stripping
agents.
(n) A stable modified asphalt blend is produced such that
it is easy to handle, transport and use without the bother
of phase separation and associated inconveniences.
6. Roofing Applications
SASOFLEX is also recommended for roofing applications
and has all of the benefits outlined above. The low viscosity
improves workability substantially in both shingle and membrane
applications and provides a higher capacity for fillers. Bleeding,
deformation and high temperature wear is substantially reduced
by the more effectively dispersed and cross-linked modifier
system.
Since substantially higher polymer loading is employed in
the Roofing Industry, SASOFLEX provides significant
savings through more effective Plymer coss-linking and reduced
overall levels to meet target specifications.
A key feature of the SASOFLEX concept is that the ratio
of Plastomer (Sasobit) to Elastomer (SBS or any Polymer) can
be easily adjusted to give the desired properties of the final
modified asphalt.
(A). UV MICROGRAPH OF ASPHALT SAMPLE MODIFIED WITHOUT
SASOFLEX BUT MIXTURE OF 1% SASOBIT AND 2% SBS
The micrograph below is that of an asphalt sample modified
with 1% SASOBIT and 2% SBS without the Cross-Linking
agent ie. without SASOFLEX.
The mixing temperature was 350°F for 90 minutes using
a Silverson high shear mixer.
The yellow fluorescent spots clearly highlight the SBS double
bonds that are still intact ie. no mechanism present to break
the bonds and promote cross-linking.
(B). UV MICROGRAPH OF ASPHALT SAMPLE MODIFIED WITH SASOFLEX
The micrograph below is that of an asphalt sample modified
with SASOFLEX which is a one pack, free flowing easy
to handle powder comprising 1% SASOBIT plus 2% SBS
plus Cross-Linking Agent .
The mixing temperature was 350° F for 90 minutes using
a Silverson high shear mixer to be comparative with the experiment
without SASOFLEX.
However in practice, a high shear mixer is not necessary
because of the unique easy dispersion of SASOFLEX in
much shorter time usually necessary for Polymers.
The yellow fluorecsent spots are no longer visible demonstrating
that the double bonds on the SBS have been utilized to produce
a complete network structure ie. the SBS has been more efectively
dispersed. In addition a second network structure is formed
by the SASOBIT crystals at the asphalt performance
temperature (eg. 140° F) and below. This dual network
structure is unique to SASOFLEX in contributing the
high tempertaure and low temperature performance.
Prem Naidoo
Asphalt Additives Business Unit Manager
Moore & Munger, Inc.
A Wholly Owned Subsidiary of Sasol Wax (USA) Corp.
Tel: 228-452-0009, ext. 103
Cell: 228-493-2851
Fax: 228-452-2201
Email: pnaidoo@mooremunger.com
Also reference Group Company at www.sasolwax.com
Jeremy A. Day
Technical Marketing Manager
Asphalt Additives Business Unit
Moore & Munger, Inc.
A Wholly Owned Subsidiary of Sasol Wax (USA) Corp.
Tel: 228-452-0009, ext. 104
Cell: 228-323-2582
Fax: 228-452-2201
Email: jday@mooremunger.com
Also reference Group Company at www.sasolwax.com
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