Printing classification

First, direct printing

Direct printing is a direct printing on white fabrics or on pre-dyed fabrics. The latter is called overprinting. Of course, the color of the print pattern is much deeper than the background color. A large number of common printing methods are direct printing.

If the background of the fabric is white or mostly white, and the printed pattern looks lighter than the frontal color from the back, then we can determine that this is a direct printed fabric (note: due to the strong penetration of the printing paste, it is light and thin Fabric cannot be judged by this method).

If the background of the fabric is the same in depth (because it is piece dye), and the print pattern is much deeper than the background color, then this is the overprint fabric.

Second, discharge printing

The discharge printing is performed in two steps. In the first step, the fabric pieces are dyed in a single color. In the second step, the pattern is printed on the fabric.

The printing paste in the second step contains a strong bleach that can destroy the base dye. Therefore, this method can produce a blue-white dotted pattern cloth. This process is called whitening. When the bleaching agent is mixed with the dye that does not react with it in the same colorant (reduced dye belongs to this type), color printing can be performed. Therefore, when a suitable yellow dye (such as a vat dye) is mixed with a colored bleach, a blue dot pattern can be printed on the blue base fabric.

Because the background color of the discharge printing is first dyed with a piece dyeing method, the color of the background color is much richer and much deeper than if the background color is printed on the floor printing. This is the main purpose of using discharge printing.

Discharge printing fabric can be printed by roller printing and screen printing, but it cannot be printed by thermal transfer printing. Because of the high production costs of the unpainted fabric compared to direct printing, the reductant required for use must also be carefully and accurately controlled. Fabrics printed in this way have better sales and higher prices. Sometimes, the reducing agent used in this process can cause the fabric at the printed pattern to be damaged or destroyed.

If the color of the front and back of the fabric is the same (because it is piece dyed), and the pattern is white or different from the background color, it can be confirmed that it is a discharge printing fabric; carefully check the reverse side of the pattern, will The traces of the original background are revealed (the reason for this phenomenon is that the chemicals that destroy the dye cannot completely penetrate the reverse side of the fabric).

Third, anti-printing printing

Anti-ink printing includes two stages:

(1) Print white fabrics with chemicals or waxy resins that prevent or prevent dye penetration into the fabric;

(2) Pieces of dyed fabric. Its purpose is to dye the background to bring out a white pattern. Note that the result is the same as for the discharge printing fabric, but the method to achieve this result is the opposite of the discharge printing.

Anti-inking printing methods are not universally used and are generally used when the background color cannot be discharged. Compared with the large-scale production base, most of the anti-dyeing printing is achieved by means such as handicraft or manual printing (such as wax anti-printing).

Because discharge printing and resist printing produce the same printing effect, they are often not visually identified by visual inspection.

Fourth, paint printing

The use of paint instead of dyes to produce prints has become so widespread that it has begun to be used as an independent printing method. Paint printing is direct printing with paint. This process is usually called dry printing to distinguish it from wet printing (or dye printing).

By comparing the difference in the hardness of the printed and unprinted parts of the same fabric, paint printing and dye printing can be distinguished. The paint print area is slightly stiffer than the unprinted area and may be a little thicker. If the fabric is dyed with dyes, there is no significant difference in hardness between the printed and unprinted parts.

Dark-colored paint prints are more likely to be harder and less flexible than lighter or lighter colours. When inspecting a piece of fabric with a paint print, make sure to check all colors as there may be both dye and paint on the same piece of fabric. White paint is also used for printing, and this factor should not be ignored.

Paint printing is the cheapest printing method in printing production because the printing of the paint is relatively simple and the required process is minimal, usually without steaming and washing. The paint has a bright, rich color and can be used for all textile fibers. Their good light fastness and dry cleaning fastness, even excellent, are widely used in decorative fabrics, curtain fabrics, and apparel fabrics that require dry cleaning. In addition, the paint will hardly produce a large amount of color difference on different batches of fabrics, and the coverage of the background color is also good when overprinting.

With continuous washing or dry cleaning, paint printing fades and its color fades. This is because the resin binder gradually falls off due to the continuous rotation and stirring during the cleaning process. After 20-30 times of cleaning, the printed cloth will obviously fade. Due to the treatment of the fabric with resin and silicone softener during the finishing process, the color fastness is improved. It is worth noting that dark colors are more likely to fade than light or light colors.

The paint makes the fabric printing part harder. When it is light-colored, this condition is not so obvious. When it is dark, it is very prominent. Coatings are not particularly resistant to wear, especially dark colors. Dark paints should especially be avoided in fabrics such as upholstery.