Kuivakehräys

Kuivakehräys, also known as dry spinning, is a process used to manufacture synthetic fibers. It involves dissolving a polymer in a volatile solvent and then extruding this solution through a spinneret into a heated chamber. The solvent evaporates in the heated air, leaving behind solid filaments.

The polymer, often cellulose acetate or certain acrylics, is mixed with a suitable solvent to create a viscous liquid called a dope. This dope is then pumped through the spinneret, which has numerous fine holes. As the dope emerges from the spinneret, it is exposed to warm air. The heat causes the solvent to evaporate rapidly.

Once the solvent has evaporated, solid polymer filaments are formed. These filaments are then collected, often by winding them onto a bobbin. The resulting fibers can be further processed, such as by drawing them to increase their strength and orientation, or they can be textured for specific applications.

Kuivakehräys is a versatile method suitable for polymers that can be dissolved in volatile solvents and are stable enough to withstand the drying process. It is commonly used for producing acetate fibers, which find applications in textiles, cigarette filters, and industrial materials. The process allows for good control over fiber properties, making it a valuable technique in synthetic fiber production.