Quantifying Physical Degradation Limits in Synthetic Elastomeric Knits
Thermal setting over 190°C and jet nozzle pressures above 0.30 MPa degrade polyurethane cores, causing permanent set and elasticity loss in synthetic knits.
Polyurethane
Versatile Polymer
Synthetic material composed of organic units joined by carbamate links that can be engineered to be either rigid or highly flexible. In the textile industry, polyurethane is frequently used as a coating for weatherproofing or as the base for elastane fibres. It provides a durable barrier against wind and water while maintaining the ability to stretch and recover.
Coating Application
Fabric finishers apply a thin layer of the liquid resin to a base cloth through a knife-over-roll or transfer coating process. This application of polyurethane creates a smooth surface that can be embossed with textures to mimic leather or left matte for technical apparel. The resin cures through a chemical reaction or the evaporation of a carrier solvent to form a continuous film.
Breathable versions contain microscopic pores that allow water vapour to escape while blocking liquid droplets. Protective qualities are enhanced by cross-linking the polymer chains during the curing stage.
Stretch Performance
Elasticity is the primary reason for including this polymer in knitted fabrics. Higher percentages of the substance allow for greater recovery after the garment is stretched during use.
Environmental Degradation
Exposure to ultraviolet light or high heat can break the chemical bonds in the material. Polyurethane may yellow or become tacky over time if it is not treated with stabilizers.