RFT dyeing: a new technology for improving the competitiveness of printing and dyeing

RFT is an abbreviation for English Right First Time, which means one-time success rate. RFT has a great effect on improving the operation of printing and dyeing enterprises. In particular, the source of raw cotton is different, and the quality is inconsistent. When dyeing, there are many uncertainties and the success rate is reduced. A large number of production practices have proved that RFT can be increased by 1%, the total production cost can be reduced by 1%, and the yield per kg of fabric can be increased by about 10%. The development of textile RFT dyeing technology and the development of textile chemicals used in RFT dyeing not only reduce the production cost for the textile printing and dyeing industry, but also has an important significance for enhancing the market competitiveness of textiles.

For these reasons, RFT must be maximized for advanced dyeing techniques. The current important dyeing process management method is the use of control dyeing technology, which is a unified integration of the company's management technology, dye design technology and dyeing application technology, apparently to achieve a high RFT, the entire dyeing process The project must be controlled to “zero defects”, ie no corrections are required. This requires the selection of dyes suitable for RFT dyeing. The establishment of a “zero defect” management system includes the establishment of operating standards, the establishment of dyeing inspection methods, and the establishment of dyeing On-line management and recording of all parameters of the processing project, establishment of verification methods for raw fabrics and water and dyeing auxiliaries (salts, alkalis, acids, etc.) and establishment of quality control methods for dyeing products.

Polyester RFT dyeing - Dyexact XP system

The RFT dyeing of polyester fibers depends on a number of parameters such as matrix (or fabric), dyeing conditions (temperature, time, pressure and bath ratio, etc.), dyes and auxiliaries and other additives, dyeing equipment, among which the most important parameters Is to give effective dispersion, emulsification, leveling and control of oligomers and water hardness additives, of course, adjuvants have good compatibility, high biodegradability and low toxicity. From this concept, BASF has developed a new Dyexact XP system for the dyeing of polyester fibers and their blends with polyurethane fibers (ie, elastic fibers). This new system provides for the control of RFT dyeing of polyester fibers. The choice of textile auxiliaries with good compatibility required by each parameter includes their effectiveness, compatibility, biodegradability and toxicity. Using this new system can reduce the dyeing cost by about 16% and save the dyeing time by 20% compared to conventional dyeing, which not only increases the dyeing capacity and productivity, but also reduces the environmental pollution. The impact index can be reduced from the conventional dyeing of 1.2 to 0.9.

RFT dyeing of polyester/cotton blended fabrics

At present, the polyester/cotton blend fabric occupies an important position in the textile market. In order to avoid defects in the dyeing of the blend fabric, effective scouring and suitable dyeing conditions are the most important parameters of the RFT dyeing. Suitable dyeing conditions are related to the dyeing process. For continuous dyeing of polyester/cotton blend fabrics, the use of disperse dyes and vat dyes or disperse dyes and sulphur dyes for dyeing is generally not a problem because of the good compatibility between them. Sex: If dyeing with disperse dyes and reactive dyes requires very careful selection of the dyeing conditions. For exhaust dyeing polyester/cotton blended fabrics, the combination of disperse dyes and direct dyes is most suitable for the one-bath dyeing process; if disperse dyes and reactive dyes are used, in order to avoid the inconsistency of the additives on the two fibers Capacitive, two baths are recommended.

One-bath treatment and dyeing technology for cotton fabrics

From the influencing factors of RFT dyeing, Stockhausen developed a successful pretreatment of cotton fabrics, and then bath dyed new pretreatment agents: Solopol ZF and Saltafon D, the former can be used to replace the currently used biodegradability with poorer complexation The agent, which is particularly effective for the emulsification removal of silicone oil and mineral oil that are not easily emulsified in the elastic fiber.

After the above-mentioned pretreated cotton fabric is stable in quality, it can be dyed with the bath, and commercially available cotton dyes can be used for dyeing without any restriction. This economical and ecological one-bath multi-functional process can obtain significant economic effects: processing costs and processing time are reduced by more than 60%; processing capacity is increased by 25% to 33%; does not affect the color fastness of dyeings; significant reduction The amount of sewage discharged.

Economic dyeing technology of polyamide fiber/elastic fiber blended fabric

ECON dye plus, a one-bath scouring, dyeing and fixing technology developed by Zschimmer Schwarz for the blending of polyamide fibers and elastic fibers in an 80:20 ratio, is an economic design based on the influence of RFT dyeing. Eco-friendly and high-performance technology that can reduce the time required to process fabrics using conventional techniques by 50% and dye baths by 80%, greatly improving the dyeing capacity of equipment and reducing the costs of dyeing, water and drainage. At the same time does not affect the color fastness of dyeings.

ECON flash is another technology similar to this technology, it is also suitable for the blend fabric of polyester fiber and elastic fiber in a ratio of 96:4.

RFT dyeing of cotton fabrics - Innovat dyeing system

This new dyeing technique is the reduction of vat dyes under vacuum conditions, and the chemical reduction of the vat dyes is performed quickly, safely and repeatedly, since the technology does not have to consider the problem of oxygen oxidation in the atmosphere, only a small amount of chemical reduction is needed Agent, so this reduction dyeing process is called a more environmentally and ecologically friendly dyeing technique. In order to realize this technology, Dystar and Brazzoli have cooperated to improve the dyeing machine, replacing the air in the jet dyeing machine with a vacuum pump to vacuum. This dyeing system has the following advantages: it is suitable for large-capacity dyeing and reduces the production cost per unit product; the oxidation engineering after reduction dyeing can be effectively controlled by continuous soaping; the air in the dyeing machine is pumped out to form a vacuum, reducing Used chemicals and waste liquids; not only for vat dyes, but also for RET dyeing of reactive dyes and the like.

Textile RFT printing

In order to adapt to the ever-increasing accuracy of color contours and reproducibility of the pattern during textile printing, companies such as Zimmer Maschinen bau have developed a series of printing equipment and printing systems that are compatible with these requirements, such as IPS - Intermittent Printing System; FDC - Rapid Pattern Change System; PWS - Printing and Washing System; BVS - Uniform Color Distribution System Using Micro Channels; Mobile Platform for Effectively Cleaning Printing Patterns; Automatic Positioning of Flat Print Carts; Up and Down Sideways Printing; flat jet technology based on spray coloring on a substrate. They ensure that RFT printing can be achieved with color contour accuracy and pattern reproducibility during textile printing.

Source: Textile and Apparel Weekly