Package types

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Sachets
Sachets are formed by sealing a product between two layers of flexible material. Typically the materials used are laminates chosen to suit the nature of the product, for example whether it requires a moisture, light or gas barrier. There is often a polythene layer to allow heatsealing. Other layers can include paper for rigidity and low cost decoration, foil for a gas and light barrier or one of a range of plastic polymers for other properties such as selective gas barrier. Sachets are formed, filled and sealed in one operation. They are usually not re-sealable, and are mostly used for unit dose/single use powders, granules, creams and liquids.

Pouches
Pouches are large sachets, often with a gusseted base to make them free-standing. Applications include pet food, ready meals and refill packs. Pouches can be re-sealable.

 

Flow Wrap
Similar in nature to sachets and pouches, flow wrap can be a single layer material or a laminate and is usually used to wrap a larger discrete item such as a bar of chocolate. Again the pack is formed around the product at the point of filling.

Blister strips
Blister strips can be made of a variety of plastic polymers or foil. They have a base layer with pockets for units of product such as tablets, and a flat ‘lidding’ layer. For products which are oxygen, light or moisture sensitive foil provides the best barrier but is expensive. PVC is widely used for blister strips and is sometimes laminated with other materials such as PVDC to increase its barrier properties.

Trays and inserts
Vacuum-formed polymer inserts are widely used to hold items in place within cartons for protection and display purposes. Polymers such as PVC are warmed to soften them and then drawn into a mould of the appropriate shape using vacuum pressure Trays are commonly used for food products such as meat and ready meals. They can be vacuum/thermoformed polymer, expanded polystyrene or foil, and are usually closed with a stretch wrap or heatseal film.

 

Ampoules
Ampoules are small rigid or semi-rigid containers typically made from glass or polymer.

Glass ampoules are made from tubular glass with the ends heated and melted to form a neck and a top that can be broken off. Commonly used for medicinal projects but have also been used for cosmetics.

Polymer ampoules are usually made in a single ‘form fill seal’ operation that melts the polymer and moulds the ampoule before sealing it. Again, they are usually opened by breaking off the top. They are used for contact lens solutions and some cosmetic applications.

Injection Vials
Injection vials are small, usually glass containers, with a closure (cap) including a polymer seal. The needle is pushed through the seal in order to draw the product into the syringe.

Tubes
There are three main categories of tubes: aluminium, plastic and laminate.

Once the universal tube type, aluminium tubes are typically restricted to creams, ointments and adhesives. The tube is a single piece, filled from the bottom, which is then crimped to form a seal. The aluminium provides good barrier properties and is relatively stiff, so when squeezed stays squeezed. Squeezing when the cap is on can cause internal pressure which makes the contents ooze as soon as the cap is opened. The tubes can be directly printed prior to filling. Labelling does not perform well because of the creases formed when the tubes are squeezed.

Plastic tubes are often made of polythene and can be a wide range of colours. Again the tubes themselves are one piece, filled from the bottom and in this case heat-sealed to form a seal. Plastic tubes tend to pop back to their original shape after squeezing so tend not to cause internal pressure and oozing. The downside is the tendency to suck product back into the body of the tube, potentially causing contamination. Plastic tubes can be directly printed or labelled, usually with a polymer label.

Laminate tubes dominate the toothpaste market. A tube is formed from a pre-printed laminate material with a pre-moulded neck /nozzle welded into one end. Laminate tubes are bottom filled and heat-sealed as for plastic tubes. They have good barrier properties, excellent decoration, and do not draw product back into the tube.

Rigid plastic packaging

This includes cups, bottles, pots, cans and closures. Rigid packaging material can be used in any packaging-related application.

 

Bottles and jars
Bottles and jars are available in a large range of sizes. Bottles can be manufactured from glass, some plastic polymers and (more recently) aluminium. The more traditional tinplate containers with screw caps are classed as cans. Glass and plastic bottles can be moulded in a variety of shapes and colours with different surface textures.

Bottles have a body, and a neck finish which allows for closing. Closures can range from a cork or stopper through a wide range of screw on, snap fit, flip top or crown caps. Some also have pump dispensers.

In general, bottles have a narrow neck and jars have a wide one. Jars can be made of a variety of materials including glass and a range of plastic polymers. Glass jars are commonly used in food, toiletry and cosmetic packaging. Plastic jars are common in toiletry and cosmetic applications, but less so in food.

 

Caps
Caps are usually manufactured from plastic polymers or metal. Plastic caps can be screw-on, push-on, push-in, snap-on, or screw-on with a flip-top, rocker-top or push-pull sports top. Flip or hinged-top caps must be made from polypropylene as this is the only material which will sustain the ‘hinge’ without splitting or breaking off. Some plastic caps incorporate a liner or wad in order to provide a good seal against the top of the bottle or jar neck, while others have a moulded lip which flexes against the container surface.

Metal caps are typically screw-on, push-on or crown caps and usually have a liner or wad to provide a seal.

Cans
Cans are made of either tinplate or aluminium and plastic, with the vast majority being tinplate. They are used for food and beverage packaging, aerosols, chemicals, oils and paints.

Food cans are typically two- or three-piece tinplate. A three-piece can is made by forming a flat sheet of tinplate into a tube, crimping one end before filling and the other end after filling. A two-piece can is made by deep drawing, effectively stamping a piece of tinplate into a tub shape, and the base can be profiled to make it fit inside the top of another for stacking. The top is crimped on after filling.

Although three-piece tinplate beverage cans are still used in a few markets they have almost universally been replaced by three-piece aluminium cans for soft drinks and beers. For steel drink cans, a special grade of low-carbon steel is coated on each side with a very thin layer of tin, which protects the surface against corrosion and acts as a lubricant while the can is being formed.

Tinplate aerosol cans are made in a similar way to food cans with the valve crimped in place before filling. Aluminium aerosol cans are deep drawn and the top is profiled to leave an opening for the valve. Aerosol cans are filled through the valve hole before the valve is crimped in place.

There has been recently been a move to plastic cans for paint, which traditionally had a three-piece construction with a large push-in lid.

Oil and chemical cans come in a variety of shapes and sizes and usually have circular or rectangular bases. These are mostly of a three-piece construction.

Labels
Virtually all products are labelled. Depending on the performance characteristics required these are usually paper or a range of plastics but can also be made from metal and other materials.

The most widely used are self-adhesive. Adhesive is applied to rolls of material with a backing paper that is usually silicon-coated for easy removal of the label on the production line. Plastic backing can also be used. Other labels are coated with heat-activated adhesive.  Plain labels which are wet-glued on the production line are still widely used for food, wine and beer.

Leaflets / Booklets
Many products require instructions or further product information. In their simplest most functional form these are printed on very lightweight paper and folded down to fit the pack. Booklets are widely used for higher value items where a large volume of reliable information is required.

Leaflet - label
For products in small sizes or without boxes the ‘leaflet’ is sometimes incorporated into a multi-layer booklet or concertina. Many these formats are patented, making them relatively expensive, but weighed against the combined cost of labels, leaflets and cartons they may still be the best option.

 

Cartons

The most common type is the everyday folding box board carton, produced by cutting a shape and creasing fold lines into solid board of around 300gsm. These are supplied flat to product manufacturers. As well as a variety of shapes and sizes there are different styles of end closing, including reverse and aeroplane tuck-in flaps and crash lock bases.

Another type of carton is the laminate form fill-seal carton popularised by Tetrapak. A variety of shapes can be produced, including the original Tetrapak tetrahedron, basic cubes and bricks and the gable top. Rolls of laminate material are folded and sealed into a continuous tube, and another seal is made across the tube to form one end of the carton before filling it and sealing the other end.

The laminates used for these packs typically comprise rigid board with a polythene moisture barrier. Some also include foil and other polymers to provide enhanced barrier properties for light and gases such as oxygen. Some manufacturers have achieved ‘windows’ as a visual guide to content level.

 

PE board
For fresh products with short shelf life in chilled distribution.
 
 

 

Alu board
For aseptic and hot filled products with long shelf life in ambient distribution, and fresh juices in chilled distribution..

 

 

 
EVOH board
For extended shelf life and long shelf life in chilled distribution, with an extruded resin barrier for product protection.

 

 

 

Corrugated cases
Corrugated packaging is crucial to the supply chains that support our modern lives. The safe bulk shipment of goods relies on its lightweight and protective qualities. Corrugated fluted board is sandwiched between paperboard liners, and a variety of grades are available, with different flute widths and different weights of the outer liners. A basic transit case may have a ‘B’ flute with moderate weight liners, while a heavier duty case could have the multiple layers known as tri-wall.

The standard liners are not suitable for high quality printing and so for some packages a high quality pre-printed sheet of paper is laminated to the corrugated material before the box is made – this is known as ‘litho-lam’ (from lithographic and lamination).

The majority of corrugated material is used to produce boxes (cases) and box inserts but it has also been used to create pallets.

Rigid boxes
Rigid boxes are more commonly used as display boxes for high value, prestige items and are made from a thicker multi-layer board. Not usually capable of folding, the structure will be half cut and taped to reinforce corners prior to covering with a pre-printed paper.

Lid and tray boxes automatically constructed from blanks are the most popular. Others are hand made to incorporate drawers, hinges, magnetic seals and clasps. All standard printing processes can be used.

Composites
Composite packs are commonly used for gravy powder, tennis balls and whisky.

Using various plies of paper a tube is formed by convolutedly wrapping round a central moving metal mandrel. Plastics and/or foil can be one of the layers. When the required thickness is attained, lengths are cut and overlabelled with pre-printed paper. Bases and lids (plastics, metal or board) are then attached. Triangular or square shapes can also be produced.

Pulp packs
Wood pulp (or another raw material) is fed into moulds and compressed with applied heat to produce a range of effective packs (egg-boxes, wine packs), and protective additions for machinery, computers or mobile telephones.