Shrink Films
Films which have gone through an orientation step in manufacturing process, which shrink significantly with application of heat.
Singlewound Film
A term used to describe a single layer of film wound around a core. It is generally used on automatic form-fill-seal equipment.
Centerfold Film
This is a film that has been folded in half lengthwise and wound around a core. Centerfold Film is usually used on slower, semi-automatic and manual packaging equipment which inserts the product between the folded film and then heat seals the remaining 3 edges.
Natural Centerfold (In-Line)
An extrusion line used to produce the centerfilded film which slits the tubular film before it is wound to core.
Mechanical Centerfold
The process by which single-wound or flat film is mechanically folded for use on L-Bar Sealers.
Core
A paper tube on which film is wound. Cores are furnished in 3" and 6" inside diameters; 3" is standard. Cryovac uses 0.660 wall cores that weighs 0.2 lbs. per inch.
Gauge
A term used to describe the thickness of film. One mil is equivalent to 1/1000 of an inch. 50- gauge film is 1/2 mil thich, 100-gauge is 1 mil thick.
Wind
The direction that centerfolded film is wound on a core. Cryovac centerfold film can unwind either from top or bottom of the roll when viewed horizontally from the open side.
Monolayer Film
A single layer film extruded from one or a blend of several raw materials (Resins)
Multilayer Film
A film formed with multiple layers of similar or differing polymers. The purpose is to obtain specific properties and characteristics.
Film Types
- Polyethylene
A simple thermoplastic polymer of ethylene. Each molecule consists of hundreds / thousands of carbon atoms. The length molecules and the amount of side branchig determine the characteristics of the film, i.e. LDPE, LLDPE, HDPE, etc.
- Polypropylene
A thermoplastic polymer of propylene. Polypropylene materials are generally oriented, heat-set (OPP) materials which do not shrink.
- Polyolefin
A generic term used to describe ethylene and / or propylene-based films.
- PVC (Polyvinyl Chloride)
A thermoplastic material composed of polymers of vinyl chloride; a colorless solid with outstanding resistance to water, alcohols and concentrated acids and alkalis. Compounded with plasticizers, PVC yields flexible film widely used in the manufacture of clothing and packaging films.
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