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 stop ...

jug A jug is a type of container commonly used to hold liquids. It has an opening, sometimes narrow, from which to pour or drink, and has a handle, and often a pouring lip. Jugs throughout history have been made of metal, and ceramic, or glass, and ...

jar A jar is a rigid, cylindrical or slightly conical container, typically made of glass, ceramic, or plastic, with a wide mouth or opening that can be closed with a lid, screw cap, lug cap, cork stopper, roll-on cap, crimp-on cap, press-on c ...

tube Tube or tubes may refer to: * ''Tube'' (2003 film), a 2003 Korean film * ''The Tube'' (TV series), a music related TV series by Channel 4 in the United Kingdom * "Tubes" (Peter Dale), performer on the Soccer AM television show * Tube (band), a ...

, or can. A closure may be a cap, cover,

lid A lid, also known as a cover, is part of a container, and serves as the closure or seal, usually one that completely closes the object. Lids can be placed on small containers such as tubs as well as larger lids for open-head pails and drums. S ...

, 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 used for the storage or transportation of its contents. Most boxes have flat, parallel, rectangular sides. Boxes can be very small (like a matchbox) or very large (like a shipping box for furniture), and can ...

es and drums 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 ...

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 permeate (a fluid such as a liquid, gas, or vapor) through a solid. It is directly related to the concentration gradient of the permeate, a material's intrins ...

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 Wrap rage, also called package rage, is the common name for heightened levels of anger and frustration resulting from the inability to open packaging, particularly some heat-sealed plastic blister packs and clamshells. People can be injured whi ...

. The force or

torque In physics and mechanics, torque is the rotational equivalent of linear force. It is also referred to as the moment of force (also abbreviated to moment). It represents the capability of a force to produce change in the rotational motion of th ...

required to open a closure is an important consideration for

packaging engineer Packaging engineering, also package engineering, packaging technology and packaging science, is a broad topic ranging from design conceptualization to product placement. All steps along the manufacturing process, and more, must be taken into a ...

s. 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 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. Thailand, Malaysia, an ...

, 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, designed to be seated in a groove and compressed during assembly between two or more par ...

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 innerseals 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, on which is written or printed information or symbols about the product or item. Information printed ...

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, 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 or fruit jar, is a glass jar used in home canning to preserve food. It was named after American tinsmith John Landis Mason, who patented it in 1858. The jar's mouth has a screw thread on its outer perime ...

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 refers to a variety of equipment used in scientific work, and traditionally made of glass. Glass can be blown, bent, cut, molded, and formed into many sizes and shapes, and is therefore common in chemistry, biology, and anal ...

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 ''tight'' fitting mating parts that produces a joint which is held together by friction after the parts are pushed together. Depending on the am ...

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 A tamper-evident band or security ring serves as a tamper resistant or tamper evident function to a screw cap, lid, or closure. The term ''tamper-proof'' is sometimes used but is considered a misnomer given that pilfering is still technica ...

; 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 siphoned ...

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 Geritol is a United States trademarked name for various dietary supplements, past and present. Geritol is a brand name for several vitamin complexes plus iron or multimineral products in both liquid form and tablets, containing from 9.5 to 18&nb ...

with a child-resistant cap File:Swing-top bottle.JPG, An opened

flip-top A flip-top, swing-top, lightning toggle, or Quillfeldt stopper (after the inventor, Charles de Quillfeldt) is a type of closure frequently used for bottles containing carbonated beverages, such as beer or mineral water. The mouth of the bottle i ...

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 A living hinge or integral hinge is a thin flexible hinge (flexure bearing) made from the same material as the two rigid pieces it connects. It is typically thinned or cut to allow the rigid pieces to bend along the line of the hinge. The m ...

on the lid of a

Tic Tac Tic Tac (stylized as "tic tac") is a brand of small, hard mint manufactured by the Italian company Ferrero. They were first produced in 1969 and are now available in a variety of flavours in over 100 countries. Tic Tacs are usually sold in sma ...

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

bung A stopper or cork is a cylindrical or conical closure used to seal a container, such as a bottle, tube or barrel. Unlike a lid or bottle cap, which encloses a container from the outside without displacing the inner volume, a bung is partially ...

s. Some early

tinplate Tinplate consists of sheets of steel coated with a thin layer of tin to impede rusting. Before the advent of cheap milled steel, the backing metal was wrought iron. While once more widely used, the primary use of tinplate now is the manufacture ...

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

porcelain Porcelain () is a ceramic material made by heating substances, generally including materials such as kaolinite, in a kiln to temperatures between . The strength and translucence of porcelain, relative to other types of pottery, arises main ...

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 ( , locally: or ) is the List of municipalities in Maryland, most populous city in the U.S. state of Maryland, fourth most populous city in the Mid-Atlantic (United States), Mid-Atlantic, and List of United States cities by popula ...

. 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( ...

resistant

aluminum Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It ha ...

was first used in prescription drug 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 of the federal government of the United States. It is bicameral, composed of a lower body, the House of Representatives, and an upper body, the Senate. It meets in the U.S. Capitol in Washin ...

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 cork Wine corks are a stopper used to seal wine bottles. They are typically made from cork (bark of the cork oak), though synthetic materials can be used. Common alternative wine closures include screw caps and glass stoppers. 68 percent of all cor ...

s File:Jam jar.jpg, bail closure on jam jar File:Wine thief and barrel.jpg,

of a wine barrel

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. An industry trade association partic ...

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