of Flexible Packaging Terms (Quicklist)
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Biaxial Orientation: Orientation of plastic films in both machine and cross machine directions by stretching. Biaxially stretched films are generally well balanced in both directions and much stronger in terms of tear strength.
BON: Biaxially oriented nylon film, with excellent oxygen and aroma barrier properties, (see Nylon), but it is a poor water vapor barrier. BON is much stiffer than cast nylon film, but cannot be thermoformed.
Extrusion Lamination: A laminating process in which individual layers of multi-layer packaging materials are laminated to each other by extruding a thin layer of molten synthetic resin (such as polyethylene) between the layers.
EVOH: Ethylene-Vinyl Alcohol copolymer, used in coextruded plastic films to improve oxygen barrier properties. It is, however, a poor water vapor barrier. Even its otherwise excellent OTR, (oxygen transmission rate) is sensitive to high humidity, therefore, for packaging applications, it is usually the core layer of coextruded plastic films, where it is shielded from moisture by protective layers of polyethylene. Its OTR also depends on its VOH (vinyl alcohol) content.
Foil: A thin gauge (0.000285 – 0.0005 inches / 6-12 microns) aluminum foil laminated to plastic films to provide maximum oxygen, aroma and water vapor barrier properties. Although it is by far the best barrier material, it is increasingly being replaced by metallized films, (see MET-PET and MET-OPP) because of cost.
Four Process Colors: The four process colors (cyan, magenta, yellow and black) are also referred to as CMYK. However it is a myth that every image can be duplicated using the “four process colors.” Additional ‘spot’ colors are often required to generate the high resolution images that are most preferred in modern packaging.
HDPE: High density, (0.95-0.965) polyethylene. Has much higher stiffness, higher temperature resistance and much better water vapor barrier properties than LDPE, but it is considerably hazier.
Heatseal Layer: A heatsealable innermost layer in plastic packaging films and laminates. Can be either adhesive laminated or extrusion coated onto a non-sealable film (or foil).
LDPE: Low density, (0.92-0.934) polyethylene. Used mainly for heatsealability and bulk in packaging.
MET-PET: Metallized PET film. It has all the good properties of PET film, plus much improved oxygen and water vapor barrier properties. However, it is not transparent.
MVTR: Moisture vapor transmission rate, usually measured at 100% relative humidity, expressed in grams/100 square inches/24 hours, (or grams/square meter/24 Hrs.) See WVTR.
Mylar™: Mylar is a registered trademark of the Dupont-Teijin Corporation. Is the industrial brand name for that corporation’s polyester (PET) film. Polyester film is a staple of multi-layer packaging for a wide variety of applications.
OTR: 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)
PET: Polyester, (Polyethylene Terephtalate). Tough, temperature resistant polymer. Biaxially oriented PET film is used in laminates for packaging, where it provides strength, stiffness and temperature resistance. It is usually combined with other films for heat sealability and improved barrier properties.
Pinholing: The term for very small holes found in aluminum foil which dramatically affects MVTR (moisture vapor transmission rate) and OTR (oxygen transmission rate). Thicker foiles have fewer pinholes.
Plow-Bottom Stand-up Pouch: a stand-up pouch that is made from one piece of film. The front, gusset, and back are continuous, so there is no seal at the gusset. Holds more weight than Doy-style pouches, so are commonly used for products weighing more than one pound.
PMS Number: The Pantone Matching System is the universally accepted color definition system. Colors can be blended or individually specified to match a specified Pantone reference color exactly.
PVDC: Polyvinylidene chloride. A very good oxygen and water vapor barrier, but not extrudable, therefore it is found primarily as a coating to improve barrier properties of other plastic films, (such as OPP and PET) for packaging. PVDC coated and ‘saran’ coated are the same.
Trap Print : Another term for Reverse Printing (see Reverse Printing). Trap printing derives its name from the fact that the ink is trapped between the outer layer of material and the substrate.
WVTR: Water vapor transmission rate, usually measured at 100% relative humidity, expressed in grams/100 square inches/24 hours, (or grams/square meter/24 Hrs.) See MVTR.
ZipSeal ™ Bag: A recloseable or reseable pouch produced with a plastic track in which two plastic components interlock to provide a mechanism that allows for recloseablility in a flexible package.
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