1. Introduction
Dyes are closely related to people's daily life. With the development of social economy, the types and amounts of dyes are increasing day by day, and their uses will also be diversified. my country's dye industry includes dyes, organic dyes, auxiliaries, and whitening agents. It is mainly used for textile printing and dyeing, coatings, inks, paper making, etc., and textiles are the main objects of use. In today's high-tech development, functional dyes (or special dyes) closely related to modern high-tech fields such as light, electricity, chemistry, and biochemistry have also been researched and developed, and have played a certain role in the promotion and application of high technology. promotion effect. Such dyes include:
l. Color-changing isomeric dyes; including photochromic dyes, thermochromic dyes, and electrochromic dyes.
2. Energy conversion dyes include luminescent dyes, solar energy conversion dyes, laser dyes, dyes for organic nonlinear optical materials, etc.
3. Dyes 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; including dyes for biological coloring, medical dyes, dyes for affinity chromatography ligands, etc.
Since textiles will still be the main users of dyes in the future and will remain the main target for expanding the dye market, the development of dyes must also be able to adapt to changes in textiles. Since the beginning of this year, we have learned from the responsible comrades of the China Textile, Printing and Dyeing Association and the Information Center, and communicated with colleagues in the textile dyeing and finishing industry in Beijing, Tianjin, Shanghai, Qingdao and other places. Through them, we have collected information and materials about the textile printing and dyeing industry, combined with dye-related information. We conducted a preliminary analysis on the development direction of the department, put forward personal opinions, and compiled this article as a reference for decision-making and market development.
2. Current situation and development trends of the textile industry
By the end of the "Ninth Five-Year Plan" period, that is, in 2000, the overall economic performance of my country's textile industry had turned losses into gains and entered a virtuous cycle. Enterprises gradually get out of trouble. The industry-wide return on net assets has reached 8.73%. According to the former leader of the State Textile Industry Bureau, starting from 2000, China's textile exports will enter a development climax in 8-10 years, and will bring three major opportunities after joining the WTO; First, joining the WTO After the textile export quota is relaxed, it will be at least 80 billion to 100 billion US dollars per year; secondly, it will prompt the industry structure to make major adjustments to change the past situation of fierce domestic competition and deserted foreign countries. The clothing, home textiles and industrial supplies in the industry The export pattern of the three pillars will be adjusted to 60%, 25%, and 10% respectively, gradually integrating with international standards. Third, after China’s accession to the WTO, it will bring all-round benefits to China’s textile design, technology, quality, environmental protection, labor force, and capital. Some Chinese clothing brands will take advantage of this impact to stand out internationally, thereby cultivating well-known international brands and well-known clothing designers.
According to statistics, my country's textile and clothing exports in 2000 were US$52.082 billion, a year-on-year increase of 20.94%. Among them: textile exports were US$16.062 billion, a year-on-year increase of 23.5%; clothing exports were US$36.02 billion, a year-on-year increase of 19.83%.
Since the reform and opening up, the dyeing and finishing industry has actively carried out industry and enterprise structure adjustments, product structure and technology structure adjustments, and regional structure adjustments, thereby overcoming information lagging, lack of product development and innovation capabilities, and environmental governance and other problems. By 1999, the output of printed and dyed fabrics had reached 16.05 billion meters, and in 2001 it had reached 17 billion meters.
The five provinces with rapid development are Zhejiang, Jiangsu, Shandong, Guangdong, and Fujian. The output statistics of the five provinces from 1995 to 1999 are as follows: (100 million meters/% of the national total)
Year
Zhejiang
Jiangsu
Shandong
Guangdong
Fujian
Accounting for % of the country
1995
23.99/17.58
22.66/16.6
12./9.45
21/15.38< /p>
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
< p> 34.52/24.4121.26/15.04
10.54/7.45
20.05/14.18
15.73/11.22
< p> 102.1/72.31998
57.48/39.24
19.25/13.14
9.96/6.76
19.55/13.34
10.58/7.22
116.82/79.7
1999
65.23/40.65
21.88/ 13.63
11.07/10.4
20.13/12.54
5.43/3.45
123.74/80.67
Above s The combined annual output of the province accounts for 75-80% of the country's total output.
Although the output of printed and dyed fabrics has continued to grow, since the process of printing and dyeing products from raw materials to finished products is a systematic project, the quality, effect, and style of the final product cannot be completely solved by bleaching and dyeing. From fiber raw materials to spinning Yarn, sizing, weaving, singeing, desizing, mercerizing, bleaching and dyeing, etc. are all hurdles at every step. Therefore, the fabrics made cannot fully meet the market demand. The printed and dyed fabrics imported every year are as follows:
< p>(100 million meters/100 million US dollars)Year
Pure cotton printed and dyed fabrics
T/C printed and dyed fabrics
Synthetic filament Fabrics
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< /p>
15.92/14.30
1997
7.69/7.81
2.14/2.53
25.0/2.49
15.57/13.98
1998
6.79/7.08
1.91/2.12
23.31/21.76
< p> 14.62/13.131999
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 currently focusing on "controlling total volume, optimizing inventory, improving quality, developing new products, improving grades, increasing processing depth, increasing product added value, and striving to add new growth "Point" policy, actively carry out industry and enterprise structural adjustments, and participate in competition in domestic and foreign markets.
The stable development of the textile industry has brought certain opportunities to the dye industry. How to seize this opportunity is a major issue we face.
3. Development Trend of Chemical Fiber Industry
(1) Current Situation
Fiber is the main raw material for printing and dyeing fabrics, and its variety, quality, and textile technology all directly affect The quality of printed and dyed fabrics also affects the variety and dosage of dyes, and its development trend also affects the development of dyes. Textile fibers generally include natural fibers such as cotton, linen, wool, silk, etc. Chemical fibers include artificial (regenerated) fibers and synthetic fibers. In recent years, internationally, the annual output of textile fiber has been about 4,600 tons, with an annual growth rate of about 2.5%. Qishin: The annual output of chemical fibers is close to 24 million tons, accounting for about 52% of textile fibers, and the annual growth rate is about 5%. Natural fibers have stabilized at around 22 million tons, accounting for 48% of textile fibers. Cotton fiber has been relegated to second place from the previous leader. Since my country uses 7% of the world's arable land to feed 22% of the world's population, in order to solve the competition for land for grain and cotton, the country has always attached great importance to the development of the chemical fiber industry, which includes man-made (regenerated) fibers and synthetic fibers. By the end of the "Ninth Five-Year Plan", The annual output of chemical fibers has 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. It has now become the country with the largest chemical fiber output in the world. Since chemical fiber is the mainstream raw material in the textile industry both internationally and domestically, this article only discusses chemical fiber raw materials.
According to statistics, the output of conventional chemical fiber varieties in 1999 is as follows:
Chemical fiber varieties
Output (10,000 tons)
Proportion (%)
Total chemical fiber
653.9
100
Among them; man-made fiber
55.2
p>8.4
1. Viscose filament
10.0
2. Viscose staple fiber
45.2
Among them; synthetic fibers
598.7
91.6
1. Polyester
458.9
2. Nylon
47.0
3. Acrylic
49.2
4. Vinyl
9.5
5. Polypropylene
33.4
6. Ammonia theory
0.7
(2) Development trends
Although the annual output of chemical fiber has exceeded 6 million tons, the amount of chemical fiber imported every year has always maintained more than 30% of my country's total chemical fiber output, which is in sharp contrast with the continuous decline in economic benefits of my country's chemical fiber industry in recent years. The key to the problem is that the product structure of my country's chemical fiber industry is unreasonable, with excess production capacity for conventional products, and many new chemical fiber raw materials required for high-end fabrics or export products cannot be met domestically.
At the same time, downstream textile processing companies that use fiber have insufficient investment in actively using new fiber raw materials and research and development, have a weak awareness of risks, have insufficient investment in new product development funds, and do not know much about market development trends. ,
The speed and quality of new product development are difficult to meet the development needs of the market and consumer trends, making it difficult for the two industries of raw materials and fabrics to interact, resulting in the level of my country's textile fabrics always hovering at a low level. At a disadvantage. During the "Tenth Five-Year Plan" period, new fiber varieties and various high-end fabrics will be vigorously developed. The dye industry must understand this market dynamics and formulate our development strategies.
The main existing or upcoming new varieties are collected and analyzed as follows:
Since there are many classification methods for new fiber varieties and they have not been recognized yet, they are temporarily divided into natural fiber varieties. , chemical and modified fibers, etc. are described.
Although natural fibers have undergone great changes through improved varieties, chemical and modified fibers are the fastest growing. Chemical fibers can be divided into synthetic and regenerated fibers. They have developed rapidly in recent years. This article temporarily uses this classification to focus on the fibers provided by the textile department. Information, focusing on new varieties of chemical fibers that are currently very popular in the field of clothing or home textiles, or will soon become the mainstream of development, the key points are as follows:
1. New synthetic fibers
New synthetic fibers The application scope of fiber 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, diving suits, etc.;
(3) Chemical fiber materials: heat-resistant or Thermal insulation, chemical resistance, filter materials, etc.;
(4) Composite fiber materials: ion exchange fibers, reinforced plastics, superconducting fibers, etc.;
(5) Biocompatible fibers Materials: blood vessels, artificial bones, blood separation, immobilized enzymes and cell culture substrates, etc.;
(6) Water-absorbent and hydrophobic fiber materials: breathable and water-repellent fabrics, water-absorbent and oil-absorbent fiber materials, special towels, oil-water separation Materials, etc.;
(7) Vacuum cleaning textiles: cleaning cloth, vacuum cleaner, filter cloth, etc.
In addition, it can also be used for insulation, printing, password and identification fabrics or high-grade paper, etc. All the above products require dyeing and finishing processing and the use of dyes. There are the following types:
(1) Superfine fiber (fine denier fiber)
This variety is made by physically modifying polyester fiber. It was industrialized in the 1970s and is now the most The fineness has reached 0.0 Oldtex, which has overcome the shortcomings of synthetic fibers in feel, appearance and wearing performance, and has now become 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 they must be screened to meet the following dyeing characteristics:
*Fast dyeing speed: not only does ultrafine fiber have a higher specific surface area than ordinary fiber Much larger, has fast adsorption speed and fast diffusion speed.
*Poor color rendering or deep dyeing: the fiber has a large specific surface area, high refractive index, strong reflection and scattering of light, and the color rendering is much lower than ordinary fibers. To obtain the same dyeing depth, dyes The concentration is much higher.
*Poor level dyeing: If the dyeing speed is fast, it is difficult to dye evenly, and so-called "glitter spots" are easy to appear on the fabric.
*Poor dyeing temperature dependence: the dyeing speed is faster at lower temperatures, the starting temperature is lower, the maximum dyeing temperature is lower than other fabrics, the holding time can be slightly shorter, and the dye transfer property It's better, and the improvement is better.
*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 fabrics
Ordinary polyester fabrics need to be dyed with disperse dyes under high temperature and high pressure, which consumes a lot of energy and requires a large amount of dye to dye dark colors. To improve the dyeing properties of polyester fiber, introduce groups containing ionic dyes into the molecular chain, or mix dyeable components into the fiber, and develop improvements that can be dyed with disperse dyes under normal pressure, acid dyes and cationic dyes. High-strength polyester has been industrially produced in large quantities.
(3) Polylactic acid fiber (PLA)
This product is also known as biodegradable environmentally friendly fiber. It is made of corn starch and lactic acid (2-hydroxypropionic acid). , polylactic acid is condensed into polylactic acid, and then made into fiber. Its characteristics are that the fabric is light, soft, dry, and has a soft luster like silk. The biggest feature is that after the waste textiles are landfilled, they decompose into CO2 and H2O, and then It becomes corn syrup through photosynthesis and does not bring any pollution to the environment. It can be used to make sportswear, outerwear, underwear, sweaters, carpets and various industrial supplies, and has a wide range of uses. Now that the United States has made carpets and put them on the market, it is also one of the main measures for my country's textile industry to enter the green channel after China's accession to the WTO. As the scale of production expands, production costs will continue to decrease. Disperse dyes are mainly used for dyeing, but the dyeing temperature is lower than polyester fabrics.
(4) Soybean protein fiber
This product is a regenerated plant protein fiber. It is the result of many years of research and spinning success by Puyang Huakang Biochemical Engineering United Group Company in Henan, my country. It is also the only one produced in my country. The first to obtain industrially produced chemical fibers. Soybean meal after oil extraction is soaked, the protein in the soybean meal is separated and purified, and a certain concentration of soybean protein spinning solution is made through the action of biological enzymes. It is wet-spun, coagulated, cross-linked, washed, dried, and curled. , cut into short fibers. It has the following characteristics: fine monofilament fineness (0.9-1.2D), light specific gravity, high strength and elongation, good acid and alkali resistance, good gloss, good hygroscopicity, etc. It also has a soft cashmere-like feel and an elegant silk-like luster. Cotton fiber's moisture absorption and moisture conductivity, wool's warmth retention and other excellent wear properties have broad application prospects.
The textile industry considers it a new fiber for sustainable development. The collected varieties and manufacturers are now listed below:
*Silk/soy protein fiber fabrics (about 40/60): Suzhou Dongwu Silk Weaving Factory, Wujiang Xinmin Textile Company, Wujiang Xinlian Silk Weaving Factory, Zhejiang Huayuan Dachang Silk Factory, Zhejiang Zhanwang Group.
*Wool/soy protein fiber fabric (about 65/35): Changzhou No. 3 Woolen Mill, Jiangsu Sunshine Group, Lanzhou No. 3 Woolen Mill, Jiangyin Sanmao Group, Shanghai Sanmao Group, Wuxi No. 1 Wool Textile Factory, Wuxi Xiexin Wool Textile Factory.
*Soy protein fiber/chemical fiber fabric (about 40/60): Wujiang Xinmin Textile Company, Huayuan Dachang Silk Company, Shaoxing Zhanwang Group.
*Pure soybean fiber fabrics: Qingdao National Cotton Factory No. 6, Luoyang Baima, Shaoxing Zhanwang Group, Zhengzhou No. 1 Cotton, Huayuan Dachang Silk Company, Shaoxing Zhanwang Group.
There are also many knitted products.
Applicable dyes include: weakly acidic, reactive, neutral, direct dyes, etc. However, since the chemical and physical structure of the fiber is different from natural protein fiber, the selection of dyes, dyeing process and use of auxiliaries are all difficult. Adjustments are needed, mainly because its dyeing depth is lower than that of silk, cotton, wool, etc.
(5) Polyurethane fiber (spandex, Lycra)
This product is mainly polyurethane (about 85% or more), which is a block polymer , there are rigid segments and flexible segments. It has become the main material for the production of elastic clothing. Compared with elastic bands, it has a relatively high modulus and good chemical stability. It is used not only in knitted fabrics such as swimwear and socks, but also in various woven products. It has the advantages of anti-wrinkle, shape setting, good drape, and water resistance. Dyeing with disperse dyes at 95°C and adding additives can increase the dye uptake rate, improve level dyeing and improve wet fastness.
2. New regenerated fiber
The new regenerated cellulose fiber is TenceI (or Lyocell) fiber, which is made of wood pulp dissolved in oxidized N-methylmorphine (NMMO). ) hydrate, a 10% viscous spinning liquid is prepared, and the regenerated natural cellulose fiber is obtained through spinning processing. Since NMMO has very little toxicity, the recovery rate is very high, and the production process does not pollute the environment. Its fabrics are Considered as a "green textile", its dry strength is second only to polyester and higher than cotton and viscose fiber. Its wet strength is only reduced by 15-17%. It has excellent wet modulus, very low shrinkage, and radial shrinkage is lower than 2%, exceeding all fibers, its water absorption and water retention are close to those of viscose fiber, and its wearing performance is comfortable. The world's output has exceeded 200,000 tons. It is expected to develop rapidly as a green fiber in this century. Various cellulose dyes can be used for dyeing, and reactive dyes have the best power, especially high-temperature dyes containing two different reactive groups or the same reactive group, such as domestic EF type and KE type reactive dyes.
(3) Textiles must enter the green channel
After my country joined the WTO, textiles entered the development process of world trade liberalization. Although quota restrictions were cancelled, they encountered "green "Barriers", currently there are two main categories in the international clothing field: one is the barriers set up for the environmental impact of textiles and clothing in the entire process from design and production to scrap recycling; the other is the impact of the product itself on the safety and health of consumers barriers. Export products must comply with mandatory laws or technical regulations issued by some national governments or regional international alliances, as well as various specific regulations derived therefrom.
These laws and regulations are also indirect barriers to the development of dyes and must be paid attention to (please refer to the latest version of Oeko-tex Standard 100 in 2002).
(4) Development of dyeing and finishing processes and equipment
The development direction of technology and equipment in the printing and dyeing industry is mainly: adapting to environmental protection, saving raw materials and energy, real-time and small liquor ratio, making printing and dyeing processing more reliable and simpler. This puts forward new requirements for dyes. The main aspects are as follows: 1. After the jet dyeing machine appeared in 1967, the difficulty of polyester dyeing was solved, and it could dye knitted fabrics and fabrics with uneven surfaces. Now there is a new overflow dyeing machine with small liquor ratio (1:4~7), short process, small batch and large capacity, low temperature dyeing, fully automatic control, environmentally friendly dyeing equipment, suitable for dyeing special fabrics .
This requires that the dye's solubility, color loading rate, level dyeing, lifting power and other properties must be superior.
2. In order to reduce the cost of dyeing water and wastewater treatment, the development of dyeing technology for non-aqueous systems has been developed. In recent years, new technologies for dyeing supercritical carbon dioxide non-aqueous systems have been successfully studied and have been developed. The development of new equipment suitable for this process has given this technology practical value. Its principle is: supercritical carbon dioxide is used as the dyeing medium. The dye dissolves as the temperature and pressure of the medium increase, prompting it to diffuse into the interior of the fiber to achieve coloring and fixation. No polluted wastewater is produced at all. Dispersants are not required for disperse dye dyeing. Fluid pressure is used to control dye dissolution. It is easy to control the depth and color. The dye utilization rate can reach 90-100%, and it is easy to obtain uniform dyeing. Since it is a green process, it is extremely A promising processing model has been industrialized in foreign countries and is being vigorously developed in China. Disperse dyes are mainly used, but varieties with suitable solubility in supercritical carbon dioxide must be screened.
3. Digital inkjet printing technology is a plateless printing technology, that is, textiles do not require any screens during the printing process. The computer directly transmits the printing design pattern information to a group of dyes (pigments). ) nozzle, and controls the opening and closing of the nozzle to complete the new technology of fabric printing. The advantages are: it can save a lot of screen plates without causing any embossing or embossing defects; there are no problems with pattern and color registration during printing; proofing and production can be carried out on the same machine without color difference; it is suitable for small batches and multiple varieties. Changeover speeds are extremely fast, allowing for fast delivery. But you need a better CAD system. Currently, dispersed, reactive, and acid dye inkjet inks have been successfully developed for various fabrics.
4. The transfer printing technology for polyester/cotton blended fabrics has been used since the 1960s. However, due to the low dye transfer rate and poor rubbing fastness, it has not been widely used. The newly developed method uses new reactive disperse dyes containing chloroacetyl groups to transfer print the fabric for 40 seconds at 195±5°C. The transfer rate reaches 52.6-70%, and it has good washing fastness and rubbing fastness. It is A promising new printing process.
IV. Conclusion
Since my country’s reform and opening up more than 20 years ago, the dye industry has developed rapidly. There are more than 2,000 large and small production plants, and the annual output has exceeded 400,000. tons, accounting for about 50% of the world's total dye production, and more than 80% is supplied to the textile industry. After joining the WTO, the textile industry will have great development, and the dye industry will also gradually shift from the original development of a single pair of dye production processes and equipment to the development of high-end, high-quality dye products for the printing and dyeing industry. This is a development trend. . According to the information provided by colleagues in the printing and dyeing industry, the development directions of several major types of dyes are summarized as follows for reference;
1. Disperse dyes
The largest usage among all dyes, with domestic output exceeding 200,000 tons, after screening, the varieties suitable for polyester microfiber dyeing are: C.I. Disperse Yellow 54, 64, 60, 64, 163; C.I. Disperse Orange 30, 76; C.I. Disperse Red 73, 82, 131, 146, 152, 153 , 167, 177, 258, 278, 343, 356; C.I.
Dispersed violet 26, 28; C.I. dispersed blue 56, 60, 73, 79, 79:1, 165, 165:1, 183, 257, 270, 284, 295; C.I. dispersed brown 19, etc. Rapid dyeing that saves energy, saves time and has a small liquor ratio is still a development issue. There are many varieties of solvent dyes that are very versatile and have the same structure as disperse dyes, and they can also be considered.
The aforementioned reactive disperse dyes used for transfer printing are basically not produced yet and should be developed as soon as possible.
2. Acid dyes
Acid dyes are mainly used for dyeing and printing of wool, nylon, and silk. They are also an important category of wool and nylon blended products, and are also used for coloring paper and leather. and solvent dyes, organic pigments, etc. It is characterized by many varieties and small dosage, and there are not many varieties produced with large tonnage. In 2000, my country's wool and nylon output were 300,000 tons and 370,000 tons respectively. There are about 120 domestic varieties used in the textile industry. From the perspective of the development of the textile sector, the main ones are weak acid dyes and 1;2 type metal complex dyes. .
3. Reactive dyes
According to the analysis of the printing and dyeing industry, the reason for the rapid growth in the demand for reactive dyes is that the consumption of cotton fiber is still growing significantly, and there are many direct dyes. Varieties have been banned, and the use of vulcanization, reduction, and ice dyes has been reduced; in addition, it has the characteristics of bright color, complete chromatography, easy application, low price, strong adaptability, less pollution, and excellent fastness. There is no accurate statistics on domestic annual output, but it is estimated to be between 20,000 and 30,000 tons.
There are nearly 70 manufacturers.
The following types of reactive dyes have been used in the textile sector,
Model
Reactive group
X
< p> DichlorotriazineK, KM
Monochlorotriazine
KE, KP
Two monochlorotriazines
KD
One or two monochlorotriazines
KN
β-Sulfate ethyl sulfone
< p>M, EF, ME, BMonochlorotriazine/β-sulfate ethyl sulfone
R/CN
Meta-carboxypyridine triazine
E
2,3-Dichloroquinoxaline
F
Trifluorochloropyrimidine
S/SX
Dichlorotriazine
P
Phosphonic acid group
PW
Bromopropylene Amide
The above types of active groups are all available from domestic resources and can be produced if conditions permit. The printing and dyeing industry believes that the most commonly used ones are X type, K type, KM type, KN type, monochlorotriazine plus dichlorotriazine type, monochlorotriazine plus vinyl sulfone type, etc. In order to improve the color fixation rate, the printing and dyeing industry hopes to use varieties with dual active groups or multiple active groups. ME type and B type dyes have high fixation rate, good level dyeing, and are suitable for medium temperature dyeing (60℃). EF type dyes have good compatibility, level dyeing, reproducibility, low dust, exhaustion and lifting power, as well as good wet fastness.