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Glossary of terms

The following is a glossary of terms and abbreviations in closure design and testing.

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z


anti-refill   A safety closure designed to prevent refilling of the bottle. Usually by a one-way valve mechanism, typically for the alcoholic beverages and spirits industries.
application torque   The torque required to securely attach a rotationally operated closure to its container. This is usually the minimum value to provide a proper seal and still permit acceptable ease of removal.

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back-off   Loss of torque once the closure has been applied, caused by the closure physically rotating back from its applied position. This can be caused by design factors or in-service conditions such as liner material properties or top-loading.
breakaway   Static torque required to initiate a closure moving in relation to a container.
bridge torque   Torque required to break bridge segments joining a cap and a tamper-evident band.

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cap adapter   An alternative term for mandrel.
capsule   (or foil) The protective sleeve covering a wine bottle cork. Usually tin or heat-shrink plastic (polyethylene or PVC), or aluminium or polylaminate aluminium. Originally, but no longer made of lead.
carbonation loss   Gas escape from a cap seal or thread.
cellular cork   ISO 7322 2014 composition cork test standard.
Child-Resistant Closure (CRC)   A closure usually featuring a dual or simultaneous action, to resist simple pull or twist removal.
crown cork   Crimped-on metal cap; may be lever-off or twist-off.

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disc closure   Cap featuring a two-position rocking disc with inner stopper, to expose a dispensing orifice.

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finish   The container region that engages with the closure, also ‘neck finish’ phrase used in some test standards.
flip-top (flip cap)   Hinged cap with integral stopper.

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incremental torque   This test is used to measure the removal torque of a cap and then reapply the cap to a specific position beyond the original starting position. This test is designed to be a non-destructive test, and prevent leaking problems by reapplying the cap to a secure position.
induction sealing   Method of fusing a layer to the top of the finish of a container, to effect a seal.

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liner   Inert layer integral to a cap, to effect a non-contaminating seal.
lug-style   Cap with a small number of lugs engaging an equivalent number of short threads on a container.

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mandrel   Device fitting the profile of a closure to enable circumferential gripping without deformation.

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over torque   Another term for strip torque.

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parasitic torque   Additional resistance to removal other than due to pristine closure contact surfaces.

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removal torque   Typical proxy for application torque, measures breakaway and initial running torque.
repeatability   Ability to run a test to identical parameters.
reproducibility   Ability to produce the same results.
re-torque   Required after induction sealing process (torqued to seat on the seal).
reverse ratchet torque   Torque to turn a two-part CRC without internal engagement of the two parts.
ROPP   Roll-on pilfer proof (e.g. Stelvin wine cap).
ROTE   Roll-on tamper evident: ROPP with an additional plastic reveal band. Also used to combat counterfeiting.
running torque   Dynamic torque required to maintain rotation.

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slip torque   Another term for breakaway torque.
strip torque   Torque required to over-tighten a screw cap and over-ride the thread.

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tamper-evident (TE)   Part of a closure that breaks away on first opening to indicate that a container has been opened.
tamper-resistant (TR)   Simple features to inhibit opening (e.g. a label or tape over a join).
TEB   Tamper-evident band.
teeth   Crown cork cap - note also now available as a twist off.
thread-locking   Parasitic torque caused by spilled contents on the thread drying and causing adhesion.
torque   Turning force causing rotation about an axis.
top-load   Axial force to cause engagement between two-part CRCs.

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wadding   Another term for cap liner.

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