Cotton: We usually prefer wearing pure cotton socks, but does “pure cotton” really mean 100% cotton? According to sock experts, the answer is no. If a pair of socks is made of 100% cotton, then it’s basically just cotton fabric. Generally, socks with over 75% cotton content can be considered as cotton socks, and those with 85% cotton content are considered high-quality cotton socks. Pure cotton has its downsides: it’s not very resistant to sunlight, it yellows easily, has poor elasticity, wrinkles easily, and is prone to mildew. Therefore, cotton socks need some functional fibers added to maintain elasticity, strength, and comfort. Common functional fibers include spandex, nylon, acrylic, and polyester. Socks without these functional fibers aren’t good socks.
Combed Cotton: Combed cotton is made using a machine called a combing machine, which removes shorter fibers from ordinary cotton, leaving longer, more aligned fibers. This makes the yarn finer and the final product smoother and more comfortable. It’s considered a higher quality type of cotton.
Mercerized Cotton: Mercerized cotton undergoes a process in a caustic soda solution that gives the cotton fibers a silk-like sheen and smoother feel without changing other physical properties. It’s often used in thin summer socks for its shiny, silky appearance.
Wool: Wool is another common sock material, known for its excellent warmth but relatively higher cost. It’s not often used for work, but it’s great for home use in cold indoor environments without heating. Wool socks are warm and have good odor resistance, but they’re not ideal for sweaty feet as their moisture-wicking capacity is limited. Poor-quality wool socks also tend to pill.
Spandex: Spandex, also known as elastic fiber, provides high elasticity and stretch, stretching up to 5-7 times its original length. Socks must contain spandex to ensure they are stretchy and fit well. Spandex makes socks easier to wear and helps them hug the foot, much like swimwear. Lycra is a type of spandex with up to 500% stretch, returning to its original shape slowly and providing a snug fit with minimal restriction. It can be used with any material, including wool, linen, silk
or cotton, to enhance the fabric’s fit, elasticity, and natural stretchiness. Unlike most spandex fibers, Lycra has a special chemical structure that prevents mold growth in wet, sealed conditions. Lycra is known as a “friendly” fiber because it blends seamlessly with both natural and synthetic fibers, improving comfort, fit, freedom of movement, and lifespan.
Nylon: Known as polyamide in technical terms, nylon is a strong, durable synthetic fiber. It’s the most durable and resilient synthetic fiber, known for its light weight and elasticity. Adding nylon to socks ensures high elasticity and strength. Nylon is commonly used in compression socks, and the “D” in compression socks refers to the density of the fabric—higher numbers mean greater thickness and pressure. For health reasons, high-D compression socks shouldn’t be worn for too long.
Acrylic: Known internationally as acrylic and domestically as polyacrylonitrile, this fiber is soft, lightweight, and warm, often called “synthetic wool.” It’s over 10% lighter than wool but more than twice as strong. Acrylic resists mold and moths, and its resistance to sunlight is ten times greater than wool and cotton. In the 1970s and 80s, “bulk yarn” was popular in southern China, made from acrylic. Acrylic’s major downside is that it pills easily and isn’t very durable. Mixing acrylic with wool creates a blend called “wool-acrylic,” which was very popular in the past for its excellent warmth. Interestingly, both bathtubs and clothing socks can be made from acrylic materials, though the former uses acrylic sheets while the latter uses acrylic fibers.
Polyester: Compared to natural fibers, polyester has good elasticity and fluffiness, making socks lightweight. The well-known Dacron shirts from the past took advantage of its lightweight and cool properties. However, polyester has low moisture absorption, poor breathability, and can pill and stain easily.
Tencel: Tencel is actually a type of rayon, similar to how Lycra is a brand name for spandex. It’s the trademark name for Lyocell fiber produced by the British company Acocdis, registered as Tencel in China.
Bamboo Fiber: Bamboo fiber is also a type of rayon. It’s made from bamboo, which regenerates much faster than wood, making it an eco-friendly option in today’s industrialized society. Bamboo fiber fabrics are soft, comfortable, durable, moisture-wicking, quick-drying, and breathable. Unlike other rayon fibers, bamboo fiber has natural antibacterial properties due to a substance called “bamboo kun,” which prevents bacteria, mites, and odors. Bamboo fiber also blocks UV rays better than cotton and has excellent anti-aging properties due to its antioxidant content. It contains essential amino acids and compounds that can moisturize skin, reduce fatigue, improve circulation, and enhance sleep quality.