Tensile testing machines, also called universal material testing machines, are testing machines that test the…
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What is the dyeing of textiles?
Dyeing is the application of dyes or pigments on textile materials such as fibers, yarns, and fabrics with the goal of achieving color with desired color fastness through physical or chemical action. Textile dyeing is to be able to select and use dyes reasonably, make dyeing process correctly for dyeing processing, obtain high-quality dyeing products.
Dyeing methods of Textiles
On the one hand, based on the requirements of production cost and product quality of textiles, on the other hand, with the consumer’s demand for individualization and fashion of garment products. The dyeing methods of textiles are diversified and can be dyed in 2 different ways, in 5 steps of production, thus giving different colors, styles, and forms of expression to the products.
1 According to the way of dyeing, it can be divided into two kinds: dip dyeing and padding.
1.1 Dip dyeing: this dyeing refers to dipping textiles in dyeing solution for a certain period, the fabric and dye are in contact with each other, so that the dye is fixed in the fiber. This dyeing method is suitable for all kinds of textiles (loose fiber, yarn, small-batch fabric, silk fabric, wool fabric, etc.). It is characterized by intermittent production, low production efficiency, simple equipment, and easy operation.
1.2 Padding: padding is a dyeing method in this way, after a brief dip in the dye solution, press the textile with a roll to squeeze the dyeing solution into the tissue gap of the fabric, and remove the excess dye solution so that the dye is evenly distributed on the fabric, then steam or hot melt, etc. This is a continuous dyeing process, high production efficiency, suitable for a large number of textile fabric dyeing, but the dyed material subjected to high tension, usually used for woven fabric dyeing, sometimes silk bundles and yarns are dyed with padding.
No matter what kind of dyeing method, it is necessary to perform color matching with dyeing / finishing testing machines before the batch dyeing to ensure the quality of the dyeing.
2 According to the production and processing links, it can be divided into 5 steps: solution dyed, fiber dyeing, top dyeing, yarn dyeing, piece dyed and garment dyed.
No matter woven fabric or knitted fabric, most of them dyed with piece dyed, yarn dyeing is the second, and other dyeing methods reflect each other, together deducing colorful fashion.
2.1 Solution dyed
When chemical fiber (man-made fiber and synthetic fiber) is made, the spinning solution should be prepared first. Generally, the original solution is colorless or white, and the fiber is also white. In order to meet certain needs, we could add colored substances (such as color masterbatch) into the original liquid or pre-spinning coloring, after full mixing and spinning, all kinds of colored fibers can be obtained, either short fiber or filament.
The colored fibers obtained by the solution dyed are stable in hue, good in color fastness, low in production cost, but the batch is large, which increases the cleaning burden of spinning equipment. As a result, only more common colors, such as blue, black and group textiles (such as army), are generally produced, while it is difficult to apply for small batch production with a rapid change of market demand.
2.2 Fiber dyeing
2.2.1 Dyeing of loose fiber
In order to enrich the color of the product, reduce the color difference of yarn, increase the hazy effect of the product, we can carry on the loose fiber dyeing, such as wool fiber dyeing, cotton fiber dyeing and so on. The dyeing way is generally dip dyeing, but also padding method. Spinning and weaving after dyeing of loose fiber, we can obtain the color spinning and color fabric.
In addition, whether it’s man-made fiber or synthetic fiber, both of them are first made of tow and then cut into staple fibers, so that the tow can also be dyed. By this method, the dyeing batch is small and the color phase can be specified at will, the cleaning of a large number of equipment in the two processes of spinning is saved. The dyeing of the tows can be padding and dip dyeing, but the application is less.
2.2.2 top dyeing
In the process of spinning (cotton mix, carding, drawing, roving, spun yarn) after the dyeing of loose fiber, there will be a small amount of color fibers remaining in the equipment, which will bring inconvenience for the subsequent cleaning work, so there is the top dyeing. This process has been mature and applied in wool spinning. In recent years, this process has been used in cotton spinning to produce color spinning.
The top dyeing also belongs to the fiber dyeing before the fiber is spun, and is the same as the purpose of dyeing the loose fiber, in order to obtain a soft color mixing effect. The top dyeing can not only get the rich color level of the yarn but also reduce the “Flos Lonicerae” to the minimum. The top dyeing is generally used for combing the wool yarn and the wool fabric.
2.3 yarn dyeing
Yarn dyeing is mainly based on dip dyeing, but also by padding (such as denim warp yarn). Yarn dyeing is generally used in yarn-dyed textile fabrics, sweaters, or indirect use of yarns (sewing thread, etc.). Yarn-dyed products (woven, knitted, woven) are obtained by dyeing yarn first and then weaving different color warp and weft yarns according to a certain rule. The products have a unique style.
Yarn dyeing is the basis of dyeing and weaving, and there are three ways.
2.3.1 Hank dyeing: Soaking loose yarn in a special dyeing tank, which is a costly dyeing method.
2.3.2 Cone dyeing: Load the cylinder with yarn into the dyeing cylinder, and the dyeing solution is circulating. The fluffy effect and softness are not as good as those of twisted yarn.
2.3.3 Slasher dyeing: It is a kind of large-scale roll dyeing, which is most suitable for common colors and dyed woven fabrics.
2.4 Piece dyed
Piece dyeing refers to a method for dyeing the woven fabric blank, and the common methods are in the form of rope-like dyeing, jet dyeing, roll-dyeing, padding and slasher dyeing, and only the piece dyeing of the fabric is introduced here.
In the current textile, piece dyeing of fabric is the most important dyeing method. In addition to dyeing in the same color, it can also be dyed in different colors, such as printing, sandwich dyeing, hair tip dyeing and so on. Fabric dyeing can be dyed with flat width or rope, or by dip dyeing, padding, gas-phase transfer dyeing and so on.
2.5 Garment dyed
In order to meet the market demand and to make a respond quickly, or in order to obtain a special style, before the dyeing or printing, the fabric should be pre-treated to make the garment. The garment is dyed by dip dyeing, both woven and knitted fabrics can be dyed. Garment dyeing is mostly suitable for knitted socks, T-shirts and other knitted clothing, sweaters, pants, shirts and other simple ready-to-wear.
In general, the dyeing cost will be relevant lower at the beginning of the dyeing process, any color can be repaired in the back production, but the market reaction speed is slow, and the amount of bonus of colored semi-product is large. At the later dyeing process, not only the amount of semi-product bonus can be reduced, but also the rapid response can be made according to the market demand, but the requirement of the dyeing uniformity, the dye and the processing process is high.
Looking back on the development history of textile dyeing, we can see that the textile dyeing is developing towards ecological dyeing, new fiber, and multicomponent dyeing. In addition, new fibers and new materials will appear faster, water-saving dyeing will be more mature, the organic combination of the bionic coloring, the multifunctional dyeing, the coloring of the pigment and the structure chromophore can greatly improve the current dyeing effect and improve the dyeing level of the textile.