Reaktioväriaineisiin

Reaktioväriaineisiin, known in English as reactive dyes, are a class of synthetic organic compounds used for dyeing textiles, particularly cellulosic fibers like cotton, linen, and rayon. Their key characteristic is their ability to form a covalent bond with the fiber molecule during the dyeing process. This chemical reaction creates a very strong and wash-fast bond, making reactive dyes highly desirable for vibrant and durable coloration.

The dyeing mechanism involves a chromophore (the color-bearing part of the molecule) attached to a reactive group. Common reactive groups include vinyl sulfone, monochlorotriazine, and dichlorotriazine. Under alkaline conditions, typically achieved by adding sodium carbonate or sodium hydroxide, the hydroxyl groups in the cellulose fiber become activated. The reactive group on the dye molecule then attacks these activated sites, forming a stable covalent linkage. This process is distinct from other dye classes that rely on physical adsorption or weaker chemical interactions.

Reactive dyes offer a wide spectrum of brilliant colors and can be applied using various methods, including exhaust dyeing, padding, and printing. Their good lightfastness and washfastness are significant advantages. However, they can also be susceptible to hydrolysis, where the reactive group reacts with water instead of the fiber, leading to reduced dye uptake and potential environmental concerns if not managed properly. The development of reactive dyes has revolutionized textile dyeing, providing both aesthetic appeal and functional durability to fabrics.