Textiles woven from natural fibers are more prone to color fading than those made from chemical fibers (especially synthetic fibers). Cotton, linen, silk, and woolen fabrics are more prone to color fading than nylon, polyester, acrylic, and so on. Especially silk and cotton fabrics are prone to fading; Secondly, textiles with thicker colors and brighter colors are prone to fading. That is to say, black, dark, bright red, bright green, bright blue, bright purple, etc. are prone to fading; And textiles with light and some darker colors are less likely to fade.
Cellulose fibers such as pure cotton are usually dyed with anionic water-soluble dyes such as direct dyes and acid dyes, which have complete chromatography and bright colors. However, due to the water-soluble groups present in the structure of these dyes, they are hydrophilic, making it easy for the colors on clothes to fade and fade during washing. The process of fading can make the appearance of clothes outdated; At the same time, the hydrolysis of the dye into the dye solution will reverse the staining of cotton clothes, resulting in staining and color matching phenomena.
Fixed color
Nowadays, manufacturers usually undergo color fixing treatment to solve this problem. Fixed color, as the name suggests, is to improve the color fastness of fabrics; The additives that can improve various types of dyeing fastness are called fixing agents. So how can manufacturers solve the problem of color fading and staining of cotton clothes from the source?
The working mechanism of color fixing agents
Firstly, dyes are dyed on different fibers, and their dyeing mechanism and fastness are different. Therefore, the fixing mechanism and application of the fixing agent used are also different.
1. By combining cationic groups such as quaternary ammonium or tertiary amine salts in the fixing agent molecules with anionic groups in the structure of ionic dyes, insoluble color blocks are formed between the dye and the fixing agent to settle on the fibers, thereby improving the color fastness of the dye on the fabric.
2. By cross-linking the reactive groups in the fixing agent molecule with the reactive groups on the dye molecule and the hydroxyl groups on the cellulose molecule, the water solubility of the dye is reduced.
3. Utilize the film forming performance of fixing agents on fabrics to improve their dyeing fastness. During the high-temperature drying process of the fabric treated with the fixing agent, the reaction groups on the fixing agent molecules self crosslink into large molecules, forming a protective film with a certain strength on the surface of the fabric and fibers, covering the dye on the fibers, making it difficult for the dye to fall off.
Types of fixing agents
From the principle of color fixing agents, we can classify them into two main categories: reactive and non reactive color fixing agents.
Reactive fixing agents refer to the introduction of reactive groups into the molecules of fixing agents, commonly known as epoxy groups. These fixing agents can form covalent bonds with certain groups in fiber dye molecules, which is more beneficial for improving dyeing fastness.
Non reactive fixing agents refer to two types: film forming on the surface of fibers and sealing water-soluble groups, which are mainly classified into cationic fixing agents and resin fixing agents.
Zhejiang Chaoyu New Material Technology Co., Ltd
Suzhou Chaoyu Textile Chemical Co., Ltd
