Adhesive Lamination

A laminating process in which individual layers of multi-layer packaging materials are laminated to each other with an adhesive. This lamination process is also known as dry lamination.

Aging

Aging (Curing) is a term in process engineering that refers to the toughening or hardening of a polymer material by cross linking of polymer chains brought by heat. It is a necessary process after adhesive lamination converting two different layers of materials together. Aging period ranges from 24 to 48 hours depends on the types of adhesive and material used.

Barrier

The ability to stop or retard the movement of one substance through another. In packaging, the term is most commonly used to describe the ability of a material to stop or retard the passage of atmospheric gases, water vapour, and volatile flavour and aroma ingredients.

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.

Biodegradable

Material that is able to degrade caused by biological activity, especially by enzymatic action, leading to a significant change in the chemical structure of the material. The European Union deems a material biodegradable if it will break down into mostly water, carbon dioxide and organic matter within six months.

Blister Packaging

Several types of pre-formed plastic packaging used for small consumer goods. The two primary components of a blister pack are the cavity or pocket made from a "formable" web, either plastic or aluminum - and the lidding, made from paper, carton, plastic or aluminum. The "formed" cavity or pocket contains the product and the "lidding" seals the product in the package.

Cast Film

Film extruded through a flat die into a quench system.

CNY

Cast Nylon, a barrier film made by Polyamide resins. It has a higher tensile, compressive and flexural strength than extruded or injection moulding Nylon-6. This is because gravitationally cast Nylo does have higher molecular weight and higher crystalinity. Cast Nylon is usually used for thermoforming and vacuuming applications.

Co-Extrution

Simultaneous extrusion of two or more different thermoplastic resins into a sandwich-like film with clearly distinguishable individual layers.

COF

Coefficient of friction, 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.

Cold Seal

A 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 minimal heat).

Corona Treatment

A surface treatment process that improves the bonding characteristics of most materials such as: paper, films, foils, and polymers by raising surface energy (dyne level).

CPP

Cast Polypropylene film. Unlike OPP, it is heat sealable, but at much higher temperatures than LDPE, thus it is used as a heat seal layer in retortable packaging. It is, however, not as stiff as OPP film.

De-Metalized

A process partially removes metal from a metalized film, leaving a clear window in an otherwise metalized design.

Density

The weight of a given volume of a material. In metric units density is given in kilograms per cubic metre, although in packaging, grams per cubic centimetre is more common. Relative density or specific gravity is the ration of the density of the observed object to that of water.

Die-Cut

The use of a metal blade, formed to match a desired shape, to make a precision cut in paper or plastic.

Drop Test

The resistance of a filled container to stocks caused by dropping in certain way (i.e. or corners, edge, faces, etc.) onto a solid surface. The test measure how well a container and its inner packaging (if any) will protect the contents against the handling encountered in shipping.

Easy Peel Film

Easy peel film is heat sealable, comprising a sealant layer which readily and easily delaminates or peels from a second adjacent film layer or plastic container after being heat sealed. Easy peel film can be used independently as a sealable packaging film, or laminated to a second film structure wherein the second film structure may comprise a single layer or multiple layers. Easy peel film are widely used as the lidding film for rigid containers.

Elongation

A test to measure the ductility of flexible material. When a material is tested for tensile strength it elongates a certain amount before fracture takes place. The two pieces are placed together and the amount of extension is measured against marks made before starting the test and is expressed as a percentage of the original gauge length.

EVA

Ethylene-Vinyl Acetate copolymer. 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.

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.

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.

Eye-mark

A machine-recognizable mark, printed on web-fed packaging materials. The eye-mark is the reference point from which the machine will register other operations such as further decoration, heat sealing, or package cutoff.

Fin Seal

A type of seal resulting from sealing together the contiguous edge areas of two sheets, usually by heat, resulting in a finlike protuberance.

Fitment

An injection molded “Spout or Valve” that is typically heat-sealed to a flexible packaging material.

Flexo Printing (Flexography)

A method of printing using flexible rubber or photopolymer printing plates in which the image to be printed stands out in relief. Fluid ink metered by an engraved roll is applied to the raised portions of the printing plate and then transferred to the substrate. Flexographic printing is used to print sheets of preformed corrugated board and for printing roll-fed plastics and papers.

Four Process Color

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.

Gauge

A unit of measure describing 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.

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.

Lap Seal

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

Machine Direction

The direction parallel to a material's flow through a machine. Flow direction through a machine may impart directional properties to a material.

Micron

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

MIL

A unit of measure. 1 MIL = 0.001 inch.

Multi-Layer

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.

NY

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.

OPP

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.

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.

Pantone Matching System (PMS)

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.

Pasteurization

A process to extend food product shelf live by using heat.

PET

Polyester (Polyethylene Terephtalate). Tough, temperature resistant polymer. Biaxially oriented PET film is used in laminates for packaging, where it providesstrength, stiffness and temperature resistance. It is usually combined with other films for heat sealability and improved barrier properties.

PLA

Polylactic acid (PLA) is a biodegradable, thermoplastic, found converted into a variety of aliphatic polyesters derived from lactic acid which in turn can be made by fermentation of various agricultural products such as corn starch, once made from dairy products.

Ply

A single layer, as would be found, for example, in a multilayer laminate.

PP

Polypropylene. Has much higher melting point, thus better temperature resistance than PE. Two types of PP films are used for packaging: cast, (see CPP) and oriented (see OPP).

PP

Polypropylene. Has much higher melting point, thus better temperature resistance than PE. Two types of PP films are used for packaging: cast, (see CPP) and oriented (see OPP).

Puncture Resistance

Performed on an Elmendorf puncture/tear testing machine, and uses a 4" diameter sample of film to measure its resistance to puncture or impact (Results are in force grams/diameter (4").

PVC

Polyvinyl chloride. A tough, stiff, very clear film. The oriented version is used mainly for shrink film applications.

PVDC

Polyvinylidene chloride. It is a polymer derived from vinylidene chloride. Polyvinylidene chloride is applied as a water-based coating to other plastic films such as biaxially-oriented polypropylene (BOPP), Nylon (NY), and polyester (PET). This coating increases the barrier properties of the film, reducing the permeability of the film to oxygen and flavours and thus extending the shelf life of the food inside the package.

RCPP

Retort CPP. A type of Cast Polypropylene film that is able to withstand the rigorous temperature and pressure conditions in retort process. RCPP can be boiled at 121℃ for 30 minutes; high temperature RCPP can be boiled at 130℃.

Recyclable

Materials that are able to be used into new products to prevent waste of potentially useful materials, reduce the consumption of fresh raw materials, reduce energy usage, reduce air pollution (from incineration) and water pollution (from land filling) by reducing the need for "conventional" waste disposal, and lower greenhouse gas emissions as compared to virgin production.

Recyclable Symbol Code

The symbol code, a single digit ranging from 1 to 7 and surrounded by a triangle of arrows, was designed to allow consumers and recyclers to differentiate types of plastics while providing a uniform coding system for manufacturers. The easiest and most common plastics to recycle are made of polyethylene terephthalate (PETE) and are assigned the number 1. Items crafted from various combinations of the aforementioned plastics or from unique plastic formulations not commonly used. Usually imprinted with a number 7. These plastics are the most difficult to recycle and, as such, are seldom collected or recycled.

Registration

The use of a metal blade, formed to match a desired shape, to make a precision cut in paper or plastic. In flexible packaging, registration indicates the exact alignment of printing. It describes whether applied colours are in their exact correct position relative to one another.

Repeat

The distance between two consecutive eye-marks. Repeat on packaging film usually indicates the length of the package that the machine will cutoff each time.

Retort Process

The thermal processing or cooking packaged food or other products in a pressurized vessel for purposes of sterilizing the contents to maintain freshness for extended storage times. Retort pouches are manufactured with materials suitable for the higher temperatures of the retort process, generally around 121℃.

Reverse Printing

The vast majority of all consumer is reverse printed. In this case, the outermost layer is printed on the back side and laminated to the rest of the multi-layer structure. While not mandatory in all industries, it is the preferred method for the food industry as it guarantees there will be no ink contact with the food product.

Rewind Direction

The film rewind direction has three basic elements. How the label feeds off the roll; inside or outside, the direction the length and width of the label comes off the roll, and finally the text and image direction on the labels itself.

Roto-gravure Cylinder

Cylinder is one of the two principal elements of Roto-gravure Printing. Plates for rotogravure are made of solid copper. Rotogravure cylinders consist of a steel mandrel on which a layer of copper has been deposited by electroplating.

Roto-gravure Printing

A method of printing using copper cylinders. With gravure printing, an image is etched on the surface of a copper cylinder. The etched area is filled with ink, then the plate is rotated on a cylinder that transfers the image to the film or other material. Gravure is abbreviated from Rotogravure.

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 colour (for example, one chosen from a PMS colour book) used instead of combining the four process colours.

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. DuPontTM 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.

Vacuum Packaging

Vacuum Metalized CPP film. The deposition, in a vacuum chamber, of vaporized aluminum molecules over the surface of CPP film thus providing a lustrous metallic appearance. VMCPP film has the same sealability as CPP film but with higher oxygen and moisture barrier property.

VMCPP

Vacuum Metalized CPP film. The deposition, in a vacuum chamber, of vaporized aluminum molecules over the surface of CPP film thus providing a lustrous metallic appearance. VMCPP film has the same sealability as CPP film but with higher oxygen and moisture barrier property.

VMPET

Vacuum Metalized PET film. It has all the good properties of PET film, plus much improved oxygen and water vapors barrier properties.

Web

Web Paper, film, foil, or other flexible material as it is unwound from a roll and passed through a machine.

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.

Yield

The amount of product that can be produced from a given weight of material. Most packaging raw materials are sold by weight. However, because of density differences, the same weight of similar materials can produce different amounts of finished product. For example, the yield for a plastic resin used for film manufacture might be expressed as the number of square meters of film that could be made from 1 kilogram of the material (square inches per pound.) In other instances, the yield might be expressed in terms of volume per unit weight, or the actual number of physical objects per unit weight.