A closure is a device used to close or seal a

container A container is any receptacle or enclosure for holding a product used in storage, packaging, and transportation, including shipping. Things kept inside of a container are protected on several sides by being inside of its structure. The term ...

such as a

bottle A bottle is a narrow-necked container made of an impermeable material (such as glass, plastic or aluminium) in various shapes and sizes that stores and transports liquids. Its mouth, at the bottling line, can be sealed with an internal ...

jug A jug is a type of container commonly used to hold and serve liquids, but not normally to drink from directly. It has an opening, sometimes narrow, from which to pour or drink, and has a handle, and usually a pouring lip. Jugs throughout histor ...

, jar,

tube Tube or tubes may refer to: * ''Tube'' (2003 film), a 2003 Korean film * "Tubes" (Peter Dale), performer on the Soccer AM television show * Tube (band), a Japanese rock band * Tube & Berger, the alias of dance/electronica producers Arndt Rör ...

, or can. A closure may be a cap, cover, lid, plug, liner, or the like. The part of the container to which the closure is applied is called the finish. Other types of containers such as

box A box (plural: boxes) is a container with rigid sides used for the storage or transportation of its contents. Most boxes have flat, parallel, rectangular sides (typically rectangular prisms). Boxes can be very small (like a matchbox) or v ...

es and

drum The drum is a member of the percussion group of musical instruments. In the Hornbostel–Sachs classification system, it is a membranophone. Drums consist of at least one membrane, called a drumhead or drum skin, that is stretched over a ...

s may also have closures but are not discussed in this article. Many containers and packages require a means of closing, which can be a separate device or seal or sometimes an integral latch or lock.

Purpose of closures

The closure is often the most critical part of a package, and must fulfill all of the basic functions of packaging in addition to being easy to open and (if applicable) reclose. Depending on the contents and container, closures have several functions: * Keep the container closed and the contents contained for the specified

shelf life Shelf life is the length of time that a commodity may be stored without becoming unfit for use, consumption, or sale. In other words, it might refer to whether a commodity should no longer be on a pantry shelf (unfit for use), or no longer on a s ...

until time of opening * Provide a barrier to dirt, oxygen, moisture, etc. Control of

permeation In physics and engineering, permeation (also called imbuing) is the penetration of a wikt:permeate#English, permeate (a fluid such as a liquid, gas, or vapor) through a solid. It is directly related to the concentration gradient of the permeate, ...

is critical to many types of products: foods, chemicals, etc. * Keep the product secure from undesired premature opening * Provide a means of reclosing or reusing the container * Assist in dispensing and use of product * Allow reasonable ease to open the container by the intended user. Difficult to open containers may cause wrap rage. The

force In physics, a force is an influence that can cause an Physical object, object to change its velocity unless counterbalanced by other forces. In mechanics, force makes ideas like 'pushing' or 'pulling' mathematically precise. Because the Magnitu ...

torque In physics and mechanics, torque is the rotational analogue of linear force. It is also referred to as the moment of force (also abbreviated to moment). The symbol for torque is typically \boldsymbol\tau, the lowercase Greek letter ''tau''. Wh ...

required to open a closure is an important consideration for packaging engineers. Many types of packaging with their closures are regulated for strength, safety, security, communication, recycling, and environmental requirements plus many others.

Types of closures

Closures need a means of attaching to the container with sufficient security. Threads, lugs, hinges, locks, adhesives, etc. are used. Many plastic closures are made by

injection molding Injection moulding (U.S. spelling: injection molding) is a manufacturing process for producing parts by injecting molten material into a mould, or mold. Injection moulding can be performed with a host of materials mainly including metals (for ...

. Many closures need to have the ability to adjust to slight manufacturing variation in the container and the closure structure. Some closures are made of flexible material such as cork,

rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Types of polyisoprene ...

, or plastic foam. Often an

o-ring An O-ring, also known as a packing or a toric joint, is a mechanical gasket in the shape of a torus; it is a loop of elastomer with a round cross section (geometry), cross-section, designed to be seated in a groove and compressed during assembl ...

or a closure liner (

gasket Some seals and gaskets A gasket is a mechanical seal which fills the space between two or more mating surfaces, generally to prevent leakage from or into the joined objects while under compression. It is a deformable material that is used to c ...

made of pulp or foam cap liner) is used. Linerless closures often use a deformable plastic rim or structure to maintain the seal. Secondary seals are common with sensitive products that may deteriorate or where extra security is needed. Foil or plastic inner seals are used on some bottles, Heat sealed lidding films are used on some tubs. External shrink bands,

label A label (as distinct from signage) is a piece of paper, plastic film, cloth, metal, or other material affixed to a container or product. Labels are most often affixed to packaging and containers using an adhesive, or sewing when affix ...

s, and tapes are sometimes used outside the primary closure structure. Additionally, many closures feature ventilation to prevent bloating, collapse or explosion due to unequalized pressure during processing or storage. Venting technologies utilize common materials such as

PTFE Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene, and has numerous applications because it is chemically inert. The commonly known brand name of PTFE-based composition is Teflon by Chemours, a spin-off fro ...

, PP, etc. These elements are preferred due to their ability to withstand temperatures of 260 °C and water intrusion pressure levels of 770 mbar.

Screw top

A screw closure is a mechanical device which is screwed on and off of a threaded "finish" on a container. Either continuous threads (C-T) or lugs are used. Metal caps can be either preformed or in some instances, rolled on after application. Plastic caps may use several types of molded polymer. Some screw tops have multiple pieces. For example, a

mason jar A Mason jar, also known as a canning jar, preserves jar or fruit jar, is a glass jar used in home canning to food preservation, preserve food. It was named after American tinsmith John Landis Mason, who patented it in 1858. The jar's mouth has a ...

often has a lid with a built in rubbery seal and a separate threaded ring or band.

Crown cap

Beverage bottles are frequently closed with crown beverage caps. These are shallow metal caps that are crimped into locking position around the head of the bottle.

Snap on

Some closures snap on. For opening, the top is designed to pry off or, break off, or have a built in dispenser.

Friction fit

Some containers have a loose lid for a closure.

Laboratory glassware Laboratory glassware is a variety of equipment used in science, scientific work, traditionally made of glass. Glass may be blown, bent, cut, molded, or formed into many sizes and shapes. It is commonly used in chemistry, biology, and analytical ...

often has ground glass joints that allow the pieces to be fitted together easily. An

Interference fit An interference fit, also known as a pressed fit or friction fit, is a form of fastening between two tightfitting mating parts that produces a joint which is held together by friction after the parts are pushed together. Depending on the amoun ...

or friction fit requires some force to close and open, providing additional security. Paint cans often have a friction fit plug.

Tamper-evident

Resistance to tampering is required for some types of products. Container closures can be one of several layers of packaging to deter tampering and to provide evidence of attempts at tampering. *Sometimes tamper resistance is obtained by a tamper-evident band; separate or integral with the closure.

Dispensing

A wide variety of convenience dispensing features can be built into closures.

Spray bottle A spray bottle is a bottle that can squirt, spray or mist fluids. History While spray bottles existed long before the middle of the 20th century, they used a rubber bulb which was squeezed to produce the spray; the quickly-moving air siphone ...

s and cans with

aerosol spray Aerosol spray is a type of dispensing system which creates an aerosol mist of liquid particles. It comprises a can or bottle that contains a payload, and a propellant under pressure. When the container's valve is opened, the payload is forced out ...

(valves, actuator) have special closure requirements. Pour spouts, triggers, sprayer cap, measuring attachments, sifting devices, etc. are common caps.

Spray bottle

A spray bottle is a bottle that can dispense, squirt, spray or mist fluids. A common use for spray bottles is dispensing cool cleaners, cosmetics, and chemical specialties.

Child-resistant

Child-resistant packaging or C-R packaging has special closures designed to reduce the risk of children ingesting dangerous items. This is often accomplished by the use of a special safety cap. It is required by regulation for prescription drugs, over-the-counter medications, pesticides, and household chemicals.

Examples

File:Spray bottle.jpg, Spray bottle cap File:Erlat.jpg, rubber stoppers on flasks File:Canned-air.jpg, spray duster with long tube for dispensing File:Closure with Roll on dispenser.jpg, Closure and roll-on device for deodorant File:Closure - dispensing and innerseal.jpg, Inverted ketchup bottle with innerseal and dispensing closure Image:Geritol tonic.jpg, Bottle of Geritol with a child-resistant cap File:Swing-top bottle.JPG, An opened flip-top bottle closure File:Wine bottle screwcap.JPG, A screw cap capsule is fitted onto a wine bottle and heat shrunk tightly File:Stöpselbild Seestadt Aspern.jpg, Recycled bottle stoppers as art in Vienna File:Mint box polypropylene lid.JPG, A living hinge on the lid of a Tic Tac box

History

Early pottery and ceramic containers often had lids that fit reasonably snug onto the body of the container. The narrow necks of ancient

amphora An amphora (; ; English ) is a type of container with a pointed bottom and characteristic shape and size which fit tightly (and therefore safely) against each other in storage rooms and packages, tied together with rope and delivered by land ...

were closed with a plug of cork, wood, or ceramic and sealed with mortar. Wooden

Barrel A barrel or cask is a hollow cylindrical container with a bulging center, longer than it is wide. They are traditionally made of wooden stave (wood), staves and bound by wooden or metal hoops. The word vat is often used for large containers ...

s often had

bunghole A bunghole is a hole bored in a liquid-tight barrel to remove contents. The hole is capped with a cork or cork-like stopper called a '' bung''. Acceptable usage includes other access points that may be capped with alternate materials providing ...

s closed by cork or wood bungs. Some early

tinplate Tinplate consists of sheet metal, sheets of steel coated with a thin layer of tin to impede rust, rusting. Before the advent of cheap mild steel, the backing metal (known as "") was wrought iron. While once more widely used, the primary use of tinp ...

cans were made with threaded necks for screw top closures. Beverage bottles started using the Hutter Stopper in 1893. This involved a

porcelain Porcelain (), also called china, is a ceramic material made by heating Industrial mineral, raw materials, generally including kaolinite, in a kiln to temperatures between . The greater strength and translucence of porcelain, relative to oth ...

plug fitted with a rubber washer, which was then forced down into the lip of the bottle. This technique only works with carbonated beverages. The Hutter Stopper became standard in beer bottling in the late 1890s / early 1900s. Bail closures on bottles were invented by Henry William Putnam in 1859. These involved heavy wire bail attached to a bottle's neck that swung over the cork to hold it in. The world's first modern bottle cap, the crown cork, was invented by William Painter in 1890 in

Baltimore Baltimore is the most populous city in the U.S. state of Maryland. With a population of 585,708 at the 2020 census and estimated at 568,271 in 2024, it is the 30th-most populous U.S. city. The Baltimore metropolitan area is the 20th-large ...

. The screw cap using

rust Rust is an iron oxide, a usually reddish-brown oxide formed by the reaction of iron and oxygen in the catalytic presence of water or air moisture. Rust consists of hydrous iron(III) oxides (Fe2O3·nH2O) and iron(III) oxide-hydroxide (FeO(OH) ...

resistant

aluminum Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has ...

was first used in

prescription drug A prescription drug (also prescription medication, prescription medicine or prescription-only medication) is a pharmaceutical drug that is permitted to be dispensed only to those with a medical prescription. In contrast, over-the-counter drugs c ...

bottling in the 1920s. Molded urea based bottle caps were first introduced in the early 1900s. A history of accidents involving children opening household packaging and ingesting the contents led the

US Congress The United States Congress is the legislature, legislative branch of the federal government of the United States. It is a Bicameralism, bicameral legislature, including a Lower house, lower body, the United States House of Representatives, ...

to pass the Poison Prevention Packaging Act of 1970. File:Pyxis Peleus Thetis Louvre L55 by Wedding Painter.jpg, Greek pottery with lid, 5th century Image:Wine Corks.jpg, An assortment of wine corks File:Jam jar.jpg, bail closure on jam jar File:Wine thief and barrel.jpg, bung in

of a wine

barrel A barrel or cask is a hollow cylindrical container with a bulging center, longer than it is wide. They are traditionally made of wooden stave (wood), staves and bound by wooden or metal hoops. The word vat is often used for large containers ...

The manufacture of closures

Th
International Society of Beverage Technologists (ISBT)
is the main

trade association A trade association, also known as an industry trade group, business association, sector association or industry body, is an organization founded and funded by businesses that operate in a specific Industry (economics), industry. Through collabor ...

for closure manufacturers. It develops voluntary industry standards for its members to use in the manufacture of closures.

References

Books

* Yam, K.L., "Encyclopedia of Packaging Technology", John Wiley & Sons, 2009, * Soroka, W, "Fundamentals of Packaging Technology", IoPP, 2002,

External links

History of Closures from the CCMA website

{{DEFAULTSORT:Closure (Container) Seals (mechanical) Containers