RUBBER_KELVAR by jbskumar

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									                                                                                            Technical Paper




                        
        DuPont Advanced Fibers Systems




                    KEVLAR Engineered Elastomer
                for Reinforcement of Rubber Roll Covers


                                                                       by




                                           C. W. Tsimpris
                                   DuPont Advanced Fibers Systems
                                         Richmond, Virginia



                                       Based on a presentation given at the
                                        Rubber Roller Group Meeting
                                            Las Vegas, Nevada
                                                May 6, 2003



        H-89940 5/03


        2003 E.I. du Pont de Nemours and Company. All rights reserved.
        The DuPont oval logo, DuPont and KEVLAR are trademarks or registered trademarks of E. I. du Pont de Nemours and Company.




DuPont Advanced Fibers Systems ■ 5401 Jefferson Davis Highway ■ Richmond, VA 23234 ■ (800) 453-8527
                     KEVLAR Engineered Elastomer
                for Reinforcement of Rubber Roll Covers


                                              ABSTRACT

KEVLAR engineered elastomer, a composite of KEVLAR pulp and elastomer,
enables incorporating high-surface-area para-aramid pulp reinforcement to rubber
compounds. It affords the rubber chemist opportunities to go beyond present limits in
designing rubber compounds. It not only provides a vehicle for aramid pulp
reinforcement of rubber compounds; but also, by its proprietary manufacturing process,
maximizes the effectiveness of aramid pulp reinforcement.

Engineered elastomer builds tensile and compressive modulus at low loadings allowing
compounds to be re-engineered to enhance properties. It is possible to obtain very high
modular anisotropy by extruding or milling a compound into a thin sheet. Tear
resistance can be increased, and tear propagation can be reduced. Compounds
reinforced with engineered elastomer have excellent dynamic properties. It enables
building modulus without significantly increasing hysteresis. It is also highly effective
as a processing aid by increasing compound green strength.

Rubber roll cover compounds reinforced with engineered elastomer have been
developed and are in routine use in several industries. Rolls covered with these
compounds have demonstrated reduced abrasion, better cut resistance, and lower cut
growth resistance – and thus a longer life in use.




                                          INTRODUCTION

DuPont KEVLAR brand fiber was introduced in the 1970’s. KEVLAR, the world’s
first para-aramid fiber, is known for its high strength to weight ratio, high modulus, and
excellent chemical and thermal stability. Initially, it was offered in continuous filament
form, and soon found applications in tires, mechanical rubber goods, bullet resistant
vests, and composites. In the 1980’s, short forms of the fiber - staple, floc, and pulp -
were introduced and quickly found acceptance in cut-resistant protective apparel,
gaskets, and friction materials. Photographs of these three product forms are shown
in Figure 1.




DuPont and KEVLAR are trademarks and registered trademarks of E. I. du Pont de Nemours and Company
Once short forms of KEVLAR and Akzo’s (now Teijin Twaron’s) para-aramid
TWARON were introduced, they were evaluated for rubber reinforcement. Using
short fibers (such as cellulosics, cotton linters, cut scrap denim, polyester, and nylon) to
reinforce rubber is common in the rubber industry. They improve green strength,
provide dimensional stability prior to cure, and improve mechanical properties of the
vulcanizate. Compounders found that they could incorporate para-aramid floc (we
define floc as short uncrimped fiber less than 6 mm long) into rubber using an
internal mixer or a roll mill, often with difficulty. An electron photomicrograph
showing floc in a rubber compound may be found in Figure 2. Incorporating the
high-surface-area pulp product (Figure 3) proved to be exceedingly difficult. Para-
aramid pulp is a low bulk density, static-prone material that is hard to handle in a
rubber plant. A few people were able to adequately disperse pulp into a rubber
compound. Their work did demonstrate the superior reinforcement potential of
aramid pulp if the dispersion limitation were overcome. Compounds reinforced with
pulp had 3-5x higher modulus at a given loading than those reinforced with floc.
Pulp reinforced compounds also had lower heat build up in dynamic applications,
and they had had better processing characteristics. An electron photomicrograph
showing pulp in a rubber compound may be found in Figure 4.

The rubber industry frequently utilizes dispersion or masterbatch technology to
incorporate materials that are difficult to mix into a rubber compound. This was
quickly identified as the preferred method for incorporating aramid pulp into a
rubber compound.

DuPont initiated studies to define a method to disperse para-aramid pulp into
rubber, and this effort led to development of a unique new technology platform for
dispersing pulp into an elastomer matrix. Products produced via this technology
showed superior dispersion of aramid pulp in rubber compounds. Two samples of
rubber compound having identical compositions were analyzed using an ultrasonic
scanning technique that measures relative porosity; the two scans are shown in
Figure 5. In the sample on the left, the pulp was introduced using engineered
elastomer; in the sample on the right, the pulp was added directly into the rubber.
Both compounds were mixed using a laboratory scale internal mixer. A uniform
color indicates a homogenous mixture. The sample made by compounding pulp
directly into the rubber shows significant color differences indicating relatively poor
fiber dispersion; the sample prepared using engineered elastomer is nearly a
uniform color, demonstrating its excellent dispersion.

Product made via this new technology enabled dispersion of pulp into rubber so
well that it was given a new name, ‘KEVLAR engineered elastomer.’ Initial
evaluation in the rubber industry confirmed that engineered elastomer was far
easier to process than dry para-aramid pulp, and confirmed the improved
dispersability of pulp made possible by using this offering. Initial adoptions for
engineered elastomer were in power transmission belts. This industry had
experience with short-fibers, a common ingredient in belt formulations.

TWARON is a registered trademark of Teijin Twaron B. V.
                         REINFORCMENT EFFICIENCY

One of the first rubber chemists who evaluated engineered elastomer found it highly
effective in rubber reinforcement. This person described the offering as having…
               “an intimacy between the rubber and particle never before
                        reached via conventional compounding.”

We also learned that several other customers who had been able to achieve good
dispersion of dry para-aramid pulp in rubber found better reinforcement when using
engineered elastomer to introduce pulp into their compound. They obtained up to 20%
higher modulus at the same fiber content when using engineered elastomer rather than
using raw pulp. Internal DuPont data illustrating the improved reinforcement efficiency
is shown in Figure 6. The NR/SBR tire tread compound reinforced with engineered
elastomer had about an 8% higher modulus than an identical compound reinforced
with dry pulp.

We proposed a hypothesis to explain the basis for this improved reinforcement; the
hypothesis is based on:

   •   Superior dispersion of the fiber,
   •   Openness of the fiber, and
   •   The microstructure of para-aramid fiber.

The importance of good dispersion of fillers in a rubber compound is well known in the
rubber industry. Dispersing fibers into a rubber compound can be more challenging
than using traditional fillers. Fibers can form tangles (called neps in the fiber industry)
that are not likely to be removed in rubber mixing. It is also important that the
concentrate be well dispersed (mixed) into the final rubber compound. Both fiber neps
and undispersed concentrate can form defect sites that can lead to failure of the rubber
compound. An example of both tangles and undispersed concentrate in a compound
is shown in Figure 7. Eliminating defects like those shown in Figure 7 requires that the
technology used to prepare the concentrate treat the pulp in a manner to avoid forming
tangles, and that the rubber mixing technology subject the concentrate to sufficient
shear to blend the concentrate into the compound.

Our quality policy states that “The KEVLAR organization will be recognized as
providing superior value and continual improvement in all the customer services and
products supplied.” We strive for continual improvement in our engineered elastomer
product. All products are tested for dispersion of pulp into the concentrate. We have
reduced the number of apparent ‘defects’ in our product by over 30%. We have
changed the physical form of the offering to a more ‘user friendly’ form that more easily
incorporates into a rubber compound. We continually look for improvements in mixing
procedures to make the mixing process easier and suggest these improvements to our
customers.
Openness is also essential to maximize the reinforcement potential of aramid pulp.
Note the number of fine fibrils present in the electron micrograph of the pulp shown in
Figure 3. Having these fibrils ‘open’ and extended is essential. Photographs of two
compound samples illustrating openness of pulp are shown in Figure 8. The photo on
the right is of a compound reinforced with KEVLAR engineered elastomer. Note the
number of extended fibrils present in the photograph. An identical compound
formulation, mixed by the same procedure, is shown on the left. The aramid pulp was
incorporated using a concentrate prepared by a technology different from that used to
produce engineered elastomer. Note that the pulp is not as extended and, in some
cases, even appears somewhat compacted.

Openness is essential to achieve interaction between the fiber and rubber. The
polymer base for para-aramid is poly(p-phenylene terephthalamide); a rigid rod
molecule. When spun into fiber, the polymer becomes highly oriented and highly
crystalline. The high orientation allows extensive hydrogen bonding between the
carbonyl and ‘N-H’ functionality in the amide groups of adjacent polymer chains (Figure
9.) KEVLAR fiber is spun from highly concentrated sulphuric acid. Free SO3- in the
solvent sulphonates some of the aromatic rings, and studies within DuPont suggest
that the resulting sulphonic acid groups tend to be accessible at the fibril surface. Thus,
the pulp fibril surface contains polar groups (amide and sulphonic acid on the polymer
backbone as well as amine and carboxylic acid end groups) that can associate with a
group on an elastomer.

We believe that the well-dispersed, well-opened pulp fiber present in KEVLAR
engineered elastomer can associate with the elastomer matix. Evidence for this
association of the elastomer with charged groups on the fibril surface is provided by
gravimetric determination of fiber content of engineered elastomer. When engineered
elastomer grades in neoprene that contain 23% fiber on a weight basis are analyzed by
gravimetric analysis, they average about 26% fiber. Gravimetric analysis of ‘apparent’
fiber content of engineered elastomer in the more polar NBR matrix averages 29.1%
fiber, although the nominal fiber concentration is 23 weight percent. Non-fiber
containing controls, subjected to our process, show no fiber present.

We propose that the gravimetric analyses provide the evidence for ‘bound rubber’ in
engineered elastomer, similar to bound rubber in carbon black. Bound rubber theories
for carbon black assume that segments of elastomer molecules adhere to ‘active sites’
or ‘reactive sites’ on the filler particles. Leblanc describes this theory in a recent
publication (1). A similar mechanism could certainly be operative in engineered
elastomer.


(1) J. L. Leblanc, J. Applied Polymer Science, 66, 2257 (1997).
The key requirement for our hypothesis is high accessibility of the surface of the pulp to
the elastomer. The patented process used to prepare engineered elastomer presents
the pulp to the elastomer in a way that the fiber is fully open to allow the elastomer to
completely wet the fibrils. The engineered elastomer process maximizes the wetting of
the pulp allowing it to reinforce with maximum efficiency. If pulp is mixed directly in an
internal mixer or roll mill, or if a ‘masterbatch’ of pulp in rubber is made by other
technologies, the pulp can become compacted to some degree, and its reinforcing
potential can not be fully realized. The process by which engineered elastomer is
manufactured creates the intimacy between the rubber and particle. Engineered
elastomer is more than a simple masterbatch or dispersion of pulp in elastomer.


                       REQUIREMENTS IN ROLL COVERS
One ‘product need’ for a roll cover is that it has long life in service. Service life can
be affected by a number of factors. Certainly, the elastomer matrix is critical; the
elastomer must be stable to the chemical environment and temperature in which
the roll will operate. Other important considerations are the physical properties of
the compound; its hardness, abrasion resistance, tear resistance, compression set,
and dynamic properties.

There are many references that summarize the chemical and thermal resistance of
different elastomer matrixes, included the Rubber Roller Group Handbook, a
benefit of being a member of the Rubber Roller Group. KEVLAR pulp is a
remarkably chemically stable material. It is stable in most organic solvents, salt
solutions, petroleum products, and many dilute acids and bases over a broad
temperature range. Its limitations are primarily strong aqueous acids, bases and
bleach over long periods of time and at elevated temperatures.

Once the elastomer matrix for a roll cover is selected, the goal is often to maximize the
abrasion and tear resistance of the rubber compound. The dynamics of a roll cover are
complex; a schematic is shown in the Roller Group Handbook. A good discussion of a
possible mechanism for abrasion of a rubber covered roll is described in an article
published by Metlikovic and Meineke(2). Abrasion results from pressure on the working
roll, which causes a stress on the rubber covering. This stress leads to a strain, or
deformation of the rubber. The strain causes a bulge in the rubber as it approaches the
pressure point (roll nip.) The shape of the roll cover changes from the dotted line to the
solid line as shown in Figure 10.


(2) P. Metlikovic and E. Meineke, “Stesses, Slip and Abrasion of Rubber Covered Conveyor Rollers, A
Review”, Paper 66, ACS Rubber Division Meeting, Louisville, 1996.
The rubber moves rapidly in the entry bulge as the turning roll approaches the point of
maximum stress. The rubber is subjected to a tangential shear stress and a normal
friction stress. Since the shear stress is greater than the friction stress between points A
and B, the rubber slips in this region. This slipping under stress can lead to abrasion of
the roll cover. A similar situation exists in the exit bulge and slipping occurs between
points C and D. The theory presented in Melokovic and Meineke’s paper predicts that
abrasion is inversely proportional to compound modulus; abrasion resistance can be
improved by increasing compound modulus.



                    EFFECT OF ENGINEERED ELASTOMER
                        ON COMPOUND PROPERTIES

KEVLAR engineered elastomer builds compound modulus very efficiently. The effect
of aramid pulp on modulus in a SBR/BR treadstock is shown in Figure 11. Modulus
increases dramatically at low fiber loading.

Para-aramid pulp has a high L/D aspect ratio. This geometry makes possible an
orientation of the particle when sheared in processing. Calendering or extruding
compounds reinforced with aramid pulp leads to modular anisotropy – a difference in
modulus between the machine direction (MD) and cross machine direction (XMD.)
This modular anisotropy is illustrated in the data shown in Figure 11. MD modulus is
about 5X that of XMD modulus in 2-mm test pieces of this NR/SBR tire tread
compound. Samples calendered or extruded to thinner sheets will display even higher
anisotropy. Some users of engineered elastomer routinely achieve MD/XMD ratios
greater than 10.

Using engineered elastomer to reinforce a roll cover compound can help reduce wear due
to slipping and abrasion. By designing the roll so fibers are aligned in the circumferential
direction (a strip builder for rolls will achieve this orientation), the modulus or stiffness of
the compound can be increased in this direction. The strain at a given stress will be
reduced, so the entrance and exit bulge in a running roll will be reduced. However
because of the modular anisotropy possible with aramid pulp reinforcement, radial and
axial moduli are increased to a lesser extent.

The ability of engineered elastomer to efficiently build compound modulus was mentioned
previously. As seen in Figure 12, aramid pulp builds modulus about 3 to 5 times more
efficiently that short fibers or flocs that are often used in neoprene power transmission belt
compounds. Figure 13 illustrates the effect of adding both carbon black and pulp to a NR
tire compound. The lowest curve is a gum rubber compound. The next three stress-
strain curves show the increase in modulus by adding 30, 45 and 60 phr N330 carbon
black. The upper two curves show the dramatic increase in modulus achieved by adding
1 and 3 phr aramid pulp to the compound. Aramid pulp addition of only 1 phr gives a
greater increase in modulus than 15 parts of N330.
Increasing compound modulus using traditional stiffening agents typically results in an
increase in compound hardness. For a roll cover, an increase in hardness may mean a
sacrifice in roll grip since a harder roll may have less desirable frictional properties.
Engineering the rubber compound by balancing the relative content of aramid pulp and
other reinforcing agents allows for increased modulus without an increase in hardness.
This is illustrated in a NBR roll compound formulation in Figure 14. Compounds were
prepared at different loadings of silica and aramid pulp. The control (no fiber compound)
has a Shore ‘A’ durometer hardness of 81. A compound of 80 durometer was prepared
with >6X higher modulus (13.1 vs 2.1 MPa) by addition of 9 phr aramid pulp while
decreasing silica from 45 to 15 phr.

Additional data from this compound study are shown in Figure 15. Incorporating
engineered elastomer into the rubber compound enabled an improvement in both tear
and abrasion – two key properties for improved performance in a rubber covered roll.
Aramid pulp enables desirable improvements in modulus, tear and abrasion resistance
without affecting hardness or affecting processability. Mooney viscosity of these NBR roll
cover compounds is shown in Figure 16. The modulus increase in the neoprene power
transmission belt compounds (Figure 12) was accompanied by a lower increase in
Mooney viscosity than when using flocs.

Compounds reinforced with engineered elastomer display modular anisotropy, a great
increase in modulus in the machine direction, and a far smaller increase in modulus in the
cross-machine direction. In contrast, tear resistance increases in both the machine (MD)
and cross-machine (XMD) direction. Data from the SBR/BR heavy duty treadstock study
are shown in Figure 17 (trouser tear) and Figure 18 (Die C Tear.) We attribute the
isotropic increase in tear resistance in compounds reinforced with engineered elastomer
to the three dimensional nature of aramid pulp, and to the openness of the pulp which
results from our manufacturing process.

Compounds reinforced with engineered elastomer behave quite differently than their no-
fiber controls in tear testing. Control compounds will stretch in the tensile test machine,
and then suddenly fail. A compound reinforced with engineered elastomer will stretch as
it is pulled in the tensile tester; one or more ‘notches’ will form on one side as stretching
continues. Ultimately, the compound reinforced with engineered elastomer will fail – at a
higher tear strength than the no-fiber control. Photographs of a tear test are shown in
Figure 19. The photo on the left is of the control compound; this EPDM based roofing
compound failed at 183 lbs/inch. The photo on the right is of the same compound
reinforced with engineered elastomer. Note the notch that has developed.                 This
compound had a tear strength of 230 lbs/inch, a 26% improvement over the no-fiber
control.

In general, it is important to reformulate a compound to make best use of engineered
elastomer reinforcement. It is unlikely that one can achieve property goals by simply
dropping aramid pulp into an existing formulation.
Roll covers are a dynamic application. The rubber compound will see cyclic stress-
strain behavior in the end-use.      We have conducted an extensive study to
determine the behavior of a compound reinforced with engineered elastomer in
cyclic, dynamic conditions.

The cyclic stress-strain behavior of para-aramid pulp reinforced NR compounds
was observed over 10 cycles up to 2.5, 10, and 50% strain. In these tests, the first
cycle was at the given strain, and subsequent cycles at the (constant) force
required to achieve this strain in the first cycle. Some of the test details are
described in Figure 20. Typical curves from the test at 10% ultimate strain are
shown in Figure 21; the curves for the first and tenth cycle are shown.

The energy loss fraction (fraction of energy dissipated in each cycle as shown in
Figure 22) was calculated from the stress-strain curves for each cycle (Figure 23.)
The energy loss fraction was:

•   Nearly constant after the first cycle;
•   Nearly the same in the machine and cross-machine direction, and
•   Nearly independent of the fiber concentration in the compound (Figure 24.)

The stress-strain behavior of engineered elastomer reinforced compounds after
cycling was also measured. These tests were conducted at 10, 30, 50 and 100%
strain, and after 2, 10 and 100 cycles. Measurements were made in both the
machine and cross-machine direction (with and against fiber orientation.) A
description of the test is shown in Figure 25. The stress-strain curves in the
machine direction for the reference (no fiber compound) after 2, 10 and 100 cycles
at 10% strain and for the compound containing 1 phr para-aramid pulp are shown
in Figures 26 and 27. The effect of cycling on stress-strain behavior is nearly
identical for both compounds. Similar nearly identical results were obtained with
samples cycled to other strains, and those measured in the cross-machine
direction.

Short-term dynamic properties in compression were measured using plied-up
cylinders (disks.) The specimens were precompressed to 10%, and were
measured from 0.1% to 5% dynamic strain at 1, 10 and 100 Hz, and at 20° and
100°C.

Curves for compound containing 1 phr aramid are shown in Figure 28 (20° C) and
Figure 29 (100°C). Stiffness at 1 and 3 phr aramid content at 1% dynamic strain is
shown in Figure 30. Stiffness, as expected, increases with increasing fiber
content. Loss angle was almost totally independent of fiber content as shown in
Figure 31.

Short-term dynamic properties in tension were measured using molded strips
prestressed to 5%. Samples were measured at 0.1% to 5% dynamic strain at 1, 10
and 100 Hz, and at 20° and 100°C.
Results were quite similar to those of the short-term dynamic properties in
compression. Curves at 20° and 100°C are shown in Figure 32 and Figure 33.
Stiffness increased with increasing fiber content (Figure 34) while loss angle was
relatively independent of fiber content (Figure 35.)

Both dynamic tests, compression and tension, showed that loss angle was nearly
independent of fiber content. This is in contrast to carbon black reinforcement
where loss angle is quite dependent upon concentration (Figure 36.)

In general, engineered elastomer enables developing high modulus compounds
with reduced potential for heat generation. High modulus power transmission belt
compounds in neoprene were developed with lower tan delta than comparable
compounds reinforced with flocs (Figure 37.) The dynamic modulus of a NR/SBR
treadstock was increased by use of engineered elastomer with no increase in tan
delta over a broad frequency range (Figure 38.)

The stress-strain curves of compounds reinforced with para-aramid pulp are nearly
linear with ‘high modulus’ at low strain, and at again with ‘lower modulus’ at high
strain. Tensile modulus in the direction of fiber orientation (machine direction - MD)
is higher than that perpendicular to the direction of orientation (cross-machine
direction – XMD.)         The MD/XMD modulus difference (anisotropy) of the
compounds peaks near 50% strain. Figure 39, shows the relationship between
modular anisotropy, strain and fiber content where anisotropy is calculated from the
absolute stress values at a given strain. Anisotropy peaks at about 60% strain for
the compound reinforced with 1 phr of para-aramid pulp, and at about 50% strain
for the compound with 3 phr reinforcement. Figure 40 shows an identical plot
where modular anisotropy is calculated by the tangential stiffness at a given strain.
Anisotropy peaks at about 40% for the compound with 1 phr of pulp, and at about
30% for the compound containing 3 phr pulp. The transition or inflection in the
stress-strain curve always occurs around 50% strain. Acoustic emission tests were
conducted on a number of compounds, both with and without engineered
elastomer reinforcement. Specimens were pulled at a constant rate of 2 inches per
minute, and the acoustic output monitored throughout. Key observations made
during the testing included:

•   Each material (non-pulp-reinforced and pulp-reinforced) showed detectable
    acoustic activity.
•   The amount of acoustic activity, as measured by the total number of events,
    was roughly proportional to the amount of pulp present (Figure 41).
•   The amplitude (intensity) of the acoustic events was similar; that is, the fiber
    compounds reinforced with pulp did not produce louder events, just more of
    them.
The peak acoustic activity was determined by plotting the data as ‘hits’ per strain
interval (Figures 42 and 43.) We found that peak acoustic activity occurs in the
range 40-60% strain; this corresponds to the region where the stress-strain curve
changes slope. The onset and peak of acoustic activity for the three compounds is
summarized below:

       Pulp concentration (phr)           0            1             3

       Onset of acoustic activity
             % Strain                   14-38        26-36         24-37
             Stress (lbs)               <10          16-18         26-30

       Peak of acoustic activity
             % Strain                   51-85        60            47-54
             Stress (lbs)               8-15         22-23         38-40

We hypothesize that reinforcement of elastomers by para-aramid pulp involves
association between charged groups on the fibril surfaces and those in the
elastomer, a mechanism similar to bound rubber theories for carbon black. It is
our belief that acoustic emission testing is recording the disruption of the
association between the charged groups on fibrils and elastomers. We therefore
recommend that engineered elastomer be considered primarily in applications
where strain does not exceed 40 to 50%.

                       ROLL COVER PERFORMANCE

Engineered elastomer is used in a number of commercial roll cover applications.
Actual end-use performance data and case histories are, of course, proprietary to
each customer and can not be reported in this paper. However, in summary, the
following can be stated regarding performance of roll covers reinforced with
KEVLAR engineered elastomer:

•   Roll life improvement ranged from 2x to 10x.
•   Tear resistance was improved.
•   Tear growth potential was reduced.

Engineered elastomer is available in a number of elastomer matrixes. A list is
included in Figure 44.
                                          CONCLUSIONS

•   Engineered elastomer can be used to significantly reinforce rubber compounds
    for roll cover applications.
•   The reinforcement efficiency is significantly greater than that of other commonly
    used reinforcing materials such as carbon black and silica.
•   A high level of modular anisotropy can be introduced to a compound by
    conventional processing techniques.
•   Hysteretic properties are nearly unaffected by the concentration of engineered
    elastomer pulp used in the compound.
•   Stress-strain and acoustic emission data suggest that association between
    elastomer and fiber exists up to 40-50% strain.
•   Tear resistance can be improved by incorporation of engineered elastomer into
    a compound.
•   Tear growth resistance can be improved by incorporation of engineered
    elastomer in a roll cover compound.
•   KEVLAR engineered elastomer reinforcement should be considered for
    demanding roll cover applications.




Product safety information is available upon request.

This information corresponds to our current knowledge on the subject. It is offered solely to provide
possible suggestions for your own experimentations. It is not intended, however, to substitute for any
testing you may need to conduct to determine for yourself the suitability of our products for your particular
purposes. This information may be subject to revision as new knowledge and experience becomes
available. Since we cannot anticipate all variations in actual end-use conditions, DUPONT MAKES NO
WARRANTIES AND ASSUMES NO LIABILITY IN CONNECTION WITH ANY USE OF THIS
INFORMATION. Nothing in this publication is to be considered as a license to operate under or a
recommendation to infringe any patent right.




H-89940 5/03
United States and South America:                        Sales Agent in the United States:

        DuPont Advanced Fibers Systems                           R. T. Vanderbilt Company, Inc.
        Customer Inquiry Center                                  30 Winfield Street
        5401 Jefferson Davis Highway                             P. O. Box 5150
        Richmond, VA 23234                                       Norwalk, CT 06856-5150
        Tel: (800) 453-8527                                      Tel: (203) 853-1400
             (804) 383-4400                                      Fax: (203) 853-1452
        Fax: (800) 787-7086
             (804) 383-4132
        E-Mail: afscdt@usa.dupont.com

Europe:                                                 Canada:

        DuPont Engineering Fibres                                DuPont Canada Inc.
        P.O. Box 50                                              Advanced Fibers Systems
        CH-1218 Le Grand-Saconnex                                P. O. Box 2200
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        Tel. ++ 41-22-717 51 11                                  Mississauga, Ontario L5M 2H3
        Fax: ++ 41-22-717 60 21                                  Tel. (905) 821-5193
                                                                 Fax: (905) 821-5177

Asia:                                                   Japan:

        DuPont (Thailand) Limited                                DuPont Toray Company, Inc.
        6-7th Floor, M. Thai Tower, All Seasons Place            1-5-6 Nihonbashi-Honcho,
        87 Wireless Road                                         Chuo-ku, Tokyo 103
        Lumpini, Phatumwan                                       Japan
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Web Address: www.kevlar.com
           Figure 1
                              ®
 Commercial Forms of KEVLAR




Pulp
         Filament

                      Staple
                   Figure 2

        Aramid Floc in Rubber




Staple on V-belt              Staple in V-belt
    surface                     compound
               Figure 3

   Pulp Versus Floc Fiber Form




0.1-0.3 m2/g              7-9 m2/g
      Figure 4

Pulp Fiber in Rubber
                   Figure 5

Fiber Dispersion and Uniformity with and without
     use of KEVLAR® Engineered Elastomer
                                         Figure 6

                 Improved Reinforcement from
                Engineered Elastomer vs Dry Pulp
                               MODULUS AT 20% ELONGATION

               800


               700


               600
MODULUS, psi




               500


               400


               300


               200


               100


                 0
                      NR/SBR    2 phr PULP via   2 phr DRY PULP   4 phr PULP via   4 phr DRY PULP
                     CONTROL          EE                                EE
              Figure 7

Compound with Undispersed Concentrate



                                 Tangled
                                  Fiber
               Figure 8

Compound Samples Illustrating Degree of
            Openness
                       Figure 9

Chemical Structure of KEVLAR


                        C=O
                                     C=O
                                                   C=O
   Na-S-O3


             C
                       O=C
                                    O=C
                 N-H          N-H
                                           N-H




  H-N
                 H-N
                              H-N
        C=O
                       C=O
                                    C=O
                                           Fiber


                  S-O3-Na
     Figure 10

Roll Cover Dynamics
                                                          Figure 11
                          Effect of Engineered Elastomer
                              On Compound Modulus
                                                                                               MODULUS AT 20% ELONGATION
                                                                                                CROSS MACHINE DIRECTION




                                                                                     8


                  MODULUS AT 20% ELONGATION
                                                                                     6
                     MACHINE DIRECTION
                                                                            Modulus,
                                                                                     4
                                                                             MPa
        8
                                                                                                      0.95       1.20                  1.80
                                                                                                                        1.79
                                                                                      2
                                                          6.04
        6                                                                                               0.79                    1.63                    44

                                                                                         0                                                         30           Parts per
                                                                                                                                                             hundred carbon
Modulus,                                                                                     0.0                                              15                 black
         4                                                                                            2.6
  MPa                                                                                                             5.2
                                    1.96                                                                                       7.8
                                                                                             Parts per hundred
                          0.93             2.20    3.19                                             fiber
         2
                           1.55
                                                                       44
                                                                               Parts per
            0                                                     30
                                                                            hundred carbon
                                                                                                     SBR/BR heavy duty tire tread
                0.0
                         2.6                                 15                 black                compound
                                     5.2
                                                  7.8
                Parts per hundred
                       fiber
                                                                                           Figure 12

Reinforcement and Mooney Comparison Between
    Engineered Elastomer and Various Flocs

                                                                              M25 (Mpa)               Mooney ML 1+4 at 100 deg C

                20                                                                                                                                                                                      100

                18                                                                                                                                                                                      95

                16                                                                                                                                                                                      90

                14                                                                                                                                                                                      85




                                                                                                                                                                                                             Mooney Viscosity....
                12                                                                                                                                                                                      80
 M25 (MPa)...




                10                                                                                                                                                                                      75

                8                                                                                                                                                                                       70

                6                                                                                                                                                                                       65

                4                                                                                                                                                                                       60

                2                                                                                                                                                                                       55

                0                                                                                                                                                                                       50
                           l
                        tro                     3.
                                                   0
                                                                        7.
                                                                          5                  10                       r1
                                                                                                                        0                       10                           10                    10
                      on                                                                  oc                                                                            le                     e
                     C                   Pu
                                           lp
                                                                 Pu
                                                                   lp                  Fl                          ibe                    nim                         ap                   los
                                                                                   n                             yF                     De                          St                 llu
                                    E"                      E"                  tto                        po
                                                                                                             l                      n                         lon                 C   e
                               "E                      "E                     Co                       m                      tto                           Ny
                                                                                                  6
                                                                                                      m                     Co                          n
                                                                                                         m                                           6n
                                                                                                      6m
                                                                                  Fiber Type and Loading (pphr)
                                   Figure 13
                     Comparison between carbon black and
                       p-aramid pulp reinforcement of NR

                                   Static stress-strain curves

                 8
                                                                                       60phr black
                                                                                       3phr Kevlar fibre
                 7                                                                     60phr black
                                                       Effect of adding                1phr Kevlar fibre
                                                       KEVLAR fibers                   60phr black
                 6                                                                     0phr Kevlar fibre
Stress (N/mm²)




                                                                                       45phr black

                 5                                                                     30phr black

                                                                                       0phr black
                 4

                 3

                 2                                                          Effect of adding
                                                                            N330 Carbon black
                 1

                 0
                     0   20   40      60        80       100              120
                                   Strain (%)
                                                                            Figure 14

                Effect of Engineered Elastomer on
          Modulus and Hardness of a Roll Cover Compound
                        MODULUS AT 25% ELONGATION




               16                                                    15.0
                                                                  15.1
               14                                       12.3

               12                                              13.1

               10
                                                  6.4
Modulus, MPa    8

                6                 2.1       4.1
                                                                                                                            HARDNESS
                4
                                      3.0
                    2                                                             45
                    0                                                        30    Parts per hundred
                        0                                               15                silica  100
                                  3                                                                                                                      96
                                                   6
                        Parts per hundred                  9                                                                          91
                                                                                                                                 86                 92
                               fiber
                                                                                                   90
                                                                                                                  81

                                                                                                                            80
                                                                                       Hardness,
                                                                                                   80
                                                                                        Shore A
                                                                                                                                               80

                                                                                                    70                 71

                                                                                                                                                                        45
                                                                                                    60                                                             30    Parts per hundred
                                                                                                         0                                                                      silica
                                                                                                                   3                                          15
                                                                                                                                  6
      NBR Roll Cover                                                                                     Parts per hundred                 9
                                                                                                                fiber
                                                                              Figure 15

Effect of Engineered Elastomer on Tear and Abrasion
        Resistance of a Roll Cover Compound
                                                 TEAR




                  120
                                                                              105
                                                           93
                  100                                                    98
                                                      77
                                        64                          91
                   80
                                                 67
   TEAR, kN/M
                   60                       59
(ISO 34 Method)
                    40
                                                                                                                                         DIN ABRASION
                    20
                                                                                          45

                        0                                                            30    Parts per hundred
                                                                                                                                    34
                               0                                                15                silica
                                        3                                                                     35
                                                       6                                                                                          29
                                                                9
                               Parts per hundred
                                                                                                              30                             28
                                      fiber                                                                                                                          28
                                                                                                                                                       24                 24
                                                                                                              25                        26

                                                                                                              20                                                22
                                                                                               Weight loss,
                                                                                                        -3
                                                                                                gms x 10       15


                                                                                                               10


                                                                                                                   5
                                                                                                                                                                                         45

                                                                                                                   0                                                                30    Parts per hundred
                                                                                                                       0
                                                                                                                                                                               15
                                                                                                                                                                                                 silica
                                                                                                                                    3
                            NBR Roll Cover                                                                                 Parts per hundred
                                                                                                                                                   6
                                                                                                                                                            9

                                                                                                                                  fiber
                                        Figure 16

    Effect of Engineered Elastomer on
 Mooney Viscosity of a Roll Cover Compound

                                         MOONEY VISCOSITY



                          100
                           90
                           80
                           70
                           60
          Mooney ML 1+4
                  o        50
            at 100 C
                           40
                            30
                            20
                            10                                            45

                                0                                    30    Parts per hundred
                                    0                           15                silica
                                             3
                                                        6
                                                            9
                                    Parts per hundred
                                           fiber
NBR Roll Cover
                                                                         Figure 17

                                 Effect of Engineered Elastomer and
                                Carbon Black Loadings on Trouser Tear
                                                                                                                TROUSER TEAR
                                                                                                           CROSS MACHINE DIRECTION




                                  TROUSER TEAR
                                MACHINE DIRECTION
                                                                                                    100                                          93


                                                                                                     80


                                                                                   Tear Strength,
                                                                                                     60
                                                              99                        ppi                                          53
                 100                                                                                                  30       32
                                                                                                                                            50
                                                                                                     40

                  80                        70                                                                         28                                       44
                                                                                                      20                                                   30           Parts per
                                                  65                                                                                                                 hundred carbon
Tear Strength,                                                                                               0.0                                      15
                  60                                                                                                 2.6                                                 black
     ppi                            39                                                                                         5.2
                                                                                                                                          7.8
                                                         54                                                Parts per hundred
                  40                                                                                              fiber

                                     29                                      44
                   20                                                   30           Parts per
                                                                                  hundred carbon
                          0.0                                      15
                                   2.6                                                black
                                            5.2
                                                       7.8
                        Parts per hundred
                               fiber
                                                             Figure 18

                        Effect of Engineered Elastomer and
                       Carbon Black Loadings on Die C Tear
                                                                                                          'DIE C' TEAR
                                                                                                    CROSS MACHINE DIRECTION



                                                                                            400
                                                                                                                                            353
                                                                                              360
                                                                                                                        306
                                'DIE C' TEAR                                                  320                              303

                             MACHINE DIRECTION                                Tear Strength,
                                                                                             280              232
                                                                                   ppi
                                                                                                                                      269
                                                                                              240

                                                                                              200
                                                                                                                                                        44
              400                                                                                              179
                                                            378                                                                                    30           Parts per
                                                                                              160
                                                                                                                                                             hundred carbon
              360                                                                                     0.0                                     15
                                                                                                              2.6                                                black
                                                                                                                         5.2
                                                                                                                                     7.8
              320                        282                                                        Parts per hundred
Tear Strength,                                 279                                                         fiber
               280              232
     ppi
               240

               200                                    217               44
                                 177
               160                                                 30           Parts per
                                                                             hundred carbon
                       0.0                                    15
                                2.6                                              black
                                         5.2
                                                     7.8
                     Parts per hundred
                            fiber
          Figure 19

Photographs of Die C Tear Test
                          Figure 20
                                                      50

Cyclic Stress-strain                                  40


Conditions                                            30




                                     Force (N )
                                                      20



• Pull Speed: 25mm/min
                                                      10


                                                        0

• Position: cross-head                                -10
                                                            0   20      40       60   80



  displacement calibrated for pull                                   Position (mm)


  speed


                                     P osition (mm)
                                                      80


• First Cycle at constant Strain                      30


• Subsequent Cycles at constant                       -20


  Force                                               50


• Test pieces: Bongos
                                     Force (N )
                                                      30



  (100 x 3.2 x 2 mm)
                                                      10

                                                      -10
                                          Figure 21

                   Cyclic stress-strain
Effect of fiber loading on 1st and 10th hysteresis cycles,
                  cycled up to 10% strain

12                                                  12
         1st cycle                                           10th cycle
10                                                  10

 8                                                   8

 6                                                   6
                                         Ref, MD
 4                                       F1NR, MD
                                                     4                                      Ref, MD
                                         F3NR, MD                                           F1NR, MD
                                                                                            F3NR, MD
 2                                                   2

 0                                                   0
     0      3        6     9        12        15         0     3       6      9        12        15
                Displacement (mm)                                  Displacement (mm)
                              Figure 22

               Definition of Energy Loss Fraction
Energy Loss Fraction = A1 / (A1+A2) =Hysteresis Energy / Stored Elastic Energy



          50



          40



          30

                                                A1
          20


                                                          A2
          10



          0
               0

                                   Strain (%)
                                   Figure 23
                         Cyclic stress-strain
        Effect of number of cycles upon Energy Loss Fraction

                    F1NR Compound – Cycles up to 10% Strain


        30,00


        25,00


        20,00
[Nmm]




        15,00
                                                                   MD

        10,00

                                                                   XMD
         5,00


         0,00
                0    2         4          6        8          10         12

                                      Cycle Nb.
                                          Figure 24
Cyclic stress-strain Energy loss fraction vs. fiber loading
                 Cycled up to 10% strain


    60                                           60
             1st cycle
                                                          10th cycle                  MD
    50                                           50                                   XMD


    40                                           40


    30                                           30
                                           MD
    20                                     XMD   20

    10                                           10

     0                                            0
         0         1         2        3     4         0        1        2         3     4
                    Fibre Loading (phr)                         Fibre Loading (phr)
                                                  Figure 25
                           Cycles Were Performed At Constant Force


                 8

                 7        Pull after cycling
                                                          6
                 6
Stress (N/mm²)




                                                          5       Original stress-strain
                                                                  curve
                 5       Cycles                           4

                 4                                        3
                                                          2
                 3
                                                          1                                 Stress-strain curve
                 2                                                                          after cycling
                                                          0
                 1                                            0     20         40          60       80        100

                 0                                                            Strain (%)
                     0        50            100     150
                                   Strain (%)
                    Figure 26
Ref MD cycled at 10% for 2, 10 and 100 cycles

    2 .5



      2



    1 .5



      1



    0 .5



      0
           0   10       20               30         40   50
                    D is p la c e m e n t ( m m )
                           Figure 27
F1NR MD cycled at 10% for 2, 10 and 100 cycles

    4

   3.5

    3

   2.5

    2

   1.5

    1

   0.5

    0
         0   5   10   15    20      25       30     35   40   45   50
                            D ispla ce me nt (mm)
                                 Figure 28
                      Short-Term Dynamic Compression
                   F1NR Compound     20°C  Plied Up Discs

                 600                                                           18


                 500                                                           15
                                                100Hz              10Hz
Stiffness N/mm




                 400                                                           12




                                                                                    Loss Angle °
                                                             1Hz

                 300                                                           9
                                                    100Hz

                 200                                                           6
                                                            10Hz

                 100                                                           3
                                                            1Hz

                   0                                                           0
                       0.1              1                                 10

                                 Dynamic strain %
                                 Figure 29
                      Short-Term Dynamic Compression
                  F1NR Compound     100°C   Plied Up Discs


                 300                                                            12


                                                                                10
                                                            1Hz
Stiffness N/mm




                                                                                     Loss Angle °
                 200                                                            8
                                                                    10Hz
                                                      100Hz
                                                    100Hz
                                                                                6
                                                                    10Hz
                 100                                                            4
                                                              1Hz
                                                                                2


                   0                                                            0
                       0.1              1                                  10

                                 Dynamic strain %
                                                                Figure 30
                              Short-Term Dynamic Compression
                                           Stiffness vs. Fiber Loading
     Piled Up Discs 20°C and 100°C at 1% Dynamic Strain

                                                                                           220

                   340
                             2 0 °C                                                                  100°C
                                                                                           200
                   320



                   300                                                                     180
Stiffness [N/mm]




                                                                        Stiffness [N/mm]
                   280
                                                                                           160


                   260

                                                                                           140
                                                                                                                                  1Hz
                   240
                                                                                                                                  10Hz
                                                                                                                                  100Hz
                                                                                           120
                   220



                   200                                                                     100
                         0            1       2         3        4                               0           1    2           3           4

                                F ib e r L o a d in g [p h r]                                           Fiber Loading [phr]
                                                 Figure 31
                        Short-Term Dynamic Compression
                      Loss Angle vs. Fiber Loading
           Piled Up Discs 20°C and 100°C at 1% Dynamic Strain


               12                                                    12
                             20°C                                                  100°C

               10                                                    10


                8                                                    8




                                                      Loss Angle °
Loss Angle °




                6                                                    6


                4                        1Hz                         4
                                         10Hz                                                       1Hz
                                         100Hz                                                      10Hz
                2                                                    2
                                                                                                    100Hz

                0                                                    0
                    0    1              2        3                        0    1              2             3
                        Fiber Loading (phr)                                   Fiber Loading (phr)
                                          Figure 32
                          Short-Term Dynamic Tension
                     F1NR Compound    20°C    Moulded Strip



                     100                                              12
                      90          100Hz

                      80                                              10
Stiffness [ N/mm ]




                                 10Hz




                                                                           Loss Angle [ ° ]
                      70         1 Hz                                 8
                      60
                      50                                              6
                      40
                      30                                              4
                      20                                              2
                      10
                       0                                              0
                           0.1                     1             10
                                          Dynamic strain [ % ]
                                            Figure 33
                           Short-Term Dynamic Tension
                     F1NR Compound     100°C   Moulded Strip



                     100                                                        12
                      90
                      80                                                        10
Stiffness [ N/mm ]




                                                                   10 Hz




                                                                                     Loss Angle [ ° ]
                      70                                                        8
                      60           100 Hz   1 Hz         100 Hz
                      50         10 Hz                                          6
                      40          1 Hz

                      30                                                        4
                      20                                                        2
                      10
                       0                                                        0
                           0.1                       1                     10
                                            Dynamic strain [ % ]
                                                        Figure 34
                                Short-Term Dynamic Tension
                                 Stiffness vs. Fiber Loading
                              Moulded strip at 1% Dynamic Strain

                   100                                                                 100

                             20 ° C                                                              100 ° C
                                                 100 Hz
                   80                                                                  80
                                                              MD
Stiffness [N/mm]




                                                                    Stiffness [N/mm]
                                                     10 Hz
                                                     1 Hz

                   60                                100 Hz                            60
                                                     10 Hz    XMD
                                                                                                                                    100 Hz
                                                 1 Hz                                                                                 10 Hz   MD
                                                                                                                                     1Hz
                   40                                                                  40
                                                                                                                                    100 Hz    XMD
                                                                                                                                    10 Hz
                                                                                                                                    1Hz

                   20                                                                  20


                    0                                                                   0
                         0       1       2       3             4                             0        1            2            3              4

                                Fiber Loading [phr]                                                       Fiber Loading [phr]
                                                             Figure 35
                               Short-Term Dynamic Tension
                          Loss Angle vs. Fiber Loading (MD only)
                            Moulded strip at 1% Dynamic Strain

                 12                                                               12
                          20 ° C                                                           100 ° C
                 10                                100 Hz                         10
                                                   1,10 Hz

                                                                                                                    1 Hz
                                                                                   8



                                                                 Loss Angle [°]
                  8
Loss Angle [°]




                                                                                                                    10 Hz
                                                                                                                    100 Hz

                  6                                                                6


                  4                                                                4


                  2                                                                2


                  0                                                                0
                      0      1        2       3              4                         0      1        2       3             4

                             Fiber Loading [phr]                                              Fiber Loading [phr]
                                                              Figure 36
             Comparison between effects of carbon black and
                  para-aramid fibers upon loss angle

        Effect of N330 carbon black upon                                Effect of fibre loading on Loss Angle
                   Loss Angle                                            Dynamic compression, Frequency
       Dynamic Shear, Frequency 1Hz, 23°C                                              1Hz, 20°C

       15                           Reference compound in compression   15

       12              0phr                                             12
                       15phr
                       30phr
        9              45phr                                             9
                       60phr                                                                                reference
        6                                                                6
                                                                                                            F1NR
                                                                                                            F3NR
        3                                                                3

        0                                                                0
            0.1                1               10               100          0.1        1         10             100
                         Dynamic strain (%)                                        Compressive strain (%)
Data from MRPRA, Engineering Data Sheets©
                                                                        Figure 37
Reinforcement and Tan Delta Comparison Between
     Engineered Elastomer and Various Flocs
                                                                   M25 (Mpa)            Tan Delta at 121 C

                          20                                                                                                        0.2

                          18                                                                                                        0.18

                          16                                                                                                        0.16

                          14                                                                                                        0.14
     M25 MD (MPa).…....




                                                                                                                                           Tan Delta…..
                          12                                                                                                        0.12

                          10                                                                                                        0.1

                          8                                                                                                         0.08

                          6                                                                                                         0.06

                          4                                                                                                         0.04

                          2                                                                                                         0.02

                          0                                                                                                         0
                                                                                                         10




                                                                                                                  10
                                 l




                                                                                                                               10
                                                                                          0
                                                                        10
                                               0




                                                               5
                              tro




                                                                                        r1
                                                             7.
                                           3.




                                                                                                     im




                                                                                                                  le
                            on




                                                                                                                               se
                                                                       oc



                                                                                      be
                                                         lp
                                          lp




                                                                                                                ap
                                                                                                    en




                                                                                                                             lo
                           C




                                                                     Fl
                                      Pu




                                                        Pu




                                                                                  Fi




                                                                                                                           lu
                                                                                                              St
                                                                                                D
                                                                    n



                                                                                 ly




                                                                                                                        el
                                                    E"
                                     E"




                                                                  to




                                                                                                             on
                                                                                               n
                                                                                po




                                                                                                                       C
                                                                ot




                                                                                               to
                                 "E




                                                   "E




                                                                                                          yl
                                                                            m
                                                               C




                                                                                            ot



                                                                                                          N
                                                                            m




                                                                                           C



                                                                                                       n
                                                                                        m
                                                                        6




                                                                                                     6n
                                                                                      6m




                                                                   Fiber Type and loading (pphr)
                                                                                                   Figure 38
                                            Hardness, Modulus, Tear Balance
                                      as affected by pulp and carbon black loadings
                                            DYNAMIC MODULUS                                                                                 TAN DELTA
                      4000
                                                                                                                     0.2300


                      3500
                                                                                                                     0.2200


                      3000
                                                                                                                     0.2100


                      2500
                                                                                                                     0.2000
M O D UL US , p s i




                                                                                                         Tan Delta
                      2000                                                   NR/SBR CONTROL
                                                                                                                     0.1900                                                     NR/SBR CONTROL
                                                                             1F722 / 2 phr FIBER
                                                                             1F722 / 4 phr FIBER                                                                                1F722 / 2 phr FIBER
                      1500                                                                                                                                                      1F722 / 4 phr FIBER
                                                                                                                     0.1800


                      1000
                                                                                                                     0.1700


                       500
                                                                                                                     0.1600


                         0
                                                                                                                     0.1500
                             0   20    40      60          80          100   120            140    160
                                                                                                                              0   20   40   60         80           100   120           140           160
                                                    Frequency, Hertz
                                                                                                                                                 Frequency, Hertz




                                 NR/SBR Tire Tread Compound
                         Figure 39

           Stress Ratio Anisotropy vs. Strain
Stress ratio anisotropy is the ratio of MD/XMD absolute
              stress values at a given strain
   2.5
                          F3NR

    2

                            F1NR
   1.5


    1
                                 Reference

   0.5


    0
         0   20     40           60          80   100   120
                           Strain (%)
                          Figure 40
             Modular Anisotropy vs. strain
Modular anisotropy is ratio of MD/XMD tangential
           stiffness at a given strain

                      F3NR
   3.5

    3

   2.5             F1NR

    2

   1.5

    1
                   Reference
   0.5

    0
         0    20       40          60       80   100   120
                               Strain (%)
                                                 Figure 41

                                         Acoustic Emission Tests

                               Acoustic Events are proportional to Fiber Loading


                        3500

                        3000
Total Acoustic Events




                        2500

                        2000

                        1500

                        1000

                         500

                           0
                               0            1             2          3             4
                                                     Fiber Loading
                                                                              Figure 42

                                                             Acoustic Emission Tests
                                                            Acoustic Activity for F1NR

                                      50
                                                                                 1phr Fiber Loading             Total Hits 443
                                      45


                                      40
Acoustic Events per strain interval




                                                                                              Maximum Acoustic Activity   55 to 60 % strain
                                      35


                                      30


                                      25


                                      20


                                      15


                                      10


                                      5


                                      0
                                           5   10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160

                                                                                            Strain (%)
                                                                               Figure 43
                                                              Acoustic Emission Tests
                                                             Acoustic Activity for F3NR


                                      250

                                                                                  3phr Fiber Loading             Total Hits 1675
Acoustic Events per strain interval




                                      200

                                                                                          Maximum Acoustic Activity   50 to 55 % strain


                                      150




                                      100




                                       50




                                        0
                                            5   10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160

                                                                                             Strain (%)
                                                                    Figure 44
K E V L A R  b r a n d e n g in e e r e d e la s to m e r
A n e la s t o m e r ic c o m p o s it e o f K E V L A R  b r a n d p u lp a n d e la s t o m e r


P ro d u c t N u m b e r                         1F722                   1F724                    1F770             1K1239

P r o p e r t ie s

M a t r ix e la s t o m e r                      N a tu ra l             SBR                      NBR               ENGAGE
                                                 Rubber                  1502                     M ed ACN          8400
P u lp c o n c e n t r a t io n                  23%                     23%                      23%               6 1 .5 %
S p e c if ic g r a v it y                       1 .0 5                  1 .0 5                   1 .1 0            1 .2 2
P h y s ic a l f o r m                           nugget                  nugget                   nugget            g r a n u le


P ro d u c t N u m b e r                         1F723                   1F1234                   1F735             1F1168           1F819


P r o p e r t ie s

M a t r ix e la s t o m e r                      N e o p re n e          N e o p re n e           N e o p re n e    N e o p re n e   N e o p re n e
                                                 GW                      GW                       GRT               GRT              W RT
P u lp c o n c e n t r a t io n                  23%                     2 8 .6 %                 23%               2 8 .6 %         23%
S p e c if ic g r a v it y                       1 .2 8                  1 .2 9                   1 .2 8            1 .2 9           1 .2 8
P h y s ic a l f o r m                           nugget                  nugget                   nugget            nugget           nugget



G e n e r a l R e c o m m e n d a t io n s
K E V L A R  e n g in e e r e d e la s to m e r e n a b le s th e c o m p o u n d e r a n d d e s ig n e r to a c h ie v e p e rfo rm a n c e ,
p r o p e rtie s a n d d e s ig n s n o t p o s s ib le in th e p a s t. C o m p o u n d s h a v e b e e n e n g in e e re d to im p ro v e
w e a r a n d a b ra s io n , a c h ie v e b e tte r fr ic tio n a l p r o p e r tie s , im p r o v e te a r , im p r o v e s h e a r re s is ta n c e ,
r e p la c e r e in fo r c in g fa b ric , r e d u c e p a r t th ic k n e s s , o r lo w e r ro llin g r e s is ta n c e .




K E V L A R  is a r e g is te r e d tr a d e m a rk o f E . I. d u P o n t d e N e m o u r s a n d C o m p a n y
E N G A G E  is a r e g is te r e d tr a d e m a rk o f D u P o n t D o w E la s to m e r s L .L .C .

								
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