extrusion cast film

1. Characteristics of extrusion casting method

The extrusion casting method is to add the material to the extruder, under the action of a certain temperature and pressure, knead and plasticize it into a melt; the molten material passes through the T-shaped die, and casts down to the surface of the cooling roller, cooling the finalized film , after traction, trimming into a sheet-like film, and then take up a film roll by a winding device.

The plastics used to produce films by extrusion casting mainly include polyethylene, polypropylene, polyamide, ethylene acetate, and ethylene copolymers.

Compared with the extrusion blown film method, the extrusion casting method has the following characteristics

1) The film has high transparency (low haze), good gloss, softness and good hand feeling

2) The thickness deviation is small, especially suitable for printing, dry compounding, automatic packaging and other processing operations

3) Sufficient film cooling and high production line speed;

4) It is not easy to produce adhesive defects of cylindrical films, suitable for the production of low-density, self-adhesive sheet films

5) The width of the film is limited by the equipment, generally 1-4m;

6) If the film is not biaxially stretched, its longitudinal and transverse mechanical properties are not as balanced as extrusion blown film

7) The price of production equipment is relatively high.

The extrusion casting method is not only used to produce single-layer films, but also to produce multi-layer co-extruded composite films. Single-layer or multi-layer films that are extruded and cast can also be stretched in one direction (longitudinal or transverse) or biaxially stretched (step by step).

Directional stretching or multi-stage simultaneous biaxial stretching) to produce stretch oriented films.

The production equipment for extruding cast film generally includes extruder, T-shaped die, air knife, cooling roll, traction roll, edge trimming and waste film recovery device, coiling device, etc.

2. Common films and applications of extrusion casting method

1) Extrusion cast polypropylene film (CPP)

PP antistatic film: electrostatic dispersion packaging film and bag;

Retort film: resistant to 100-120 ℃ retort bacteria packaging composite film substrate;

High-temperature cooking film: Composite film base material resistant to high-temperature cooking and sterilization packaging above 140°C;

Composite substrate film: Composite film substrate for extrusion lamination and dry lamination;

Vacuum aluminized film: base material of vacuum aluminized film;

Matting film: food packaging bags.

2) Extrusion cast polyamide film (CPA6)

PA antistatic film: electrostatic dispersion packaging film and bag;

Meat product packaging film: composite film base material for high temperature cooking and freezing packaging;

Composite substrate film: Composite film substrate for dry lamination.

3) Extrusion cast polyethylene film (CPE)

PE antistatic film: electrostatic dispersion packaging film and bag;

Medical material film: film base for ointment, medical insurance products (gloves, shoe covers, etc.);

Composite substrate film: Composite film substrate for extrusion lamination and dry lamination;

Packaging film: film for automatic mechanical packaging;

Stretch film: food preservation film, stretch film.