Elastomer compatibility explanation

Elastomer compatibility explanation

If you want to know what's behind our lubricant-elastomer database, then read on...

Lubricant

This is a list of our special lubricants for elastomers in alphabetical order.

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Material

This displays the elastomer trade names. The sub-divisions in three columns are based on material names from our parent company, Freudenberg & Co., where:

The first column indicates the Shore A hardness,

the second column shows the elastomer type,

the third column displays the material number.

Key to material names...

Time/temp
This column shows the test duration in hours (h) and, separated by a slash, the temperature in °C at which the elastomers were tested.
Please note that certain elastomer-lubricant combinations have been tested twice or more, but for different times. This was mainly done in the case of combinations considered critical. Some test results may be quite acceptable after a test duration of 168 h but may deviate excessively after 1000 h.

Further, the test temperature cannot be considered equivalent to the operating temperature of a dynamically loaded seal. With dynamically loaded seals, high temperatures can develop very quickly at the sealing lip, which are considerably higher than the ambient temperature.

Change in vol.

This column indicates the change in volume in %.

Rule of thumb: values between +5 and –5% by volume are acceptable. However, it is also possible that certain values might be acceptable which deviate clearly , e.g. 40% in the case of special silicone elastomers and +10% for specially hydrated NBR. In such cases, further tests or the observation of practical results are necessary to obtain reliable information about permissible swelling.

Change in hardness

This column shows the change of hardness in Shore A when compared to the initial condition.

Rule of thumb: the manufacturing and testing process provides a tolerance of ą5 degrees hardness.
NBR: acceptable change in hardness ą 10
ACM: acceptable change in hardness ą 5
FPM: acceptable change in hardness ą 5
Generally, a change of ą 5 degrees in hardness is considered acceptable

Change in tensile strength
This indicates the change in tensile strength in % compared to the original value.
Rule of thumb: the maximum acceptable reduction is 40 %.

Change in elongation at tear
This column indicates the change in elongation at tear in % compared to the initial value.
Rule of thumb: it is necessary to differentiate between several different elastomer types:
NBR: acceptable change up to –70 %
ACM: acceptable change up to –60 %
FPM: acceptable change up to –70 %
Generally, a change between –60 and –70 % is considered acceptable.

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				Elastomer compatibility explanation




				If you want to know what's behind our lubricant-elastomer database, then read on...




				Lubricant This is a list of our special lubricants for elastomers in alphabetical order.
	< back




				Material This displays the elastomer trade names. The sub-divisions in three columns are based on material names from our parent company, Freudenberg & Co., where: The first column indicates the Shore A hardness, the second column shows the elastomer type, the third column displays the material number. Key to material names...



				Time/temp This column shows the test duration in hours (h) and, separated by a slash, the temperature in °C at which the elastomers were tested. Please note that certain elastomer-lubricant combinations have been tested twice or more, but for different times. This was mainly done in the case of combinations considered critical. Some test results may be quite acceptable after a test duration of 168 h but may deviate excessively after 1000 h. Further, the test temperature cannot be considered equivalent to the operating temperature of a dynamically loaded seal. With dynamically loaded seals, high temperatures can develop very quickly at the sealing lip, which are considerably higher than the ambient temperature.



				Change in vol. This column indicates the change in volume in %. Rule of thumb: values between +5 and –5% by volume are acceptable. However, it is also possible that certain values might be acceptable which deviate clearly , e.g. 40% in the case of special silicone elastomers and +10% for specially hydrated NBR. In such cases, further tests or the observation of practical results are necessary to obtain reliable information about permissible swelling.



				Change in hardness This column shows the change of hardness in Shore A when compared to the initial condition. Rule of thumb: the manufacturing and testing process provides a tolerance of ą5 degrees hardness. NBR: acceptable change in hardness ą 10 ACM: acceptable change in hardness ą 5 FPM: acceptable change in hardness ą 5 Generally, a change of ą 5 degrees in hardness is considered acceptable



				Change in tensile strength This indicates the change in tensile strength in % compared to the original value. Rule of thumb: the maximum acceptable reduction is 40 %.



				Change in elongation at tear This column indicates the change in elongation at tear in % compared to the initial value. Rule of thumb: it is necessary to differentiate between several different elastomer types: NBR: acceptable change up to –70 % ACM: acceptable change up to –60 % FPM: acceptable change up to –70 % Generally, a change between –60 and –70 % is considered acceptable.
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