Which material is used for blown film extrusion?
Polyethylenes such as LDPE, LLDPE and HDPE polymers are common resins that are used to create blown films. The most common product created by blown films is disposable grocery bags and other types of food and consumer packaging. Other types of film include greenhouse films and shrink wrap films.
What is plastic film extrusion?
In its simplest form, the process involves pushing molten polymer through a circular or slot die. This continuous process enables the production of a consistent high quality product to extremely accurate gauge. For most thin gauge films, the film extrusion process takes the form of blown or cast extrusion.
How does film extrusion work?
The Process Plastic melt is extruded through an annular slit die, usually vertically, to form a thin walled tube. Air is introduced via a hole in the centre of the die to blow up the tube like a balloon. Mounted on top of the die, a high-speed air ring blows onto the hot film to cool it.
What is cast film extrusion?
admin 1 | Jan 01, 2006. Production of cast film is a continuous process where a thermoplastic material is extruded from a slot die onto a chill roll, quenched, and wound. The resulting film has machine direction orientation compared to a somewhat limited bidirectional orientation achieved in blown film processing.
What are the types of plastic extrusion?
What are the Different Types of Plastic Extrusion?
- Tubing Extrusion. This extrusion type is used for the extrusion of tubes and pipes.
- Blow Film Extrusion. This type is used for the production of plastic films tubes through a continuous sheeting.
- Sheet Film Extrusion.
- Over Jacket Extrusion.
How is polythene film made?
This plastic film manufacturing process starts with melting down small plastic pellets, ( called resin ), until they become molten and pliable. The molten plastic is pushed, ( extruded ), through a circular die to form a continuous tube of plastic called the bubble.
What is the difference between cast and blown film?
Cast film is minimally pre-stretched compared with blown film giving it improved depth of drawing for thermoforming operations. The cooling process can be used to produce different characteristics in the final product. Cast film can be thinned by winding the film out of the roller faster than it is extruded.
Where is cast film used?
Cast films are used for food and textiles packaging, flower wrapping, as photo album page protectors, as coating substrates in extrusion coating processes or laminated to other materials in the formation of more complex films, among others.
What does PP stand for in plastic?
Polypropylene (PP) is one of the most commonly used thermoplastics in the world. Polypropylene uses range from plastic packaging, plastic parts for machinery and equipment and even fibres and textiles.
Which is better LDPE or HDPE?
LDPE’s long- and short-chain branches keep the material from packing tightly in its crystalline form. This gives it less tensile strength than HDPE, but greater ductility….In a nutshell: the chemistry of LDPE and HDPE.
| LDPE | HDPE |
|---|---|
| Good abrasion resistance | Excellent abrasion resistance |
| Lightweight | Lightweight |