Polyester spin finish is a critical additive system in polyester fiber production. It is applied immediately after filaments are extruded from the spinneret, coating the fiber surface. This process directly impacts fiber formation quality, subsequent processing performance, and the final quality of the textile product.
Polyester spin finish is a functional oil film applied to polyester filaments during spinning, drawing, and winding processes. Typically composed of multiple surfactants, antistatic agents, lubricants, and emulsifiers, its primary functions include lubrication, antistatic properties, uniformity, and hydrophilicity.
1. Lubrication: Reduces friction between filaments and between filaments and guide components, preventing breakage and fuzzy filaments.
2. Antistatic: Polyester is inherently hydrophobic and insulating, prone to static buildup during high-speed winding and friction. The oil effectively suppresses static accumulation, ensuring uniform winding and smooth weaving.
3. Oil uniformity: An even oil film ensures stable fiber sliver consistency, facilitating subsequent processes like drawing, false twisting, weaving, or dyeing.
4. Hydrophilicity enhancement: Improves polyester's water affinity, facilitating dyeing and finishing treatments.
Different types of polyester fibers and processing techniques require tailored spin finish formulations:
1. POY (Pre-Oriented Yarn): Requires superior lubricity and antistatic properties to provide stable conditions for subsequent FDY or DTY processing.
2. FDY (Fully Drawn Yarn): Demands low friction and uniform oil film retention during high-speed spinning.
3. DTY (Draw Textured Yarn): Demands heat and friction resistance during twisting and texturing processes.
When evaluating polyester spin finishes in industrial applications, the following key metrics are typically considered:
1. Coefficient of Friction (COF): Determines the smooth operation of fibers on spinning equipment.
2. Electrical Conductivity / Surface Resistivity: Measures antistatic performance.
3. Thermal Stability: Ensures no decomposition or volatilization during high-speed spinning and thermal processing.
4. Emulsion Stability: Prevents sedimentation or separation during formulation and application processes.
5. Residual Oil Content: Measures the oil agent adhesion on fiber surfaces (typically 0.2–1.0%), requiring strict control based on downstream process requirements.
