What are the common problems in the finishing of sweaters?

1. Wool is a natural protein fiber. It is favored by consumers for its fluffy, plump, and warm characteristics, and enjoys the reputation of "fiber gem". The finishing process of woolen sweaters has been greatly developed since the late 1990s, especially the application of mercerized shrink-proof technology for woolen garments, which has significantly improved the quality and added value of sweaters. With the development of economy and the improvement of people's living standards, the color and composition of sweaters have changed in recent years; the trend of diversification of styles and accessories is obvious. It is no longer a single pursuit of the traditional requirements of warmth, machine wash, shrink-proof, and smooth feel, but also pay attention to the colorful colors, personalized styles, health and environmental protection, easy care, and multi-function. These requirements have brought new opportunities and challenges to the dyeing and finishing of wool sweaters. At the same time, the above-mentioned many new requirements have more diverse and complicated problems in the finishing process.

2. Common problems

2.1 Color

At present, the chlorinated shrink-proof finishing technology of wool garments is the best method of shrink-proof effect. The technology is mature, the control is simple, and the cost is the lowest. The finished product can meet daily machine washing and can also obtain very good super softness. Hand feel, so it is widely used. In this process, the consistency of the color of sweaters before and after processing is the most critical element in investigating the quality of processing. However, the problem of color and fastness changes before and after processing is very common due to the types of fiber materials, the types of dyes used, and the color fastness. Such changes directly affect the designer's design goals and the overall quality of the sweater.

2.1.1 Fading

Fading is the most common phenomenon in the processing of woolen sweaters in medium colors, especially dark colors (black, dark navy, red, etc.). If only a small amount of floating color fades, it generally does not affect the quality of the sweater. But in the past two years, this phenomenon has become more and more common and serious. From the results of the random inspection of the clothes we processed, most of them were caused by poor dye fastness, incomplete washing of floating colors, and poor chlorine resistance of dyes.

2.1.2 Staining and matching

With the fashionable design of sweater styles, jacquard fabrics have occupied the mainstream of the market, and the jacquard has a wide variety of colors and a large contrast of color shades. Under such circumstances, the staining and color matching phenomenon caused by severe fading will increase.

2.1.3 Discoloration

1. Yellowing

The reasons are: ①The chlorinated shrink-proof process itself is yellowing (the lighter the color, the more obvious); ②The alkali treatment in the mercerizing process; ③The steaming after printing will make the wool yellow; ④The clothes themselves contain fluorescent brighteners, which should increase The whitening agent is not resistant to chlorine or fades during processing;

2. The dye is not resistant to chlorination and changes color

The reasons are: ① In order to increase the color fastness, inappropriate reactive dyes are selected. The color fastness of the yarn is acceptable when the yarn leaves the factory. However, since the selected dyes have not been screened for chlorine resistance, they will appear after chlorination and shrink-proof processing. Decreased fastness or discoloration; ②Contains a larger amount of cellulose fiber (more than 10% discoloration is obvious), the reason is that the reactive dyes used are not resistant to chlorine;

3. Discoloration of accessories:

The reasons are: chlorinated discoloration of non-wool accessories, such as zippers and buttons that are not resistant to chemical corrosion or residual chemical additives.

In summary, fading, staining and discoloration are independent of each other, and there is a close internal connection. However, the color fastness is a major prerequisite, which is directly related to the difficulty of finishing and processing quality. If the color fastness is not high, it will bring great difficulty to the finishing and directly affect the overall quality of the sweater.

Function of non-aldehyde fixing agent:

Formaldehyde-free color fixing agent belongs to the synthesis of polyamine cationic polymers, which can form water-insoluble macromolecular compounds with textile dyes, thereby improving the washing resistance, dyeing fastness and rubbing fastness of dyed fabrics. It is a new type of formaldehyde-free Fixing agent, suitable for the fixing treatment of reactive, direct dye-dyed fabrics or the dyed fabrics after printing and fixing are washable and resistant to rubbing. Can significantly improve the soaping, perspiration, water immersion and rubbing fastness of dyed fabrics. Improve the color fastness of the fabric without causing discoloration or fading of the fabric. Steam and dry heat are quite stable, the fabric has little or no color change, and has good reproducibility. Improve the wet fastness and washing fastness of the fabric without affecting the hand feel, sewing performance, and color change. It can improve the fastness of reactive and direct disperse dyes.