How to test Rubber
Updated: Apr 28
Shore hardness of rubber and plastics
Rubber, elastomer, plastic, and other similar compounds can be tested with this test.
MOR Industries conducts three rubber tests in the laboratory, the first of which is this one. The hardness of the material is measured using a cured button sample. The sample was created when mixing compounds in the mill, a step along producing rubber industrially.
The high-quality raw material components are mixed into an integrated blended mixture called a compound, after which a small sample of 25 grams is cooked for a set amount of time at a set temperature. Our team goes to the laboratory of MOR industries with the cured test button and the raw (uncured) rubber sample of 20 grams for the three tests required: Hardness Test, Rheometer Test, and Specific Gravity Test, which validate the rubber's quality, colour, and conformance.
To ensure that the final product has all the characteristics and properties that we anticipate. These tests are conducted before the start of any production process, such as rubber extrusion or rubber moulding.
To conduct the test, a durometer is used, which measures the hardness of rubber on a scale of 1 to 100.
As per ASTM D2240 test standard, they use a specific spring force and an indenter shape combination to measure indentation depth and corresponding resistance.
Like this, when the number is higher, the scale indicates a greater resistance and thus harder material.
Depending on the material, different test scales are used, such as Shore A, which is common for rubbers and elastomers of a softer to medium hardness. Shore D is used for harder compounds. Shore O, Shore OO, Shore B, and Asker C are also used.
In the MOR Industries Rubber Lab, we perform two different testing methods depending on the type of rubber that will be produced: The Shore A test and the Shore C test.
The hardness of the rubber determines its use. Some examples of the application of the rubber according to its Shore A hardness, are specified in the previous table.
Validation and certification
A secondary hardness test is carried out 24 hours after the first hardness test, in order to ensure that there has been no change to the rubber and that the material remains within the specified parameters.
To ensure that our rubber products comply with all the required specifications and regulations, MOR Industries conduct hardness tests in accordance with ASTM D2240 test specifications.
A Certificate Of Conformity that proves the quality of rubber and the tests performed at MOR industries laboratory can be obtained through our laboratory and quality management system (ISO 9001).
Would you like to learn more about this topic and more specialties about rubber, please contact us!