As early as the 1970s, foreign countries began to study the application of foam finishing in dyeing and finishing, and the process has also been basically mature. Chinese scientific workers also conducted extensive exploration and practice in the 1980s. At that time, many research units and colleges, including Shanghai Textile Science Research Institute and East China Textile Academy, invested a lot of enthusiasm and achieved some research results. Their related technical achievements have been applied by many domestic printing and dyeing enterprises, and some products have been launched in domestic and foreign markets, but limited to the low equipment conditions and technical level at that time Due to cumbersome operations and weak environmental awareness among people, this technology has not achieved the expected development in China.
Since the beginning of the 21st century, with the shortage of energy and water resources, people's environmental awareness has greatly increased. In addition, the country has vigorously promoted energy-saving and emission reduction technologies, and the pressure on printing and dyeing enterprises to reduce production costs, energy consumption, and wastewater discharge has doubled. These factors have made foam finishing, an efficient and energy-saving dyeing and finishing technology, regain people's attention and favor. It is reported that some scientific research institutions and enterprises at home and abroad are actively developing new foam finishing equipment and related processes, such as Shanghai Yuhui Chemical Co., Ltd., Hong Kong DTC (Datacolor) Technology Co., Ltd., etc. They use advanced computer control technology, which greatly improves the automation of equipment, reduces the difficulty of operation, and improves production efficiency.
1、 Foaming finishing
Foaming finishing is a process in which foaming agent (usually surfactant) is added into the finishing working fluid with high concentration, and then mixed with air by foaming equipment to form a certain quality of foam, and then foam is evenly applied to the fabric surface through the foam applicator.
1.1 Advantages of Foam Finishing
(1) Energy saving: low liquid content, low heat loss, and low chemical reagent usage:
(2) Improve production efficiency: shorten process flow and time;
(3) Reduce or eliminate migration, reduce fiber damage, and improve product quality;
(4) Capable of wet to wet processing;
(5) Can perform single or double sided processing on heavy fabrics and surface structured fabrics (two different dyeing and chemical additives can be applied to both sides of the fabric at the same time);
(6) Reducing environmental pollution has good social and ecological benefits;
(7) It can shorten equipment length, factory area, and reduce investment.
1.2 Precautions for Foam Finishing
(1) Stability of foam
The stability of foam directly determines the quality of foam. The ideal stable foam should be able to burst itself immediately when the foam contacts with the fiber. The time interval between foam from fiber contact to fiber entry is very short. In this process, the finishing agent foam is never allowed to suspend on the surface of the fabric. If the stabilization time is too short, the foam will burst prematurely. Easy to cause uneven wetting of the fabric in blocks and strips, resulting in color difference; If the stabilization time is too long. The foam on the fabric cannot break evenly and enter the fabric quickly, which will also cause color difference.
(2) Uniformity of foam
Foam coating has certain waterproof, breathable, and water pressure resistance