Aluminum foil packaging material

Plastics can also be combined with other materials such as aluminum, steel, and wood to provide specific properties. Examples include PVC/wood window frames and plastic/ aluminum-foil packaging material. All combinations require that certain aspects of compatibility such as processing temperature and linear coefficient of thermal expansion or contraction exist. 

Aluminum foil Al foil is a solid sheet of an appropriate Al alloy, cold rolled very thin, varying from a minimum thickness of about 0.0017 in. (0.00432 mm) to a maximum of about 0.0059 in. (0.1499 mm). In the Al industry, thickness of at least 0.006 in. (0.1524 mm) is sheet material (sheet). After (oil) cold rolling, the foil is annealed to restore its workability. From the standpoint of packaging as well as other applications, one of its most important characteristics is its impermeability to water vapor or gases. Bare foil 1.5 mil (0.0015 in. or 0.0038 mm) and thicker is completely impermeable and used in plastic coating and packaging process systems. 

Table I shows the chemical composition limits of various aluminum alloys presently used for packaging applications (3). In general, these alloys have good corrosion resistance with most foods. However, almost without exception, processed foods require inside enameled containers to maintain an acceptable shelf life (4, 5). Moreover, when flexible foil packages are used for thermally processed foods, the foil is laminated to plastic materials that protect it from direct contact with the food and also provide heat sealability as well as other physical characteristics (6,7).

Any material used for packaging natural cheeses must prevent moisture loss, maintain good product appearance, protect against microorganisms, and act as an oxygen barrier. Aluminum foil laminates provide this type of protection for cheese. Cream cheese is packed in lami-... 

Among the commonly used flexible packaging materials, aluminum foil probably provides the most complete permeation barrier while paper is the most permeable. Although aluminum foil provides a barrier to moisture, gas, grease, and light, it usually needs protection from the contents of the package and from the environment since it is a soft metal and subject to chemical attack. 

We use extrusion coating to apply thin layers of polymer to the surface of non-polymeric substrates such as cardboard or aluminum foil. Extrusion coated materials are extensively used in food packaging. Products include the coated cardboard used to make milk cartons and the coated aluminum foil used to seal dairy product tubs. The process of extrusion coating has much in common with film casting. 

The technique generally used to minimize the degree of change in crystallinity of the milled product is to eliminate the water or other solvents from the product, usually by packaging the material within a suitable barrier (for example, aluminum foil laminate). Other techniques include the production of a 100% crystalline material, which may eliminate the effects of moisture. This technique, however, may require a secondary production stage of armealing or a period to allow the product to equilibrate under controlled storage conditions. 

The most common forms of flexible packaging are the blister package and the pouch. A blister package usually consists of a lid material and a forming film. The lid material is usually a laminate, which includes a barrier layer (e.g., aluminum foil) with a print primer on one side and a sealing agent (e.g., a heat-sealing lacquer) on the other side. 

The new packaging system developed by Tetra Pak is known as the Tetra Brik , and is generally available in 1-1, 200-ml, and 250-ml sizes. The system is considered to be an alternative to metal and glass containers. The packaging material comes in roll stock form and is a 6-or 7-layer laminate. Polyethylene and aluminum foil offer the major barrier properties to the package. 

In order to prevent the exchange of ambient air and gas phases in long-term storage, vials, stoppers, boxes, and bags, used as specimen containers and packaging must be made of nonporous materials and sealed hermetically. Glass, plain metal, synthetic rubber, silicon, polyethylene, and plastic-coated aluminum foils are common for this purpose. The packaging material must be dried and desorbed of contaminated gas before use. 

The wrapping materials used in the wrapping operation shown in Figure 20 may be parchment, laminated aluminum foil, plastic-coated material, or plastic foil (63). For packaging of margarines, the first two wrapping materials are commonly used. 

Today, aluminum is the most widely used metal in the world after iron. It is used in the manufacture of automobiles, packaging materials, electrical equipment, machinery, and building construction. Aluminum is also ideal for beer and soft drink cans and foil because it can be melted and reused, or recycled. 

The mixed board and flexible packaging material (MB/EP) consisted solely of printed production waste. The main components were cardboard, paper, plastics, metallized foil, and laminated aluminum foil. 

Materials that are used most frequently are polyethylene, silica, and aluminum foil. Polyethylene satisfies requirements 2 and 3 listed above, but it has low resistance to radiation and temperature. It becomes brittle after exposure to a fluence of 10 -10 neutrons/m. Polyethylene tubes of different diameters are routinely used in radiation laboratories. The tubes can be easily cleaned and sealed. Silica containers are not as useful as polyethylene because they are not as pure, they become radioactive, and sealing is more complicated. Aluminum foil is useful for packaging solids, but it becomes radioactive through Al(n, y) Al and Al(n, a) Na reactions. The second reaction is more troublesome than the first because the half-life of Na is the 15 h, whereas the half-life of A1 is only 2.3 min. 

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