Dye selection is an important link in process design, which not only affects the quality of dyed products, but also directly affects product cost and economic benefits. The selection of dye categories should generally be based on factors such as fiber raw materials, color characteristics, fastness requirements, processing costs, equipment conditions, and environmental protection requirements. The determination of the dyeing process should be determined according to factors such as dye category, production batch, equipment conditions, production cost, etc., and comprehensive consideration in combination with the actual situation of the factory.
1. According to the properties of fiber raw materials
The fiber raw materials that make up the fabric are the most basic basis for dye selection. Dyes suitable for dyeing common textile fibers
For blended or interwoven fabrics, appropriate dyes and processes should be selected according to the composition and content of the fibers, and the dyes that are applicable to both fibers should be selected as much as possible, so that the dyeing method and process can be relatively simple.
If there is no suitable one, two types of dyes can be selected to dye two different fibers, but the process adaptability of the two types of dyes should be considered.
For example, polyester-cotton blended products can be dyed with soluble vat dyes, coatings, etc., as well as disperse/reactive and disperse/vat dyes.
Another example is brocade/cotton interwoven fabrics, which can be dyed with reactive dyes, and can also be dyed with disperse/reactive, weak acid/reactive dyes and other processes.
2. According to customer's sample requirements
The sample requirements generally include color difference, brightness, color fastness, product use, etc. For some fiber products, there are often many types of dyes, but not all dyes can meet customer requirements. There are often questions about customer requirements in Dyers Without Borders.
For example, some dyes can only be dyed in a specific color; some dyes may be suitable for dyeing dark and heavy colors, and some dyes are only suitable for dyeing light colors; some dyes have good fastness, and some dyes have poor fastness.
This requires us to have a sufficient understanding of the application properties of various dyes, including their color spectrum, brightness, color fastness, price, etc., and then choose the most suitable dye according to the customer's requirements for color, fastness, etc.
If the customer needs to process a batch of bright green cotton products for washing clothing fabrics, the optional dyes include reactive dyes, reduction dyes, coatings, etc., but considering the use and cost, there is absolutely no need to choose high fastness, expensive and complicated processes. Vat dyes, while the preferred dye should be paint, followed by reactive dyes.
Three, according to the basic conditions of process implementation
When the dye variety is selected, the dyeing process is basically determined.
Therefore, when selecting dyes, process designers must consider the implementation conditions of the process, such as the adaptability of equipment to the process, the technical literacy of operators and production management level, etc., to ensure that the selected dyes and processes can be implemented smoothly.
For example, the continuous pad dyeing machines of some factories are not suitable for dyeing with sulfur dyes (a long time of wet steaming is required after padding the dyeing solution) and soluble vat dyes (acid color development padding tanks need to be corrosion-resistant), and some factories do not have High-pressure closed equipment, the high-temperature and high-pressure dyeing process of disperse dyes cannot be implemented.
Fourth, according to the production cost
The factors that affect the production cost mainly include the raw material cost of dyes and auxiliaries, the energy consumption in the dyeing process, and the management cost.
The principle of dye selection is to choose dyes with low price, low energy consumption, easy operation and low pollution as much as possible under the premise of meeting customer requirements for product color, fastness, etc., which is conducive to reducing production costs.