Double rubs are a method of determining a fabric's abrasion resistance and durability. One back-and-forth motion equals one double rub. This testing approach is intended to simulate the "wear and tear" of daily use. Double rubbing fabrics will leave a similar mark when done by hand or with an automatic washing machine.
The American Association of Textile Chemists and Colorists (AATCC) tests fiber and fabric for durability. There are two types of durability tests: abrasion and erosion. In an abrasion test, which measures wear resistance, a defined amount of force is applied to a sample of the material using a mechanical instrument called a durometer. The more force needed to deform the sample, the more resistant it is to abrasion. Erosion tests measure damage caused by chemicals and water. In this case, a sample is immersed in a solution and then dried. If the sample retains its original color and quality, it has passed the test.
In general, the harder a fabric is, the better it will last. But that isn't always the case. Some people make their own clothes from natural fibers such as cotton and linen, which have a very soft texture and are very susceptible to abrasion. They need fabrics that will protect their clothes over time from abrasive elements such as dust particles and sweat.
Rub tests are used to measure how much regular use a cloth can withstand before showing signs of damage. Abrasion resistance is evaluated using a machine that rubs the cloth repeatedly until it wears through. The number of passes required to achieve this stage is referred to as the fabric's rub count. Most fabrics have a rub count of 100 or less.
The abrasion resistance of fabrics varies depending on how they are made. Fabrics composed of fibers such as cotton and linen are generally more durable than those containing silk or nylon. The amount of friction between the rubbing surfaces also affects rub resistance. The smoother these surfaces are, the more resistant the fabric will be to damage. For example, a sheet of paper has a very smooth surface, while a brick has quite a bit of texture. The paper can be folded over and over without tearing, but the brick would quickly wear out from all the touching up against the wall.
Fabrics also vary in their ability to resist stains. In general, darker colors tend to stain hands and clothes more easily because they have more opportunity to contact the dye source. Light colors like white, yellow, and blue contain no protective colorants in the fiber itself, so they are highly susceptible to staining. Black has been shown to retain its colorfulness even after many washes.
There are several ways to increase rub resistance of fabrics. The first thing you should do is choose fibers that are naturally durable.
Double-faced textiles are a type of double cloth that consists of one warp and two sets of wefts, or (less frequently) two warps and one weft. Most blankets, satin ribbons, and interlinings are made with two right sides or faces and no wrong side. Double weaving is a centuries-old technique. Modern examples can be seen in fabrics used by the Chinese for clothing and bedding.
According to the Oxford English Dictionary, "double-faced" was first used in print in 1611 to describe a book with "a front and back page." And here I thought it meant something more modern like "dual personality." No, it's just plain old double-faced.
They say knowledge is power, and with this in mind, let's look at some other words you might see on fabric labels...
Warp (n.) The length of yarn used to weave a textile item; also called the line of pull. Warp threads are those strands within the yarn that cause it to take on a horizontal orientation when woven into a fabric. They will always be listed last when describing the ingredients of a yarn package. For example, "40% cotton, 40% polyester, 2% silk". The cotton is the warp, the polyester is the weft.
Weft (n.) A length of yarn used to weave a textile item; also called the cross-thread.