There are also secrets between printing and dyeing
Printing process is the process of applying patterns to textile fabrics with dyes or pigments. Printing can be divided into fabric printing, wool top printing, and yarn printing, with fabric printing being the main form. Wool top printing is used for making mixed color tweeds; Yarn printing is used to weave special style colored patterned fabrics. Textile printing has a long history.
Dyeing refers to coloring, also known as coloring, which refers to the use of chemical or other methods to affect the substance itself and make it colored. Under the conditions permitted by technology, objects can be rendered in various colors that people need through dyeing, and colorful colors can be used to decorate life. The method of dyeing has existed since ancient times and continues to develop.
Differences and similarities between printing and dyeing
From the perspective of the mechanism of dyeing fibers with dyes, printing and dyeing are the same, except that in printing, a certain color of dye is applied to the part of the textile according to the requirements of the pattern pattern, and after certain post-processing, the dye is dyed onto the fiber, thereby obtaining a printing product with one or more colors on the textile. Therefore, printing can also be said to be "partial dyeing".
When using the same type of dyes for textile dyeing and printing, the chemical additives used and their physical and chemical properties are similar, so their coloring and fixation principles are also similar or the same; For the same variety of fiber products, if the same dye is used for dyeing and printing, they can have the same dyeing fastness, such as good fastness when dyeing with vat dyes, and good fastness on printed products.
In printing and dyeing, dyeing processes use aqueous dye solutions, while printing processes use color paste, which is a paste with a certain viscosity made by adding a paste to the dye solution or dispersion.
Its use can prevent unclear pattern contours, pattern distortion, and dye migration during post printing drying caused by pattern infiltration during printing; The concentration of dyes and chemical additives in the color paste is much higher than that in ordinary dyeing baths. In addition, it contains a large amount of paste, resulting in difficulty in dissolving the dyes. Therefore, auxiliary solvents such as urea and alcohol should be added to the printing paste; During dyeing, the dye penetrates and diffuses sufficiently, while during printing, the dye is not easily diffused and permeated in the pulp. Therefore, after printing, measures such as steaming or baking are required to improve the diffusion rate of the dye to help the dye dye onto the fiber.
Printing vs dyeing
If color matching is required during dyeing, it is generally required to use the same type of dyes for color matching, while printing can use several different types of dyes for co printing on the same textile, such as: coating and insoluble azo dyes for co printing, reactive dyes and insoluble azo dyes for co printing, reactive dyes and fast sulfonic dyes for co printing, insoluble azo dyes and polycondensation dyes for co printing, etc, Sometimes different types of dyes can also be used in the same color paste for the same paste printing;
For example, paints and insoluble azo dyes are mixed in the same pulp, disperse dyes and reactive dyes are mixed in the same pulp. In this way, there will be mutual influence between dyes and auxiliaries. Printing workers must have a very in-depth understanding of the characteristics of various dyes and auxiliaries, and use the contradictions and compatibility between dyes and auxiliaries to serve the product, printing some printing products with special styles.
Dyeing VS printing
The dyes used for printing and dyeing are roughly the same, but there are also some dyes that are specifically used for printing, such as reactive dyes for printing (domestic P-type reactive dyes, etc.), stable insoluble azo dyes, temporary soluble dyes, etc; "There are white flowers or very white ground in printed products, which requires that the semi-finished products after pre-treatment be similar to bleached fabrics. After printing, bleach water is generally required, while dyed fabrics, especially before dyeing with deep and strong colors, may not be bleached;"; Printed fabrics should not have skewed weft, especially for patterns such as checkered, horizontal, square, or figure patterns. The skewed weft requirements for semi-finished products are strict; There should also be certain requirements for the door width of the fabric to avoid skewness and deformation of the patterns on the fabric during stretching after printing. The weft skew control requirements for dyed fabrics are not as strict as those for printed fabrics.
For printed semi-finished products, the wool effect should be uniform and have a good "instantaneous wool effect". The main reason is that during printing, the dye action time is short, and the printed pattern should have uniform color, clear outline, smooth lines, and no broken lines. Therefore, each step of the pretreatment processing of printed fabrics is important. Only by obtaining good semi-finished product quality can the printing quality be guaranteed, so the pretreatment requirements for printed semi-finished products are higher than those for dyed semi-finished products; The masking printing of grey fabric defects is better than dyeing, especially for some disordered patterns, which can effectively mask some grey fabric defects.
In short, for colored textiles, dyed products require uniform and plump color, bright and transparent core, while printed products require clear and generous patterns with national characteristics, clear patterns and contours, fresh flowers and white ground, and full color, which are artistic industrial products.