Properties of vulcanizates based on Baypren®

 

With the correct formulation, finished products made of Baypren® display the
following characteristic properties in addition to their excellent rubber-elastic
behavior:

  • Resistance to weathering, both in dry and humid climates
  • Excellent combustion behavior
  • Average resistance to oils
  • Aging and heat resistance
  • Good tensile strength, tear and wear resistance
  • High dynamic fatigue resistance
  • Resistance to water and a large number of chemicals over a long period
  • Good adhesion to suitably pretreated reinforcing substrates consisting of textiles, metals or glass fibers
  • Resistance to fungi and soil bacteria
  • Low gas permeability
  • Electrical properties sufficient for a large number of applications

The suitability of a Baypren® compound for a particular application should be established by relevant testing. Thanks to its excellent set of properties, Baypren® is being used for the production of highly stressed rubber articles in many sectors, primarily in the automotive industry, mechanical engineering, plant construction, ship-building, mining and mineral oil production. The properties of Baypren® vulcanizates are influenced by the type of modification of the raw polymer (see above).

 
Aging and heat resistance

Baypren® vulcanizates display excellent aging resistance, especially those with an optimized antioxidant content. They neither soften nor harden at high temperatures or over long periods of stressing and remain elastic and serviceable. The heat resistance of Baypren® vulcanizates is considerably better than that of natural rubber vulcanizates. It corresponds roughly to the heat resistance of nitrile rubber.

 
Weathering and ozone resistance

While vulcanizates produced from many other rubber types tend to crack and harden relatively quickly and degrade when exposed to weathering and/or ozone, suitably formulated Baypren® vulcanizates do not exhibit any significant deterioration, even after many years of exposure to atmospheric influences such as light, rain, industrial gases and oxygen. By extrapolating the change in mechanical properties after many years of weathering in an ozone-rich atmosphere, it can be concluded, on the basis of current technology, that technical rubber goods made of Baypren® can be expected to display sufficient elasticity for the majority of static applications (for example structural profiles) after more than 50 years.

 
Resistance to water and chemicals

By employing specially formulated compounds, it is possible to obtain Baypren® vulcanizates that are resistant to water, acids, alkaline solutions
and a large number of industrial chemicals. With a good resistance to ydrocarbons, Baypren® vulcanizates show sufficient performance in contact with mineral oils to make them suitable for many applications. The corresponding volume change in mineral oils decreases with increasing naphthenic and, in particular, aliphatic content of the oil. Baypren® vulcanizates cannot match the very high swelling resistance to hydrocarbons of similarly formulated nitrile rubber vulcanizates, but their swelling resistance is considerably better than that of vulcanizates based on styrene-butadiene rubber, natural rubber or ethylene-propylene rubber.

 
Resistance to fungi and bacteria

Items made of rubber that are in contact with soil for long periods of time are susceptible to attack by soilborne bacteria and fungi. In the long term, this can lead to underground cables, for example, being destroyed. In contrast to the majority of other rubber types, Baypren® displays superior resistance to these microorganisms. This resistance can be enhanced still further through suitable compound formulation.

 
Abrasion resistance

Baypren® vulcanizates are highly wear-resistant. Their abrasion resistance is similar to that of nitrile rubber.


Resilience

Suitably formulated Baypren® vulcanizates possess very good resilience, although they do not attain the level of natural rubber. Very good resilience values are achieved in vulcanizates with a relatively high hardness.

 
Dynamic fatigue resistance

Baypren® vulcanizates are highly resistant to dynamic fatigue. Special grades are available to meet extremely stringent specifications, such as those applied to drive belts. The loss factor and hence the heat build-up under dynamic load are low.


Deformation properties

Baypren® vulcanizates have a low compression set over a temperature range of -10 to +145 °C. The low-temperature compression set is a key value employed in the assessment of vulcanizates for use in seals. At higher temperatures, where aging also plays a role, the compression set curves are lower than those of a large number of other elastomers.

 

Combustion behavior

Baypren® vulcanizates can be compounded for improved combustion behavior. The good combustion behavior of the polymer itself means that even stringent end-user specifications can be met. Limiting oxygen index (LOI) values in excess of 50 % can be attained with Baypren®. The requirements placed on the flame retardance of conveyor belts for underground mining applications can be met with properly compounded Baypren®.