Resistance of elastomers

Elastomers are among the most versatile and technically demanding materials in modern industry. They combine enormous elasticity with damping capacity, chemical resistance and design freedom. In virtually all industrial sectors – from the vehicle and mechanical engineering industry through medical technology to food production – elastomers are used in the form of seals, hoses, profiles or vibration elements. They must remain stable over long periods, even under extreme exposure to chemicals, high temperatures or mechanical pressure.

A well-founded assessment of their resistance is therefore the key to the reliability of technical systems and to minimising failure risks. The better the influences are understood, the more precisely materials can be selected and optimised – with a measurable impact on product quality, maintenance intervals and sustainability.

What does resistance mean for elastomers?

Resistance is understood as the ability of an elastomer to retain its physical, chemical and mechanical properties over a defined period under load – regardless of whether this involves environmental influences, thermal exposure or contact with chemicals. In practice, this means that the material reliably fulfils its function – such as sealing effect, elasticity or dimensional stability – even after years.

Assessing resistance is demanding, as various influencing factors act simultaneously. Temperature, ozone, UV radiation, pressure, media and mechanical movement can reinforce one another. For example, a combination of high temperature and oil contact can lead to accelerated ageing, even though the elastomer would still be suitable for each condition considered individually.

At the molecular level, resistance is based on the stability of the polymer chains and the quality of the crosslinks between them. Crosslinked systems are more resistant to thermal decomposition and chemical attack, while unsuitable additives or insufficient crosslinking lead to premature ageing. The production parameters, such as vulcanisation temperature, press time and post-treatment, also have a decisive influence on resistance.

A further aspect is what is known as long-term resistance. This describes how the properties of an elastomer change over its entire service life. Ageing tests, material simulations and empirical values can be used to predict how seals, hoses or damping elements will behave after years in operation. For safety-critical applications – for example in aviation, medical technology or the chemical industry – these findings are essential in order to prevent material failure.

Chemical resistance: media, ageing and swelling

Chemical influences are among the most critical loads for elastomers. Depending on their composition, liquids, vapours and gases can affect the polymer to varying degrees. The effects range from surface swelling to complete chemical decomposition.

Typical reactions and mechanisms

• Swelling: absorption of media into the polymer network, associated with an increase in volume and loss of stress.
• Extraction: leaching of low-molecular-weight constituents such as plasticisers, leading to hardening and brittleness.
• Hydrolysis: cleavage of chemical bonds on contact with water or steam.
• Oxidation: reaction with oxygen, often accelerated by heat or ozone, leads to cracking.

Chemical resistance is usually assessed using standard tests (e.g. DIN ISO 1817, ASTM D471). Mass changes, hardness and volume are determined after a defined exposure time. Diffusion and permeation measurements are also becoming increasingly important, for example in applications in the pharmaceutical or food industry, where media migration is critical.

Chemical resistance in comparison

Medium	EPDM	NBR	FKM	Silicone	CR
Water	very good	good	good	very good	good
Oils / fuels	poor	very good	excellent	poor	moderate
Acids / alkalis	very good	moderate	good	good	good
Ozone / UV	excellent	weak	excellent	excellent	good
Solvents	poor	good	very good	moderate	moderate

Depending on the operating environment, a compromise must therefore be found between chemical and physical resistance.

Thermal resistance: temperature, ageing and fatigue strength

Temperature is one of the most decisive influencing variables on the service life and performance of elastomers. Every type of thermal exposure – whether through environmental influences, media contact or self-heating during operation – changes the material structure. If the permissible continuous temperature is exceeded, degradation of the polymer chains begins, and there is a gradual loss of elasticity. At low temperatures, by contrast, the glass transition occurs, at which the material hardens, loses flexibility and becomes brittle.

Influence of temperature on ageing

Thermal ageing describes all chemical and physical changes in the material that arise from the effect of heat over time. These include the oxidation of the polymer chains, the migration of plasticisers, but also the reaction with atmospheric oxygen and ozone. These processes lead to an increase in hardness and a decrease in elongation capacity. In seals, this manifests as leaks or material failure.

Temperature fluctuations are also critical: repeated heating and cooling processes cause microscopic stresses that can develop into cracks. Particularly in combination with media contact (e.g. oil or acid), so-called synergistic ageing effects arise – the damage occurs exponentially faster than with a single influence.

Typical temperature ranges:

Material	Continuous temperature	Short-term	Remark
EPDM	–40 °C to +150 °C	up to 180 °C	very good weathering and ozone resistance
NBR	–30 °C to +100 °C	up to 120 °C	resistant to oils and fuels
FKM (Viton)	–20 °C to +200 °C	up to 250 °C	excellent chemical and heat resistance
Silicone (VMQ)	–60 °C to +200 °C	up to 230 °C	outstanding flexibility in cold and heat
HNBR	–40 °C to +150 °C	up to 180 °C	improved ageing resistance compared with NBR

In high-temperature environments, such as exhaust systems, steam lines or chemical reactors, careful material selection is decisive. Modern special elastomers such as FKM or FFKM now achieve continuous service temperatures of up to 250 °C and enable a considerable extension of maintenance intervals. In addition, simulation-based design is increasingly being used in order to predict temperature profiles and ageing mechanisms realistically already during the development phase.

Mechanical resistance: load, friction and dimensional stability

Elastomers must withstand repeated mechanical loads – often over millions of cycles. They are not merely passive sealing or insulating materials, but actively perform functions for energy absorption, damping and vibration reduction. Mechanical resistance describes the ability to withstand such forces without permanent deformation, cracking or material failure.

Influencing factors and typical failure mechanisms

The most common types of load are tension, compression, shear and torsion. In practice, they rarely occur in isolation, but act in combination. Repeated stretching leads to material fatigue, while constant compressive load leaves a permanent deformation set (compression set). Friction and sliding movements cause abrasion or local heating, which in turn can lead to material weakening.

In addition to the formulation, the component geometry also plays a role. Sharp edges, uneven cross-sections or excessive clamping promote local stresses and cracking. Modern finite element simulations (FEM) help to identify these load zones in advance and specifically mitigate them.

Mechanical resistance is assessed using characteristic values such as tensile strength, elongation at break, tear resistance and Shore A hardness. The compression set is equally decisive, as it provides information about the recovery capacity. Materials such as HNBR, FKM or CR show particularly good values here. In applications with high vibration loads, for example in engine mounts or pump systems, composite solutions are often used in which elastomers are reinforced with metal or fabric in order to counteract fatigue and crack propagation.

A further central aspect is surface quality: a fine, even surface reduces friction and therefore abrasion. Lubricants or special coatings can also considerably extend the service life of mechanically stressed elastomer parts.

Comparison of the most important elastomers

Elastomer	Chemical resistance	Thermal resistance	Mechanical strength	Typical applications
EPDM	very good against water, acids, alkalis	good	good	Seals, profiles, hoses
NBR	good against oils, fuels	moderate	very good	Hydraulic seals, hoses
FKM	excellent against chemicals	very good	good	Chemical industry, engine compartment
Silicone (VMQ)	good against many media	very good	moderate	Food technology, medical technology
CR (Neoprene)	good against weathering, moderate against oils	good	good	Vibration elements, cable sheathing
HNBR	very good against oils, ageing and ozone	very good	very good	Automotive engineering, high-pressure systems

Test methods and standards

Standardised test methods are used to assess resistance in order to obtain reproducible results:

• DIN ISO 1817: resistance to liquids
• DIN ISO 188: heat resistance
• DIN ISO 1431: ozone resistance
• DIN ISO 815: determination of compression set
• DIN ISO 23529: standardised test conditions for rubber products

In addition, industry-specific tests are carried out for special applications, such as FDA conformity in the food industry or ASTM D2000 for automotive applications.

Sustainability and service life assessment

Sustainability is also playing an increasingly strategic role for elastomers. While function and cost were previously the main focus, service life, repairability and recyclability are now coming to the fore. A longer service life not only reduces resource consumption, but also maintenance and replacement costs. The development towards bio-based and recyclable elastomers – for example based on natural rubber, TPEs or sustainable plasticisers – is gaining importance rapidly. At the same time, simulations and AI-supported material analyses are making it possible to predict life cycles more precisely, which enables more sustainable planning and production.

In combination with improved additives and crosslinking systems, a service life up to twice as long as a decade ago can now be achieved. Here, sustainability means not only environmental friendliness, but also technical efficiency.

Practical example: seals in the chemical industry

In chemical processes, extreme conditions coincide: high temperatures, aggressive media and constant pressure changes. A seal that does not withstand these influences can cause serious safety and environmental risks. EPDM seals are eminently suitable for aqueous media, steam and alkaline solutions, but show weaknesses with mineral oils or organic solvents. In these cases, FKM seals are used, which seal reliably even at 200 °C and in aggressive acids.

An example from practice: in a chemical company, the service life of pump seals was doubled by switching from NBR to FKM. The reason lay in the higher temperature and chemical resistance of the fluoro rubber. For CIP/SIP processes in the food industry, silicone is in turn used, as it is hygienic, odour-neutral and FDA-compliant. This example shows how decisive the precise selection of the elastomer is for operational safety, efficiency and cost-effectiveness.

Future prospects: intelligent elastomers and self-healing

The future of elastomer technology is intelligent and adaptive. New material systems combine chemical stability with functional responsiveness. Self-healing elastomers, for example, can independently repair microcracks through reversible chemical bonds – a mechanism that considerably extends service life. In parallel, sensory elastomers are emerging that detect pressure, temperature or strain and transmit it digitally. This turns seals or bearings into intelligent components for the first time, able to actively monitor the condition of their environment.

Hybrid materials are also gaining importance: combinations of elastomer and plastic or metal enable new design forms, weight reduction and functional integration. Future developments aim to make elastomers fully circular and, with the help of AI-based material simulation, to tailor them optimally to their application already during the development phase.

In summary

The resistance of elastomers is a complex interplay of numerous influencing variables – from chemical attack through thermal loads to mechanical wear. No single factor decides service life, but rather the interplay of material structure, operating conditions and maintenance. A precise material selection based on the operating environment, combined with well-considered design and regular quality control, is therefore the key to long-lasting products.

Elastomers make a substantial contribution to operational safety in virtually all branches of industry: they seal, damp, insulate and protect. Their resistance determines not only the service life of individual components, but also influences the overall reliability of complete systems. Modern developments – such as AI-supported material simulations or self-healing polymers – show that progress in this field is far from complete. In future, the combination of material intelligence, sustainability and precision will play an even greater role.

Frequently asked questions

Which elastomers are most resistant to oil? NBR (acrylonitrile butadiene rubber) and FKM (fluoro rubber) offer outstanding oil and fuel resistance. HNBR is a good alternative if high temperature requirements also apply.

Which elastomers withstand high temperatures? Silicone and FKM elastomers can be used up to above 200 °C and retain their elasticity in the process. For even higher ranges, special perfluoro rubbers (FFKM) are used.

How can the service life of elastomers be extended? Through correct material selection, protection from UV light and ozone, regular inspections, moderate temperatures and suitable lubricants. Storage conditions (dark, dry, cool) also play a major role.

What does compression set mean? Compression set describes the degree of permanent deformation of an elastomer after sustained load. A low value stands for good recovery capacity and is particularly decisive for static seals.

What role does sustainability play for elastomers? New developments aim at bio-based, recyclable or long-lasting elastomers. In this way, they make an important contribution to conserving resources and to reducing CO₂ in industrial manufacturing.

Our rubber sheets

For industry and trade, we offer a wide variety of rubber sheets.

SBR rubber sheet

Our high-quality SBR rubber sheet (styrene butadiene rubber) is the solution for numerous industrial and commercial applications. This rubber sheet is manufactured from first-class styrene butadiene rubber and is distinguished by its outstanding physical properties.

EPDM rubber sheet

Discover the versatility and reliability of our EPDM rubber sheet, which is manufactured from ethylene propylene diene monomer (EPDM). This high-quality elastomer solution has been specially developed to meet the most demanding industrial and commercial applications.

NBR rubber sheet

The NBR rubber sheet is a high-quality industrial product that has been specially developed for applications requiring excellent resistance to oils, greases and various chemicals.

Viton rubber sheet

The Viton rubber sheet is a high-quality technical product that is used for a wide range of industrial applications. Manufactured from fluoro rubber (FKM), it offers outstanding properties that make it the ideal choice for extreme conditions.

FKM rubber sheet

The FKM rubber sheet is a high-quality technical product that is ideally suited for use in demanding industrial applications. Made from fluoro rubber (FKM), it is distinguished by a wide range of outstanding properties that make it the optimal choice for extreme operating conditions.

Silicone rubber sheet

The silicone rubber sheet is a first-class technical product that has been specially developed for applications placing high demands on temperature resistance and flexibility.

PUR rubber sheet

The PUR rubber sheet, manufactured from high-quality polyurethane, is a technically advanced product that has been developed for applications placing the highest demands on abrasion resistance and mechanical load capacity.

Neoprene rubber sheet

The Neoprene rubber sheet, manufactured from high-quality chloroprene rubber (CR), is a versatile technical product that is ideally suited for a wide range of industrial and commercial applications.