Dye selection is an important link in process design. It not only affects the quality of dyed products, but is also directly related to product cost and economic benefits. The selection of dye categories should generally be based on fiber raw materials, color characteristics, fastness requirements, processing costs, equipment conditions, environmental protection requirements and other factors. The dyeing process should be determined based on factors such as dye category, production batch size, equipment conditions, production cost, etc., and should be considered comprehensively based on the actual situation of the factory.
Based on the properties of fiber raw materials
The fiber raw materials that make up the fabric are the most basic basis for dye selection. The dyes commonly used for dyeing textile fibers are shown in Table 16-1.
Blended or interwoven fabrics should choose appropriate dyes and processes according to the composition and content of the fibers. Try to choose dyes that are suitable for both fibers. This can make the dyeing methods and processes simpler. .
If there is no suitable one, you can choose two types of dyes to dye two different fibers respectively, 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, paints, etc., or disperse/reactive, disperse/vat dyes.
Another example is brocade/cotton interwoven fabrics, which can be dyed with reactive dyes, or dispersed/reactive, weakly acidic/reactive dyes and other processes.
Based on customer sample requirements
Sample requirements generally include color difference, brightness, dye fastness, product use, etc. For some fiber products, there are often many suitable dye varieties, but not all dyes can meet customer requirements. Questions about customer requirements often appear in the website.
For example, some dyes can only be dyed to a specific color; some dyes may be suitable for dyeing deep colors, and some dyes are only suitable for dyeing light colors; some dyes have good fastness , some dyes have poor fastness, etc.
This requires us to have a sufficient understanding of the application performance of various dyes, including their chromatography, brightness, dye fastness, price, etc., and then according to the customer’s color, luster, Choose the most appropriate dye according to requirements such as fastness. The application properties of commonly used dyes for cotton fabrics are shown in Table 16-2.
If the customer needs to process a batch of bright green cotton products for use as washed clothing fabrics, the optional dyes include reactive, reduced, coatings, etc., but considering the use and cost, it is completely There is no need to choose vat dyes with high fastness, expensive price and complicated process. The first choice of dyes should be coatings, followed by reactive dyes.
Based on the basic conditions for 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 the equipment to the process, the technical literacy of the operators, and the level of production management, etc. 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 sulfur dyes (which require a long time of steaming after padding) and soluble vat dyes (acid color padding). The tank needs to be corrosion-resistant) dyeing, and some factories do not have high-pressure sealing equipment, so they cannot implement high-temperature and high-pressure dyeing processes with disperse dyes.
Based on production costs
The factors that affect production costs mainly include the raw material costs of dyes and auxiliaries , energy consumption and management costs in the dyeing process, etc.
The principle of dye selection is to choose dyes with low price, low energy consumption, easy operation and low pollution as much as possible on the premise of meeting the customer’s requirements for product color, fastness and other aspects. of dyes, which helps reduce production costs. </p