Packaging Glossary


The disintegration of plastic materials by means other than by the biological process such as dissolving, heat aging or ultraviolet ageing.


A diverse group of specialty chemicals incorporated into plastic formulations before or during processing, or to the surfaces of finished products after processing. Their primary purpose is to modify the behavior of plastics during processing or to impart useful properties to fabricated plastic articles. (Modern Plastics Encyclopedia 1995).


Degradation in the presence of air. Composting is a way of aerobic degradation.


The main standardization body for materials standards in the United States. Including materials standards and testing protocols for plastic sheeting.


Degradation in the absence of air, as occurs in dry landfills. Anaerobic degradation is also called biomethanization.


This term indicates 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.


The American Society of Testing and Materials defines biodegradable as "Capable of undergoing decomposition into carbon dioxide, methane, water, inorganic compounds, or biomass in which the predominant mechanism is the enzymatic action of microorganisms, that can be measured by standardized tests, in a specified period of time, reflecting available disposal condition." For practical purposes claims about biodegradability of plastic should specify a timeframe.


Polymers that exhibit controlled degradation through the incorporation of prodegradant additive master batches or concentrates. Such polymers oxidize and are embrittled in the environment and erode under the influence of weathering.


A packaging technique, which involves the heat seal of a rigid, thermoformed outer shell, which houses a product, to a coated back card. A method commonly used for retail items.


Plastic films produced from synthetic resins (such as polyethylene) by the blown process. In this process, the molten resin is extruded through a circular die into a tube. This tube is expanded ("blown") by internal air pressure into a larger bubble with a much reduced wall thickness and cooled with external air quenching.


Term used to describe bottom of a can liner.  The three types of bottom seals are:

  • Flat Seal - Straight seal along bottom of a can liner (looks like a pillow case).  The flat seal is used to create the strongest possible seal for heavy weight bags.
  • Star Seal - The star seal is the most common type of seal in the market. Designed without gussets, the star seal eliminates gaps along the seal where leaks can occur. This allows the bag to easily conform to the shape of the container and distribute the weight of the contents evenly inside the bag. This type of seal maximizes the bag's carrying capacity while minimizing the likelihood of leakage.
  • Gusset Seal - A flat-style bag manufactured with both sides tucked in to form gussets.  Also refers to the distance across the open face of the folded side or pleat: can also refer to the tuck or pleat itself.

A very popular method of packaging heavier items such as cases on juice, vegetables, soda, etc. The film is cut to size and is shrunk around product leaving a bull’s eye at each end of the package.


Plastic film produced from synthetic resins (such as polyethylene) by the cast process. In this process, the molten resin is extruded through a slot die onto an internally cooled chill roll.


A custom thermoformed PVC tray that is typically designed with 2 halves connected with a hinge. A more expensive option, this package is selected by companies who have a heavy or expensive retail item that requires tamper proof protection. These packages can be designed with a hang hole or with afoot, for a standalone option.


Normally pallets of product packaged to conform to Club Store requirements. A lot of Club Store packaging consist of volume buys or variety type packaging.


The assembly or sorting of many different items in a pre-specified order or arrangement.


A general term referring to a service that is performed on a product utilizing various assembly and / or packaging techniques intended for the enhancement of a product.


A source that performs a manufacturing service for a customer.


A term referring to a service that specializes in material handling, storage, inventory control and distribution of a company’s product or products.


The term used to indicate converting plastic bags from a continuous roll to separate bags in a given configuration.


Bags or tubing is rolled on cardboard cylinders (looks similar to a roll of paper towels).  


Bags are rolled with perforations or are interleaved in a roll configuration.


The simultaneous extrusion of two or more different thermoplastic resins into a sandwich-like film with clearly distinguishable individual layers. This involves a process where parts are blow-molded with walls containing two or more layers of different material. Co-extrusion offers wide latitude for material selection and also allows the use of recycled materials. A material with good barrier properties, for example, can be used for the inside and outside surfaces of a blow molded bottle, while recycled material can be used for the internal layer. (Modern Plastics Encyclopedia 1995).


The coefficient of friction is a measurement of "slipperiness" of plastic films and laminates. Measurements are usually done film surface to film surface. Measurements can be done to other surfaces as well, but not recommended because COF values can be distorted by variations in surface finishes and contamination on test surface.


Compostable materials are capable of undergoing biological decomposition in a compost site, to the extent that they are not visually distinguishable and break down to carbon dioxide, water, inorganic compounds, and biomass, at a rate consistent with known compostable materials (e.g. cellulose). See also 'compostable plastic'.


A polymer is 'compostable' when it is biodegradable under composting conditions. The polymer must meet the following criteria: a) Break down under the action of microorganisms (bacteria, fungi, and algae); b) Total mineralization is obtained (conversion into CO2, H2O, inorganic compounds and biomass under aerobic conditions); c) The mineralization rate is compatible with the composting process and consistent with known compostable materials (e.g. cellulose).


The term used to describe the activity of breaking down plant and animal material using microorganisms under aerobic conditions. For successful composting there must be sufficient water and air to allow the microorganisms to break down the material, and the compost should reach and maintain a warm temperature.


This is a term to describe pressure sensitive adhesive coating on plastic films or laminates that will allow the packages to be sealed by application of pressure (with no heat or with minimal heat).


Degradable materials break down, by bacterial (biodegradable), thermal (oxidative) or ultraviolet (photodegradable) action. When degradation is caused by biological activity, especially by the enzymatic action of microorganisms, it is called 'biodegradation'.


The tendency of a body to return to its original shape after it has been stretched or compressed


Electro-static Discharge.


A colorless gaseous aldene obtained from petroleum and natural gas and used in manufacturing the most common plastic bags.


Ethylene-Vinyl Acetate copolymer is an additive. Much softer and clearer than LDPE or LLDPE and has lower melt temperature. Its melt temperature goes down, while its softness increases with increasing vinyl acetate (VA) content. EVA resins with 2-18% VA content are used for cast and blown packaging films.


One of the most common plastics processing techniques covering a vast range of applications in which resins are melted, heated and pumped for processing. Extrusion machines accomplish these tasks by means of one or more internal screws. In extrusion, the material to be processed is sheared between the root of the screw and the wall of the barrel that surrounds it. This process produces frictional energy that heats and melts the substance as it is conveyed down the barrel. Melted extrudate from the machine is further processed after the extrusion phase, which typically produces pellets, sheet, cast film, blown film, fibers, coatings, pipes, profiles or molded parts. (Modern Plastics Encyclopedia 1995).


Food and Drug Administration.


This term refers to the physical strength of the can liner.  Some resins have higher film strength than others.  Our can liners are made from highest quality resins, giving them the highest quality film in the market place. Various types of strength testing are:

  • Dart Drop Test - ASTM test used to determine the resistance of a bag to local failure or puncturing.
  • Elmendorf Tear Test - ASTM test used to measure the resistance to tearing.
  • Wet Load Capacity - Measurement of how much wet weight a can liner will hold.
  • Dry Load Capacity - Measurement of how much dry weight a can liner will hold.

Also known as Horizontal Wrapping. This type of packaging is very well known and very popular. You would find this packaging on a candy bar, two pack of cookies, etc. This can be done with foil packaging or plain film, contract packaging.


Small clear bags designed to hold a variety of small objects (e.g., bread, poultry, vegetables, etc.)


The overall logistics associated with a product or products including but not limited to material handling, collation, incoming inspection, order processing & tracking, inventory control, warehousing, assembly and / or transportation.


Term used to describe thickness of a plastic sheet, measured in mil's or microns.

  • Mil (One thousandths of an inch) Term used in the measurement of LDPE and LLDPE can liners.  One mil is .001".  Can liners range between 0.35 to 4.0 mil.
  • Micron Term used in the measurement of HMW-HD can liners.  25.4 microns equals .001".  1,000 microns (M) = 1mm.  HMW-HDPE can liners are 6 to 24 microns.

Gussets are indented folds on the sides or bottom of a poly bag that allow the bag to expand up to the limits of the fold in order to comfortably accommodate variable volume or shaped contents. Gusseted bags are designated in three dimension measurements; Side Seal = W X Gusset X Length; Bottom Gusset = W X L + BG.


A process by which heat is introduced to 2 substrates to seal them together. Heat sealing is a generic term and is part of many packaging processes, but it mainly refers to the closure of poly bags.


This is the acronym for High density, (0.95-0.965) polyethylene. It has much higher stiffness, higher temperature resistance and much better water vapor barrier properties than LDPE, but it is considerably hazier.


A conventional (not biodegradable) plastic, as used commonly in single-use plastic carry bags (HDPE).


This is the chemical term for an organic compound containing only carbon and hydrogen.

LDPE (Low Density Polyethylene):

This resin was used with older can liner technology.  The resin has good clarity but weak film strength.  Today it is used primarily for Food and Utility bags. A plastic used predominantly in film applications due to its toughness, flexibility and relative transparency. LDPE has a low melting point, making it popular for use in applications where heat sealing is necessary. Typically, LDPE is used to manufacture flexible films such as those used for plastic retail bags and garment dry cleaning and grocery bags. LDPE is also used to manufacture some flexible lids and bottles, and it is widely used in wire and cable applications for its stable electrical properties and processing characteristics. (Adapted from Modern Plastics Encyclopedia 1995)

LLDPE (Linear Low Density Polyethylene):

This is the primary type of resin used in modern can liner manufacturing technology.  Bags made from LLDPE film provide excellent combination of film strength, puncture resistance and tear resistance. This is a plastic that is used predominantly in film applications due to its toughness, flexibility and relative transparency. LLDPE is the preferred resin for injection molding because of its superior toughness and is used in items such as grocery bags, garbage bags and landfill liners. (Adapted from Modern Plastics Encyclopedia 1995; Plastic Packaging Opportunities and Challenges, February 1992).


A “mil” is a unit to measure thickness of the paper or plastic. 1 MIL is equal to 1/1000th of an inch.


This is the chemical term for a simple compound whose molecules can join together to form polymers.


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 (see CAN), or oriented, (see BON).


A term to indicate the hiding power of pigmented (mostly white) plastic films. It is beneficial for packing materials sensitive to light (visible or ultraviolet).


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)


The act of physically sending out a product to a contract supplier for assembly, packaging or manufacturing.


Degradation of the polymer is triggered by UV light and assisted by the presence of UV sensitizers. In this process the polymer is converted to low molecular weight material (waxes) and in a second step converted to carbon dioxide and water by bacterial action.


A process where ultraviolet radiation degrades the chemical bond or link in the polymer or chemical structure of a plastic.


A very thin piece of thermoplastic resin that is considerably longer than it is wide with a thicknesses of 10 mils (1 mil = 0.001 inch) or less (averaging 0.7 mils to 1.5 mils).


A comparatively thick piece of thermoplastic resin that is much longer than it is wider and as thick as 10 mils (1 mil = 0.001 inch) or more (up to 30 mils thick).


An acronym for Point of Purchase. This is a merchandiser which holds multiple items in a free standing display which can be found in an aisle or end cap in a retail establishment. These are typically designed and made out of corrugated material.


A lightweight thermoplastic used especially in packaging. Polyethylene (PE) molecules have two hydrogen atoms attached to each carbon atom in a chain. This structure gives polyethylene it's tough, flexible and chemical resistant characteristics.


PET is clear, tough and has good gas and moisture barrier properties. Some of this plastic is used in PET soft drink bottles and other blow molded containers, although sheet applications are increasing. Cleaned, recycled PET flakes and pellets are in great demand for spinning fiber for carpet yarns and producing fiberfill and geo-textiles. Other applications include strapping, molding compounds and both food and non-food containers. (Adapted from Modern Plastics Encyclopedia 1995).


A Polymer is a Molecule. A high-molecular-weight organic compound, natural or synthetic, whose structure can be represented by a repeated small unit, the monomer (e.g., polyethylene, rubber, cellulose). Synthetic polymers are formed by addition or condensation polymerization of monomers. If two or more different monomers are involved, a copolymer is obtained. Some polymers are elastomers, some plastics. (Plastics Engineering Handbook of the Society of the Plastics Industry, Inc., edited by Michael L. Berins, 1991).


Polypropylene has excellent chemical resistance, is strong and has the lowest density of the plastics used in packaging. It has a high melting point, making it ideal for hot-fill liquids. In film form it may or may not be oriented (stretched). PP is found in everything from flexible and rigid packaging to fibers and large molded parts for automotive and consumer products. (Adapted from Modern Plastics Encyclopedia 1995; Plastic Packaging Opportunities and Challenges, February 1992).


Polystyrene is a very versatile plastic that can be rigid or foamed. General purpose polystyrene is clear, hard and brittle. It has a relatively low melting point. Typical applications include protective packaging, containers, lids, cups, bottles, trays and tumblers. (Plastic Packaging Opportunities and Challenges, February 1992).


Any plastic that has entered the stream of commerce, served its intended purpose, and has now been diverted for recycling or export. This includes residential, commercial and institutional plastic. This does not include industrial scrap material like factory regrind and plant scrap used within the primary manufacturing facility. (Post-consumer plastic resin is also known as PCR). (1995 post-consumer plastic Plastics Recycling/Recovery Rate Survey, Glossary of Terms, R.W. Beck & Associates).


Are collected only after they were used for the purpose for which they were originally manufactured. Post consumer materials are acquired by residential curbside collection programs, drop-off programs, and collection at institutions such as schools and colleges. These materials are limited to PET and HDPE (bottle and film grade), some polypropylene from battery casings collected from vehicle battery return programs, and LDPE and HDPE film grocery bags collected at recycling stations by supermarkets

PRN Bags:

PRN refers to the Latin abbreviation for "take as needed". The PRN bags contain medication (usually pain or anti-nausea medicine) that can be consumed by the patient on an "as needed" basis.  The blue or orange color of this type of bag is provided as a preference -choice for the clinic to assign color code use.


This is a task that may include either applying a label over an existing label, removing an existing label prior to applying a new label or just applying a label to an original product or box.


Redoing or undoing an existing type of packaging to reflect new standards.


The total processing involved with taking in returned goods from the field and reworking or repackaging them to conform to the standards of original goods.


This is a short term for Polyethylene (PE) resin.  The three types of PE resins are LDPE, LLDPE and HMW-HDPE (see below).  Other plastic resins include vinyl, polypropylene, styrene and nylon.

  • LDPE (Low Density Polyethylene) - This resin was used with older can liner technology.  Resin has good clarity but week film strength.  Today it is used primarily for Food and Utility bags.
  • LLDPE (Linear Low Density Polyethylene) - This is the primary type of resin used in modern can liner manufacturing technology.  Bags made from LLDPE film provide excellent combination of film strength, puncture resistance and tear resistance.
  • HMW-HDPE (High Molecular Weight - High Density Polyethylene) Bags made from HMW-HDPE resin provide excellent film strength and puncture resistance, but less tear resistance than LLDPE.
  • Butene - One of three types of LLDPE resin.  Butene has weaker film-strength properties than Hexene or Octene.
  • Hexene - One of three types of LLDPE resin.  Some manufacturers use a  Higher Alpha Olefin (High Grade Hexene) in the manufacturing of can liners.  Properties include high film strength and increased tear resistance.
  • Octene - One of three types of LLDPE resin.  Used in other applications because of its excellent physical properties.
  • Prime Resin - Refers to the usage of high-quality, "fresh from the reactor", resin.
  • Blended Resin - Refers to the combination of two or more types of resin.
  • Reprocessed Resin - Refers to resin that has been used at least once before.  Can be post-industrial (scrap) or post-consumer (recycling).  Property of resin is decreased each time it is reused

The series of activities by which discarded materials are collected, sorted, processed and converted into raw materials and used in the production of new products.


Probably the most common of all packaging methods, shrink wrapping is accomplished by trimming a piece of shrinkable film around an object, and then sending it through a heat tunnel which shrinks the film to conform to the exact size of an outer box or product. This is a tamper resistant covering that is very common at the retail level on products such as gift sets, software, and games, to name a few. The gloss effect created by the film tends to give a product or box a richer appearance.


A packaging technique whereby a film is sucked down over a product and onto a preprinted skin card. As heat is introduced, the adhesive coating on the card and the Surlyn film adhere together. This is an attractive packaging option and is preferred for retail because the product is displayed clearly yet is protected by the transparent covering. It is a cost effective solution for higher volume runs.


A packaging technique that allows a product to be encapsulated between 2 halves of a hinged header card, with a Surlyn or clear film which is part of the card but acts as a window for the item. Following the heat sealing of the outer card together, the film in the window is then heated and then shrinks around the geometry of an item. This method is a combination of blister, skin, clamshell and shrink wrapping. It is an attractive option, but more expensive than some of the other methods. Batteries and Pharmaceuticals are commonly stretch packaged.


A bag with gussets on both sides, with a fin-seal running from top to bottom and sealed horizontally at the bottom and the top. Commonly used in the coffee industry.


(1) Capable of being repeatedly softened by heat and hardened by cooling. (2) A material that will repeatedly soften when heated and harden when cooled. Typical of the thermoplastic family are the styrene polymers and copolymers, acrylics, cellulosics, polyethylenes, polypropylene, vinyls and nylons. (Plastics Engineering Handbook of The Society of the Plastics Industry, Inc., edited by Michael L. Berins, 1991).


Ultra Violet Inhibitor. This is an additive used in making plastic sheeting that requires protection from sunlight.


A reference to an additional operation or service that is done by a supplier to a product or products that provides a customer with a more complete solution.


This is a term that refers to pure and clean (no recycled material is included) resins.


These are labels on packaging that indicate improper use of the enclosed products and warning of the dangerous results of improper use. This type of label is required by law.


A wicketed bag is used in factories for rapid packaging. There are two holes on the top to be held onto the machine. They can be quickly opened and filled. The most common type of wicketed bags are bread bags.


A reclosable or re-seable pouch produced with a plastic track in which two plastic components interlock to provide a mechanism that allows for recloseablility in a flexible package.