Fluorescent Whitening Agent NFW

Fluorescent Whitening Agent NFW/NFW-L is a versatile brightening agent primarily used in the textile industry. It appears as a yellow-green powder with an anionic ionicity and is chemically structured as a stilbene derivative. With a slightly violet shade, it closely resembles products like Uvitex NFW from Huntsman.

Key Features of Fluorescent Whitening Agent NFW/NFW-L

1. High Affinity for Specific Fibers  
   - Fluorescent Whitening Agent NFW/NFW-L has a low affinity for cellulose fibers like cotton but exhibits a strong affinity for wool and nylon fibers. This makes it highly effective for fabrics composed of these materials.
   
2. High Fluorescence Intensity  
   - The product offers bright whiteness with a slightly purple hue, enhancing the overall appearance of treated fabrics. The high fluorescence intensity ensures that the fabrics maintain their brightness over time.
   
3. Excellent Stability Across the pH Range  
   - Fluorescent Whitening Agent NFW/NFW-L is stable across a broad pH range from 2 to 12, making it adaptable for various dyeing processes. It retains its efficacy even under acidic or alkaline conditions, ensuring consistent results.
   
4. Compatibility with Bleaching Agents  
   - The product is stable when used with sodium hydroxide and hydrogen peroxide, commonly used in textile processing. However, it is less stable when exposed to sodium chlorite and sodium hypochlorite, which may impact its performance.

Applications of Fluorescent Whitening Agent NFW/NFW-L

1. Nylon and Cotton Fabrics  
   - Fluorescent Whitening Agent NFW/NFW-L is suitable for both dip dyeing and continuous pad dyeing processes, especially for nylon and cotton fabrics. Despite its low affinity for cellulose fibers, it can still be effectively used in cotton fabrics when combined with nylon.

2. Wool and Silk Fabrics  
   - The agent is also highly effective in treating wool and silk fabrics, where its high affinity enhances the whitening effect. This application is particularly beneficial in achieving bright and vibrant colors in luxury textiles.

3. Versatile Use in Textile Dyeing  
   - The product's adaptability across various textile materials makes it an ideal choice for manufacturers looking to enhance the brightness and whiteness of their products. Its application is broad, extending to numerous textile types and dyeing methods.

Usage Method for Fluorescent Whitening Agent NFW/NFW-L

1. Nylon and Cotton Treatment  
   - After the reduction bleach process, Fluorescent Whitening Agent NFW/NFW-L should be used at a dosage of 0.1-0.5% based on the weight of the fabric (o.w.f). Sodium sulfate is added at 2-5g/L with a liquor rate of 1:10-20. The treatment should be conducted at a temperature range of 80-100°C for 30-60 minutes.

2. Wool and Silk Treatment  
   - For wool and silk, the agent should be applied after peroxide and reduction bleach processes. The recommended dosage is 0.1-0.3% o.w.f, with the pH adjusted to 4-6 using acetic acid. The liquor rate remains the same at 1:10-20, with the temperature set between 60-100°C for 20-60 minutes.

Precautions When Using Fluorescent Whitening Agent NFW/NFW-L

1. Temperature and Electrolyte Sensitivity  
   - The product’s affinity is closely related to temperature and electrolyte content in the dye bath. Careful control of these parameters is essential to achieve good whitening results.

2. Limited Use of Cellulose Fibers  
   - While Fluorescent Whitening Agent NFW/NFW-L is highly effective on wool, silk, and nylon, its use on cellulose fibers like cotton is more limited. Manufacturers should consider this when planning their dyeing processes.

3. Water Solubility  
   - The agent has good water solubility and can be fully dissolved with a small amount of warm water, making it easy to handle during preparation and application.

4. Compatibility with Acid Dyes  
   - When adjusting the shade of the fabric, it is advisable to use acid dyes alongside Fluorescent Whitening Agent NFW/NFW-L to achieve the desired color intensity and brightness.

5. High-Temperature Washing  
   - If the processed fabric requires high-temperature washing, adding electrolytes to the washing process is recommended to maintain the whiteness and brightness imparted by the whitening agent.

6. Sodium Chlorite Bleaching  
   - Sodium chlorite bleaching can remove Fluorescent Whitening Agent NFW/NFW-L from both cellulose and nylon fabrics, which may be necessary in certain post-processing stages.