Packaging Glossary

A unit of measure describes the thickness of film. The gauge system used in the United States is the U.S. Manufacturer's Standard. 100 gauge = 0.001 inch = 1 MIL.

Heat Resistance

Conventionally taken to be the maximum temperature that a material will withstand and still retain at least 50% of its physical properties when subjected to this temperature for a specified time.

Heat Sealant Layer

A layer of film can be laminated to each other if enough heat and time are applied

Heat Seal Strength

A measurement of sealing strength after the heat seal is done.

In-Mould Labelling

In-mould labeling (IML) is a technology that fuses a printed label or flexible material directly onto the surface of your plastic moulding. Producing vivid colorful labels which are not susceptible to peeling. The label serves as the integral part of the final product, which is then delivered as pre-printed item.


Low density polyethylene, heat sealable, is commonly used in bulky packaging.


Linear low density polyethylene is heat sealable and commonly used in the inner layer of packaging. Stronger than LDPE but with low clarity (high haze).

Lap Seal

A method of sealing plastic films where the two pieces to be sealed are overlapped as “surface-to-substrate”, and then heated to form a seal.

Machine Rewind Direction

The direction parallel to a film flow through a machine. Without the correct film rewind direction, the graphics on the film may not show up according to the design.

(same as VMPET)

Metalized Polyester film. an enhanced version of polyester film with better oxygen, moisture and light barrier. Barrier is not as good as foil but it provides great heat resistant and puncture resistant.


A depreciated, although still used, term for micrometer. One millimeter = 1,000 micrometers. (25.4 micrometers = 0.001 inch.)


A unit of measure. 1 MIL = 0.001 inch.


A film which consists more than one layer of plastic. The layers of plastics are “glued” together by dry lamination process or extrusion lamination process. Reverse printing are usually used for multi-layer film since the ink can be “trapped” between two layers of film.


Nylon. Polyamide resins, with very high melting points, excellent clarity and stiffness. Two types are used for films - nylon-6 and nylon-66. The latter has much higher melt temperature, thus better temperature resistance, but the former is easier to process, and it is cheaper. Both have good oxygen and aroma barrier properties, but they are poor barriers to water vapor. Also, nylon films can be cast or oriented.

Offset Printing

An indirect printing process in which the inked image created by the imageproducing plate (lithographic, gravure, or flexographic) is transferred to an intermediate roll (the blanket roll) and subsequently applied to the substrate. See also blanket roll.


Oriented Polypropylene film. A stiff, high clarity film, but not heat sealable. Usually combined with other films, (such as CPP or LLDPE) for heat sealability. Can be coated with PVDC (polyvinylidene chloride), or metalized for much improved barrier properties.


Oxygen transmission rate. OTR of plastic materials varies considerably with humidity, therefore it needs to be specified. Standard conditions of testing are 0, 60 or 100% relative humidity. Units are cc./100 square inches/24 hours, or cc/square meter/24 Hrs. cc = cubic centimeters.