Raw Material Mixing
Polypropylene (PP) granules are thoroughly mixed with precisely measured additives according to performance requirements (e.g., gloss, stiffness, heat seal-ability)
Melting & Extrusion
The mixture is heated, melted, homogenized, and filtered to remove impurities via a twin-screw extruder, then stably output by a gear pump.
Casting
The melt is extruded through a wide-slit die and rapidly cooled by adhering to a high-speed rotating cold roller to form a thick sheet.
Longitudinal Stretching (MD)
The preheated and softened thick sheet is uniaxially stretched using a set of rollers with progressively increasing speeds, followed by immediate cooling to set the orientation.
Transverse Stretching (TD)
The film is placed in a tenter frame where its edges are gripped by clips. It is heated by hot air, stretched transversely, heat-set to stabilize the molecular structure, and then cooled.
Surface Treatment and Winding
The film undergoes corona treatment to increase its surface tension (improving printability /laminating), is monitored by online thickness gauges, and finally wound into larger jumbo rolls.
Slitting
The wide jumbo roll is slit into rolls of specific widths according to customers’ orders, ensuring clean-cut edges.
