Wear of fabrics
By R. David Whitby, Contributing Editor | TLT Worldwide May 2024
Three test methods can be used to determine the wear resistance of fabrics.
As I have written previously about friction with fabrics, I thought I should follow this up with a column about wear with fabrics.
It should not come as a surprise to anyone that fabrics wear out. This happens to carpets, furniture, bath towels, sweaters, socks, shirt collars and many other items. Surprisingly, it happens to flags (particularly large ones) that flutter from tall flagpoles. Moderate and high winds tend to shred the ends of flags, and those flown from public buildings need to be replaced every six months or so. It also happens to pant pockets with keys in them. The constant movement of the keys in the pocket results eventually in a hole appearing at the bottom of the pocket.
Increasingly, followers of fashion deliberately rip fabrics, notably jeans and shorts, to make them appear older and worn. But this has nothing to do with the wear of these fabrics, as some manufacturers of jeans and shorts market and sell them as already ripped.
Hundreds of different types of fabrics are sold, all of which are made from a number of textile fibers. These fibers are generally grouped as acrylonitrile (acrylic), cotton, leather, linen (flax), mohair, nylon, polyester, rayon, silk, spandex (lycra), viscose and wool. Blends of these fibers also are used to create fabrics with different characteristics. The fibers are generally either woven or knitted into a fabric. These can range in texture from very smooth, like cashmere, to quite rough, such as tweed. They also can be very light duty, such as lace, or tough, such as canvas.
One commonly used method of determining the durability (wear resistance) of a fabric is the ASTM D4966 Martindale Abrasion Test. This oscillates discs of sandpaper or wool over the fabric to determine how many times the discs rub before the fabric shows signs of distress. The test fabric is assigned a numerical score to indicate its durability. The results of the test show how much wear and tear a fabric will take before there is a noticeable change in its appearance. Higher values indicate a more durable fabric.
However, the test method is not considered satisfactory by ASTM for acceptance testing of commercial shipments of fabric. The reproducibility of the test is poor because of the nature of abrasion testing and technicians frequently failing to obtain results that agree when using the same type of test instrument, whether within or between laboratories. The test is useful because it is used widely, particularly outside North America.
Another test, more commonly used in North America, is the Wyzenbeek Test (ASTM D4157). A piece of cotton duck or wire is placed on a special machine and rubbed against the fabric being tested in a back-and-forth motion along the warp and weft until signs of wear are observed. The Wyzenbeek cotton test method is run in sets of 5,000 double rubs until the fabric shows “noticeable wear” or two yarn breaks. The Wyzenbeek wire test method is usually used for fabrics that claim to be extremely abrasion resistant.
For both tests, a fabric with a score of 10,000 or lower is suitable as a decorative fabric, for example on cushions. Fabrics with scores between 10,000 and 20,000 are for light domestic use, such as for occasional furniture. Scores between 20,000 and 25,000 are general domestic use fabrics, while fabrics with scores between 25,000 and 30,000 are suitable for heavy domestic use. Commercial use fabrics need to have scores higher than 30,000.
A third test, the Taber Test, is most commonly used to measure the abrasion resistance of leather but can be used on a variety of different materials. A cut portion of the test fabric is attached to a thick paper backer and then placed on a horizontal wheel that spins like a record player, while two smaller abrading wheels rub against it on a vertical axis. Two types of abrading method are used, CS-10 (mildly abrasive) and H-18 (more abrasive). Weights are used to control the pressure of the abrading wheels on the cut portion of the fabric.
Unfortunately, there appears to be very little correlation between the three test methods. In my next column, I will explain why different fabrics have greater wear resistance than others.
David Whitby is chief executive of Pathmaster Marketing Ltd. in Surrey, England. You can reach him at pathmaster.marketing@yahoo.co.uk.