Packaging Glossary
Saran

It is the trade name for a number of polymers made from vinylidene chloride (especially polyvinylidene chloride or PVDC), along with other monomers. The main advantage of Saran film is a very low permeability to water vapor, flavor and aroma molecules, and oxygen compared to other plastics. The barrier to oxygen prevents food spoilage, and the barrier to flavor and aroma molecules helps food retain its flavor and aroma.

SOP

Heat sealable Oriented Polypropylene (OPP) film comprising a base oriented polypropylene film having on one or both surfaces layers of a random propylene/ethylene copolymer (ethylene content 2-6% by weight). SOP is heat sealable to any other sealable PP film such as CPP. The film can be surface printed and can be used to package merchandise on packaging machine without laminate with a sealant layer.

Spot Color

A specified color (for example, one chosen from a PMS color book) used instead of combining the four process colors.

Surface Printing

The process where by the ink is deposited directly onto the outermost surface of the packaging film or material. The process is most commonly used in short run printing. A UV (ultraviolet) coating may be added to provide a hard exterior finish that prevents the ink from flaking or chipping.

Surlyn®

Surlyn® is a tough, easily formed thermoplastic film supplied by DuPont™. Typically used as a food contact or sealant layer in flexible packaging. DuPont Surlyn® packaging resins are optimized for efficient blown film and extrusion coating. It is a milky clear film whose transparency improves as thickness decreases. It is also commonly used in orthotics/prosthetics applications where the need is high for toughness, durability and high resistance to chemical attack.

Tensile Strength

The amount of strength required to break a 1" wide strip of film (Results are in gram force/sq inch).

Thermoforming Film

Plastic used in thermoforming which is a manufacturing process where a plastic film is heated to a pliable forming temperature, formed to a specific shape in a mold, and trimmed to create a usable product. Vacuum forming is a type of thermoforming that is used in packaging. The film is heated and stretched onto or into a single-surface mold, and held against the mold by applying vacuum between the mold surface and the film.

Tolerance

Permissible maximum and minimum deviation from the specified dimensions or qualities.

Top Load / Bottom Load

Opening is located at the top or bottom of the bag according to the direction of main image.

Trap

In printing, inks may be overlapped slightly to ensure that no substrate shows through within the register variations of the printing press. Trapping is the ability of one ink to adhere to a previously, applied and still wet ink.