Shrink Film Terminology
Do You Know the Shrink Film Terminology Used By Packaging Professionals?
Angel Hair
Thin strands of shrink film appearing at the cut end of film resulting from the heat sealing.
Ballooning
A pillow effect created when air is trapped within the shrinking bag and cannot escape.
Bead Seal
A thin round weld created when pressure and heat are applied to two layers of film.
Bi-Axial Orientation
Molecules Oriented along both X and Y-axis of the film web.
Blocking
A condition in which two layers of like film adhere to one another.
Blown Film
A film extruded by air inflation. Ex: blown stretch film such as: blown hand stretch film
Burn Through
A temperature or condition where a film becomes cloudy or burns in the shrink tunnel.
Centerfold Film
A film that has been folded in half, lengthwise.
Centerfolder
A mechanical device used to create centerfolded film.
Coextrusion
Two or more polymers extruded and combined in a die, each forming a distinct layer in the final film.
Cold Sli
The amount of force required to slide two surfaces against one another at ambient temperature.
Cold Flex (CF)
Ability of a film to perform at low temperatures without failure.
Copolymer
Result of two monomers being combined through polymerization.
Core
A paper tube on which film is wound.
Cross-Linking
A process which binds the polymer chains into a network. Significantly increasing a films heat stability and strength.
Crow’s Feet
A series of wrinkles radiating out from a finished package’s corners.
Dog-Ears
Triangular projections of unshrunk film at the corners of finished packages.
Drape
The softness of a film characterized by the ability to conform to irregular shapes.
Electron Beam
A device used in the cross-linking process.
Fish Eyes
A scalloped surface on a finished product surface.
Form-Fill-Seal
A type of shrink wrap equipment which produces a tube of film into which packages are introduced.
Gauge
A term used to describe the thickness of a material such as shrink film / shrink wrap or stretch film / stretch wrap or pallet wrap ex: 100 gauge shrink film, 60 gauge stretch film, 70 gauge pallet wrap.
Hole Punch
A mechanical device used to produce an air evacuation hole.
Hot Slip
The amount of force required to side two surfaces of heated film against on another.
Impulse Seal
A heat sealing technique where the element is pulsed with voltage during the sealing cycle.
L-Sealer
A term used to describe equipment where the seal area is in the shape of a “L”.
Laminate
A general term used to describe structures comprised of two or more materials.
Lap Seal
A seal made with two layers of film overlapping one another.
Machinability
The ability to form and seal on overwrapping equipment.
Machine Direction (MD)
The direction the film is manufactured and moves through the sealing equipment.
Memory
The ability of a film to maintain its characteristics after shrinking.
Monoaxial
A film which is oriented to shrink in only one direction.
Monolayer Film
A single layer film extruded from one or a blend of raw materials.
Mutilayer Film
A film comprised of more than one layer of similar or different polymers.
Opaque
Relatively impervious to light. Ex: opaque white stretch film, opaque black stretch film (stretch wrap)
Optics
The visual properties of a film. Examples of shrink film products with good optics include: Exlfilm HSP shrink film – a superior optic shrink film, Exlfilmplus LTF Shrink Film – shrink film has excellent optics & strength, LTG Shrink Film – a light gauge polyolefin shrink film with excellent clarity, gloss and tear resistance and Exlvalue Anti Fog Shrink Film (AF Shrink Film) – a anti fog shrink film providing clear presentation in refrigerator and freezer applications.
Orientation
The stretching technique used in the manufacturing of film.
Oriented
The stretching and aligning of a film’s molecules at a temperature below its melting point.
Perforations
Air evacuation holes in a film made by pin perforators.
Pin Perforators
A device used to produce small holes in film to allow air to escape during the shrinking process.
Polyethylene
A simple thermoplastic polymer of ethylene.
Polymer
A material made through the process of polymerization.
Polymerization
A gas heated under pressure forms a solid.
Polyolefin
A generic term used to describe ethylene and/or propylene based plastics. Also see polyolefin shrink film and shrink film packaging products
Polypropylene
A thermoplastic polymer of propylene.
Preferential Shrink
The characteristics of a film to shrink more or less in a specific direction.
PVC
Polyvinyl Chloride. Also a type of shrink film.
Seal Wire
An element made from nichrome wire used to seal film.
Selvage
Another term for trim waste.
Shrink
Defined as the ability to become smaller.
Shrink Tunnel
A type of equipment featuring a chamber producing heat and airflow designed to shrink film.
Singlewound Film (SW)
A single layer of shrink film wrapped around a core.
Slip
The quality of a film to move over surfaces with little resistance.
Static
An electrical charge built-up in plastic film.
Static Sea
A type of longitudinal seal used in FFS equipment. Overlapping film edges are adhered to one another via a static charge.
Tap Switch
An electrical device used to control the amount of voltage introduced to sealing elements.
Tear Initiation
The amount of force required to initiate a tear.
Tear Resistance
The ability of a film to resist the propagation of a tear.
Transverse Direction (TD)
The direction parallel to the film width.
Trim
The amount of excess film severed during the sealing process.
Trim Seal
A seal made by using a sealing wire element.
Unbalanced
Unequal orientation in the LD and TD.
Wind
The direction in which the film or shrink film is wound on the core.
