Printing and dyeing industry is an important link in the textile industry chain, and is the key process to enhance the added value of textiles and clothing. After long-term development, the production and processing capacity of China's printing and dyeing industry has ranked first in the world, but there are still problems such as insufficient innovation capacity, low added value of products, and inadequate environmental protection. The printing and dyeing industry is in urgent need of industrial transformation and technological upgrading, and digital printing has become an "outlet" for the development of the industry.
Textile digital printing inks are mainly divided into four types: dispersion, activity, acidity and coating inks. At present, disperse ink accounts for about 60%, activity about 30%, acidity about 7% and coating about 2% in the market.
At present, disperse ink is mainly used in heat transfer printing, and its main component is low temperature disperse dye. Its digital printing process is simple, and there is no sewage discharge. At present, the market of heat transfer printing is becoming saturated. The future development trend of distributed digital printing is to adopt the production mode of direct spray of cloth, use high-temperature disperse dye ink, do not need heat transfer paper, and reduce the production cost.
As the active digital printing process is mature, the future development direction is to further improve the printing speed, mainly through the assembly of more high-speed industrial nozzles. The other direction is to widen to 3.2m to meet the demand of home textile market.
1. The development space of paint ink is huge
Pigment printing has many advantages and has been widely used in the field of traditional printing. At present, more than 50% of the world's printed fabrics are processed by coating printing process, while in the field of digital printing, the proportion of coating application is still quite low. In the case of high-speed roll to roll digital printing machine (printing speed is higher than 300m2 / h), reactive, acid and disperse inks are widely used in mainstream machines, and the proportion of coating inks may be less than 5%. Only in the field of garment digital printing, the use of coating ink is relatively large.
Paint ink can be used for digital printing of almost all fabrics, especially for blended fabrics, and many types of blended fabrics can only be printed with paint ink. The advantage of digital printing of coatings is simple technology. After printing, the finished products can be processed directly through high temperature baking. Generally, there is no need for washing and sewage discharge. It is a real energy-saving and environmental friendly textile printing method.
Specifically, it is also cotton fabric printing, coating printing process saves water washing and other processes, compared with reactive printing, it can significantly save more than 67% water. Compared with the conventional printing process, digital printing can save about 60% water, so the use of paint digital printing can further save water and is more conducive to environmental protection. Compared with active digital printing, another advantage of coating digital printing is that the light fastness of printed fabric is better. However, there are still some problems to be solved in the digital printing of coatings. For example, the color of printed fabrics is not bright enough, the color fastness to rubbing and water washing is poor, and the hand feel is not good enough. However, with the progress of technology, the color density and color fastness of paint ink are also gradually improved. With the low color requirements in some industries, such as windows, it is also cotton fabric printing. The process of paint printing saves water washing and other processes. Compared with reactive printing, it can save more than 67% water. Compared with the conventional printing process, digital printing can save about 60% water, so the use of paint digital printing can further save water and is more conducive to environmental protection.
Compared with active digital printing, another advantage of coating digital printing is that the light fastness of printed fabric is better. However, there are still some problems to be solved in the digital printing of coatings, such as the color of printed fabrics is not bright enough, the color fastness to rubbing and water washing is poor, and the hand feeling is not good enough. However, with the development of technology, the color density and color fastness of paint ink are also gradually improved. With the application of paint digital printing in some industries with low color requirements, such as curtains, decorative fabrics and other industries, the market share of paint digital printing is gradually expanding.
In the preparation of paint ink, it is necessary to grind the pigment into very small particles, which can be stably dispersed in the ink system without agglomeration or precipitation. The particle size of pigment in pigment ink is much smaller than that in traditional pigment printing paste, and it is also much smaller than the diameter of nozzle (usually 20-55 μ m). It is generally required that the particle size of pigment particles in paint ink is 100-150nm.
Paint ink has been supported by more and more sprayers. Sensitive technology, meijiani, durst, etc. have put forward a paint high-speed digital printing scheme. MS is also developing a paint printing scheme for its single pass machine. Sensient technology and meijiani put forward a solution of digital printing for Kyocera kj4b, which is suitable for roll to roll high-speed digital printing machine. In order to obtain the ideal color fastness, the fabric must be pretreated before printing.
2. Development trend of printing ink
In recent years, with the increase of printing ink supply, the competition of ink price has gradually intensified. Some * ink manufacturers began to develop differentiated products, and several new types of ink came out successively.
Kornit digital has developed a pull out ink that can be used with its ready to wear printing system, kornitavalanchedcpro. Kornitavalanchedcpro has two additional nozzles, through which the pull out ink will be applied to the dye molecules of dark clothes to pull out the color, so as to provide a light color printing base for CMYK printing, so that the finished product retains a natural and good feel.
The water-based sublimation ink developed by Mimaki can realize the direct sublimation heat transfer of polyester fabric with special fabric pretreatment. The high quality of deinking itself