This International Standard specifies three methods for deter-mining the decrease in counterforce exerted by a ring-shaped test piece of vulcanized or thermoplastic rubber which has been compressed to a constant deformation and maintained thus at a predetermined test temperature. The methods are particularly suitable for the determination of stress relaxation in liquid environments.
In method A, the compression is applied, and all counterforce measurements are made, at the test temperature.
In method B, the compression is applied, and all counterforce measurements are made, at standard laboratory temperature.
In method C, the compression is applied at standard laboratory temperature and all counterforce measurements are made at the test temperature.
An alternative method, using cylindrical test pieces, is specified in ISO 3384.
NOTES
1 The three methods, A, B, and C, of carrying out the measurement do not give the same values of stress relaxation and comparison of values obtained from the three methods must be avoided. The method selected for use depends on the purpose of the test.
2 Testing at temperatures below standard laboratory temperature is not specified. The methods have been used for low temperature testing, but their reliability under these conditions is not proven.
DS/ISO 6056:1989 history
1989DS/ISO 6056:1989 Rubber, vulcanized or thermoplastic — Determination of compression stress relaxation (rings)