Summary of Jiayuan's participation in the 24th China International Dye Industry, Organic Pigments and Textile Chemicals Exhibition
1. Basic information of the exhibition
Exhibition name: The 24th China International Dye Industry, Organic Pigments and Textile Chemicals Exhibition
Time: April 16-18, 2025
Location: Shanghai World Expo Exhibition & Convention Center
Scale: Exhibitors from more than 30 countries/regions around the world, over 800 companies, and more than 30,000 professional visitors.
Theme: "Green Technology Drives the Future of Textiles"
2. Introduction to the company's product applications
Application and technical analysis of aniline black in dye industry.
Aniline Black, also known as aniline oxide black, is a high-molecular black dye produced by oxidative polymerization of aniline. It is widely used in dyeing textiles, leather, paper and other fields. Its unique dark effect, high color fastness and weather resistance make it occupy an important position in specific industrial scenarios. The following is a detailed description of the technical principles, application fields, advantages and disadvantages, and development trends :
1. Preparation principle of aniline black
Chemical synthesis route
Aniline black is produced by the oxidation polymerization of aniline in an acidic medium (such as hydrochloric acid or sulfuric acid) catalyzed by a strong oxidant (such as potassium dichromate, sodium chlorate). The reaction process is divided into three stages:
Aniline oxidation: Aniline molecules are oxidized to aniline radicals;
Free radical polymerization: free radicals combine to form linear or cross-linked polyaniline chains;
Final color development: The polymer is further oxidized to generate a black product with a conjugated structure.
In-situ dyeing process
In the textile industry, aniline black is often dyed in situ using the "pad-oxidation" method:
The fibers (such as cotton and linen) are first immersed in a solution containing aniline, an oxidant, and a catalyst;
After high-temperature steaming or acid treatment, aniline polymerizes on the fiber surface to form an insoluble black deposit.
This process can achieve uniform coloring inside and outside the fiber and improve color fastness.
2. Application fields and characteristics
Main application scenarios
Textile dyeing:
Cellulose fiber (cotton, linen, viscose): Aniline black has a high affinity for cotton fibers and is often used in black denim, military uniforms, tents and other products that require high color fastness;
Blended fabrics: Through process optimization, it can be applied to polyester-cotton and polyester-linen blended materials.
Leather industry: Used for dyeing black leather products such as leather shoes and bags, with excellent friction resistance.
Paper and ink: Black colorant for special papers (such as waterproof packaging paper) and printing inks.
Performance Advantages
High color fastness: resistant to washing (4-5 levels), sunlight (6-7 levels), sweat and friction, far exceeding ordinary direct dyes;
Dark effect: can dye pure black, and not easy to be red or green;
Environmental compatibility: does not contain azo groups (non-banned dyes), and complies with EU REACH, OEKO-TEX and other standards.
3. Technical limitations and improvement directions
Existing issues
Complex process: The concentration of oxidant, pH value and temperature need to be strictly controlled, otherwise it will easily lead to color difference or fiber damage;
Environmental controversy: The traditional process uses dichromate (Cr⁶⁺) as an oxidant, which poses a risk of heavy metal pollution;
Higher cost: Aniline raw materials and oxidation process consume more energy than alternative dyes such as sulphur black.
Technology upgrade direction
Green oxidant replacement: using chromium-free oxidation systems such as persulfate and hydrogen peroxide to reduce wastewater toxicity;
Nanocatalytic technology: introducing metal oxide nanoparticles (such as TiO₂, Fe₃O₄) to improve oxidation efficiency and reduce reaction temperature;
Bio-based aniline: Aniline is produced by biological fermentation to reduce dependence on petroleum-based raw materials.
4. Market status and comparison with alternatives
Market position of aniline black
It is still irreplaceable in high-end black textiles (such as military and outdoor equipment), with an annual global demand of about 50,000 to 80,000 tons;
China is the main producer and Jiayuan has sufficient inventory .
Comparison with Sulphur Black
| characteristic | Aniline Black | Sulfur Black |
| Color fastness | High (wash and sun fast) | Medium (easy to fade) |
| Environmental protection | No sulfur, no heavy metals (after improved process) | Sulfide-containing (complex wastewater treatment) |
| cost | Higher | Low |
| Application Scenario | High-end clothing, special materials | Ordinary workwear, low-end fabrics |
5. Future development trends
Green transformation driven by policies
The EU's "Zero Pollution Action Plan" and China's "Dual Carbon" goals promote the popularization of chromium-free oxidation technology;
The research and development of biodegradable aniline black is accelerated to meet the needs of the circular economy.
Functional expansion
Develop high-end applications such as conductive aniline black (used in antistatic fabrics) and photothermal conversion coatings (military camouflage materials).
6. Summary
Aniline black is still competitive in certain industrial fields due to its irreplaceable dark color effect and high fastness. In the future, it needs to increase its added value through greening of processes and diversification of functions, while forming differentiated competition with alternatives such as sulphur black and reactive black to consolidate its position in the high-end market.
3. Industry Trends
Industry Trend Observation
Environmental compliance is accelerating: more than 80% of exhibitors focus on "low-carbon" and "non-toxic" labels, and the EU carbon tariff (CBAM) forces companies to upgrade their technology.
Digital printing explosion: Equipment manufacturers and dye companies jointly launched a "one-stop digital solution", and the demand for small orders and quick response increased sharply.
Cross-border technology integration: Emerging fields such as nano-coating dyes (UV/waterproof) and intelligent temperature-sensitive color-changing materials are attracting attention.