Semi-Rigid Foil Containers

	product name:	Semi-Rigid Foil Containers
	Place of Origin:	Peoples Republic of China
	Post Date:	February 10, 2011
	Edit Date:	March 30, 2011

Detailed Product Description:

Semi-Rigid Foil Containers

For the purpose of this discussion of the many present and potential applications, the following types of all foil, foil/board, and foil or foil/film containers are classed as semi-rigid:

Die Formed containers 

Folding cartons 

Collapsible tubes

As opposed to flexible containers that conform to the shape of the product, semi-rigid containers have a shape of their own. Of course, they can be deformed from that original shape, either as they are emptied (the collapsible toothpaste tube - see heading, Collapsible Tubes), or before they are filled (the folding carton). The formed container may be classified as semi-rigid, in comparison to a foil/fibre or metal can or drum, because of the thin walls, which are of foil gauges. Frozen food bake-in pans are an example.

Semi-rigid containers also offer a degree of protection, against mechanical damage. To state the obvious, they are intermediate between flexible containers and rigid containers, such as cans and drums.

Die Formed Aluminum Containers

Formed aluminum containers are among the most versatile of all packages. They easily withstand all normal extremes of handling and temperature variation, including sub-zero for frozen foods and infra-red oven heats for various types of prepared foods. While they are designed and used commercially as a one-way, disposable container, practically every householder saves some of them. Their domestic re-uses include cooking, planting, craft work, workshop, and toy applications, as well as many others. Bare foil is used for most products, but protective coatings are employed on the containers for some food and other products. 

One of the earlier formed containers, the aluminum frozen dinner tray, literally revolutionized America¡¯s eating habits. Here was a container that allowed an entire dinner to be frozen, distributed, stocked, purchased, stored, prepared, served and even, if necessary, the leftovers, stored in the refrigerator, without soiling a single dish, pot, or pan. How could anyone ask more of a package?

Far from being limited to the shape of the dinner tray, the aluminum formed container is available in scores of shapes and sizes, from 1/2 ounce portion cup packs for jelly to full-sized steamtable containers for institutional feeding. Some of the more familiar semi-rigid foil container shapes include shallow pie plates, rectangular loaf pans, deep-dish pie pans, and many other family or individual-size foil pan packages. 

Closures for these containers vary according to the amount of protection needed for the product. Most foil pans are closed with various types of laminated hooding foil, plain, printed or embossed, cut to size, and heat-sealed or crimped with pan edges

One of the more unusual closures is found on the popcorn pan. It is so designed that a folded aluminum foil lid expands as the corn is popped, after an outer paperboard cover is removed.

More recently developed is the hermetically sealed closure for smooth-walled containers, consisting of an air-and-vapor-tight foil laminate. This allows the container to be used for dehydrated products, such as potato casserole, to which water is added just before the product is baked by the consumer. The jelly portion packs usually have a foil or a film peel-off cover heat-sealed to the container. Containers for carry-out service may have a paperboard cover that is hand crimped for a simple, effective seal.

Despite the many sizes and shapes of formed aluminum which are the result of creative design, considerable progress has been made in establishing standards for the benefit of the consumer, the manufacturer, and the packager. In this effort, the prime motivator is the Aluminum Foil Container Manufacturers¡¯ Association (AFCMA), which has presented to its members a set of voluntary standard container categories. Recommended shapes are shown in Table 2. 

Types of rim edge finishes also have been defined by AFCMA. These include raw and hemmed edges, and several sizes and types of curled bead edges, as shown in Table 3. One other set of AFCMA standards specifies how semi-rigid formed containers shall be measured, as also illustrated in Table 3.

Folding Cartons and Trays

Foil folding cartons and trays may have the foil lining on the inside or outside, or using a double-lined sheet, the foil may be on both sides. Cartons may be of conventional or sift-and-leak proof designs. Printing is done by any method, prior to the cutting and creasing, or other forming, and gluing operations. 

Folding cartons offer important protective and display characteristics unique in packaging, and have some of the advantages of both the flexible and the rigid container. Before use, when it is folded flat, the folding carton offers the storage economy of the flexible bag. When it is filled, it offers much of the protection of the set-up box.

Collapsible Tubes

Collapsible tubes, traditionally an impact-extruded aluminum, lead or tin product, were first used as an oil paint container. These were first made of lead and used by artists more than 100 years ago. Today, both the aluminum alloys and modern plastic closures, employed have greatly improved these handy packages. Collapsible tube nomenclature is given in here. 

A proprietary foil/film version of collapsible tubes is now being produced for packaging toothpaste and products of similar consistency including hair coloring and depilatories. Typical laminated structure is poly/print/poly/paper/poly/foil/poly. Aluminum foil provides the vital barrier to permeation of the oils used in the toothpaste flavoring, and of similar compounds in other products. 

The new foil/film tube roll stock can be printed by process gravure in up to seven colors on standard equipment, compared, to the 4-color dry offset process used for conventional tubes. The high fidelity color process printing thus offered, back-printed on the protective poly-film opens up new vistas for toothpaste graphics.

In this process the tubes are produced by a new process that forms the laminated roll stock into continuous tubing by use of heat and pressure. The tubing is cut into individual sleeves, which are then handled much like all-plastic sleeves. Each tube is automatically headed by injection molding, capped and packed for shipments to the customer for filling and bottom closure. For toothpaste applications, an insert is sometimes molded into the tube head to minimize permeation where required.

Sealing after filling is done either with direct contact heat and pressure application to weld the layers together, or by induction heating and pressure. 

Of the three principal metals used for collapsible tubes, aluminum, tin, and lead, aluminum of 99% purity or higher is now the leading material. Aluminum tubes have these advantages: light weight, high strength, flexibility, and good corrosion resistance. It also has excellent permeability, plus the quality appearance of bright metal, shiny or matte, natural or colored, with transparent or opaque inks. Products packaged in collapsible aluminum tubes include toothpaste, shaving cream, cosmetics, food products, adhesives, lubricants, and others of similar consistency.