The color fastness of fabrics (referred to as dyeing fastness) refers to the color or printing of fabrics subjected to external factors (extrusion, friction, washing, rain, exposure, finishing, sea water) during use or finishing. The degree of discoloration under the action of dipping, saliva dipping, water stains, sweat stains, etc. is an important indicator of fabrics. Good fastness to dyeing, fabrics do not simply fade during post-finishing or use. Poor fastness to dyeing may cause discoloration, slight color, or staining, which causes a lot of trouble.
The dyeing fastness of fabric products usually includes:
Resistant to soaping, abrasion, endurance, bleach or oxidant (reducing agent), ironing resistance, perspiration resistance and perspiration fastness. Among them, soaping resistance, friction resistance, endurance resistance, water resistance, and perspiration resistance are several indicators of dyeing fastness that most buyers pay more attention to in actual production and trade.
1.Common problems of dyeing fastness of cloth products
In daily spot checks and consumer complaints, the most common fabric fastness problems are as follows:
1) Unsatisfactory fastness to sunlight. During the wearing of the work jacket, the color of the parts exposed to the sun will be lighter or discolored (usually on the back and shoulders), while the areas that are not illuminated or lighted will not change or change light, causing the original colors to be consistent The products have different shades of color and can no longer be used.
2) The fastness to washing, fastness to soaping, and fastness to dry cleaning are unacceptable. Advanced silk workwear, wool workwear, and cotton workwear have the simplest problems in this regard.
3) Unsatisfactory fastness to rubbing dyeing. During the use of fabric products, because different parts of the product are subject to different degrees of friction, the degree of discoloration is different. For example, the elbows, collars and underarms of the shirts and sleeves are the easiest to fade. In addition, the hips and knees of the pants also faded easily.
4) Unsatisfactory fastness to sweat staining. It is mainly summer clothing or undergarment that fades after being soaked with sweat when worn.
2. Factors affecting the fastness of dyeing and improvement methods
Products with poor fastness to dyeing fade during wearing, which will affect other workwear worn on the body, or stain other clothes when washing with other clothes, affecting aesthetics and wearability; on the other hand, good and fast dyeing fastness It is also directly related to human health and safety. Dye molecules and heavy metal ions on products with poor fastness to dyeing may be absorbed by the body through the skin and endanger the skin, or even damage the health of the body.
The factors that affect the fastness of dyeing of fabrics are divided into internal factors and external factors. The internal factor refers to the firmness of the combination of the dye and the fiber, and the external factor refers to the external force applied to the product or the environmental conditions provided by the product during its use. External factors cannot be manipulated, so producers must strive to improve the color fastness of the product itself. Here are a few solutions to personal practical experience for everyone to learn from.
