The technical requirements for master rolls primarily cover raw materials, dimensions and specifications, physical properties, and appearance quality. As a crucial raw material for subsequent slitting and processing, the master roll must exhibit stable performance and good processability to ensure the finished film meets packaging requirements.
Raw Materials
Master rolls are typically produced using linear low-density polyethylene (LLDPE) as the primary material. High purity and stable performance are required, along with the appropriate addition of functional additives-such as tackifiers and antistatic agents-based on the intended application. Raw material quality directly impacts the master roll's tensile properties, toughness, self-adhesion, and service life; therefore, formulation ratios and processing conditions must be strictly controlled during production.
Dimensions and Specifications
Master rolls must meet customer or production equipment specifications, including parameters such as film width, thickness, roll diameter, length, weight, and paper core dimensions. Film thickness must remain uniform, without significant variations. The roll must be wound evenly and tightly with neat end faces, free from loose winding, telescoping, or wrinkles, to ensure stability during subsequent slitting.
Performance Requirements
Master rolls should exhibit high tensile strength, elongation at break, tear resistance, and elastic recovery. The film must retain good toughness after stretching without easily rupturing, while also maintaining stable self-adhesion to ensure the processed stretch film can effectively wrap and secure loads. Additionally, properties such as temperature resistance, moisture resistance, and aging resistance should be tested based on the intended operating environment.
Appearance Quality
The surface of the master roll must be smooth and clean, free from defects such as air bubbles, impurities, damage, or significant color variations. Winding tension must be uniform to prevent issues like edge curling, wrinkling, or interlayer adhesion. Strict adherence to these technical requirements ensures the stability of the master roll during transport, storage, and processing, ultimately enhancing the quality and production efficiency of the finished stretch film.