September 22, 2018 | Author: Raymond Dalton | Category: N/A
1 Cellasto A microcellular polyurethane elastomer2 When NVH BASF The Chemical Company BASF is the world s leading chemic...
Cellasto® A microcellular polyurethane elastomer
When NVH BASF The Chemical Company BASF is the world’s leading chemical company: The Chemical Company. Its portfolio ranges from oil and gas to chemicals, plastics, performance products, agricultural products and fine chemicals. As a reliable partner BASF helps its customers in virtually all industries to be more successful. With its high-value products and intelligent solutions, BASF plays an important role in finding answers to global challenges such as climate protection, energy efficiency, nutrition and mobility. At BASF, we create chemistry.
is critical Cellasto ® Cellasto
is
the
trade
name
for
BASF
The outstanding features are:
Polyurethanes’ high performance, microcellular
n Low compression set
polyurethane elastomer. Cellasto components
n High volume compressibility with minimum
have been used successfully for over 35 years as
lateral expansion
the NVH (Noise, Vibration, Harshness) solution for
n Excellent mechanical properties & durability
automotive chassis and suspension applications
n Highly versatile - noise isolation at small
such as jounce bumpers, shock absorber top
amplitude
&
high
frequency;
vibration
mounts and coil spring isolators. Cellasto is also
isolation at large amplitude & low frequency
used in many other applications outside of
n Abrasion resistant
automotive such as: elevator safety buffers; paper
n Resistant to ozone, oils, greases and other
conveying components; friction dampers; subframe, motor & body mounts; and more.
aliphatic hydrocarbons
Progressive load deflection behavior Cellasto components are based on a microcellular
The maximum compression of a Cellasto molded
polyurethane elastomer. The molded components
component depends on its density. The spring
are produced in a closed-mold foaming process.
deflection increases with decreasing density,
Depending on the amount of the material used, the
and can reach up to 80% of the original length
molded
of the component.
components
have
densities
of
350 to 650 kg/m . The pore volume accounts for 3
50 – 63% of the molded volume.
Large spring deflection and low block height characterize
The pore diameters are in the range of a tenth of a
molded
components
made
from
Cellasto material.
millimeter and are partially closed. For Cellasto components, a compressive stress of During compression loading, the pore volume is the
4 MPa represents the dynamic continuous load limit.
first to compress followed by material compression.
However, the material is not destroyed by a single
As compression increases, the material gains
impact generating stresses of up to 20 MPa.
rigidity
and
transitions
from
flexible/soft
to
rigid/stiff. This non-linear or progressive load4
deflection behavior is depicted in Figure A.
bulk density g/cm3 0.65 0.60 0.55 0.50 0.45 0.40 0.35 normal climate conditions
3
2
Compressive stress [MPa]
Figure A. Progressive pressurecompression behavior
1
0 0
10
20
Compression [%]
30
40
50
60
70
80
Low lateral expansion and high volume compressibility Compact elastomers show large lateral expansion when compressed. However, this is not the case with cellular
polyurethane
elastomers.
They
are
characterized by low lateral expansion. Cellasto spring elements are therefore suitable for applications where the surrounding structural space is confined or where the spring is located within an enclosure.
rubber
63%
P Cellasto rubber
100%
0%
P
Cellasto
Compression between two plates Compression in enclosed space
100 (45 Shore A) 80 rubber 60 Cellasto 3 0.35 g/cm 40 20 20 40 60 80 100 Compression [%]
Scale representation of the compression (compressive deformation of Cellasto and rubber between two plates)
Compressive stress
Figure B. Low lateral expansion and high volume compressibility
Increase in diameter [%]
120 rubber in a cylinder
Cellasto in a cylinder 20 60 100 Compression [%]
Material grades: Cellasto and rubber in the initial compression range (rubber 45 Shore A. 1.18 g/cm 3; Cellasto: 0.35 g/cm3)
Characteristic curves as a function of temperature The
mechanical
properties
of
plastics
are
temperature dependent, and are also subject to
They
are
then
suitable
for
applications
to
approximately -40°C (-40°F).
temperature limits. Cellasto Cellasto
components
decreasing
temperature
gradually and
stiffen
are
components
gradually
soften
with
with
increasing temperature. As demonstrated in Figure
for
C, the characteristic curve for Cellasto components
suitable
applications to about -30°C (-22°F).
changes only slightly up to a temperature of approximately
80°C
(176°F),
making
Cellasto
Cellasto components that must maintain their
suitable for use in ambient temperatures of up to
elasticity at low temperatures can be manufactured
80°C (176°F) without loss in elasticity performance.
from Cellasto specially formulated for cold flexibility.
4 bulk density 0.50 g/cm3
3
-30°C
2
-20°C Compressive stress [MPa]
Figure C. Characteristic curves as a function of temperature
0 - 80°C
1
0 0
10
20
Compression [%]
30
40
50
60
70
80
Temperature increase caused by damping The material dampens a portion of the mechanical
molded component temperature as a function of
energy input and converts it to heat. The dissipating
spring deflection and frequency. These conditions
heat thereby increases the temperature in the
are taken into consideration in the development
stressed molded component. This temperature
phase to determine if the critical temperature may
should not exceed 110°C (230°F).
be reached for a particular application.
An equilibrium temperature is reached for molded
Cellasto components which become stiffer at low
components subjected to stresses of constant
temperatures regain their elastic properties as the
frequency and constant spring deflection. The family
mechanical energy is converted to heat and the part
of curves depicted in Figure D is an example of the
temperature increases.
Temperature [°C]
Figure D. Temperature increase caused by damping
180 160 140 120 100 80 60 40 20 0
3.0
Fr
eq
n ue
cy
[H
z]
MH 24–50 60 50 Crit ≈ 110 ˚C
2.0
1.0 0.63
10 20
Sp rin
40
g de fle ct io n
60
[% ]
Static load-related creep When designing molded Cellasto components, the
The creep measurements shown in Figure E were
increased compression over time at constant load,
carried out over a period of years, and in this
or creep, must be considered from the outset. The
example,
scale of creep, in comparison with reversible
compression under constant load. In addition, the
compression, is extremely low and can generally be
linearity of the curves allow for extrapolation beyond
disregarded in standard applications.
the measurement period.
demonstrate
the
small
change
in
Dynamic load-related creep Under dynamic loading, deformation or compression
The curve in Figure F flattens out in the load
is determined by the load frequency and number of
controlled test. The low increase in compression
load cycles. Compression increases with increasing
equals the permanent set. At the end of the test, the
load frequency. The increasing frequency raises the
sample virtually recovers to its original height.
temperature of the Cellasto test specimen causing the material to become softer and more flexible.
Figure E. Static load-related creep
Figure F. Dynamic load-related creep
80
σ= 2.0 N/mm
20
Compression [%]
50
σ= 1.0 N/mm2
30 20
σ= 0.5 N/mm2
10 5 102 2
5 103 2
5 104 2
20
20 MH 24-65
50
σ= 1.5 N/mm2
40
0 0 10 2 5 101 2 Time [h]
60
7
70 2
Compression [%]
60
20
20
70
80
40
f=15 Hz
30 1/3 3 Hz ff=3 =3 3 1/ Hzz
20 f=15 Hz
10 0 2 5 103 2 5 104 2 10 2 Alternating load [cycles]
f=3 1/3 Hz
5 105 2
5 106 2
Amplitude dependent damping In order to provide optimum isolation performance
and
in the field of Noise, Vibration and Harshness (NVH),
contrasting requirements are met equally well with
materials need to have low damping properties at
the use of Cellasto.
high
frequencies.
At
those
frequencies
safe
driving
purposes.
These
seemingly
the
amplitudes are usually small. This is the opposite of
Figure G clearly shows the steep rise in “loss angle”
large movements at low frequencies where the
(a measurement of damping), with the increasing
material requirement is rapid damping for dynamic
amplitudes for all material densities.
Dynamic stiffening Cellasto exhibits a very low dynamic rate ratio even
amplitude of 0.1 mm is then applied. The dynamic
at high frequencies. Figure H shows the dynamic
rate ratio decreases with increasing density.
modulus values to a basis of 1 Hz. The data was This quality makes Cellasto an ideal material for
30% of its original height. A sinusoidal load with an
mounting elements to isolate noise and vibrations.
Figure G. Amplitude dependent damping
Figure H. Low dynamic rate ratio
10 Precompression: 30% Frequency: 10 Hz
MH 24-35 MH 24-45
Loss angle [˚]
8 6
MH 24-55 MH 24-65
4 Ø 30 mm
2 30 mm
Dynamic rate ratio [relative to 1Hz]
obtained by statically precompressing a cylinder by
1.4
MH 24-35 MH 24-45 MH 24-55 MH 24-65
Precompression: 30% Amplitude: 0.1 mm
1.35 1.3 1.25 1.2 1.15 1.1
Ø 30 mm
1.05
30 mm
1.0
0 0
1
2 3 Amplitude [mm]
4
5
1
20 40 60 80 100 120 140 160 180 200 Frequency [Hz]
Material characteristics Material designation: Cellasto MH24
Tested in accordance with
-35
-40
-45
-50
-55
-60
-65
Bulk density
ASTM D3574, A
350
400
450
500
550
600
650
kg/m 3
Tensile strength
ASTM D3574, E
3.0
3.5
4.0
4.5
5.5
6.5
7.0
MPa
Elongation at break
ASTM D3574, E
350
350
400
400
400
400
400
%
8.0
10.0
12.0
14.0
16.0
18.0
20.0
N/mm
deformation at 50%/70h/20°C ASTM D3574, D
3.5
3.5
3.5
3.5
3.5
3.5
3.5
%
deformation at 50%/22h/70°C ASTM D3574, D
5.0
5.0
5.0
5.0
5.0
5.5
5.5
%
Property
Tear Strength
Dimension
Compression set
Cellasto is the NVH
Our Commitment BASF can work with you to develop innovative solutions that address a multitude of performance attributes. BASF is committed to our customer's success, and delivers: n In-house technical expertise n Customized solutions n Collaboration between your engineering teams and BASF experts n Value added products through increased driving comfort, light weighting and noise reduction
To learn more, visit us at: basf.us/cellasto.com
solution
BASF Corporation 1609 Biddle Avenue Wyandotte, MI 48192 Phone: 734-324-6285 E-mail:
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For more information on Cellasto from BASF, scan the QR Code above, or visit: basf.us/cellasto.com
The statements in the product literature and label are guidelines only. Users should test this product in advance to verify suitability for particular uses. BASF Corporation neither makes nor authorizes to be made any express or implied representation or warranty with regard to this product concerning the performance, use, fitness for particular purpose, suitability for use on any surface or merchantability of this product, whether used alone or in combination with other products. The furnishing by us of information and products either as experimental samples or by sales, contains no recommendations respecting the use of these products or the lack of infringement of any patent nor does it grant a license under any patent owned by our company. BASF assumes no liability for any damage of any kind regardless of cause, including negligence. Cellasto ® is a registered trademark of BASF Polyurethanes GmbH. © 2011 BASF, Wyandotte, MI 48192. All rights reserved. CellastoCPE v1.0-09/15/11.