To effectively bleach cotton yarn, heat it in a bleaching solution at a high temperature range of 90°C to 100°C for 1 to 1.5 hours. This high-temperature process is crucial for achieving the desired results.
Following the bleaching phase, the yarn requires specific post-treatment steps to ensure quality and prepare it for further processing. First, perform a hot rinse to remove residual bleaching chemicals. Then, neutralize the yarn with acetic acid. This neutralization step helps stabilize the pH and stop the bleaching action.
Why Bleach Cotton Yarn?
The purpose of bleaching cotton yarn serves two primary functions, as indicated by industry practices:
- Improving Whiteness and Cleanliness: Bleaching is essential to produce a yarn that is trash-free and exhibits a good white color. This removes natural impurities, seed fragments, and other trash that can affect the yarn's appearance.
- Preparing for Dyeing: A properly bleached yarn is also critical for preparing it for dyeing, particularly for achieving vibrant results with light colors and bright colors. A clean, white base ensures that the dye colors appear true and brilliant without being dulled by natural yarn color or impurities.
Key Bleaching Parameters
Based on the provided reference, here are the key parameters for bleaching cotton yarn:
| Parameter | Specification |
|---|---|
| Temperature | 90°C - 100°C |
| Duration | 1 hour - 1.5 hours |
| Post-Treatment | Hot rinse, Neutralize with acetic acid |
By following these steps, cotton yarn can be effectively bleached to improve its appearance and prepare it for subsequent dyeing processes.
