Mechanical characteristics

1 Environmentally friendly industry: No need to use other chemical additives, zero water usage, zero sewage discharge.

2 Cyclic dyeing: The entire process uses anhydrous medium for cyclic dyeing, with medium reuse reaching 99.8%.

3 Wide range: suitable for dyeing various types of chemical fiber disperse dyes, such as bobbin yarn, loose wool, warp zippers, etc.

Low pressure waterless dyeing technology for polyester

1  Traditional polyester dyeing methods and existing problems

Traditional polyester dyeing is done using dispersed dyes in a water bath, which has many irrationality. Due to the extremely low solubility of dispersed dyes in water, a large amount of dispersant is required to ensure stable dispersion of the dyes in water and achieve uniform dyeing results. In addition, polyester fibers require pre-treatment with surfactants before dyeing, and a large amount of water, alkali agents, reducing agents, and surfactants are also required in the rinsing stage after dyeing. Due to these additives ultimately remaining in dyeing wastewater, wastewater treatment is difficult and costly, seriously affecting the sustainable development of the textile printing and dyeing industry.

2  Supercritical carbon dioxide ultra-high pressure dyeing

For many years, the global textile industry has conducted extensive research on the clean dyeing technology of polyester, and supercritical carbon dioxide fluid anhydrous dyeing is a typical representative. Due to the necessity of using ultra-high pressure devices (200-300 atmospheres) for supercritical carbon dioxide dyeing, this technology has drawbacks such as high equipment cost, high investment, difficult dyeing operation, high operating costs, and low production safety. In the foreseeable future, it will be difficult to become a universal mainstream dyeing method.

3  Low pressure anhydrous dyeing technology

In response to the above issues, after long-term exploration, a new universal low-pressure waterless dyeing technology for polyester has been developed. This technology dyes under low pressure conditions, using a medium circulation method and utilizing its excellent thermal and mass transfer functions to promote fiber expansion and uniform dye uptake, without the need for post dyeing reduction cleaning. After dyeing, it is dried by a pressure dryer. With the help of a dedicated recycling system, the medium recovery rate can reach up to 99%. The recovered medium can be reused for dyeing, successfully achieving the goal of zero sewage discharge throughout the dyeing process, making the entire dyeing process no longer subject to sewage indicators.

Comparison of production costs between waterless dyeing and traditional water dyeing of polyester tube yarn

Comparison of Energy Consumption between Waterless Dyeing of Polyester Tube Yarn and Traditional Water Dyeing

This technology is suitable for dyeing various forms of textiles such as polyester tube yarn/ribbon/fabric, and is also suitable for dyeing other hydrophobic fibers such as acetate fiber and nylon fiber. The low-pressure waterless dyeing technology for polyester tube yarn/ribbon has been continuously improved in laboratory research and has been verified for technical and economic feasibility in pilot tests. Currently, the polyester waterless dyeing production base has basically built a polyester production demonstration line with a daily production capacity of 3 tons, and has entered trial production.

This technology has significant advantages over supercritical carbon dioxide dyeing in terms of product applicability, economy, and safety. The entire dyeing process is carried out in an anhydrous state, significantly reducing carbon emissions during the dyeing process, achieving the goal of zero sewage discharge, breaking the constraints of sewage indicators and high energy consumption on the development of the printing and dyeing industry. Moreover, the dyeing cost is comparable to traditional water bath dyeing, and it is expected to replace traditional processes on a large scale, Fundamentally changing the current situation of high wastewater discharge and high treatment difficulty in China's synthetic fiber textile dyeing industry, creating conditions for downstream related enterprises to develop green textiles and clothing, and contributing to the sustainable development and comprehensive ecological transformation of China's textile industry.