ISO 815-1 is the first part of the multi-series standard that specifies methods for the determination of the compression set characteristics of vulcanized and thermoplastic rubbers at ambient or elevated temperatures.
The methods described in ISO 815-1 are intended to measure rubbers’ hardness within the range of 10 IRHD to 95 IRHD to retain their elastic properties at specified temperatures after prolonged compression at constant strain (normally 25 %) under one of the alternative sets of conditions described.
Note 1: When rubber is held under compression, physical or chemical changes that prevent the rubber from returning to its original dimensions after the release of the deforming force can occur. The result is a set, the magnitude of which depends on the time and temperature of compression as well as on the time, temperature, and conditions of recovery. At elevated temperatures, chemical changes become increasingly more important and lead to a permanent set.
Note 2: Short-time compression set tests, typically for 24h, at elevated temperatures are commonly used as a measure of the state of cure, a means of material classification, and a specification to ensure the quality of the compound. Longer tests, typically for 1 000 h, at elevated temperatures take account of the effect of ageing and are often used to predict service performance, including that of sealing materials. Short-time tests at ambient temperature show mainly the effect of physical changes (re-orientation of the molecular chains and the fillers).
ISO 815-1 on rubbers or thermoplastics is relevant to:
Thermoplastic rubber is a relatively new class of polymer, which combines the solubility and thermoplastic of polystyrene with the toughness and resilience of vulcanized natural rubber or polybutadiene at ambient temperatures.
In ISO 815-1, a calibration schedule is given that contains all of the parameters and requirements stated in the test method. A parameter and requirement may relate to the main test apparatus, to a part of the apparatus, or an accessory apparatus.
Overall, ISO 815-1 is a comprehensive guide to provide methods for determining the compression set at ambient or elevated temperatures, so users will gain a comprehensive understanding of the quality of thermoplastics and rubbers to improve durability and strength.
BS ISO 815-1:2019 supersedes BS ISO 815-1:2014, which is withdrawn and includes
ISO 815-1