Co-extrusion

Fabrication of a multi-layer film by pumping the various materials through separate extruders and then merging the extrudates into a common die assembly.

• D

Dart Drop

A method of measuring a film’s impact strength or dynamic toughness. A hemispherical shaped, weighted "dart" is dropped onto a film sample.

Die

A device used in extrusion processes to shape the extrudate. We use circular dies for blown products and slot dies for cast products.

• E

Elastic Recovery

The ability of a material to return to its original shapes or sizes after having been deformed or subjected to strain.

Extrusion

The process of feeding, melting, and pumping a material such that a desired shape or configuration can be created. It is a continuous process and utilizes a device similar to a meat grinder.

• G

Gauge

Used as a synonym for film thickness or film caliper. Sometimes expressed as 80 gauge or 100 gauge.

Gauge Band

A conformation irregularity found in rolls of material. A thick area in a film will produce a raised or elevated ring in a finished roll of product. Conversely, a thin area will result in a soft ring in a finished roll.

Gloss

The shine or "sparkle" of a surface. In LDPE film, it is described as the amount of light reflected from the surface.

• H

Hand Film

Stretch film designed for hand application.

• L

LDPE

Low Density Polyethylene

LLDPE

Linear Low Density Polyethylene

• M

Machine Direction

Perpendicular to film web width

Machine Films

Stretch film designed for stretch film equipment.

Metallocene

Newly developed polyethylene resins produced using "Metallocene" catalyst. It allows the resin manufacturer to custom tailor properties. Compared to other linear low density resins, Metallocene resin stretch film .can achieve greater puncture resistance and greater clarity.

Micron

A unit of length equal to one millionth of a meter (micron = mil x 25.4)

• R

Reactor

The equipment used to transform ethylene gas to polyethylene.

Roping

A method of bunching stretch film.

• S

Stretchability

A combination of factors related to the ability of a material to be stretched or elongated (i.e. how easily does a film stretch, how much will it stretch, does it return to its original length?)

• T

Tackifiers

Chemical substances added to increase the "tack" of the parent or base material.

Tear Resistance

The resistance of the film to be torn. This is quantified by Elmendorf Tear testing, and is measured as the force required to propagate an initiated tear in the MD or TD direction.

Transverse Direction

Direction across the stretch film web.

• Z

Zippering

Lack of resistance to tear propagation or an initiated TD cut or tear. Once the film has been torn or cut, the resulting slip rapidly opens and completes a full web break.