GB/T 13642-2015 in English

《GB/T 13642-2015硫化橡胶或热塑性橡胶 耐臭氧龟裂 动态拉伸试验》由TC35（全国橡胶与橡胶制品标准化技术委员会）归口，TC35SC2（全国橡胶与橡胶制品标准化技术委员会通用试验方法分会）执行，主管部门为中国石油和化学工业联合会。
本标准规定了硫化橡胶或热塑性橡胶在动态拉伸应变下，暴露于含一定浓度臭氧的空气中和在规定温度且无光线直接影响下的环境中进行的耐臭氧龟裂的试验方法。 本标准适用于硫化橡胶或热塑性橡胶。 注1：不同橡胶的相对耐臭氧性能取决于其所处的条件，尤其是臭氧浓度和温度，因此试图将标准试验的结果推广到使用情况时应特别小心。另外，用薄试样进行拉伸试验的结果与实际应用中制品的老化情况会因尺寸、形状和变形的不同存在差异。 注2：测定臭氧浓度的方法见ISO1431-3。

1 Scope

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:

Foreword I
1 Scope
2 Normative references
3 Terms and definitions
4 Principle
5 Apparatus
6 Test pieces
7 Conditioning
8 Test conditions
9 Test procedures
10 Test results
11 Test report