HT/HP Dyeing Process and Equipment
topic
HT/HP dyeing of polyester at 130°C in pressurised jet dyeing machines (autoclave, pressure 2–3 bar). Liquor ratio 1:5–1:10. Temperature profile: ramp 2–3°C/min (critical through 80–100°C to prevent unlevel strike), hold 30–60 min at 130°C, cool 1–2°C/min (prevent crease-setting). pH 4.5–5.5 (acetic acid) improves dye dispersibility. Machine types: jet dyeing, beam dyeing, jigger (fabric); package dyeing (yarn).
Role
HT/HP dyeing process engineering is the dominant industrial polyester dyeing route. Understanding temperature profiles, machine hydrodynamics, and process control is essential for achieving level, reproducible dyeing — the primary goal of industrial textile dyeing.