Reaktiiviväreillä

Reaktiiviväreillä, also known as reactive dyes, are a class of dyes that form a covalent bond with the substrate they are applied to. This chemical bond is what gives reactive dyes their excellent wash fastness properties, making them highly resistant to fading or bleeding during washing. They are primarily used for dyeing cellulosic fibers such as cotton, linen, and rayon, but can also be used for wool and silk under specific conditions.

The dyeing process with reactive dyes typically involves an alkaline medium, which activates the fiber and the dye molecule. The dye then reacts with hydroxyl groups in cellulose or amino groups in protein fibers, creating a permanent link. This reaction is often facilitated by heat and time, with different dye types and brands having specific recommended temperature and duration guidelines.

There are several classes of reactive dyes, including monochlorotriazine (MCT), dichlorotriazine (DCT), vinyl sulfone (VS), and mixtures of these. Each class has different reactivity and application characteristics. For instance, MCT dyes are known for their good build-up and moderate reactivity, while VS dyes are generally more reactive and can be applied at lower temperatures.

The advantages of using reactive dyes include their bright shades, excellent all-around fastness properties, and versatility in application methods, such as exhaustion dyeing, padding, and printing. However, they can also be prone to hydrolysis, where the dye reacts with water instead of the fiber, leading to reduced dye uptake and potential color yield loss. Careful control of pH, temperature, and time is crucial for successful reactive dyeing.