The low temperature properties of rubber materials play a decisive role in the utilization of rubber products in colder climates.
The prerequisites for these properties have long been part of technical specifications, particularly in the automotive industry.
Low Temperature Testing Methods
The following are the most common standardized test procedures for low temperature testing:
- ISO 2921, ASTM D1329 Temperature retraction, TR-test
- ISO 1432, ASTM D1053 Low temp stiffening, Gehman
- ISO 812, ISO 974, ASTM D746, ASTM D2137 Brittleness point
- ISO 815-2 Low temp compression set
Elastocon offers testing equipment for all these four methods. Previously, a long time was required to perform these tests. However, this issue has been eliminated with today’s more automated instruments, which have also improved the accuracy of the results remarkably.
Low Temperature Compression Set (LTCS)
Figure 1. Rig for LTCS in accordance with ISO 815-2 from Elastocon
Figures 1 and 2 depict a rig and a modified laboratory freezer for LTCS in accordance with ISO 815-2. The test result will show the recoverability of a rubber material after being compressed at low temperature. Using equipment from Elastocon there is no need to open the freezer during the test - all measurements are taken automatically. These features enables you to have a better repeatability and reproducibility of your test as well as a reduction in manual work when compared to the old method which required manual opening of the freezer.
The software from Elastocon will automatically carry out the calculations from the compression set as the remaining deformation.
Figure 2. Modified laboratory freezer for LTCS from Elastocon
The following video demonstrates LTCS in more detail:
Figure 3. Temperature Retraction Test apparatus from Elastocon
The Temperature Retraction Test or TR-test as outlined in ISO 2921 demonstrates the elastic retraction of rubber materials at various temperatures.
The temperatures at which point specified retractions take place are then calculated. The software will present a test report as illustrated in Figure 4.
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Figure 4. Test report for a TR-test.
The TR Test is explained in more detail in the following video: http://vimeo.com/53078031
Figure 5. Brittleness testing apparatus from Elastocon
A brittleness test is performed to determine the lowest temperature at which point the rubber material does not demonstrate brittle failure while impacted under the specified test conditions. The software will generate a test report as depicted in Figure 6. One of the more crucial points for this test is the strokes speed when it hit the samples and immediately after. If you want to know more about this, contact the experts at Elastocon, they will be glad to help you!
Figure 6. Test report for a brittleness test
The brittleness test is explained in more detail in the following video: http://vimeo.com/53078026
Figure 7. Gehman test apparatus from Elastocon
The Gehman test is used to determine the relative stiffness of a material over a wide temperature range. This test can be utilized for both thermoplastic and vulcanized rubber. The results can be illustrated in a graph as the relative modulus against temperature between the stiffness at each temperature and room temperature, as shown in Figure 8.
Figure 8. Test report for a Gehman test.
The Gehman test is explained in more detail in the following video: http://vimeo.com/53141584
Combined TR-test, Brittleness-test and Gehman-test
The combined equipment offered by Elastocon for Low Temperature Testing is depicted in Figure 9. Users can perform one, two, or all three test methods combined in the same equipment, thus saving considerable lab space. To our knowledge Elastocon is the only manufacturer that offers their customers to choose if they want 1, 2 or all 3 test methods in the same unit.
Figure 9. Combined equipment for Low Temperature Testing from Elastocon
Switching between the various test methods is simple with this equipment because the rigs are placed on a carousel which can be turned around very easily.
The system also includes the software and a computer with the first year support agreement. More information for Elastocon solutions for low temperature testing can be found here.
This information has been sourced, reviewed and adapted from materials provided by Elastocon AB.
For more information on this source, please visit Elastocon AB.