Ministry Of Industry And Commerce: Technical Guide For Printing And Dyeing (Digital Printing) Industry Green Development (2019 Edition)

Recently, the Ministry of industry and Commerce issued the "printing and dyeing industry green development technology guide (2019 Edition)". It involves pollutants disposal and resource comprehensive utilization technology of stereotype exhausts, printing and dyeing wastewater, etc. The full text is as follows:

Notice of the Ministry of industry and information on printing and distributing the technical guide for printing and dyeing industry green development (2019 Edition)

Consumption of Ministry of industry and Commerce [2019] 229

The departments responsible for Industry and information technology of all provinces, autonomous regions, municipalities directly under the central government, cities under separate planning and Xinjiang production and Construction Corps are now printing and printing to you the technical guide for printing and dyeing industry green development (2019 Edition). Please conscientiously carry out the implementation in light of the realities of various localities.

Technical guide for green development in printing and dyeing industry (2019 Edition)

Preface

The printing and dyeing industry is an industry with large energy consumption and large water consumption in the textile industry chain. It is also a weak link that restricts China's textile industry to go to the middle and high end. Promoting the green development of the printing and dyeing industry is related to the new expectations of the people for a better life. It is related to the sustainable development of the textile industry and the success of the battle against pollution. In recent years, China's printing and dyeing industry has unswervingly implemented the decision making plan of the CPC Central Committee and the State Council, actively implemented the concept of green development, conscientiously implemented the printing and dyeing industry standard conditions, reduced energy consumption and water consumption, and continuously reduced the discharge of waste water. A number of green and intelligent equipment have been promoted and applied, and the overall development level of the industry has been continuously improved. With the rapid development of the industry, there is also a large gap between the development level of printing and dyeing enterprises in different regions, different scales and different types. The green development level of some printing and dyeing enterprises can not meet the requirements of the new era of ecological civilization construction, and the contradiction between the development of printing and dyeing industry in some areas and the protection of ecological environment is still more prominent. In order to provide guidance for local governments to promote transformation and upgrading of printing and dyeing industry, guide the direction of technological transformation for printing and dyeing enterprises, focus on technological research for relevant research institutions, and effectively improve the level of green development in the printing and dyeing industry, and formulate this guide.

This guide consists of 5 parts. The 1-4 part is green advanced and applicable technology. It mainly includes technologies of high utilization of resources, high energy consumption, low pollution discharge, good economic benefits, suitable for the development of China's printing and dyeing industry, relatively mature, reliable, technology providing units and suitable popularization and Application technologies. The fifth part is the frontier science and technology tackling technology, which mainly includes the wide attention of the industry, basic research, great potential for popularization, and the direction of green development of the industry. However, there are still some major problems that need to be solved in tackling key problems and promoting application.

Environment friendly pre-treatment and finishing technology

(1) biological enzyme pretreatment

Application: pretreatment of cotton and its blended fabric.

Technical characteristics: amylase desizing can decompose starch efficiently, amylase has been commercialization and widely used in starch slurry or desizing with starch slurry as the main ingredient and low content of PVA mixture. In practical application, the mixture of slurry is more common. Amylase and alkali oxygen treatment are usually combined to achieve the one-step pretreatment of bleaching and bleaching.

Application effect: amylase desizing treatment can significantly improve the biochemical performance of pretreatment wastewater, reduce the dosage of chemicals, reduce COD emissions, and reduce the comprehensive cost by 15%-20%. In the upstream industry chain weaving enterprises, the use of non starch slurry restricts the application and popularization of the technology.

(two) bio enzyme anti felting

Application: wool anti felting treatment. It can be used not only for pre dyeing process but also for finishing process of dyed fabric.

Technical characteristics: using enzyme, lipase and other biological enzymes to treat wool surface scales, change the scale structure of wool, and achieve wool no chlorine anti felting treatment.

Application effect: it avoids the environmental pollution problem caused by chlorination anti felting treatment technology, and can enhance the anti sphericity of wool products, reduce the damage to wool fibers and improve the uniformity of shrinkage prevention and processing without affecting the dyeability and spinnability of wool products. In order to improve the treatment effect, biological enzyme activator can be used.

(three) pretreatment of cotton and its blended fabrics at low temperature

Scope of application: pretreatment of cotton knitted fabric, woven fabric and cheese yarn.

Technical features: high efficiency hydrogen peroxide catalytic / active agent and low temperature scouring agent are used to remove impurities on cotton fiber surface under the temperature of desizing and bleaching under traditional high temperature hydrogen peroxide, and achieve 40 degree -75 low temperature scouring and bleaching.

Application effect: avoid fabric bleaching holes, improve fabric feel and improve the quality of cotton fabric. Compared with the traditional H2O2 pretreatment, the energy consumption can be greatly reduced, the amount of chemicals can be reduced, and the water consumption will be reduced by about 10%, and COD emissions will be reduced under the premise of ensuring the dyeing effect.

(four) pretreatment for continuous flat width of knitted fabrics

Application: suitable for continuous flat width pretreatment of cotton and its blended knitted fabrics in large quantities.

Technical features: using expanding disk to make knitted fabric on both sides to prevent curling, through the control of fabric tension, alkali liquor concentration, liquid ratio and other process parameters, using uniform and uniform alkali rolling process, combined with efficient washing, continuous high efficiency knitted fabric pre processing.

Application effect: it can improve production efficiency, reduce labor intensity, avoid wrinkle printing caused by mechanical abrasion and rope processing, effectively control fabric shrinkage and reduce surface hairiness. Compared with conventional knitted fabric pretreatment, water saving and energy saving are about 50%. This technology requires higher process control than intermittent pretreatment.

(five) cold pad batch pretreatment

Scope of application: pretreatment of cotton and cotton fabric, viscose fabric, pretreatment of high density fabric such as polyester, nylon and so on.

Technical features: fabric pre rolling working fluid at low temperature before rolling, and then rotate at room temperature for a period of time. The technology optimizes the technological parameters such as rolling rate, rolling speed, fabric tension, liquid ratio and so on, so as to ensure the consistency and reproducibility of fabric treatment.

Application effect: strong adaptability and little fabric strength loss. Compared with the traditional continuous high temperature pretreatment process, cotton and cotton fabrics have a comprehensive energy saving of about 30%, and chemical fiber fabrics save energy by 20%-30%.

(six) pretreatment of chemical fibre woven fabric with continuous flat width.

Scope of application: pretreatment of chemical fiber and its blended woven fabric with open width.

Technical characteristics: choose efficient and stable desizing agent system and precise on-line monitoring system for alkali concentration, and adopt continuous processing instead of traditional intermittent mode.

Application effect: avoid mechanical abrasion of fabric and avoid wrinkle printing on fabric. The production efficiency is high and the amount of lye is low, which can reduce pollutant discharge and reduce the difficulty of sewage treatment. Compared with the traditional batch pretreatment process, it can save water and save energy by about 30%. Process control is more demanding than batch processing, and it has poor effect on fabric with high density and high density. It is difficult to remove rust spots and other defects.

(seven) waterproof finishing without fluorine

Scope of application: waterproof finishing of all kinds of fabrics.

Technical features: the fabric is treated with waterproofing agent without fluorocarbon resin. The surface tension of the fabric is between water and oil, and the waterproof finishing effect is excellent without oil proof effect. Attention should be paid to color change and hand feeling when using.

Application effect: it has good waterproof and washability, and has no adverse effect on the color and feel of the fabric. It is not easy to deposit in organism, easy to degrade, avoiding environmental problems caused by fluorine containing finishing agents such as PFOS and PFOA.

(eight) water-based polyurethane finishing

Scope of application: coating finishing of all kinds of fabrics.

Technical characteristics: waterborne polyurethane molecular chain contains hydrophilic groups and has strong affinity with water. Water soluble polyurethane is replaced by water instead of traditional organic solvent as dispersing medium.

Application effect: the coating fabric produced is non-toxic and smells small, avoiding organic solvent volatilization and polluting the environment. It has good abrasion resistance, chemical resistance and low temperature resistance, good waterproof and moisture permeability, good elasticity and feel.

(nine) mechanical softening finishing

Scope of application: soft finishing of all kinds of fabrics.

Technical features: no chemical treatment agent is used, only mechanical treatment of fabric such as flapping, kneading and so on through airflow.

Application effect: fabric is not easy to crease, finishing effect uniformity is good, can increase fabric softness, fluffy, dimensional stability and stereoscopic visual effect, production reproducibility is good. It can reduce the use of chemicals and water, reduce pollutant emissions and chemical residues in fabrics. The effect is not as good as chemical softness finishing.

(ten) foam finishing

Application: it is used for soft, resin, coating and special finishing in dyeing and finishing.

Technical characteristics: transform the finishing liquid into foam, then apply and spread the foam onto the fabric surface and penetrate into the fabric. It is necessary to precisely control the amount of liquid in the fabric and ensure the same liquid volume in the left and right sides of the fabric.

Application effect: compared with the rolling process, the fabric liquid rate decreased from 60%-80% to 20%-40%, the water consumption decreased by 50%, the amount of dyeing chemicals and auxiliaries decreased by about 30%, and the energy consumption in the drying process was about 40%. It requires high uniformity and poor permeability.

(eleven) medium pressure steam setting

Scope of application: all kinds of fabrics are stereotyped.

Technical features: medium pressure (2.5MPa-3.0MPa) steam is used instead of heat conducting oil, and the fabric is finalized by the heat of steam. By controlling the steam pressure and flow rate, the precise temperature control is realized.

Application effect: medium pressure steam is generally supplied by combined heat and power generation, which is conducive to energy saving and emission reduction. Compared with the heat conduction oil setting machine, the enterprise does not need to provide its own heat transfer oil boiler. It can use heat according to the requirement according to the starting rate of the stereotype machine, and medium pressure steam can realize cascade utilization of energy. The medium pressure steam setting machine has the advantages of low comprehensive cost, high safety and good environmental and social benefits. Medium pressure steam setting requires higher steam pressure stability.

Two. Dyeing and printing technology for energy saving and emission reduction

(1) gas-liquid dyeing machine

Scope of application: dyeing of cotton, polyester and other fabrics.

Technical characteristics: gas-liquid separation technology, combined with the advantages of airflow dyeing and overflow jet dyeing, is especially suitable for sensitive color dyeing.

Application effect: the gas-liquid dyeing machine has less consumption than the air flow dyeing function, and is smaller than the overflow and jet dyeing machine bath ratio. It can adapt to the variety of fabrics, flexible production, improve the leveling dyeing property of the fabric, and the dyeing effect of sensitive color is better.

(two) no guide cloth jet dyeing machine.

Scope of application: dyeing process of all kinds of chemical fiber and blended woven fabrics.

Technical features: dyeing machine is equipped with dye leveling device, cloth groove load adjustment device, etc., fabric circulation operation using liquid jet drive, no need to guide cloth wheel fabric.

Application effect: it can reduce fabric folding and cloth bruise, high reproducibility and good surface quality.

(three) large capacity low tension dyeing machine

Scope of application: all kinds of woven fabrics with high requirements for tension and flatness.

Technical features: by optimizing the design of heating pipes, the double scraper technology is used to make the dyestuff evenly distribute and heat evenly on the fabric surface. The whole machine control system has the functions of automatic reversing, full automatic stopping and so on. It will not affect the cloth surface effect when the cloth volume is increased by 30% than that of the conventional dyeing machine.

Application effect: it can reduce fabric wrinkle printing and improve the dyeing success rate of fabric. By increasing the amount of single cylinder billet, reducing the consumption of dyeing auxiliaries and water resources, reducing the difficulty of sewage treatment and reducing pollution emissions. Double scraper mode has potential scratch risk when processing ultra-thin products, and is suitable for the production of elastic fabric.

(four) digital automatic dyeing of cheese yarn

Scope of application: cheese dyeing of cotton, chemical fiber, linen, wool and other fibers.

Technical features: using digital and automation technology to realize automatic production of cheese dyeing based on central control system, realize the overall planning of dyeing task, real-time detection of process parameters and online feedback, task information online inquiry and tracing, and production process online monitoring.

Application effect: compared with the traditional cheese dyeing technology, the production efficiency is increased by 10%-15%, the average tonnage yarn is more than 25% water saved, the dye consumption is more than 5%, and the labor consumption is reduced by about 70%. It is suitable for new plant construction, and the old plant is difficult to transform, and the investment is large at one time.

(five) salt free continuous pad dyeing

Application scope: pad dyeing process for cotton machine fabric.

Technical characteristics: through the selection of dyes and the use of a new reactive dye fixing agent, the dye solution is applied separately from traditional dyes and alkali agents. It is optimized to apply both dyes and alkali agents at the same time, and the conventional rolling and steaming process is shortened to the process of rolling and steaming.

Application effect: compared with conventional pad dyeing process, without adding inorganic salts to promote dyeing and reducing COD emissions, it can save about 30% energy, and has the color effect of cold pad dyeing and rolling, drying, steaming and dyeing.

(six) low urea reactive dye printing

Scope of application: reactive dyestuff printing of cotton fabric, regenerated cellulose fabric and real silk fabric.

Technical characteristics: in the process of commercialization of dyes, by adding electrolytes, dispersants, cosolvent and so on, the solubility of dyes can be improved. In the existing reactive dyes, reactive dyes which are suitable for low urea or urea free printing process are screened out.

Application effect: reducing the amount of urea in printing production, obviously reducing the concentration of ammonia nitrogen in printing wastewater and reducing the burden of sewage treatment.

(seven) disperse dyes alkaline dyeing

Scope of application: one bath process for polyester fabric and one bath process for polyester cotton fabric.

Technical characteristics: alkali resistant (pH7-13) disperse dyes contain alkaloid insensitive groups. They are mainly linked to alkali resistant groups on mono nitrogen structure and can be dyed in polyester fabric in alkaline bath.

Application effect: dyeing cost is reduced by about 15% compared with acid dyeing, saving dyeing time and reducing sewage discharge. Moreover, it can avoid inadequate washing after pretreatment or alkali reduction, and it has poor dyeing reproducibility and inaccuracy of color and light after dyeing by acid condition.

(eight) printing and dyeing of liquid disperse dyes

Application: dyeing and printing of polyester fabric with automatic dyeing system.

Technical characteristics: the dispersed dose of liquid disperse dyes is much less than that of powdered dyes, and it is easy to prepare nano particles. The dye is easier to diffuse and stick to the fiber, and the dye remaining on the fiber surface is less.

Application effect: liquid disperse dye has good dispersibility, simple material, accurate measurement and convenient operation, and can improve dye uptake and fixation rate. Under the condition of less water washing, it still has the advantages of bright color and high fastness. When liquid disperse dyes are used for printing, the amount of printing paste is reduced.

(nine) digital inkjet printing

Scope of application: all kinds of fabric printing.

Technical features: no need to separate color, draft and plate making. The flower pattern designed by computer can be directly printed onto the fabric through the nozzle to print the printed fabric. In addition to coating ink, the fabric needs sizing before printing, and after printing, it needs fixing and washing.

Application effect: the process is simple, the process is short, the printing accuracy is high, it can meet the needs of many varieties and personalized orders, and the comprehensive use cost of the nozzle and ink is high.

(ten) high fastness pigment printing

Scope of application: pigment printing for all kinds of fabrics.

Technical characteristics: through the use of new adhesive, to meet the requirements of hand feel to obtain excellent printing fastness, solve the fabric handle and printing fastness can not be taken into account. The color paste is easy to modulate, and can be used for special printing methods such as gold powder and silver powder printing.

Application effect: compared with dye printing, it can save water and reduce energy consumption. Rubbing fastness and touch are slightly worse than dye printing.

(eleven) color separation printing

Scope of application: printing of all kinds of fabrics.

Technical features: color separation printing is not restricted by the color and number of frames in flat screen printing and rotary screen printing. With fixed basic colors, the wide color gamut, high precision flat screen and rotary screen printing are produced by using the principle of color superposition and mixing, and colorful printed fabrics are printed.

Application effect: color separation printing is more expressive and clearer than traditional screen printing. It has higher efficiency than digital inkjet printing, low production cost, and is not affected by factors such as sprinkler head and ink. The printing effect is similar to digital inkjet printing. Under the premise of low cost, color separation printing achieves high color fastness, natural color transition and wide gamut printing effect. It realizes the standardized reuse of color paste, improves the utilization rate of color paste, and has certain energy saving and emission reduction effects. The requirement of color separation plate making is high.

Three. Pollutant treatment and comprehensive utilization of resources

(1) efficient collection and treatment of exhaust gas and reuse of waste heat.

Application: it is used for waste gas treatment and waste heat recovery.

Technical features: through the uniform and efficient filtration, spray, high voltage electrostatic treatment, automatic cleaning, fogging, heat recovery system and other systems to achieve waste gas treatment and heat recovery.

Application effect: dust and oil fume removal rate is high, achieving discharge standards. The hot air tail gas at 180 degrees Celsius of the molding machine is reduced below 60 degrees, and the recovered heat energy can produce hot air or hot water, which saves energy and reduces production cost.

(two) membrane treatment and reuse technology

Scope of application: advanced treatment and reuse of printing and dyeing wastewater to remove pollutants such as chroma, COD, BOD and salinity (electrical conductivity) in wastewater.

Technical characteristics: membrane has different permeability to different substances. Membrane technology is actually a technology for separating wastewater. The membrane separation technologies used for printing and dyeing wastewater treatment include microfiltration (MF), ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO). MF and UF are often used as pretreatment of NF and RO. UF can separate macromolecular organic matter, colloid, suspended solid, NF can desalted and concentrated, RO can remove soluble metal salts, organic matter, colloidal particles and retain all ions.

Application effect: membrane treatment technology not only removes residual organic matter in water, reduces chromaticity, but also removes inorganic salts. However, the cost of membrane treatment technology is high and the membrane components are easy to be polluted to shorten their service life.

(three) heat pump heat utilization

Scope of application: printing and dyeing high temperature waste water cooling and waste heat reuse.

Technical features: heat recovery and utilization through heat pump units, heat exchangers, pumps and control systems.

Application effect: the waste heat of 70% of the waste water from the process can be recovered. The cooling capacity of the unit can be used for cooling the waste water, cooling the equipment and cooling the workshop environment. The system has high filtration accuracy and high automation. It can prevent the hardness of new water and waste water and chemical agents from causing fouling and corrosion damage to heat pump units, and reduces the frequency of cleaning of heat exchanger systems.

(four) magnetic levitation fan

Scope of application: aeration treatment of all kinds of printing and dyeing wastewater.

Technical features: magnetic levitation technology is applied to blower, and the energy consumption of waste water treatment is reduced by using magnetic bearing technology, high speed and high-power permanent magnet synchronous motor technology, high efficiency fluid technology and intelligent control technology.

Application effect: compared with the traditional roots blower, it can save about 25% energy, and can save about 20% energy compared to the multi-stage centrifugal blower. It can reduce the noise of equipment and improve the working environment. The cost of purchase is higher than that of traditional fans.

Four, intelligent information technology

(1) automatic weighing, dispensing and conveying system of dyes and chemicals

Scope of application: automatic weighing, converting and conveying of dyes and dyes in printing and dyeing enterprises.

Technical features: the system is mainly composed of three parts: weighing, chemical and conveying. According to the formulation of the production process, the dyestuff needed for production is formulated according to the requirements. According to the production instructions, the prepared dyestuff and auxiliaries are automatically conveyed to each production machine platform to realize the unified dispatching and management of chemical logistics and information flow in printing and dyeing production.

Application effect: the matching between the small sample formula and the large production formula is higher, the process is stable and reproducible; the consumption of dye auxiliaries in the production is accurately counted, the employment is reduced, the labor intensity is reduced, and the working environment is improved. The first rate of products is increased by 1%-2%, the rework rate is reduced by 3%-5%, and the labor cost is reduced by 20%-30%. The early investment is large, and the quality of workers is higher.

(two) automatic printing paste system

Scope of application: automatic transfer of printing paste in printing production.

Technical characteristics: through the chemical material distribution system, the mother liquor storage system, the automatic paste feeding system of the paste preparation system, the fully automatic powder material system, etc., the centralized management of the printing order, technological formula, mixing amount and other information is carried out to accurately control the key parameters of the colorant processing formula.

Application effect: it can improve the accuracy of printing and sizing formula, reproducibility of process formula, reduce artificial uncertainty factors, ease the management of prescription, increase production efficiency, improve the working environment, reduce labor intensity, achieve residual pulp reuse in printing and sizing, and reduce waste of color paste. The early investment is large, and the quality of workers is higher.

(three) on-line acquisition and control system of process parameters

Application: collection and control of main process parameters of printing and dyeing production.

Technical features: real time data acquisition for process parameters sensors of printing and dyeing equipment, comparative analysis of data acquisition and processing parameters, accurate on-line detection and control of key process parameters, and ensuring that the process parameters are within the set range.

Application effect: automatic control of pH value, hydrogen peroxide concentration, fabric density, rolling rate, weft deviation and other process parameters, reduce errors in artificial adjustment of process parameters, improve process reproducibility and product qualification rate, improve production automation level, and energy saving and emission reduction effect is more obvious. The quality of system maintenance and management personnel is higher.

(four) printing and dyeing ERP system

Scope of application: collecting, summarizing and analyzing all kinds of data in production and operation of printing and dyeing enterprises.

Technical features: the printing and dyeing ERP system includes production planning, supply chain management, energy management, cost analysis, performance appraisal and so on. Information technology is used to integrate data from various departments of printing and dyeing enterprises, and the decision support information is formed through systematic and scientific analysis.

Application effect: real-time understanding of tracking orders, production orders, gray cloth storage, finished goods delivery, etc., can be analyzed and summarized in the printing and dyeing production of water, electricity, steam, dyes, chemicals, labor, etc., and timely cost accounting and control. Through the implementation of ERP management, improve production efficiency, reduce production management costs, optimize process and stabilize product quality, and enhance enterprise information management level. It is necessary to cooperate with professionals in dyeing and printing and information technology to make good use of ERP system.

Five, frontier science and technology tackling key technologies

(1) dyeing of reactive dyes in non aqueous medium

Scope of application: dyeing of cellulose fibers such as cotton.

Technical characteristics: non aqueous media instead of water as dyeing medium to cotton fiber and other cellulose fibers dyed with reactive dyes. The polar non aqueous medium with high solubility for reactive dyes can make plasticizing and swelling of fibers, and achieve the adsorption and fixation of dyes on dyes, so as to achieve the purpose of dyeing without salt or without water. At present, the main research directions include reactive dyes mixed solvent dyeing, polar solvents replacing some water for dyeing, polar and non-polar solvents mixed dyeing.

Application prospect: the stability of reactive dyes in non-aqueous media is better, avoiding the ineffective hydrolysis of dyes, and higher utilization rate of dyes. Dyeing process does not need to use a large amount of inorganic salts to promote the adsorption of dyes and reduce the difficulty of dyeing wastewater treatment. Reduce dyeing and dyeing after washing water, energy saving and emission reduction effect is remarkable.

Technical difficulties: most of the non-aqueous media are non-polar media, so it is difficult to effectively expand cotton fibers. Dyestuffs are difficult to dye. The safety and environmental protection of solvents need to be emphasized. The recovery and reuse of solvents need to be improved.

(two) dyeing with supercritical carbon dioxide

Application: polyester fiber dyeing.

Technical characteristics: the dyeing principle of supercritical CO2 is based on the traditional dyeing principle of water medium. The dyeing process can be roughly divided into three stages: adsorption, diffusion and fixation. The CO2 molecules in supercritical state are nonpolar and have good solubility for dyes with non-polar or weak polarity and small molecular weight. Under supercritical conditions, CO2 rapidly swelled the fibers and made the dye easy to dye the fibers. Supercritical CO2 has a strong plasticizing effect on fibers, which can reduce the glass transition temperature of fibers, increase the activity and free volume diffusion of fiber chains, so that they can be dyed at lower temperatures and greatly reduce dyeing time.

Application prospect: no need of water and no waste water. No need to dry after dyeing, shorten the process flow and save energy. The dyeing speed is fast, the leveling and penetrating performance are good, and the dyeing reproducibility is good. CO2 is stable, easy to obtain, and can be repeatedly used to reduce pollution. Some high performance fibers can be dyed.

Technical difficulties: at present, supercritical CO2 dyeing is still in the small batch test stage. There are still several problems to be solved in the large-scale application. First, the production equipment is high pressure system, the price is high and the one-time investment is large; two, there are few dyes available, and the dyeing process needs to be further studied and optimized. Three, the dyeing effect of natural fibers is not ideal, and fiber modification, fluid modification or dye modification are needed.

(three) full width pad dyeing of tension sensitive fabric

Scope of application: continuous and plain dyeing of tension sensitive fabric such as knitted fabric and elastic fabric.

Technical features: through the anti wrinkle flat width pre-processing equipment, plain dyeing pre drying equipment and large diameter multi roll steaming and fixing equipment, the deformation and tension of tension sensitive fabric in flat width operation are controlled, and the continuous production process of tension sensitive fabric at low temperature plain width before treatment, after dyeing, finishing and shaping is established.

Application prospects: it can effectively reduce unit energy consumption and water consumption, improve production efficiency, reduce labor consumption, reduce defects such as scratches and creases, and improve product quality.

Technical difficulties: at present, the whole process of tension sensitive fabric is still in the small batch test stage, and there are still some problems to be solved. First, the pad dyeing and fixing equipment needs further optimization; two, the suitable high compatibility dyes are still being further screened, and the dyeing technology needs to be further studied and improved. Three, compared with intermittent dyeing equipment, the investment cost of the equipment is higher.

(four) continuous dyeing of polyester fabric with little water.

Application: velvet fabric, including super soft, flannel, coral velvet, pure polyester dry hair towel, woven fabric advertisement, curtain, sand release, luggage cloth, lining cloth, pocket cloth, linen cloth, frock cloth and so on.

Technical characteristics: Based on the principle of disperse dyes dyed by hot melt, the dispersion and fixation of disperse dyes into amorphous regions of fibers can be improved by disperse dyes ultrafine processing. As most disperse dyes enter sublime fibers into amorphous areas, the dye remaining on the fiber surface is very small. Besides the washing with high color fastness, washing is generally not required, so as to achieve the purpose of water saving.

Application prospect: dyeing process is less than 80% of the traditional dyeing and printing because of no need of washing or less water washing, and the cost of running is 15%.

Technical difficulties: there are certain limitations on the product, not all polyester fabrics are suitable; disperse dyes should be screened and refined; knitted products will lose some of their original style.

(five) recycling of salt containing dyeing wastewater

Scope of application: cellulose fiber products reactive dyes intermittent dyeing wastewater recycling.

Technical characteristics: using acidic cationic cationic oil extractant and reactive dye dyestuff in dyeing wastewater, the dye in dyeing wastewater is extracted and the hydrolyzed dyes in dyeing wastewater are separated. After the extraction, the colourless dyeing wastewater containing salt can be recycled for other dyeing processes, and the hydrolyzed dyestuffs can be made harmless by making sludge or solid after dehydration. The extractant can be reused by reverse extraction.

Application prospect: the dye removal rate of reactive dye dyeing wastewater can reach more than 95%, and the dyeing wastewater after decolorization can be used for dyeing medium and deep colored fabrics. The dyeing wastewater can be recycled at low cost and high efficiency to realize the reuse of salt, reduce the consumption of salt in printing and dyeing production and reduce the discharge of salty wastewater.

Technical difficulties: dyeing product quality, wastewater treatment effect and technical feasibility should be further optimized and adjusted. The potential environmental risks of extractant may be improved, and relevant environmental risk assessment analysis should be improved. It is necessary to further study the reuse or treatment technology of high concentration dye waste.

(six) digital inkjet printing nozzle

Application: for digital inkjet printing machine.

Technical features: the digital inkjet printing nozzle has two main types: piezoelectric and foaming. The piezoelectric sprinkler uses piezoelectric ceramics to generate deformation by pressing the piezoelectric crystal, generating ink droplets on the surface of the fabric by extruding the ink to produce high pressure, and forming a droplet on the surface of the fabric. The foaming nozzle is heated in a very short time through the thermal resistor element on the nozzle, and the ink is heated to form bubbles in the ink jet area. The pressure generated by the expansion of the bubble presses a certain amount of ink to overcome the surface tension and spew from the nozzle to form ink droplets.

Application prospect: the piezoelectric nozzle is easier to control the shape and size of the ink dot, and has high resolution, easy to achieve high precision inkjet printing effect, good color reproducibility and strong applicability to ink. The foam nozzle usually adopts the integrated structure of ink box and nozzle. The electronic drive is simple and easy to implement, but it is difficult to change and control the size of the droplet.

Technical difficulties: the technical requirements of the panels, piezoceramic, glue and other components of the production sprayer are high. Our country's technical reserves in this area are insufficient, and the level of material selection and precision machining should also be improved simultaneously.