Link to original video by Textile Vlog

Knit Fabric Dyeing and Finishing Process - A to Z Explanation

Outline Video Knit Fabric Dyeing and Finishing Process - A to Z Explanation

Short Summary:

This video details the complete dyeing and finishing process of cotton knit fabric, from raw grey fabric to a finished product. Key processes include pre-treatment (demineralization, scouring, bleaching, bio-polishing), dyeing (using reactive dyes, with careful control of temperature, chemicals, and pH), and finishing (dewatering, slitting, stentering, compacting). Specific machinery like winch dyeing machines and stenter machines are highlighted. The overall implication is to demonstrate the complex and precise steps required to produce high-quality, consistent, and comfortable knit fabrics. The video also specifically details the open-line finishing process.

Detailed Summary:

The video can be broken down into the following sections:

  1. Introduction: The video introduces the process of dyeing knit fabric in a factory setting, using a winch dyeing machine capable of processing approximately one ton of fabric at a time. The goal is to explain the entire process, from raw grey fabric to the finished product.

  2. Pre-treatment: This stage prepares the fabric for dyeing. It involves:

    • Demineralization: Removing mineral ions (calcium, magnesium) to improve dye consistency and quality.
    • Scouring and Bleaching: Removing impurities, waxes, oils, and natural color to create a clean surface for dye absorption. The process involves specific temperatures (40°C, 60°C, 70°C, 98°C), chemicals (detergent, wrinkle reducing agent, cleaner, CTIC soda, hydrogen peroxide), and time intervals (7 minutes, 1 hour). Fabric absorbency and brightness are checked after bleaching.
    • Bio-polishing (Enzymatic Singing): Using cellulase enzymes to remove protruding fibers and improve fabric smoothness, reducing pilling. This is followed by a wash cycle with acetic acid neutralization and peroxide killer. The pH is checked and adjusted to 6-6.5 for optimal dyeing.

  3. Dyeing: This section focuses on the dyeing process itself using reactive dyes (with mention of direct and vat dyes as alternatives). A leveling agent is used to ensure even dye distribution. The process involves precise addition of salts, dyes, and soda ash, along with meticulous temperature control (reaching 60°C). Samples are checked at various stages to ensure even color uptake.

  4. After-treatment: This stage enhances color fastness and fabric softness. It involves soaping to remove unfixed dyes, using fixing agents to improve color fastness, and applying softeners to enhance the feel of the fabric.

  5. Finishing (Open Line Process): This section details the finishing process, specifically the open-line method.

    • Dewatering and Slitting: Excess water is removed, and the tubular fabric is slit open using a slitting machine. This process aims to deliver the fabric in an uncreased, tension-free state.
    • Stentering: The fabric is passed through a stenter machine for heat setting, drying, and chemical treatments. This step addresses stretching or shrinking issues and maintains the GSM (grams per square meter) of the fabric.
    • Compacting: The final finishing step, compacting increases fabric density and thickness, reduces length, and improves texture and hand feel.

The video consistently emphasizes the importance of precise control over temperature, chemicals, and timing in each stage of the process to achieve high-quality results. No specific quotes are highlighted, but the overall message is a detailed, step-by-step explanation of the complex manufacturing process.