Understanding Martindale Abrasion.
For decades, the Wyzenbeek test has served as the litmus for the abrasion resistance of textiles. Designers often specify a fabric, based upon how many double-rubs the material has achieved. It is believed that the higher the number, the better it will perform. However, as the fabric selection pool became more global, another type of abrasion began to emerge on fabric specification cards: The Martindale Abrasion. This led many to ask, ‘What happened to my double rubs?’, and ‘What is this Martindale test? Are the results just as good?’ Here’s what you need to know.
The Martindale abrasion test originated in the UK in the early 1940s. It was created in a collaboration between Dr. J.G. Martindale (for whom the test and its machine would ultimately be named) and the Wool Industries Research Association (WIRA). Their goal was to create a more realistic, abrasion resistance test than what existed at that time. This would be especially critical as they were testing carbon-impregnated cloth for use in protective gear employed for gas attacks during World War II! Eventually, several Martindale methods would be established to test not only apparel but also upholstery, shoes, luggage, and even flooring.
How it Works.
Three 38mm specimens are cut and placed in holders so that they are face down against a worsted wool abradant. The specimen holders are equipped with a weighted handle such that the material is held with 12kPa (1.74psi) of pressure to maintain constant and consistent contact with the abradant. The machine then moves the specimen against the abradant in a shifting elliptical motion known as a Lissajous pattern.
While this has incorrectly been cited as a ‘figure 8’ motion, it operates just as a Spirograph®, familiar to many. As the specimen is moved through the series of shifting ellipses, a box shape is formed. (Figure 1) In the US, one elliptical movement constitutes a cycle. Those cycles are then counted and reported for abrasion resistance. Like Wyzenbeek, failure occurs based upon the type of construction being tested. Plain weaves are typically evaluated for yarn breakage. Conversely, pile fabrics, along with coated and printed fabrics are assessed for objectionable changes in their surface sufficient to cause a customer to complain.
Martindale v. Wyzenbeek.
Is there is any correlation between the Wyzenbeek and Martindale methods? In short, no. The methods are conducted in completely different manners, with differing weights, tension, and abradants. All factors in which contribute to the materials performance. Just because a material performs well on one of the methods, does not mean it will on the other method. But does that mean one is better than the other? Again, no. Both tests have a substantial history of providing guidance for abrasion resistance, which is why the Association for Contract Textiles (ACT), has included the ASTM Martindale method (ASTM D4966) in its performance guideline as an alternative to Wyzenbeek abrasion. Their recommendation is a minimum of 20,000 cycles for low traffic environments and 40,000 for high traffic environments.
So, what does this all mean?
In conclusion, Wyzenbeek and Martindale are both valid methods for assessing abrasion resistance even results do no correlate. Sometimes, one test may more accurately reflect a particular construction’s abrasion resistance than the other. Particularly when it has known reliability in the field, but performs poorly on a test. When it comes to meeting ACT requirements, you have the option of selecting the method that best reflects your construction’s true performance.
1 History information obtained from the following sources:
BTTG “Our History” www.bttg.co.uk\aboutus\timeline
SATRA Bulletin, Dec. 2012, p.36