Greige Fabric Certification Scope and Restricted Chemical Testing Protocols
Greige fabric certification demands batch testing of sizing agents, spin finishes, and biocide residues before finishing treatments mask regulated chemicals.
Sizing Agents
Protective Film Formulation
Polymeric film-forming substances applied to warp yarns before weaving increase tensile strength and smooth surface hairiness to withstand loom shedding stresses. Spun cotton yarns and synthetic staple blends require sizing agents to bind loose surface fibers to the core yarn structure. Modified starches and polyvinyl alcohol form cohesive protective coatings that prevent yarn breakages during high-speed air-jet weaving.
Proper application balances yarn flexibility against stiffness to maintain high loom weaving efficiency.
Abrasion Reduction
Repeated friction between warp ends, drop wires, and reed dents causes yarn fraying and premature shedding on high-speed weaving machines. Applying sizing agents encapsulates protruding fiber ends, reducing frictional drag during shed opening cycles. Film flexibility allows warp yarns to flex continuously over back-rest rollers without flaking off dust particles that clog electronic loom sensors.
Desizing Evaluation
Quantitative size pickup measurements calculate added polymer weight relative to dry yarn mass before warp beam winding. Iodine staining tests evaluate starch distribution uniformity across warp ends, while hot water wash-off trials verify complete size removal prior to dyeing operations.
Chemical Boundary
Excessive size add-on creates brittle warp yarns that snap under cyclic weaving tension, while under-sizing causes severe fiber entanglement. Incomplete size removal during wet pretreatment blocks dye liquor penetration, causing blotchy fabric color.