Textile printing, dyeing and finishing is a huge systematic project, involving multiple processes such as raw materials, semi-finished products, weaving, printing and dyeing, and finishing. Among them, spinning, weaving, printing, dyeing and finishing are three relatively independent industries.
In the printing and dyeing industry, according to different raw materials, different yarn types, Different fabric structures, different printing and dyeing requirements, the process flow is not a completely fixed model, such as chemical fiber textile printing and dyeing, wool textile printing and dyeing, silk reeling weaving and dyeing, the difference is quite large, even between them Basically there is no way to learn from it. So, let us first understand the conventional processes in the three industries of spinning, weaving, printing, dyeing and finishing, so as to have a simple understanding of the spinning, printing and dyeing industry, and at the same time have an overall impression of the source of bedding fabrics.
Main processes of spinning process: cleaning, carding, combing, drawing, roving, spun yarn
Main processes of weaving process: winding, warping, sizing, threading Warping, weaving, and finishing
These are the main processes. Each company will have slightly different processes based on its products and its own needs. Let’s take cotton as an example to share with you the conventional cotton textile printing and dyeing process.
Cotton textile printing and dyeing process:
Preparation of blanks – seam head – singeing – cold rolling car – deboiling and bleaching – mercerization – predetermined tenter – -Pulp mixing–Printing (flat screen or rotary screen printing)–Steamer–Soaping machine–Finishing and shaping–Pre-shrinking machine–Calender–Quality inspection
Packaging
1. Singeing
Usually, after the gray fabric enters the printing and dyeing factory , first of all, it needs to go through the processes of inspection, turning, batching, blank matching (blank matching: the front and back sides of two pieces of gray cloth are put together with the same side) and seaming, and then perform singeing processing.
Singeing: The process of singeing looks very magical. At the scene, you will see the fabric quickly passing through the high-temperature flames, and the cloth slides quickly on the fierce flames without burning. It is really a bit ” A state in which not a single leaf among the flowers touches the body.”
This is because the cloth body is relatively dense and heats up slowly. Before it reaches the ignition point, it has left the flame or the red-hot metal surface, thereby burning away the fluff. without damaging the purpose of the fabric. Reason: The unsinged cloth surface has too much fluff, varying lengths, poor smoothness, and easy staining. It is easy to lose hair during subsequent dyeing and finishing processes, resulting in printing and dyeing defects.
Meaning:
1. The purpose of singeing is to burn off the fluff on the cloth surface, make the cloth surface smooth and beautiful, and prevent dyeing due to the presence of fluff during dyeing and printing. Unevenness and printing defects. Improve the gloss of the cloth surface and improve the smoothness;
2. Improve the anti-pilling performance (especially chemical fiber fabrics);
3. Improve the style, singeing will make the fabric stiff .
Cold rolling car: a process after singeing, the gray cloth needs to be cooled for more than 20 years hours
2. Deboiling and bleaching
Deboiling and bleaching, that is, desizing and scouring ,bleach.
Desizing: The sizing on the gray cloth should be removed before scouring. This process is called desizing.
In order to increase the wear resistance, smoothness and antistatic properties of warp yarns during weaving, increase their strength and improve their weavability, sizing is required before weaving. The sizing on the gray fabric affects the water absorption performance of the fabric, and also affects the quality of the dyeing and finishing products, and increases the consumption of dyeing chemicals. Therefore, the sizing should be removed before scouring. This process is called desizing. That is to remove it from the fabric.
Scouring: Refining is also called scouring. Its purpose is to remove fiber impurities (natural impurities, artificial impurities) and improve fabric processing properties, especially wetting properties.
When cotton fibers grow, they are accompanied by natural impurities (pectin, waxy substances, nitrogen-containing substances, etc.). After desizing the cotton fabric, most of the sizing and some natural impurities have been removed, but a small amount of sizing and most of the natural impurities still remain on the fabric. The presence of these impurities makes the cotton fabric surface yellower and has poor permeability. At the same time, due to the presence of cotton seed hulls, the appearance quality of cotton cloth is greatly affected.
Therefore, the fabric needs to be scoured in high-temperature concentrated alkali solution for a long time to remove residual impurities.
Bleaching: After scouring cotton fabrics, due to the presence of natural pigments on the fibers, their appearance is not white enough. When used for dyeing or printing, the brightness of the color will be affected.
The purpose of bleaching: to remove pigments and improve whiteness is the main purpose of bleaching processing.
3. Mercerization
Mercerization: Use concentrated alkali solution to treat cotton woven fabrics, and the surface will appear It produces silky luster and, more importantly, improves its dimensional stability, that is, the cotton woven fabric is shaped.
This processing process is called Mercerization or Mercerizing, which is translated into Chinese as Mercerization or simply mercerizing.
The significance of mercerizing treatment:
1. Improved dimensional stability and reduced shrinkage;
2. Changes in mechanical properties such as reduced breaking strength;
3. Improved adsorption;
4. Silky appearance�� Ze.
4. Tenting
Tentering is to tighten the warp and weft of the fabric again. , making the width and density of the fabric consistent in the warp and weft directions, and increasing the dimensional stability of the fabric.
5. Mixing and shaping
Jacquard varieties undergo varying degrees of processing before calendering. Sizing allows the sizing to adhere to the surface of the fibers to prevent the fabric door pair from shrinking. Sizing has a softening effect and promotes friction between fibers.
6. Printing
There are currently two most widely used printing methods, rotary screen and flat screen. Screen printing. Due to the small tension, it is not easy to deform, the colors are bright and full, and the screen printing defects are less, so it is especially suitable for multi-variety production. Rotary screen and flat screen printing both require screens in terms of installation. It originates from pattern printing, which is a printing method that uses paper plates, metal plates or chemical engraving to create hollow patterns.
The rotary screen uses a nickel circular metal mesh, while the flat screen uses a screen stretched on a metal or wooden rectangular frame. Flat screen printing is divided into manual (table printing) and mechanical (flat screen printing). Due to different printing methods, the size has a certain allowable range, and the flat screen size is 305~1200mm. Generally, the circumference of rotary screen printing mesh is 640mm, 820mm, and 1018mm. The perimeter is a multiple of the loop of the pattern.
The characteristic of the rotary screen is that the patterns are connected and there is no printing. The screen of flat screen printing is square, so its circulation is not restricted, and the flat screen has connecting spaces.
In general, rotary screen printing has the largest output, generally 3,500 yards per hour. The speed depends on the difficulty of the pattern. Flat screen printing fineness and flower return size are better than rotary screen, but the production efficiency is not as fast as rotary screen. In actual selection, it is necessary to weigh whether to choose a rotary mesh or a flat mesh based on the fabric use, pattern size, fabric and other aspects.
7. Steaming and Soaping
Steaming: Textiles After printing, except for ice dyes and soluble vat dyes, general dyes must be steamed.
Purpose: to enable the printed textiles to complete the moisture absorption and heating of the fiber and color paste film, accelerate the reduction of the dye and the dissolution of the dye on the fiber, so that the dye can diffuse into the interior of the fiber and be fixed on it. On the fiber, it diffuses into the fiber to produce solid color. The steaming process conditions vary with the nature of the dye and fiber.
Soaping: It is a very necessary and important process after steaming. During the soaping process, the soaping agent interacts with the dye through physical and chemical interactions, and utilizes the dispersion, suspension, and complexing effects of the soaping agent to prevent it from staining the fabric, thereby improving soaping fastness and preventing staining. the goal of.
8. Pre-shrinking finishing
The fabric is stretched by mechanical tension during the printing and dyeing process. There is internal stress in stretching. When the fabric is wet, the internal stress relaxes, which will cause a shrinkage effect. Therefore, in actual production, the fabric must be mechanically preshrunk to reduce the shrinkage of the cotton fabric, stabilize the size of the finished product, and maintain the fabric width. Neat and improve the added value of the product.
9. Calendering treatment
Also called calendering. A process of fabric finishing. A finishing process that utilizes the physical plasticity of fibers under high-pressure or high-temperature conditions to flatten or create patterns on the surface of the fabric to increase the luster of the fabric. Similar to ironing, surface flattening and ironing methods are used to give the fabric a special luster, increase the brightness of the fabric, and make the fabric drape well and smooth.
10. Taste inspection and packaging
At this step, the printing and dyeing of the cloth is completed. Quality inspection and marking. If there is any leakage in the pattern, the flower will need to be trimmed manually and packaged for shipment.
From the above we understand that from cotton to cloth to bedding and clothing, it requires a lot of processes, manpower, technology, creativity, technology, etc. Before reading this article, you may not have thought that producing fabrics requires so many complicated processes, nor that printing and dyeing flowers on cloth requires so much energy and concentration. </p
