BS ISO 3387:2020 pdf download.Rubber — Determination of crystallization effects by hardness measurements.
7.2 Preparation
7.2.1 Vulcanized rubber
Test pieces of vulcanized rubber shall be prepared in accordance with ISO 23529. To obtain the necessary thickness, it is permissible to superimpose two pieces of rubber (but no more than two), provided that these have flat, parallel surfaces.
7.2.2 Raw and unvulcanized rubber
Test pieces of raw and of unvulcanized (compounded) rubber shall he prepared by placing a suitable quantity in a preheated mould and then applying heat and pressure 5) for a suitable time. The mould, still under pressure, shall be cooled to standard laboratory temperature (see ISO 23529). After 15 mm, the pressure shall be released, and the test piece removed. It shall be free from blisters and porosity. Values of mould temperature and time of application of pressure required to produce a suitable test piece depend upon the type of rubber. A temperature of 150°C applied for 3 mm has been found suitable for many raw rubbers, while a temperature of 120 °C applied for 3 mm has been found satisfactory for many compounded rubbers. However, for some materials, longer times or higher mould temperatures might be necessary to ensure a smooth and flat test piece surface. Under no circumstances shall conditions be used that cause incipient cure or degradation.
7.3 Conditioning
7.3.1 Time-interval between vulcanization and testing
When appropriate, the time interval between vulcanization and testing shall be in accordance with ISO 23529.
7.3.2 Decrystallization and conditioning
Test pieces of vulcanized rubber or test pieces moulded from raw or unvulcanized (compounded) rubber kept for more than 8 h after moulding before testing shall be decrystallized immediately before testing by heating them in an oven at 70 °C for 45 mm. They shall then be conditioned at the standard laboratory temperature (see ISO 23529) for at least 30 mm and no more than 60 mm before testing.
11 Test report
The test report shall include the following information:
a) sample details:
1) full description of the sample and its origin;
2) compound details, and cure details, where appropriate;
3) method of preparation of test pieces from sample, for example, moulded or cut;
b) test method:
1) a full reference to the test method used;
2) the method of measuring hardness;
3) the type of test piece used;
c) test details:
1) the standard laboratory temperature;
2) decrystallization and conditioning prior to test, if carried out;
3) the test temperature;
4) time of storage at the test temperature;
5) details of any procedures not specified in this document;
d) test results:
1) the number of test pieces used;
2) the individual test results;
3) the median results;
4) date of test.BS ISO 3387 pdf download.