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Glossary of Packaging Terms

ANNEALLING

A temperature controlled process by which glass is gradually cooled in “Lehrs” to reduce stresses and strains within the glass due to or uneven cooling. Glass which is not properly annealed is more susceptible to thermal shock and breakage.

AQL

Abbreviation for acceptable quality level. A quality control method which outlines how many defective units are acceptable for a given sample.

BACK OFF

Loosening of a cap due to improper application, incompatible cap and container selection, vibration or impact during transit or general use.

BLOW MOLDING

The process by which a “Parison” (a warm hollow tube) is placed in a mold and forced to assume the shape of a given mold “cavity” through air pressure. Once the parison has reached the limits of the cavity, the mold is opened and the finished product is ejected. For our purposes, there are three main types of blow molding processes- “Extrusion Blow Molding”, “Injection Blow Molding” and “Stretch Blow Molding”.

BLOWN GLASS

Process by which molten glass is forced into a “Mold” to assume a desired shape. Containers are then ejected or extracted from the mold and undergo an “Annealling” process to relieve stress and temper the glass for everyday use.

BOSTON ROUND

A style of bottle characterized by a round cylindrical body and a short, curved shoulder. Typically used by the drug, chemical and essential oil industries, Boston Round bottles are traditionally made of Amber Glass, but are also made of various plastic resins and colors.

CAPACITY

Related closely to “Volume”, for the purposes of our website, capacity refers to the amount of water a given container will hold. For example, our 270ml Hex Jar has a capacity of 270 milliliters (ml), or 9.1 fluid ounces (oz). Depending on your particular product and how it compares to water, the “Net Weight” of your finished good might be heavier or lighter than containers fluid capacity. Please also note the difference between capacity and “Overflow Capacity” 

CAVITY

The hollow part of a “Mold” which determines the shape of a particular container.

CC

Cubic centimeter. A unit for measuring volume, where 1 cc = 0.0338 ounce.

CHEMICAL RESISTANCE

The ability of a container to maintain form and function when exposed to chemicals. Chemical resistance is determined based on a containers ability to resist the following properties- Discoloration, swelling, softening, material degradation and structural integrity.”

CHILD RESISTANT CLOSURE

Abbreviated CR—A closure that requires two distinct, dissimilar motions which make removal by a child difficult. Two common examples are “Push Down & Turn Closures (PDT)” and “Squeeze Lock Closures”

CO-EXTRUSION

Melting two or more layers of “Thermoplastic Resin” materials to form a chemically combined resin which is often more ridged, has higher tolerances to heat, moisture, oxygen and chemicals when compared to single extrusion containers. Limited to plastics.

COMPATIBILITY

Ability of a container, closure and product to co-exist without reduction in form and function starting when the container in question is originally filled through its required product life-

CONTINUOUS THREAD FINISH

Abbreviated CT—an uninterrupted thread found on the neck of both plastic and glass containers.

 Continuous thread (CT) is a type of “finish” found on many glass and plastic containers where the “threads” wrap continuously around the “neck” of a given container. Continuous thread finishes can be found on both glass and plastic containers. Containers with a continuous thread finish require corresponding continuous thread caps which are easily applied by hand and provide a great seal between the rim of a given container and its corresponding cap. Continuous thread containers (& caps) are often shown as two numbers, separated by a back slash. The first number refers to the diameter of the opening of a jar from rim to rim, measured in millimeters. The second number refers to the depth of a closure. For the purposes of our website, the most shallow continuous closure is 400 (expressed as x/400) while the “deepest” closure is denoted as 485. 

DEBOSSING

Depressing portions of a surface below the standard surface level. Debossing can be found on glass, metal, plastic and/or closures. Debossing requires a custom “mold” and is generally done for aesthetic purposes to create lettering or a company’s logo.

DEEP SKIRT

A cap which has a deeper appearance.

DEFLASHING

The process by which extra material, also known as “flash”, is removed from a molded container.

DESICCANT

A drying agent which helps controls humidity levels in sealed packages

DIE

A tool or device to cut, shape or form a given material into a desired shape.

DISC TOP CAP

Injected molded dispensing closure which reveals an “orifice” when pressure is applied to a designated area on the top of the cap. Commonly found on sunscreen and other cosmetic containers.

DOME

A style of closure where the top surface is rounded. Dome caps create a sleek appearance and are often used in conjunction with Round Bottom Jars.

DROP TEST

A method of testing in which a container, or collection of containers (case) is dropped from a standard height a specific number of times, or until the items fails.

EMBOSS

Raised design or lettering on the surface of an object, usually for decorative or branding purposes.

ENVIRONMENTAL STRESS CRACKING

The susceptibility of a thermoplastic article to cracking or crazing under the influence of certain chemicals and stress

EXTRUSION BLOW MOLDING

A plastic manufacturing process by which a “parison”, (a warm, hollow plastic sleeve, or tube) is pushed, or extruded from a die. While the parison is still warm, two halves of a mold, (a template for the final shape) enclose the parison and through the use of air pressure, expand to fill the mold cavity. Once the plastic has sufficiently cooled, the mold is opened and excess plastic, also known as “Flash” is removed through a process known as “Deflashing”.

F217 LINER

A foam liner found in plastic caps which is comprised of a low density foam core between two solid layers of low density polyethylene. F217 liners provide excellent chemical resistance and greatly reduce the transmission of moisture.

FILL POINT

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

FINE MIST SPRAYER

A style of dispensing closure which produces a fine, splatter free mist.

FINISH

The specifically shaped container opening which will eventually accept a specific closure. Two common types of finishes include “Continuous Thread (CT)” and “Twist-Off (T/O)or Lug Finish”.

FITMENT

Used in combination with a primary, non-dispensing closure, a fitment is inserted within the neck of a bottle to impede the flow of a given product. The user will remove the primary closure to dispense product, while the fitment remains.

FLAME TREATING

A process by which plastic containers are exposed to an open flame to promote oxidation and increase receptivity to inks, paints and adhesives.

FLASH

Extra plastic attached to a particular item found along the Parting Line. Before the item can be considered a finished good, it must go through a “Deflashing” process.

FLINT

Clear glass used for all types of containers.

FOIL LINER

Found in metal caps, foil liners are laminated with polyester film and bonded to a pulp board backing. Foil liners are resistant to hydrocarbon based products, such as paraffin wax and oil based products. Foil liners are not recommended for use with highly acidic or alkali products.

FTL

Abbreviation for full truckload.

GLASS DROPPER

Closure with a plastic bulb and glass pipette which extends into a given container. When the plastic bulb is squeezed, product is drawn into the pipette and dispensed as needed. Commonly paired with Boston Round bottles & Vials for cosmetics, essential oils and fragrances.

HDPE

Abbreviation for high density polyethylene. A naturally translucent and moderately rigid thermoplastic resin, HDPE provides an excellent moisture barrier, has excellent impact and cold resistance. HDPE has maximum recommended fill temperature of 160°F and provides a poor oxygen barrier. For more information, please visit our resin information page.

HEADSPACE

Space between the “Fill Point” of a container and the closure. Headspace is required to allow for expansion due to heat or pressure.

HEEL

The lower portion of a container where the body begins to curve into the base and usually terminates at the resting point.

HERMETIC SEAL

An airtight, or vacuum seal which will completely prevent the transfer of air and/or other gases.

IMPACT RESISTANCE

The ability of a given container to maintain form and function when dropped or subjected to other physical force or impact.

INDUCTION MACHINE

A machine, which emits an oscillating, electromagnetic field to seal a foil lined cap to a particular container.

INDUCTION SEALING

A process, which bonds a specialized foil liner over the opening of a plastic container through the use of induction current (produced with an “Induction Machine”), which heats the foil liner & polymer coating creating a bond between the liner and rim of given container. The liner will remain in place until the consumer physically removes the liner before use. Induction sealing has been recognized by the FDA as an effective method of tamper evidency.

INDUCTION SEAL LINER

A specialized liner, comprised of several layers including wax, foil and a polymer coating which bonds to the lip of a given container through the use of an “Induction Machine”. The type of liner required is determined by the material of the container in question.  

INJECTION BLOW MOLDING

A two-stage process of plastic bottle manufacturing where a “preform" is “injection molded”. The “finish” of the given container is formed at this time. The preform is then transferred to a blow mold where the “Axial Rod” stretches the preform vertically while air pressure forces the preform to take the shape of a given cavity.

INJECTION MOLD

A mold into which a plastic resin is introduced by pressure from an exterior heated cylinder.

INJECTION MOLDING

A molding process whereby a heat softened plastic resin is forced from a heating cylinder into a relatively cool cavity which gives the product a desired shape.

LABEL PANEL

The area of a given container where labels are applied or decoration is printed.

LDPE

Abbreviation for low density polyethylene. LDPE is very similar to “HDPE” in composition, but differs in the branching structure of the polymerized ethylene. LDPE, when compared to HDPE, has polymer chains consisting of many branches, producing a less compact molecular structure. Due to its decreased density, LDPE bottles are great for products which require a squeeze application. For more information, please visit our resin information page.

LIFT GATE (DELIVERY)

Used to lower a pallet from the back of tractor trailer to the ground. If access to a fork truck and/or loading dock is not available at a given delivery location, for an additional charge, lift gate service can be requested. The request must be made before a given order leaves Burch Bottle’s warehouse.

LIGHT RESISTANCE

The ability of a plastic item to withstand exposure to sunlight or ultraviolet light without fading to compositional degradation.  Nearly all plastics tend to darken when exposed.

LINERLESS CLOSURE

A type of plastic closure which has a sealing ring around the top of the cap where contact with a given container will occur. When a linerless closure is matched to a compatible container, the sealing ring will prevent liquid from leaking. Differs from an “Unlined Closure”.

LTL

Less than truck load. Any shipment not meeting the required weight, or number of pallets to be considered a “Full Truckload (FTL)”.

LUG FINISH

Also called a “Twist-Off (T/O) Finish”. Found on the neck of glass containers, a lug finish is identified by intermittent, non-continuous threads which allow specially designed caps to slide between the threads and close tight with a partial turn of the cap.

MOLD

The tool used to form the shape of the desired product in a repetitive manner.

MULTI-CAVITY MOLD

A mold with more than one cavity impressions. Although additional startup expenses are required, a multi-cavity mold is more productive in that it produces two or more bottles per molding cycle.

MULTI-LAYERED

A bottle which is co-extruded with two or more layers of plastic. Multi-layered plastic containers allow for higher fill temperatures, higher chemical resistance and decreased oxygen transmission.

NECK

Found just above the shoulders of a container, the neck is the uppermost section where the “finish” is found.

OPAQUE

A descriptive property of a material or substance which will not transmit light.

ORIFICE

An orifice is the opening of a container through which a given product is dispensed.

ORIFICE REDUCER

Plug or fitment which reduces the flow of a given product.

OVERFLOW CAPACITY

The capacity of a container when filled to the point of overflow. The overflow capacity differs from a containers “Fill Point”. 

PAIL LID

HDPE lid with sealing gasket.

PANELING

Occurs when the pressure of a filled container decreases in comparison to the ambient pressure outside, causing the walls partially collapse resulting in a “sucked in” appearance. Paneling occurs with plastic containers- glass is not susceptible to paneling. The most common reason for paneling is when a given product is hot filled into a plastic container. As air (located in the “Head Space”) and the product cools and contracts, negative pressure causes the walls of the container to also contract.

PARISON

A warm, hollow, tube like piece of plastic resin from which a container is manufactured based on the shape of a given mold.

PERMEABILITY

The rate at which a gas, vapor, liquid or solid passes or diffuses through a porous material, such as a plastic container.

PET

Abbreviation for Polyethylene terephthalate. In its natural state, PET is a colorless, transparent thermoplastic resin. Based on processing, PET can be semi-rigid to rigid, very lightweight and impact resistant. PET also provides a fair oxygen barrier and moisture barrier. For more information, please visit our resin information page.

PHENOLIC

Generic name for phenol-formaldehyde, a type of “Thermosetting Plastic”. Phenolic caps feature a LDPE cone which seals the inside diameter of a given container making phenolic caps ideal for chemicals, essential oils and other aggressive products.

PLASTISOL LINER

A pliable, “PVC” based material found around the inside of both “Continuous Thread (CT)” and “Twist-off (T/O) or Lug” metal closures. When warm plastisol molds to the rim of a matching container, the result is a gasket-like effect. Upon cooling, the plastisol resin solidifies, creating an airtight, vacuum seal. Plastisol lined caps are not recommended for use with home canning processes which subjects the caps to temperatures exceeding 212°F for extended periods as distortion can occur.

POLYCONE CAP

Phenolic cap with a LDPE cone shaped liner which makes contact with the inner diameter of a given container to prevent leakage of liquid products. Recommended for essential oils and other aggressive products.

POLYETHYLENE

Abbreviated as PE, polyethylene is a “Thermoplastic Resin” and categorized by its density. From a packaging standpoint, “high density polyethylene (HDPE)” and “low density polyethylene (LDPE)” are the two most common forms.

POLYMER

A substance whose molecular structure is comprised of a large number of similar units which are bonded together.

POLYPROPYLENE

A translucent, semi rigid, thermoplastic polymer that provides a good moisture barrier, and is highly resistant to acid and alcohols. One of the main advantages of polypropylene is its ability to withstand temperatures up to 212°F. On the flip side, polypropylene can become brittle and susceptible to cracking under cold temperatures. For more information, please visit our resin information page.

POLYSTYRENE

Abbreviated PS, Polystyrene is a clear plastic which is very rigid, but exhibits poor impact strength. Some disadvantages of polystyrene are its inability to withstand high temperatures, cold temperatures and highly acidic products.  For more information, please visit our resin information page.

POLYVINYL (PV) LINER

Found in metal closures, PV liners feature a polyvinyl film with pulp board backing. Polyvinyl liners are resistant to mild acids, alkalis and solvents. Not recommended for active hydrocarbon or bleach based products.

PREFORM

Similar to a “Parison”, a preform is an injection-molded tube-like piece of plastic which has the “Finish” or threads of a particular container already in place.  The preform is then heated and through “Stretch Blow Molding” transformed into a finished product.

PS-22 LINER

A type of liner, composed of a pressure sensitive (PS) foam and adhesive.  When pressure (such as screwing a cap onto a particular container) is exerted, the adhesive sticks to the rim of the container. When the end user removes the cap for the first time, the PS-22 liner remains, which the customer will remove before use.

PUMP

Allow products to be evenly dispensed with each stroke.  Lotion pumps and treatment pumps are available. Generally speaking, lotion pumps dispense more product per stroke than treatment pumps.

PURGING

In plastic bottle manufacturing, purging is the process by which a particular resin or color is forced out of the extruder or injection cylinder before a different resin or color can be used.

PVC

Abbreviation for Polyvinyl Chloride. PVC is a rigid, transparent plastic which provides excellent resistance to oxygen permeation, excellent resistance to oils and fair impact resistance.

RECESSED PANEL

An aspect of container design in which the flat area for labeling is indented or recessed.

REGRIND

In plastic bottle manufacturing, regrind is excess material from “flash” and trimmings which is usually blended with virgin material and remolded.

REIKE PAIL LIDS

Lid for plastic HDPE pails which has a spout for dispensing product.

RESIDENTIAL DELIVERY

Additional charge which applies to freight shipments where the delivery location is not a business.

RESINS

Physically similar polymerized synthetics or chemically modified natural resins including polyvinyl chloride (PVC), polystyrene (PS), high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP) and polyethylene terephthalate (PET).

RIBBED CLOSURE

Series of vertical grooves around the outside edge which help the end user establish a grip to remove a given closure. Ribbing can be found on many styles of plastic caps such as lotion pumps, snap-top caps, as well as standard, non-dispensing plastic closures.

SEALING SURFACE

The lip, or rim of a glass or plastic container which will make contact with a given cap and/or liner to create a seal.

SHOULDER

Part of a container found between the main body and the neck.

SIFTER FITMENT

A plastic or metal disc which snaps over the bead, or rim of a given container which regulates the amount of product, usually a spices or meat rubs dispensed when shaken.

SKIRT

A part, or attachment serving as a rim, border or edging.

SMOOTH CLOSURE

The opposite of a “Ribbed Closure”, smooth closures are often preferred for their visual appeal. Smooth closures can be found in many styles, including lotion pumps, snap top caps, flip top caps and standard, non-dispensing plastic caps.

SNAP TOP CAP

A type of dispensing cap that features an “orifice”, of various sizes with a hinged lid to prevent leakage.

SPICE CAP

Dispensing closure which has built in sifter holes to dispense product when shaken.

SPOUT CAP

A plastic, dispensing closure which reveals and orifice for dispensing product when a spout is lifted from the top of the cap.

STORAGE LIFE

The period of time that a given product can be stored under specified temperature conditions and remain suitable for use.

TAMPER RESISTANT SEAL

A seal, such as a foil seal induction liner that cannot be opened without destroying part of the closure system.

TAMPER-EVIDENT BAND

A secondary closure which must be removed, torn or broken before a container is opened.

THERMAL SHOCK

A condition which can cause glass to crack, shatter or break due to rapid changes in temperature. The “Annealing” process helps to relieve internal stresses within the glass and reduce a particular containers susceptibility to thermal shock.

THERMOPLASTIC RESIN

A plastic resin which is soft and pliable when exposed to heat, rigid at normal temperatures and has the ability to become soft and pliable upon the reapplication of heat.  Common thermoplastic resins include, PET, PVC, PP, HDPEL, LDPE and PS.

THERMOSET

A plastic resin which permanently hardens through the formation of chemical bonds when heated. Thermoset resins do not revert to their liquid or pliable state when reheated. 

THREAD

Helical protrusions found on the skirt of a container and complimentary caps. Threads can be continuous “Continuous Thread (CT)”, or intermittent (broken), which describe “twist-off (T/O), or lug caps”.

TOLERANCE

An acceptable allowance for deviations from standard dimensions or weight without compromising form and/or function

TORQUE - APPLICATION

The amount of rotational force required for application and/or removal of a given closure. Excessive

torque may result in a stripped cap which causes improper alignment of threads between a given

container and closure resulting in loose caps and no seal. Caps which are applied with proper torque will remain sealed under expect conditions of temperatures, vibration, humidity and pressure.

TORQUE TESTER

A device which measures the application and removal torque of a given closure. Measurements from a torque tester can be used to adjust the torque used by a capping machine, especially helpful for the application of lug, or twist-off caps which are prone to stripping if too much torque is used during application.

TRANSLUCENT

Description of a given material which permits the passage of light, but is not clear enough to be seen through.

TRANSPARENT

Description of a given material or substance which permits the passage of light and is clear enough to be seen through.

TRIGGER SPRAYER

A type of closure which dispenses product as a stream or mist.

TUB LID

Flexible plastic closure with grooves which mate to a particular plastic tub and provide a leak-proof seal.

TWIST TOP CAPS

Dispensing closure which reveals and orifice when the top is twisted. Most commonly seen on glue containers, twist top caps are great for dispensing viscous products such as condiments and lotions

UNLINED CLOSURE

A closure which does not have a liner. Differs from a “Linerless Closure

VACUUM CLOSURE

Any closure equipped with a liner capable of holding a vacuum. For our purposes, these are plastisol lined closures which are available for both “Continuous Thread” and “Twist-Off (T/O) or Lug” finishes.

VOLUME

Closely related to “Capacity”, volume is the amount of substance a given container is designed to hold. For our purposes, the volume of a container is measured in fluid ounces (oz.), milliliters (ml) or any other fluid measurement.

YORKER SPOUT CAPS

A LDPE spouted dispensing closure which reveals an orifice when red cover is removed from the tip.