Process Description:
Cold pile (not yet implemented in this preliminary acceptance): According to the original environmental impact assessment, about 30% of the raw fabric adopts the cold rolling pile pre-treatment process according to customer requirements. The main principle is low-temperature long-term reaction, and the stacking time is 24 hours. It is an energy-saving and environmentally friendly treatment method. Add additives such as hydrogen peroxide and liquid alkali, without diluting them with water. The temperature of the cold reactor is controlled at 40 ℃ and steam indirect heating is used.
Refining, bleaching, and boiling (not yet implemented in this preliminary acceptance): The cold stack process is equipped with a bleaching and refining process, which combines boiling and bleaching processing into one step. This process has the characteristics of environmental protection, energy conservation, and consumption reduction. The main purpose is to remove natural impurities, as well as slurries, additives, and other stains from textiles, in order to improve their lubricity, whiteness, luster, and dimensional stability, which is conducive to further processing processes. The bleaching temperature is controlled at around 90 ℃, and steam indirect heating is used to add additives such as hydrogen peroxide, liquid alkali, and desizing agent. After bleaching and refining, water washing is also carried out in the bleaching and refining machine, using countercurrent rinsing.
Alkali reduction (not yet implemented in this preliminary acceptance): According to the original environmental impact assessment, approximately 15% of the grey fabric needs to undergo alkali reduction treatment according to customer requirements. At a certain temperature, the hydrolysis phenomenon of polyester fibers on the surface of fibers in caustic soda solution, also known as "peeling" of polyester fibers. After the polyester fiber is peeled by an alkaline solution, the yarn will become thinner, and the space for movement between the yarns will increase. The rigidity of the polyester fiber will be reduced, and the texture of the fabric will be significantly improved. The process of reducing weight and softening the feel under the action of hot alkali solution is the alkali reduction of polyester woven fabric. This project uses an intermittent alkali reduction machine, with an alkali reduction temperature controlled at around 90 ℃. It is indirectly heated by steam and additives such as hydrogen peroxide, liquid alkali, and desizing agent are added. After alkali reduction, water washing is also carried out in the alkali reduction machine.
Pre order type: According to customer requirements, the fabric's tissue density and size are adjusted accordingly, and the texture and some special functionalities of the fabric are processed. The pre order type temperature is about 160 ℃. The acceptance project finalization machine is a natural gas direct combustion finalization machine.
Pre treatment water washing inside the dyeing machine: The main purpose is to remove oil stains on the surface of the yarn and other impurities that affect the dyeing performance, improve the dyeing quality. The pre treatment temperature is generally around 50 ℃, and the bath ratio is 1:6. According to the product color and customer requirements, it is generally cleaned 4 times.
Dyeing: According to the customer's requirements, different dyes and additives are added to the dyeing machine, and the grey fabric is colored at a certain temperature and pressure. Steam indirect heating is used for heating. The cylinder temperature is 50 ℃, and the dyeing temperature is around 128 ℃, allowing the dye to disperse inside the yarn. The dyeing heating rate is 2 ℃/min, and the insulation is 40-60 minutes. After the insulation is completed, the dyeing solution is cooled to about 70 ℃ and discharged, and enters the subsequent water washing process. The bath ratio during the dyeing process is 1:6.
After dyeing, water washing: The dyed product needs to be washed with water to remove any floating color residue on the surface of the grey fabric. In order to ensure the quality of product dyeing, the enterprise conducts two washes. The washing temperature is about 50 ℃, and the bath ratio is about 1:6. There are two washes in total.
Soap washing: In order to further remove the floating color residue on the surface of the yarn, pure alkali, insurance powder, and water are added under alkaline conditions, and the soap washing temperature is 80 ℃. The heating rate is 2 ℃/min. Cool down to around 70 ℃ and discharge, and enter the subsequent water washing process.
Soap washing followed by water washing: four light colored cleaning cycles, with the first cycle using the last cycle for drainage, and the actual wastewater discharged into the sewage station using three cycles of cleaning water; There are five dark cleaning processes, with the first cleaning process using the last cleaning process for drainage, and the actual wastewater discharged into the sewage station being four cleaning processes; The washing temperature is about 50 ℃, and the bath ratio is about 1:6.
Softness: To increase the softness of the grey fabric, a softening agent is added to the water and subjected to a softening treatment at 50 ℃, with a bath ratio of about 1:6.
Dehydration: Place the dyed and softened grey fabric into a dehydrator for dehydration.
Setting: Reduce the shrinkage rate of the fabric, stabilize the size of the finished product, and keep the fabric width neat; The setting temperature is approximately 160 ℃. The finalizing machine for this project is a natural gas direct combustion finalizing machine.
Brushing (not yet implemented in this preliminary acceptance): Using mechanical action to evenly pull out a layer of fuzz or long hair on the surface of the fabric, making the fabric loose, soft, warm, and wear-resistant, with hidden patterns and soft and beautiful patterns.
Pre shrinkage and drying: Pre shrinkage is a process in which physical methods are used to reduce the shrinkage of fabrics after immersion in water to reduce the shrinkage rate. During the weaving, dyeing and finishing process, fabrics are subjected to tension in the warp direction, resulting in a decrease in the bending wave height in the warp direction, leading to elongation. When hydrophilic fiber fabrics are soaked and soaked, the fibers swell, and the diameter of the warp and weft yarns increases, resulting in an increase in the bending wave height of the warp and shortening of the fabric length, leading to shrinkage. After the fabric dries, the swelling disappears, but the friction between the yarns still keeps the fabric in a contracted state. Mechanical preshrinking is to wet the fabric by spraying steam or spray, then apply longitudinal mechanical extrusion to increase the buckling wave height, and then dry it loosely (80-100 ℃, steam is heated indirectly). The shrinkage rate of the pre shrunk grey fabric can be reduced to about 3%, and the softness of the fabric's feel can also be improved due to the mutual compression and rubbing between fibers and yarns. Fabric can be treated with relaxation and pre shrinkage. After being soaked in warm water or sprayed with steam, the fabric is slowly dried in a relaxed state, causing shrinkage in both warp and weft directions. Pre shrinkage does not add any additives, only replenishes water, and a single unit has a daily wastewater capacity of 90t. The acceptance project includes a total of 2 pre shrinkage machines, with a daily discharge capacity of 180t/d. The wastewater enters the comprehensive wastewater collection tank.
Process Flow Diagram of Chemical Fiber Fabric Dyeing (dashed boxes are not yet implemented in this stage of acceptance)
