Dyeing & Finishing Process of Silk Fabric

The colorful silk is the crystallization of the exquisite dyeing and finishing process. The printing process plays an important role in the production process of silk. Because only by using dyeing and finishing technology, we can perfectly reproduce our favorite colors and patterns on the white blank, so that the fabric is more artistic. The process mainly includes four processing steps of raw silk and fabric refining, dyeing, printing and finishing.

The first is the refinement of the fabric. The silk consists of two monofilaments, the main body of which is silk protein, and the outer layer is wrapped with sericin. Most of the pigments, oils, waxes and inorganic salts are present in sericin. These impurities have a great influence on the effect of printing and dyeing, so they must be removed before dyeing. In long-term practice, people have mastered the characteristics of sericin that is easy to dissolve in hot water under the action of chemical agents or enzymes, and take advantage of the weakness of sericin to put raw silk or raw silk into soap (or synthetic detergent) and The mixed solution of soda ash (sodium carbonate) is heated, and the sericin is heated and then hydrolyzed. After such refining, the sericin is removed and the silk protein is preserved, and impurities such as pigments, fats, and waxes are removed, so as to obtain silk products with white color. The raw silk after degumming is called cooked silk. The degree of raw silk degumming must be determined according to production requirements.

After the white silk is refined, it begins to enter the dyeing stage. The dyeing process is the process of dyeing various colors by chemical reaction between dyes and silk. Since silk is a protein fiber, it is not alkali-resistant, so dyeing should be carried out in an acidic or near-neutral dyeing solution. At present, the main dyes used in silk fabrics are: acid dyes, reactive dyes, direct dyes and vat dyes. The color dyed with acid dyes is brighter. After dyeing, it is treated with cationic fixing agent to improve the washing fastness of the product. Reactive dyes have good washing fastness on silk. The dyeing method of fabrics varies with the types of fabrics. For example, crepe and gauze fabrics are dyed with rope or overflow jet dyeing, and spinning, silk, and satin fabrics are dyed with open width or roll dyeing.

The PandaSilk Way of Natural Silk Dyeing

In addition to these methods, natural dyeing is a unique and exquisite handicraft. This technique combines the elegance of silk, a soft and smooth natural fiber, with the beauty of dyes derived from natural plants and minerals. The process involves a series of steps such as cleaning, soaking, dyeing, and drying to infuse the fabric with color. The advantage of natural plant-dyed silk lies not only in its aesthetic appeal but also in its environmental and health benefits. As the raw materials are natural and do not contain harmful chemicals, they are harmless to the human body and reduce environmental pollution, embracing the concept of green textiles. PandaSilk, for example, uses natural dye, avoiding harmful chemicals. Each piece of naturally dyed silk is a unique work of art, presenting exquisite beauty and endless possibilities.

After all, a color is monotonous. In addition to dyeing, people also use printing techniques to make silk colorful. Printing refers to a process in which dyes are printed on fabrics in accordance with the designed colors. Printing on refined fabrics with direct printing, discharge printing, and anti-dye printing is a common printing process.

• Direct printing means that the colorant is printed directly on the silk fabric through the screen printing plate. It is one of the basic printing methods of printing and can be printed with a variety of dyes.
• Discharge printing, also called engraving printing, is a process of discharging with whitening agent. Before printing and dyeing, the silk is dyed with acid dyes and reactive dyes with azo structure, and then printed on the colored silk according to the pattern. The engraving (discharge) paste made from the engraving agent that destroys the pigment, after steaming, the ground color of the engraving paste becomes white, which is called “carving white”.
• Anti-dye printing is to print silk fabrics with “anti-white” paste or “color-resistant” paste in a pattern, and then dye it after drying. Because the pattern part has the anti-dyeing agent in the “anti-white” paste or the “color-proof” paste, it will not be dyed, while the rest are all colored.

After the silk fabric is refined, dyed, and printed, the final finishing work can be carried out on the fabric. The finishing process mainly solves the problems of dampness, wrinkles, and uneven width left over from the previous processes, highlights the softness of the silk fabric itself and increases its wearing function, and mainly adopts two methods of mechanical finishing and chemical finishing.

• Mechanical finishing includes tentering and weft finishing finishing, steam iron finishing, calendering and other methods;
• Chemical finishing is mainly to add chemical agents, such as softener, antistatic agent, fire retardant, sand lotion composed of soda ash and trisodium phosphate, etc., so as to achieve the effect of anti-wrinkle, anti-shrinkage, softness and thickness.

The treated fabrics are not only more suitable for wearing, but the consumption field of silk is also broadened. After the printed silk is made, you can start to make exquisite handicrafts and noble and gorgeous silk sheets with oriental charm.