Multilayer package

The production of foamed films and sheets from polypropylene and polystyrene is discussed, with particular reference to packaging applications. Advantages of foamed materials for this application are examined, and the chemical and physical foaming processes are described. Extrusion technology for film and sheet by chemical and physical foaming processes is discussed, and recent developments in the coextrusion of multilayer packaging trays for the food industry are considered. 

Shrunk thick-walled layers 3 Core tube 4 Multilayer package 5 Monobloc (single wall)... 

Defoose, M., Soft-Drink Giants Stae Interest in Multilayer Packaging Alternatives, MP, Feb. 2003. 

Transition metal carbides can be used as diffusion barriers like transition metal nitrides in multilayer metallization schemes for integrated circuits. Layers on the order of lOOnm are applied and are produced by sputtering methods. The high chemical stability of these transition metal carbides, especially those of group 4, are exploited to prevent interaction of metal or component layers such as silicon, aluminum, and silicides upon thermal load in production processes. This load would cause electrical or even structural deterioration of the multilayer packages. 

Typical substrates found in flexible multilayer packaging and reasons for their inclusion are summarised in Table 16.1. Individual component layers in flexible materials normally range in thickness from 2.5 pm to -125 pm, with the total thickness normally being less than 250 pm. Thicker laminates are normally considered to be sheet materials and are rigid in nature. 

Flexible multilayer packaging is used for retort processing of various food products. These retort pouches are capable of preserving their contents for many months up to 1-2 years. A layer of aluminium foil normally provides the primary barrier properties of the packaging. A typical structure would be PET polyester ( 18 p,m)/print 5 pm/adhesive 3 pm/aluminium foil ( 20 pm)/adhesive 4-5 pm/cast PP 30 pm. 

The Rapra review report on flexible packaging (Rolando, 2000), provides a large amount of information on lamination and the adhesives used in multilayer packaging. 

The antimicrobial additive may be applied in a controlled way where material is not lost, such as incorporation into the food-contact layer of a multilayer packaging material. 

In multilayered packaging material, antimicrobials may be incorporated into the food contact layer. 

The concept of modern multilayer packaging means that there is a minimum use of plastic material, because various characteristics can be combined into one thin packaging film. The most widely used plastic for combination is PE. The PA-PE combination processed by coextrusion has a good gas resistance. It can be deep drawn, and its fat resistance and IlexibiUty are suitable, too. These combinations are very widely used for vacuum packages. In addition, the PET-PE combination is heat resistant, and the PE-PP is sterilizable. As an illustration of the effectiveness of plastic composites, WilUams presents multilayer plastic... 

Flexible multilayer packaging materials obtained by an extrusion coating process are widely used for food, cosmetics or medicines. The low molecular weight compounds formed during processing can impart undesirable odors and tastes to the content of the packaging. The odor- responsible compounds... 

Typical Thin Film Multilayer Package Structure... 

Using any standard numerical routine, the above set of coupled equations, eqns 1-5, can be solved to simulate both the retort and storage of a multilayer package. 

Y., and Burger, J. (2014) Protective multilayer packaging for long-term implantatble medical devices. Surf. Coat. Technol., 255, 124-129. 

The method of structural encapsulation eliminates thermal effects for inhibitors known for their low thermal stability. Its drawback is Cl loss due to uneven distribution within the pol3mier matrix and diffusive isolation from both sides of the film. The described films are good as the inner layer of multilayered packages. 

A layer in a multilayer packaging structure that acts to retard, limit, or prevent migration of components from package layers exterior to it, into the package contents is called a functional barrier. This barrier may or may not be the food contact material itself. For example, in a multilayer structure containing an inner layer of aluminum, the aluminum can be expected to be an excellent barrier to any possible migrants from all layers from the outside of the package up to the aluminum. 

Raman measurements needed no sample preparation or only minor preparation, such as by pressing of solids into a conic hollow at the flat edge of aluminium cylinder (as well as a node of a few fibres) or by making a multilayer package of films on a mirror surface to increase the scattering intensity. Liquid samples were measured using a special quartz cell with a mirror-back. 

The functional properties of Honeywell Capron Nylon 6 resin make it a highly cost-effective nylon resin for use in multilayer packaging films. It combines easily with polyolefins and other materials. ... 

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