This standard specifies procedures intended for use in estimating the resistance of vulcanized or thermoplastic rubbers to cracking when exposed, under dynamic tensile strain, to air containing a definite concentration of ozone and at a definite temperature in circumstances that exclude the effects of direct light.
This standard is applicable to vulcanized or thermoplastic rubber.
Note 1: The relative ozone resistance of different rubbers depends on the conditions they are under, especially the concentration and temperature of the ozone, so, special attentions shall be paid in trying to extend the results of standard tests to usage. Moreover, the results of tensile strain test using thin specimen will be different from the aging conditions of the products in actual application due to difference in dimension, shape and deformation.
Note 2: See ISO 1431-3 for the method to determine the ozone concentration.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the normative document (including any amendments) applies.
GB/T 2941 Rubber - General procedures for preparing and conditioning test pieces for physical test methods (GB/T 2941-2006, ISO 23539:2004, IDT)
GB/T 11206 Standard test method for rubber deterioration - Surface cracking
ISO 1431-3 Rubber, vulcanized or thermoplastic - Resistance to ozone cracking - Part 3: Reference and alternative methods for determining the ozone concentration in laboratory test chambers
3 Terms and definitions
For the purpose of this standard, the following terms and definitions apply.
3.1
dynamic strain
strain (normally a tensile strain) varying sinusoidally with time at some selected repetition rate or frequency
4 Principle
Test pieces of vulcanized or thermoplastic rubber are exposed, under continuous dynamic tensile strain, or under alternate periods of dynamic and static tensile strain, in a closed chamber at a constant temperature, to an atmosphere containing a fixed concentration of ozone. The test pieces are examined periodically for cracking.
Two alternative evaluation procedures of ozone cracking are described for selected values of ozone concentration and exposure temperature in the test:
