Dyes are closely related to people's daily life. With the development of social economy, the variety and dosage of dyes are increasing day by day, and their uses will be diversified. China's dye industry includes dyes, organic dyes, auxiliaries and brighteners. Mainly used in textile printing and dyeing, coating, ink, paper making, etc. Textiles are the main users. Today, with the development of high technology, functional dyes (or special dyes) closely related to modern high-tech fields such as light, electricity, chemistry and biochemistry have also been developed, which has played a certain role in promoting the popularization and application of high technology. These dyes are:
Length-changing isomeric dyes; Include photochromic dyes, thermochromic dyes and electrochromic dyes.
2. Energy conversion dyes include luminescent dyes, solar energy conversion dyes, laser dyes and dyes used for organic nonlinear optical materials.
3. Dyes used for information display and recording include liquid crystal dyes, color filter dyes, optical disc information recording dyes, electrophotographic dyes and pressure, heat and photosensitive dyes.
4. Biochemical and medical dyes; Include dyes for biological coloring, medical dyes, dyes for affinity chromatography ligands, and the like.
As textiles will still be the main users of dyes in the future and the main targets of expanding the dye market, the development of dyes should also be able to adapt to the changes in textiles. Since the beginning of this year, I have learned from the responsible comrades of China Textile Printing and Dyeing Association and the information center, exchanged information with colleagues in the textile dyeing and finishing industries such as Beijing, Tianjin, Shanghai and Qingdao, and made a preliminary analysis based on the development direction of dye-related departments, put forward my personal views and compiled a cost paper as a reference for decision-making and market development.
Second, the present situation and development trend of textile industry
By the end of the Ninth Five-Year Plan, that is, in 2000, the overall economic operation of China textile industry had turned losses into profits, entered a virtuous circle, and state-owned enterprises gradually got rid of difficulties. The return on net assets of the whole industry reached 8.73%. According to the former leader of the State Textile Industry Bureau, from 2000, China's textile exports will enter the development climax of 8- 10, and will bring three major opportunities after China's entry into WTO. First, after China's entry into WTO, textile export quotas will be relaxed, at least $80 billion to 1000 billion per year; Second, we should substantially adjust the industrial structure and change the past situation of fierce domestic competition and cold and cheerless foreign countries. The export pattern of the three pillars of clothing, home textiles and industrial supplies in the industry will be adjusted to 60%, 25% and 10% respectively, which will gradually be in line with international standards. Thirdly, China's entry into the WTO will have an all-round impact on China's textile design, technology, quality, environmental protection, labor and capital.
According to statistics, in 2000, China's textile and clothing exports reached US$ 52.082 billion, up 20.94% year-on-year. Among them, textile exports were US$ 6,543.8+US$ 06.062 billion, a year-on-year increase of 23.5%; Clothing exports reached $36.02 billion, up 19.83% year-on-year.
Since the reform and opening-up, the dyeing and finishing industry has actively carried out the adjustment of industry and enterprise structure, product structure, technical structure and regional structure, which has overcome the problems of backward information, insufficient product development and innovation ability, environmental protection management and so on. By 1999, the output of printed and dyed fabrics will reach160.5 billion meters, and it will reach1700 million meters in 200 1 year. The areas with rapid development are Zhejiang, Jiangsu, Shandong, Guangdong and Fujian. 1995- 1999 The output statistics of the five provinces are as follows: (100 million meters/%of the national total)
age
Zhejiang Province
Jiangsu Province
Shandong (province)
Guangdong
Fujian Province
Accounted for% of the country.
1995
23.99/ 17.58
22.66/ 16.6
12./9.45
2 1/ 15.38
4.47/3.27
85. 13/62.28
1996
24.22/20.07
19.02/ 15.76
10.83/8.97
18.93/ 15.86
5.07/4.2
78.07/64.86
1997
34.52/24.4 1
2 1.26/ 15.04
10.54/7.45
20.05/ 14. 18
15.73/ 1 1.22
102. 1/72.3
1998
57.48/39.24
19.25/ 13. 14
9.96/6.76
19.55/ 13.34
10.58/7.22
1 16.82/79.7
1999
65.23/40.65
2 1.88/ 13.63
1 1.07/ 10.4
20. 13/ 12.54
5.43/3.45
123.74/80.67
The sum of the annual output of the above-mentioned S provinces has accounted for 75-80% of the national total output.
Although the output of printing and dyeing fabrics has been increasing, the quality, effect and style of the final product can not be completely solved by bleaching and dyeing because the printing and dyeing products are a systematic project from raw materials to finished products. From fiber raw materials to spinning, sizing, weaving, singeing, desizing, mercerizing and bleaching and dyeing, the fabrics made can not fully meet the market demand. Imported printed and dyed fabrics are as follows:
(1 billion/1 billion dollars)
age
Pure cotton printed and dyed cloth
Polyester cotton printing and dyeing cloth
Synthetic filament fabric
Among them; Filament brocade
1995
7. 18/7.57
2.00/2.42
23.38/24.64
17.26/ 15.50
1996
2.03/2.43
23.84/25.29
23.84/25.29
15.92/ 14.30
1997
7.69/7.8 1
2. 14/2.53
25.0/2.49
15.57/ 13.98
1998
6.79/7.08
1.9 1/2. 12
23.3 1/2 1.76
14.62/ 13. 13
1999
6.22/7.33
2.28/2.46
25.02/22.48
15.39/ 13.82
It is understood that the textile printing and dyeing industry is actively adjusting its industry and enterprise structure and participating in domestic and foreign market competition on the principle of "controlling the total amount, optimizing the stock, improving the quality, developing new products, upgrading the grade, improving the processing depth, increasing the added value of products and striving to increase new growth points".
The steady development of textile industry has brought certain opportunities to dye industry. How to seize this opportunity is a major issue we are facing.
Third, the development trend of chemical fiber industry
(1) current situation
Fiber is the main raw material of printing and dyeing fabrics. Variety, quality and textile processing directly affect the quality of printed and dyed fabrics, as well as the variety and dosage of dyes. Its development trend also affects the development of dyes. Textile fibers generally include natural fibers such as cotton, hemp, wool and silk, while chemical fibers include man-made (regenerated) fibers and synthetic fibers. In recent years, the international annual output of textile fibers is about 4,600 tons, with an annual growth rate of about 2.5%. Uses: The annual output of chemical fiber is close to 24 million tons, accounting for about 52% of textile fiber, with an annual growth rate of about 5%. Natural fiber is stable at about 22 million tons, accounting for 48% of textile fiber, and cotton fiber has retired to the second place from the past. Because China feeds 22% of the world's population with 7% of the world's arable land, the state has always attached importance to the development of chemical fiber industry to solve the land competition of grain and cotton. Chemical fiber includes man-made (regenerated) fibers and synthetic fibers. By the end of the Ninth Five-Year Plan, the annual output of chemical fiber had reached 6.5 million tons, more than double that at the end of the Eighth Five-Year Plan, accounting for about 27% of the world's total output, and now it has become the country with the largest chemical fiber output in the world. Because chemical fiber is the mainstream raw material of textile industry at home and abroad, this paper only discusses chemical fiber raw materials.
According to statistics, the output of conventional chemical fiber varieties from 65438 to 0999 is as follows:
Chemical fiber variety
Output (ten thousand tons)
Proportion (%)
Total amount of chemical fiber
653.9
100
Among them; artificial fiber
55.2
8.4
1. viscose filament
10.0
2. Viscose staple fiber
45.2
Among them; synthetic fibre
598.7
9 1.6
1. polyester
458.9
2. Nylon
47.0
3. Acrylic fiber
49.2
4. Vinylon
9.5
5. Polypropylene
33.4
6. Ammonia theory
0.7
(2) Development trend
Although the annual output of chemical fiber has exceeded 6 million tons, the annual import of chemical fiber has always remained above 30% of the total output of chemical fiber in China, which is in sharp contrast with the situation that the economic benefits of chemical fiber industry in China have been declining in recent years. The key problem lies in the unreasonable product structure of China chemical fiber industry, the overcapacity of conventional products, and the new chemical fiber raw materials needed by many high-grade fabrics or export products cannot be met in China.
At the same time, the post-textile processing enterprises that use fiber have insufficient investment in the active use and research and development of new fiber raw materials, weak risk awareness, insufficient investment in new product development and little understanding of market development trends.
The development speed and quality of new products can't meet the development demand of market and consumption trend, which leads to the difficulty of interaction between raw materials and fabrics, and leads to the low level of textile fabrics in China, which is always at a disadvantage. During the Tenth Five-Year Plan period, we will vigorously develop new fiber varieties and various high-grade fabrics. The dye industry should understand this market trend and formulate our development strategy.
Collect and analyze the main new varieties existing or being developed as follows:
Because there are many classification methods of new fiber varieties, and they have not been recognized, they are temporarily described as natural fibers, chemical fibers and modified fibers. Although great changes have taken place in natural fibers through improved varieties, chemical fibers and modified fibers are the fastest, and chemical fibers can be divided into synthetic fibers and regenerated fibers, which have developed rapidly in recent years. In this paper, it is classified according to the information provided by the textile department, and it is a new chemical fiber variety that is very popular in the field of clothing or home textiles or will soon become the mainstream of development. The main points are as follows:
1. New synthetic fiber
The application scope of new synthetic fibers is constantly expanding, including the following aspects:
(1) Soft suede appearance textiles: such as peach skin, imitation deerskin, imitation leather, imitation
Silk, etc.
(2) Textiles with low surface friction resistance: such as ski suits, swimsuits and diving suits;
(3) Fiber materials for chemical industry: heat-resistant or heat-insulating, chemical-resistant, filter materials, etc.
(4) Composite fiber materials: ion exchange fiber, reinforced plastic, superconducting fiber, etc.
(5) Biocompatible fiber materials: blood vessels, artificial bones, blood separation, immobilized enzymes and cell culture substrates;
(6) Water-absorbing and hydrophobic fiber materials: breathable and water-repellent fabrics, water-absorbing and oil-absorbing fiber materials, special towels, oil-water separation materials, etc.
(7) Vacuum cleaning textiles: cleaning cloth, vacuum cleaning, filter cloth, etc.
In addition, it can also be used for insulation, printing, password and identification of fabrics or high-grade paper. All the above products need dyeing, and dyes are used. There are the following:
(1) superfine fiber (fine denier fiber)
This variety is physically modified from polyester fiber and industrialized in 1970s. At present, the finest denier has reached 0.0Oldtex, which overcomes the shortcomings of synthetic fibers in hand feel, appearance and wearability and becomes the main variety of new synthetic fibers. Microfiber is mainly polyester fiber, but there are also other chemical fibers. Polyester microfiber has been widely used in wool-like and silk-like fabrics.
The dyes used are still mainly disperse dyes, but after screening, they meet the following dyeing characteristics:
* Fast dyeing speed: superfine fiber not only has a much larger specific surface area than ordinary fiber, but also has a faster adsorption speed and diffusion speed.
* Poor color rendering or deep dyeing: the fiber has large specific surface area, high refractive index, strong reflection and scattering of light, and its color rendering is much lower than that of ordinary fiber. In order to obtain the same dyeing depth, the dye concentration is much higher.
* Poor levelness: If the dyeing speed is fast, it is not easy to dye evenly, and the so-called "bright spot" is easy to appear on the fabric.
* Poor dyeing temperature dependence: the lower the temperature, the faster the dyeing speed, the lower the initial temperature, the lower the highest dyeing temperature than other fabrics, the shorter the holding time, the better the dye transfer performance and the better the lifting performance.
* Poor dyeing fastness: This is due to the large specific surface area and small radius of the fiber. The higher the dyeing depth, the lower the light fastness.
(2) polyester modified fabric
Ordinary polyester fabrics need to be dyed with disperse dyes at high temperature and high pressure, which consumes a lot of energy and uses a lot of dyes for dark dyeing. In order to improve the dyeability of polyester fiber, groups containing binding ionic dyes were introduced into the molecular chain or dyeable components were mixed into the fiber, and modified polyester dyeable with disperse dyes at atmospheric pressure, acid dyes and cationic dyes was developed, which has been industrialized on a large scale.
(3) Polylactic acid fiber
This product is also called biodegradable and environmentally friendly fiber. It is made of corn starch into lactic acid (2- hydroxypropionic acid), concentrated into polylactic acid, and then made into fiber. Its characteristic is that the woven material is light, soft, dry and silky. The biggest feature is that waste textiles are decomposed into CO2 and H2O after landfill, and then turned into corn syrup through photosynthesis, which will not bring any pollution to the environment. It can be used to make sportswear, coats, underwear, sweaters, carpets and various industrial supplies, and has a wide range of uses. Now the United States has made carpets and put them on the market, which is one of the main measures for China's textile industry to enter the green channel after its entry into WTO. With the expansion of production scale, production costs will continue to decrease. Disperse dyes are mainly used for dyeing, but the dyeing temperature is lower than that of polyester fabric.
(4) Soybean protein fiber.
This product belongs to regenerated plant protein fiber, which was successfully spun by Kang Hua Biochemical Engineering Joint Group Company in Puyang, Henan Province for many years, and it is also the only chemical fiber industrially produced in China. Soak the oil-squeezed soybean meal, purify the protein separated from the soybean meal, make soybean protein spinning solution with a certain concentration under the action of biological enzyme, and make short fiber through wet spinning, coagulation, crosslinking, washing, drying, curling and cutting. It has fine monofilament fineness (0.9- 1.2D), light specific gravity, high tensile strength, good acid and alkali resistance, good luster, good hygroscopicity and other excellent wearability, as well as soft hand feeling of cashmere-like, elegant luster of silk, moisture absorption and moisture conduction of cotton fiber, warmth retention of wool and other characteristics, and has a very broad application prospect.
The textile industry believes that this is a new type of fiber with sustainable development. The collected varieties and manufacturers are as follows:
* Silk/soybean protein fiber fabric (about 40/60): Suzhou Wu Dong Silk Weaving Factory, Wujiang Xinmin Textile Company, Wujiang Xinlian Silk Weaving Factory, Zhejiang Huayuan Dachang Silk Weaving Factory and Zhejiang Prospect Group.
* Wool/soybean protein fiber fabric (about 65/35): Changzhou No.3 Wool Mill, Jiangsu Sunshine Group, Lanzhou No.3 Wool Mill, Jiangyin Sanmao Group, Shanghai Sanmao Group, Wuxi No.1 Wool Mill and Wuxi Xiexin Wool Mill.
* Soybean protein fiber/chemical fiber fabric (about 40/60): Wujiang Xinmin Textile Company, Huayuan Dachang Silk Company and Shaoxing Prospect Group.
* Pure soybean fiber fabrics: Qingdao Guomian No.6 Factory, Luoyang Baima, Shaoxing Prospect Group, Zhengzhou Yimian, Huayuan Dachang Silk Company and Shaoxing Prospect Group.
There are also many knitted products.
Suitable dyes include weak acid, reactive, neutral and direct dyes. However, because the chemical and physical structure of fiber is different from that of natural protein fiber, the selection of dyes, dyeing processes and auxiliaries needs to be adjusted, mainly because its dyeing depth is lower than that of silk, cotton and wool.
(5) Polyurethane fiber (spandex, Lycra)
This product is mainly polyurethane (about 85%), which is a block polymer with rigid and flexible segments. It is the main material for exporting elastic clothing. Compared with rubber band, it has relatively high modulus and good chemical stability. It is not only used for knitted fabrics such as swimwear and socks, but also used for various woven fabrics. It has the advantages of wrinkle resistance, setting, good drape and washing resistance. Dyeing with disperse dyes and adding auxiliaries at 95℃ can improve dye uptake, levelness and wet fastness.
2. New regenerated fibers
The new regenerated cellulose fiber is Tencel (or lyocell) fiber. Because wood pulp is dissolved in N- methylmorpholine oxide (NMMO) hydrate to prepare 10% viscous spinning solution, regenerated natural cellulose fibers are obtained by spinning. Because NMMO has low toxicity, high recovery rate and pollution-free production process, its fabric is known as "green textile" with dry strength. Compared with cotton and viscose fiber, the wet strength only decreases by 15- 17%. It has excellent wet modulus, extremely low shrinkage, less than 2% in radial direction, surpassing all fibers, and its water absorption and water retention is close to viscose fiber, so it is comfortable to wear. The world output has exceeded 200,000 tons, and it is expected to develop rapidly as a green fiber in this century. All kinds of cellulose dyes can be used for dyeing, among which reactive dyes are the best, especially high-temperature dyes containing two different reactive groups or the same reactive group, such as domestic EF reactive dyes and KE reactive dyes.
(C) textiles must enter the green channel
After China joined the WTO, textiles also entered the process of world trade liberalization. Although the quota restriction was abolished, it encountered a "green barrier". At present, there are two main types in the field of international clothing: one is the barrier against the environmental impact of the whole process of textile and clothing from design and production to scrapping and recycling; Second, the product itself affects the safety and health of consumers. Export products must comply with mandatory laws or technical regulations issued by some governments or regional international alliances, as well as various specific regulations derived from them. These regulations are also indirect obstacles to the development of dyes, which must be paid attention to (refer to the latest version of Oeko-tex standard 100 in 2002).
(D) the development of dyeing and finishing technology and equipment
The development direction of technology and equipment in printing and dyeing industry is mainly: adapting to environmental protection, saving raw materials and energy, instant small bath ratio, more reliable and simpler printing and dyeing processing. This puts forward new requirements for dyes. There are mainly the following aspects: 1 and 1967 air-jet dyeing machines have solved the problem of difficult dyeing of polyester, and knitted fabrics and fabrics with uneven surfaces can be dyed. At present, there is a new overflow dyeing machine with small bath ratio (1: 4 ~ 7), short process, small batch, large load, low temperature dyeing, full control, environmental protection and suitable for special fabric dyeing.
This requires that the solubility, dye uptake, levelness and lifting power of dyes should be superior.
2. In order to reduce the treatment cost of printing and dyeing water and wastewater, non-aqueous printing and dyeing technology was developed. In recent years, the new dyeing technology of supercritical carbon dioxide non-aqueous system has been successfully studied, and new equipment suitable for this process has been developed, which makes this technology practical. Its principle is: using supercritical carbon dioxide as dyeing medium, the dye dissolves with the increase of temperature and pressure of the medium, promoting its diffusion into the fiber, and realizing coloring and fixation. No polluted wastewater is generated at all, disperse dyes can be dyed without dispersant, the dissolution of dyes is controlled by fluid pressure, and the depth and color are easy to control. The dye utilization rate can reach 90- 100%, and it is easy to get uniform dyeing. Because it is a green process and a promising processing method, industrialized production has been realized abroad, and it is developing vigorously in China. Disperse dyes are mainly used, but varieties with suitable solubility in supercritical carbon dioxide should be screened.
3. Digital ink-jet printing technology is a plateless printing technology, that is, in the process of textile printing, the information of printing design pattern is directly transmitted to a group of dye (pigment) nozzles through a computer, and the opening and closing of the nozzles are controlled without any screen to complete textile printing. The advantages are: a large number of screen plates can be saved, and any defects such as embossing and embossing will not be caused; There is no problem of cross-matching and color matching when printing; Proofing and production can be carried out on the same machine without color difference; Small batch and multi-variety conversion speed is extremely fast, which can realize fast delivery. But we should have a good CAD system. At present, disperse, reactive and acid dye ink-jet inks have been successfully developed for various fabrics.
4. The transfer printing technology of polyester-cotton blended fabric was adopted in 1960s, but it was not widely used because of its low dye transfer rate and poor rubbing fastness. The newly developed method is to transfer print the fabric with a new reactive disperse dye containing chloroacetyl at195 5℃. The transfer rate reaches 52.6-70%, and it has good washing fastness and rubbing fastness. This is a promising new printing process.
Four. Concluding remarks
Since the reform and opening up in China for more than 20 years, the dye industry has developed rapidly. There are more than 2,000 large and small factories with an annual output of more than 400,000 tons, accounting for about 50% of the world's total dye output, and more than 80% are supplied to the textile industry. After China's entry into WTO, the textile industry will develop greatly, and the development of dye production technology and equipment will gradually shift to the development of high-grade and high-quality dye products for the printing and dyeing industry, which is a development trend. According to the information provided by colleagues in the printing and dyeing industry, the development direction of several main dyes is summarized as follows for reference;
1, disperse dye
Among all dyes, the dosage is the largest, and the domestic output exceeds 200,000 tons. After screening, the varieties suitable for dyeing polyester microfiber are C.I. Disperse Yellow 54, 64, 60, 64,163; C.i. scattered oranges 30 and 76; Disperse Red 73,82, 13 1, 146, 152, 153, 167,177,258,277. Informant.
Disperse violet 26, 28; C.i. Disperse Blue 56, 60, 73, 79, 79: 1, 165, 165: 1, 183, 257, 270, 284. Disperse brown 19, etc. Small bath is more energy-saving and time-saving than fast dyeing dyes, which is still a development problem. There are many kinds of solvent dyes, which are widely used. They have the same structure as disperse dyes and can also be considered. The above reactive disperse dyes for transfer printing have not been produced at present, and should be developed as soon as possible.
2. Acid dyes
Acid dyes are mainly used for dyeing and printing wool, nylon and silk, and are also an important category of wool and nylon blended products. They are also used in paper and leather coloring, solvent dyes and organic pigments. It is characterized by many varieties, small dosage and few varieties produced in large tonnage. In 2000, the output of wool and nylon in China was 300,000 tons and 370,000 tons respectively, and about 120 domestic varieties were used in the textile industry. From the development of textile industry, the main products are weak acid dyes and 1. Type 2 metal complex dyes. .
3. Reactive dyes
According to the analysis of printing and dyeing industry, the reasons for the rapid growth of reactive dyes are as follows: the consumption of cotton fiber is still increasing substantially, many varieties of direct dyes are banned, and the consumption of sulfide, reduction and ice dyeing dyes is reduced; In addition, it has the characteristics of bright color, complete chromatography, simple application, low price, strong adaptability, less pollution and excellent fastness. There is no accurate statistics on domestic annual output, which is estimated to be between 20,000 and 30,000 tons.
There are about 70 manufacturers.
Reactive dyes used in the textile sector are as follows.
model
active group
X
Dichlorotriazine
kilometre (km)
Monochlorotriazine
KE、KP
Two kinds of monochlorotriazines
Kiln-dried (in kiln)
One or two monochlorotriazines
(=knot) in the sea
β -ethyl sulfate sulfone
Male, female, male, female
Monochlorotriazine/β-ethyl sulfone sulfate
R/CN
M-carboxypyridine triazine
E
2,3-dichloroquinoxaline
F
Trifluoropyrimidine
SX south
Dichlorotriazine
P
Phosphonate group
police-woman
Bromoacrylamide
The above active groups are available in domestic resources and can be produced conditionally. The most commonly used types in printing and dyeing industry are X-type, K-type, KM-type, KN-type, monochlorotriazine plus dichlorotriazine, monochlorotriazine plus vinyl sulfone and so on. In order to improve the fixation rate, the printing and dyeing industry hopes to use varieties with double active groups or multiple active groups. ME and B dyes have high fixation rate and good levelness, and are suitable for dyeing at medium temperature (60℃). EF dyes have good compatibility, levelness, reproducibility, low dust, dye uptake and lifting power, as well as good wet fastness.