Elastomer development promises product innovation

New elastomers form the basis of innovative products in the field of sealing and vibration control technology.

Freudenberg Simrit works continually with interdisciplinary teams of specialists on new types of materials in order to pave the way for optimised sealing and vibration control technology solutions.

Recently developed elastomers, such as the Simrit low-temperature polyurethane, and the use of nanocomposites illustrate elastomer's potential for innovation and how this potential can be realised through consistent development work.

One striking feature makes elastomer materials really stand out from all other metallic and nonmetallic materials: even the tiniest change in their composition and chemical makeup has a major influence on the durability of elastomer components.

This is why these materials are, in fact, high-tech products that should, where possible, be developed by a single company: from the selection of the raw material to the blending of the mass that is capable of being processed, formation, and the use of the elastomer in the production of a saleable product.

Over the past few decades, Freudenberg Simrit has fine-tuned this knowledge to create an exemplary symbiosis of materials expertise, processing knowhow, product knowledge, and application experience.

Only interdisciplinary approaches that involve users and customers make it possible to consistently and accurately transform visions into innovations.

Freudenberg Simrit channels the extensive, specialist knowledge of chemists, chemical engineers, physicists, technicians, statisticians, and electricians into the elastomer development process.

This allows the company to work consistently and in a targeted manner on the realisation of a specifically required set of properties for sealing or vibration control components.

A topical example of this is the solution created for a construction machinery manufacturer's critical application.

When outdoor temperatures are low, the resilience of conventional hydraulic seals in excavators drops below an acceptable level.

If an excavator is left leaning on its shovel, the hydraulic seals in its arm are slightly deformed by the transverse loads on the cylinder.

If temperatures drop below zero while the excavator is not in use, this can cause the seal to "freeze".

When the excavator is started up again, the rod begins to move.

However, the seal, which went rigid as a result of the low temperatures, cannot immediately fulfill its sealing function.

The leakages that result can be considerable because the hydraulic seal does not have its full force of pressure during this startup phase.

To ensure that modern mobile hydraulic plants perform fully and instantly in winter in all climatic zones, the specialists at Freudenberg Simrit have used more than 50 years of experience in dealing with polyurethane to develop a corresponding hydraulic sealing material.

For example, the low-temperature range for the new Simrit 94 AU 21100 polyurethane has been lowered by approximately 15C.

The recovery and functional reserves of this new PU generation hydraulic seal have been improved so dramatically that mobile hydraulic systems now no longer demonstrate any noteworthy leaks when starting up - even at extremely low temperatures.

This hydraulic sealing material also retains most of its elastomer sealing properties and the same physical hardness and tensile strength properties as standard PU materials even at temperatures as low as -50C.

Moreover, 94 AU 21100's friction values are comparatively low - a property that significantly reduces the material's stick-slip effect.

Freudenberg Simrit has recently started using nanoscale crosslinking additives, so-called nanopregs, in its production process.

Nanopregs are innovative systems in which nanoparticles are applied to inert carriers in order to allow the properties of the nanoparticles to be used in a more targeted manner.

This is necessary for cases where the intermolecular van der Waals forces are so great that the nanoparticles would otherwise form agglomerates during the compounding process.

This is not the case with nanopregs, the so-called nanocomposites.

Here, the carriers and the nanoparticles form a processable unit in the compounding process.

With zinc oxide/silica nanocomposites, nanoscale zinc oxide is applied to inert silica carrier particles in a clever structure.

Thanks to this nanocomposite, it is now possible to reduce the zinc concentration in rubber compounds by over 50% while retaining mechanical properties.

This illustrates how nanocomposite technology helps realise the full potential of the large specific surface of the zinc oxide nanoparticles.

These nanocomposites have the major advantage that they allow the concentration of the environmentally dangerous - but technically essential - zinc oxide to be reduced significantly.

Moreover, this technology means that the elastomer does not age as quickly when exposed to heat.

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