When we buy clothes, we often see cotton, kapok, velvet cotton, mercerized cotton, etc. where the ingredients are marked on the tag. Are these cotton? If it’s not cotton, what does it have to do with cotton fiber?
Cotton fiber’s “cousin”
Kapok is the fruit of the kapok tree. By removing the kapok seeds from the kapok fruit, you can initially obtain kapok fiber for textile processing. Ethnic minorities in Yunnan use kapok to hand-make bedding.
Kapok
Kapok fiber and cotton fiber are generally white. They are all natural cellulose fibers, and one fiber is a single cell of kapok.
They have many similarities, but there are also many differences.
What is the difference between kapok fiber and cotton fiber?
Both kapok and cotton fibers are single-cell fibers, and their main components are cellulose fibers. They have many similarities, but also many differences.
Kapok fiber has higher hollowness, lower density, better gloss, stronger warmth retention, and less distortion and deformation than cotton fiber, but the dyeing rate of kapok fiber lower.
Longitudinal shape
Kapok fiber is cylindrical, with smooth surface, no twist and good gloss, but it is easy to fold longitudinally song. Therefore, the cohesion force is poor and the spinnability is poor.
Cotton fiber is in the shape of a flat ribbon with natural twist. Therefore, it has good cohesion and good spinnability.
Cross section
Kapok fibers are round or oval, hollow, and have thin cell walls. Kapok fiber has a high hollowness, so kapok fiber is often used to make warm filling materials and sound-absorbing and heat-insulating materials. At the same time, the fiber is light in volume and has good buoyancy. When the kapok block is soaked in water for 30 days, the buoyancy only decreases by 10%. Therefore, kapok fiber is often used to make life jackets and other water life-saving supplies.
The cotton fiber is waist-shaped and the middle cavity is visible. The warmth retention of cotton fiber is excellent, but lower than that of kapok fiber.
The “renovator” of cotton fiber
In order to improve the characteristics of cotton fabrics such as easy shrinkage and easy wrinkles, cotton fibers are finished.
Mercerized cotton
Under normal temperature conditions, cotton fibers are processed using an alkali solution with a mass concentration greater than 180 g/L. Mercerizing treatment to prepare mercerized cotton with silky luster.
Liquid ammonia finishing cotton
Liquid ammonia finishing is carried out on cotton fibers to prepare liquid ammonia finishing with silk-like luster cotton.
What effect does mercerization have on cotton fibers?
Principle: Treating cotton fiber with dilute alkali solution at room temperature will replace hydrogen on the primary hydroxyl group of cellulose macromolecules to form alkali cellulose, and Twist the crystalline structure and puff the fibers.
Changes in the morphological structure of cotton fibers after mercerization treatment
After The morphological characteristics of the mercerized cotton fiber have undergone physical changes. The natural twist disappears, the fiber cross-section expands, the diameter increases, and the cross-section is approximately circular, which increases the regular reflection of light, making the surface of cotton fiber products appear silky. The general luster is bright; and due to the tight arrangement of molecules, the strength is higher than that of non-mercerized yarn, which improves the strength of cotton fiber and the adsorption capacity of dyes.
What is liquid ammonia finishing?
Liquid ammonia finishing is a new finishing method used to replace mercerizing treatment in order to reduce the environmental pollution caused by high-concentration alkali liquid. Liquid ammonia finishing uses liquid ammonia to treat cotton fibers.
Tips
Liquid ammonia: liquid ammonia formed by cooling ammonia gas to below -34 ℃. The surface physical state of liquid ammonia is the same as water and easy to flow, but its viscosity and surface tension are lower than water. Liquid ammonia can easily penetrate into cotton fibers without damaging the fibers, and can seep out quickly and easily.
Changes in the morphological structure of cotton fibers after liquid ammonia finishing
The principle of liquid ammonia finishing is the same as that of mercerizing treatment. By swelling the fibers, the fibers become smooth and straight in the longitudinal direction, the natural twist is reduced, the gloss of the fabric is increased, and the shrinkage and anti-wrinkle properties are significantly improved.
Cotton fiber “imitator”
Purely natural cotton fiber cannot meet the needs of the broad market, so people use cellulose fibers widely found in nature to make some artificial cotton similar to cotton fiber through chemical treatment and mechanical processing.
Artificial cotton
Viscose is the earliest regenerated cellulose fiber developed and produced.
Mo �Modal is a patented product of Austrian Lenzing Company, a high wet modulus regenerated cellulose fiber.
Lyocell is a regenerated cellulose fiber prepared by a green solvent method.
Cotton fiber “counterfeiter”
There are many filling cottons on the market, such as PP cotton, pearl cotton, down cotton, etc. Although they all have the word cotton, these fibers are composed of high molecular polymers and their chemical structures are different from cotton fibers.
PP cotton
PP cotton is also called doll cotton or hollow cotton. It has good resilience, smooth feel and warmth. It has good sex characteristics and is mainly used in stuffing of plush toys or thicker cotton clothes.
Pearl cotton
Pearl cotton is a granular Cotton and pearl cotton are characterized by good warmth retention, light hand feel, and can regain their fluffiness after washing and are not easy to move.
Velvet cotton
Down cotton is treated with a special process. The texture is like down, so it is called down cotton. It is thin, delicate and soft to the touch, has good thermal insulation, is not easy to deform, and is not easy to leak. Down cotton of the same weight has better warmth retention than down, so down cotton is widely used. Down cotton is divided into filaments and short filaments.
