USCC Glossary

Aesthetics — The sum total of the visual response to the beauty of an object. Elements of aesthetics may include: color, shape or particular features of the object.

Aging — The physical and/or chemical change of a material with respect to time, under defined environmental conditions, leading to improvement or deterioration of properties.

Amber — A chromatic (brown) color of glass or plastic containers. It is used principally to protect the contents of the container from exposure to light.

Antioxidant — A chemical substance added to a plastic resin to minimize or prevent the effects of oxygen attack on the plastic, e.g., yellowing or degradation. Chemical attacks by oxygen can render a plastic brittle or cause it to lose desired mechanical properties.

Antistatic Agent — A chemical substance applied to the surface of a plastic article or incorporated in the plastic from which the article is made. The antistatic agent renders the surface of the plastic article less susceptible to the accumulation of electostatic charges that attract and hold fine dirt or dust on the surface of the plastic articles

Application Torque — The torque force, measured in inch-pounds, required to screw a closure onto a container.

Applicator Cap — A closure designed to apply the contents of the container

Back-Off — A term used to denote relaxation of forward thrust, i.e. loss of torque following application of the closure. Back-off can be affected by top loading, compressibility and resiliency of the closure liner, consistency of application torque, and mechanical interaction of the closure and bottle.

Backing Liner — A compressible material, usually pulp or foamed polyethylene, to which the facing liner is attached or adhered. This compressible material compensates for any irregularities on the sealing surface

Bail — A metal wire formed into a semi-circle to serve as a container handle. The ends fit into the ears on a general line can. Bails are common on lard and paint cans.

Band — That portion of the closure that releases when the closure is removed from a bottle. The band is used for tamper indication

Barrier Resins — A group of resins specially formulated to resist the transmission of oxygen, water, solvents, essential oils, etc

Bead — A depressed or raised circle or ring around a container or closure

Body — The sidewall of a container. The portion of a container to which the top and the bottom ends are attached by double seaming.

Binding — Excess drag when the closure is applied to the bottle.

Blow Molding — A method of fabrication in which a warm plastic hollow tube is placed between the two halves of a mold (cavity) and, by using air pressure, the hollow tube is forced to assume the shape of the cavity. The air pressure is introduced through the inside of the hollow tube. The air pressure forces the plastic against the surface of the mold that defines the shape of the container

Bottoming-Out — A condition where the bottom skirt of the closure makes contact with the container before the land area of the container and the closure create a seal

Buttress Thread — A design of thread profile (cross section) that takes the form of a truncated triangle or slight modification of that form. It is usually positioned so the right angle is at the bottom of the thread cross section and adjacent to the neck of the bottle finish. The horizontal leg of the right triangle is the bearing surface for a matching cap thread. It is designed to withstand maximum force in one direction only

Capacity — The amount of space provided inside a container for a given amount of product.

Cavitation — The number of molding stations within a mold

Cavity — A mold component that forms the exterior or external surface of the closure.

Center Gated Mold — A mold in which the cavity is filled with resin through an orifice interconnecting the nozzle and the center of the cavity area.

Child Resistant Closure "CRC" — A closure requiring dissimilar motions making removal by a child difficult. Child Resistant closures are subject to current government regulations.

Chime — The expanded edge or rim of a barrel, pail, or drum.

Clarity — Freedom of haze or cloudiness in a plastic material.

Closure — Any structure or device designed to close off the opening of a container and prevent loss of its contents.

Closure Height — The overall height of the closure. Closure height is measured from the closure top to the open end of the closure.

Closure Lining Machine — A high speed, specialized machine using a punch’s die or specialized cutters to automatically cut and insert liners into closures.

Closure Removal Torque — The amount of force necessary to loosen, open, or remove a closure from a bottle.

Closure Skirt — The vertical wall of a closure.

Closure Stripping Torque — The amount of force required to cause the closure and/or bottle finish to distort and override the matching closure bottle threads.

Coating — A thin film of varnish, lacquer, or enamel applied to a can making plate by means of a roll coater.

Cocking — Mis-application of a closure to a container. The closure’s appearance is uneven on the container or it is pulled off to one side, due to an uneven downward pull of threads.

Color Concentrate — A measured amount of dye or pigment incorporated into a predetermined amount of plastic. This pigmented or colored plastic is then mixed into larger quantities of plastic material used for molding. The "concentrate" is added to the bulk of plastic in measured quantity in order to produce a precise, predetermined color of the molded bottles.

Composite Can — A can having a fiber body composed of a composite of paper with one or both ends made of metal. The label and liner can be aluminum foil or plastic

Compression Molding — A molding process whereby plastic material is dropped into a cavity and formed under pressure by a force. The process is primarily done on a rotary molding machine.

Cone Top — A tapered shape top generally used on the general line cans.

Continuous Thread Closure "CT" — A non-interrupted spiral design threaded closure. The main purpose of a CT closure is to mate with corresponding bottle threads and provide sealing and re-sealing of the container.

Convolute — A paper can body term indicating paper wrapped straight in plies. A laminated fiber container formed by winding material around a cylinder with material fed at right angles to the axis

Corrosion — The deterioration of a metal by chemical or electrochemical reaction with its environment.

Cover —Loose end of an open top can, pail, or drum.

Curl — A tubular structure formed at the open end of a metal closure to provide a smooth, strong edge. The curl facilitates automatic handling of the closure.

Cycle — The sequence of operations in a process to complete one set of parts. The cycle is taken at a point in the operation and ends when this point again starts.

Deep Screw Cap — A cap having a deeper skirt and generally a heavier thread than the 400 finish series.

Deflashing — Any technique or method removing excess unwanted material from a molded article. Specifically, the excess material is removed from places on the article where parting lines of the mold that formed the article may have caused the excess material to be formed.

Density — Weight per unit volume of a substance. Density is expressed in grams per cubic centimeter, pounds per cubic foot, etc.

Discoloration — Any change from the original color. Discoloration can be caused by overheating, light exposure, irradiation, or chemical attack.

Dispensing Closure — A snap on or threaded closure that allows for product dispensing, and usually resealing, without removing the closure from the package.

Dome — A closure that has a rounded top surface.

Dropper Cap — A closure that includes an attached dropper and rubber bulb.

Ears — Parts bumped or riveted to side of can into which a carrying bail is inserted.

Environmental Stress Cracking (ESC) — The susceptibility of a thermoplastic article to cracking under the influence of certain chemicals and stress.

Extrusion — The compacting of a plastic material and forcing of it through an orifice in more or less continuous fashion.

F" Style Can — A rectangular base general line can fitted with a screw cap closure. "F" style cans are made in several sizes for liquid measure. "F" style originated as a designation for the "Flit" style can.

Facing Liner — The liner material attached or adhered to the backing liner. The facing acts as a barrier to the chemical reaction of the product.

Fill Point — The level to which a container must be filled to furnish a designated quantity of the contents.

Finish — The plastic forming the opening of a container and shaped to accommodate a specific closure.

Fitment — A device used as part of a closure assembly to accomplish a certain purpose such as, dropper, sprinkler, powder shakers, etc.,

Fittings — Any part other than the ends necessary to complete the closure of a can. Fittings can be rings, plugs, screw necks or caps, and all spouts.

Flame Treating — A method of rendering inert thermoplastic objects receptive to ink, lacquers, paints, adhesives, etc. The object is bathed in an open flame to promote oxidation of the surface of the article.

Flash — Excessive undesirable plastic materials on containers or closures formed along mold seams or parting lines. Flash results from plastic flowing into the clearance between mold components.

Flowed-in (As in Flowed-in Gasket)— A method of applying fluid sealing compounds with a nozzle.

Fluorination — An extra process in which a thermoplastic article (container or closure) is exposed to fluorine gas. The fluorine substitutes with some hydrogen atoms in the polymer chain creating a barrier and surface enhancement. Benefits include improved barrier properties and reduced solvent absorption and permeation.

Friction cap — A closure held on by friction upon application to the container, building up resistance to the movement of the closure.

Friction Top Can — A can with a removable cover consisting of a plug that fits into a ring in top end of can. The cover depends on friction fit to retain its position. There are basically three types of friction to cans — full friction, single-friction and multi-friction. Each gets its name from the number of points of contact between the lid and the can opening.

Gasket — A liner applied between the sealing surface of container lip and closure. A gasket provides the ultimate seal.

Gate — An orifice through which the molten resin enters the cavity.

Glued-In Closure Liners — Closure that have liners attached to the inside roof of the closure by a hot melt adhesive.

HDPE — An abbreviation for High Density Polyethylene.

Head Space — The space between the fill level of a container and the sealing surface.

Heel — The part of a bottle between the bottom bearing surface and the sidewall.

Impact Resistance — Relative susceptibility of plastics to fracture by shock. Impact resistance is indicated by the energy expended by a standard pendulum type impact machine in breaking a standard specimen in one blow.

Induction Seal Liners — A specialized laminate containing aluminum foil and a plastic heat seal film that hermetically seals a container through use of an "Induction Cap sealing Machine."

Injection Blow Molding — A blow molding process in which the parison to be blown is formed by injection molding.

Injection Molding — A molding procedure whereby a heat-softened plastic material is forced from a cylinder into a relatively cool cavity giving the article the desired shape.

Interference — A condition where an exterior diameter in the finish area of the bottle is larger than the mating interior diameter of the closure.

Internal Threads — The threads on the interior of the closure.

Interrupted Threads — Non-continuous threads on a closure causing gaps.

Knurl — The indented or crimped portion on the skirt at the top of the cap used for holding the liner in the cap. The knurl is also used as a grip for removing the cap. The knurl provides a non-skid surface during the threading operation.

L" Style Thread — A type of thread contour (cross-section) roughly trapezoidal in outline. The outermost part is radiussed a "general purpose" thread contour designed for use with metal or plastic closures.

Land — The lip of the container to which the closure liner or land seal linerless feature compresses or conforms to tolerance.

Land Seal — A sealing device that seals by applying pressure to the top or land of the container finish.

Light Resistance — The ability of a plastic material to withstand exposure to light, usually sunlight or the ultraviolet part of the light spectrum, without change of color or loss of physical and/or chemical properties.

Liner — A disk of paper, cork, foam, plastic, etc., retained in a closure to provide a flexible barrier between the closure and the sealing surface of the container.

Liners, Cap — A gasket material inserted into a screw cap that serves to seal the closure against leakage of the container contents.

Liner Well — The space provided in a closure for a liner.

Linerless Closure — A thermoplastic closure incorporating a molded-in sealing feature which, when applied to a container with the appropriate finish, seals most liquids within the container.

Lithography — A printing process, a branch of Planography, involving employment of stones or metal plates whose printing surfaces are partly water repellent and ink repellent. The process is especially adapted to fine half tone color effects or smooth ink solids.

Lug — A type of thread configuration designed so the thread segments are disposed equidistantly around a bottle neck. The closure has matching portions that engage each of the thread segments.

Lug Cap — A closure with raised internal impressions that inter-mesh with identical threads on the finish of container.

Lug Pail Cover — A type of cover commonly used on open and 5 gallon steel pails. The pail cover is lined with puff type compound which seats on the top rim of the pail. The seal is affected by compression of the cover to the pail. The seal is maintained by clinching the lugs, an integral part of the cover, to the pail rim.

Mechanical Breakaway Bands — A closure with a portion or section of the skirt perforated or weakened in some manner so when the closure is opened, the section is designed to break apart and either remain on the container or attach to the closure to indicate the package has been opened.

Mil — A unit of measurement equal to .001 inch.

Minimum Wall — A term designating the minimum thickness of the wall of a bottle.

Modified Buttress Thread — Commonly referred to as "M" style. The modified buttress thread was developed, with a 10-degree pressure angle, to offer more closure-to-bottle thread contact.

Mold — The cavity or matrix into which the plastic composition is placed and from which it takes its form.

Molding, Compression — A process of shaping or forming material through the use of molds, heat, and pressure.

Molding, Injection — A process of shaping or forming plastic objects from powder or granule form in a mold by cooling the previously heated plastic.

Mold Seam — A vertical line formed at the point of contact of the mold halves. The prominence of the line depends on the accuracy with which the mating mold halves are matched.

Mouth — The open end of the cap opposite the top.

Multi-layer bottle - A bottle that is co-extruded with two or more layers to contain oxygen sensitive foods or industrial chemicals.

Narrow Mouth — A finish of a plastic container in which the diameter is small relative to the diameter of the body.

Neck — The part of a container where the shoulder cross section area decreases to form the finish.

Neck Rings — That part of the mold equipment that forms the finish of the bottle.

Nesting — A can or pail is tapered so one fits into the other to conserve space when storing or shipping empty containers.

Non-Threaded — Designates items which do not require threading action when applied to glass or plastic containers. Examples of non-threaded closures are snap caps, sifter fitments, pour-out fitments, etc.

Oblong — Refers to the shape of a general line container where the top and bottom ends are rectangular in shape with rounded corners. Oblongs are also called "F" style can.

Offset Neck — The vertical axis of the neck finish is off center from the vertical axis of the container.

Offset Printing — A printing technique in which ink is transferred from a reservoir to a printing plate.

Opaque — A term describing a material or substance that will not transmit light.

Open Top Can — A classification of round hermetically sealed cans with welded side seams and compound lined double seams. Products packed in these containers are usually heat processed.

Orientation — The alignment of the crystalline structure in polymeric materials so as to produce a highly uniform structure. Orientation can be accomplished by cold drawing or stretching during fabrication.

Orifice — An opening in a plug, fitment, or dispensing cap through which the product is dispensed.

Overflow Capacity — The capacity of a container to the top of the finish or to the point of overflow.

Overseal — An additional closure that tamper-proofs the primary closure. The overseal is usually made of foil or aluminum.

Pail — A flaring or tapered body metal container equipped with a bail or handle.

Paneling — Distortion, sidewall collapse of a container occurring during aging or storage. Paneling is caused by the development of a reduced pressure inside the bottle.

Parting Line — A mark on a molding or casting where the halves of mold meet in closing.

Permeability — The passage or diffusion of a gas, vapor, liquid, or solid through a barrier without physically or chemically affecting it.

PET (Polyethylene Terephthalate) — Known as thermoplastic polyester. PET has the unusual ability to exist in either an amorphous or highly crystalline state. The crystalline state is necessary for extruding the material. The amorphous state permits it to be oriented.

Phenolic lining — A synthetic phenolic resin baked on as a lining. It provides a non-reactive barrier between the metal plates and atmosphere or one or more of various types of paints or chemical products.

Pigment — This is inorganic material of various hues added to coatings on varnishes in order to color them.

Pipette — The glass or plastic tube portion of a medicinal dropper closure.

Pitch — The number of turns a thread would circle a neck if the neck were extended one inch. Pitch is commonly referred to as threads per inch.

Plasticize — To soften a material and make it plastic or moldable by means of a plasticizer or the application of heat.

Plastisol — A liquid mixture of resins and plasticizers solidified by the application of heat.

Polyethylene — A thermoplastic material composed of polymers of ethylene. It is normally a translucent, tough, waxy solid unaffected by water and a large range of chemicals.

Polypropylene — A tough, light-weight rigid plastic made by the polymerization of high-purity propylene gas in the presence of an organometallic catalyst at relatively low pressures and temperatures.

Polystyrene — A water-white thermoplastic produced by the polymerization of styrene (vinyl benzene).

Polyvinyl Chloride (PVC) — A thermoplastic material composed of polymers of vinyl chloride. PVC is a colorless solid with outstanding resistance to water, alcohols, and concentrated acids and alkalies

Pour-Out Finish — A container finish having uniform undercut lips as a sealing surface. The pour-out finish is designed to facilitate pouring without dripping.

Preform — Used in the blow molding processes. A heat-softened polymer is formed into a shape similar to a thick test tube with neck threads. This tube is subsequently inflated while inside a blow mold to create the shape of the desired article.

Programming — The extrusion of a parison that differs in thickness in the length direction in order to equalize wall thickness of the blown container.

Push-Up — The recessed area on the bottom of a bottle designed to allow an even bearing surface on the outside edge to prevent the bottle from rocking.

Regrind — A thermoplastic from a processor’s own production that has been cleaned and reground.

Removal Torque — The torque force, measured in inch-pounds, required to unscrew a closure from a container.

Resin — Any class of solid or semi-solid organic products of natural or synthetic origin, generally of high molecular weight, with no definite melting point. Most resins are Polymers.

Screen Printing A printing technique involving the passage of printing medium, such as ink, through a web or fabric, which has been stretched on a frame, to which a refined form of stencil has been applied. The stencil openings determine the form and dimensions of the imprint thus produced.

Sealing Surface — The lip portion of the finish that makes contact with the sealing gasket or liner to form a seal.

Shell — The hat shaped, preliminary form of a metal closure prior to being threaded and knurled.

Shrinkage — The decrease in dimension a molded article undergoes after being molded. Shrinkage is caused by cooling and subsequent contraction of the plastic material.

Side Seam — The seam joining the two edges of a blank to form a body.

Sifter Fitment — A plastic component of a package designed to allow the shaking out of dry products, such as a table salt shaker. The sifter fitment snaps over the glass bead with a metal or a plastic cap applied over the fitment.

Skirt — The vertical wall of a closure.

Slip Cover — The removable cover in which the cover proper fits over and around the open end of can. The position is retained by friction fit.

Snap Fit Closure — A closure held in place through the use of beads or undercuts rather than threads.

Spiral Can — A laminated fiber container formed by winding material around a cylinder at an angle to its axis.

Spiral Winding — A diagonal wrapping or paper plies in continuous operation.

Spout Cap — A closure designed to facilitate the pouring of the contents of the container.

Stacker Cap — A closure designed specifically to nest with the bottom plate of a container to facilitate the stacking of filled containers one on top of each other.

Straight Sided — A round can or pail that has the same top and bottom diameter; a straight body metal container that must be stacked upon the top of another.

Stress Crack — An external or internal crack in the plastic caused by tensile stress less than that of its short-time mechanical strength. The development of such cracks is frequently accelerated by the environment to which the plastic is exposed. The stresses that cause cracking may be present internally or externally or may be combinations of these stresses.

Stripping Torque — The amount of application torque that causes the threads of the closure to override the container threads.

Surface Treating — Any method of treating a plastic to alter the surface and render it receptive to inks, paints, lacquers and adhesives. Examples of surface treating are chemical, flame, or electronic treating.

Tamper Band — The tamper-evident feature of the closure. The tamper band is usually connected to the closure skirt by leaders or bridges.

Tamper Evident Breakaway Band Closure — The section of the closure skirt that is weakened or perforated in some manner. When the closure is opened that section is designed to either remain on the container or stay partially attached to the closure. The tamper evident breakaway band closure is designed to reveal removal of the closure was attempted.

Tamper Evident Closure — A closure or liner system incorporating a feature that visually indicates if the closure has been removed or the product has been exposed. Removal of the closure or liner system activates the indicating feature.

Tamper Evident Tear Band — A closure with a band, usually with a tab for grasping, designed to be detached by the consumer. The tamper evident tear band is designed to reveal removal of the closure was attempted.

Tapered nesting pail — A flared or tapered body metal container formed with a nesting ring which allows one container to be stacked within another.

Thermoplastic — Capable of being repeatedly softened by heat and hardened by cooling.

Thermoset — A material that will undergo or has undergone a chemical reaction by the action of heat, catalysts, ultraviolet light, etc., leading to a relatively infusible and cross-linked state. Typical of the plastics in the thermosetting family are the epoxies, glytals, melamines, urea formaldehyde resins, and phenolics. Thermosets are typically supplied in powder, granules, or modules, and are normally processed by compression molding. Thermosets cannot be remolded once processed.

Thread — Complimentary, helical protrusions on the closure and the container.

Thread Profile — The cross section configuration of a closure thread.

Thread Engagement — The actual contact made by the closure and bottle finish thread. Thread engagement is usually specified in number of turns.

Thread Start — The position at which the full thread depth toward the open end of the closure first occurs.

Thread Turns — The measurement of thread revolutions in a closure or on a container finish.

Tinplate — A thin sheet of steel with a layer of tin used in manufacturing metal closures.

Tolerance — The permissible maximum deviation from specified dimensions, quantities, or specifications. The amount of variation allowed from the nominal dimension.

Tooling — The specific components in contact with the plastic that form the closure.

Top Load — The amount of weight bearing on the top of a container.

Torque — The rotational movement used during application or removal of a continuous thread closure from a container.

Torque Meter — A devise used to measure application and removal torque. It is expressed in pound-force inches and commonly referred to as "inch-pounds."

Unlined Closure — A closure without a liner disk inserted, but designed to accept one.

UV Stabilizer — Any chemical compound which, when admixed with a thermoplastic resin, selectively absorbs UV rays and minimizes chemical and/or physical changes that may be engendered by UV.

Valve Cap — A closure that includes a valve to regulate the flow of the product from the container.

Value Seal — A sealing devise which seals on the inside of the neck finish of the container in the fashion of a plug. A controlled inside finish diameter is required to accomplish a seal.

Volume — Referred to as "Displacement" and also as "Capacity." The amount of water displaced by a model of a bottle. Volume is used to estimate its capacity. (2) The amount of product a bottle is designed to hold, i.e., up to the fill point of the bottle.