Mould Packaging

The most important representatives of this group are polyethylene terephthalate (PET) and polybutylene terephthalate (PBT). The consumption of PET in the world (excluding fibers) was about 4x 106 t in 1997 (audio and video films, technical mouldings, packaging, particularly bottles). Even though the cost of these plastics is presently in the medium price range, one can count on a reduction in their price in the future due to their widespread use. 

Expanded poiystyrene foam (EPS) is usually white and made from expanded PS beads. It is lightweight, absorbs shocks and is a very good sound and heat insuiator. It crumbles easily and burns readily unless flame proofed. Familiar uses include moulded packaging material to cushion fragile items inside boxes and as heat insulation in the construction industry. It is also widely used to make foam cups, plates, food containers, meat trays and egg cartons. 

Figure 37 General scheme of the die attachment process on copper leadframe before the assembly is encapsulated into an epoxy moulded package (A). Other packaging techniques are the hermetic Cerdip package (B) and glob top encapsulation of surface-mounted...

Cheap moulded objects. Toughened with butadiene to moke high-impact polystyrene (FIIPS). Foamed with CO2 to moke common packaging. 

One particular growth area for polypropylene mouldings is for thin-wall packaging such as margarine tubs. This is largely at the expense of polystyrene and arises partly from economics and partly from the wish to have a produet free of residual styrene monomer. 

Uses reported include motor housings for portable fans, food blender bases, tape storage housings, tough, clear toys, injection blow moulded products and thermoformed packages. 

Poly(vinyl alcohol) is employed for a variety of purposes. Film cast from aqueous alcohol solution is an important release agent in the manufacture of reinforced plastics. Incompletely hydrolysed grades have been developed for water-soluble packages for bath salts, bleaches, insecticides and disinfectants. Techniques for making tubular blown film, similar to that used with polyethylene, have been developed for this purpose. Moulded and extruded products which combine oil resistance with toughness and flexibility are produced in the United States but have never become popular in Europe. 

The largest outlet for polystyrene is in packaging applications. Specific uses include bottle caps, small jars and other injection moulded containers, blown containers (a somewhat recent development but which has found rapid acceptance for talcum powder), vacuum formed toughened polystyrene as liners for boxed goods and oriented polystyrene film for foodstuffs such as creamed... 

The initial use was as a blow moulded vessel for vegetable oil candles. However, because of its biodegradability it is of interest for applications where paper and plastics materials are used together and which can, after use, be sent into a standard paper recycling process. Instances include blister packaging (the compound is transparent up to 3 mm in thickness), envelopes with transparent windows and clothes point-of-sale packaging. 

In 1997 it was estimated that global production of PET was about 16.7 X 10 t.p.a., of which 12 million tonnes was used in textiles, 2 million tonnes for audio and video film (with a small quantity for technical mouldings) and 3 million tonnes for packaging, particularly bottles. The tremendous growth in the bottles market from zero in the late 1970s to 1.5 million tonnes in the USA alone in 1998 is, in consumption terms, one of the most spectacular examples of growth in plastics materials in recent times and will be considered later in this section. 

According to the end use application, PEs are processed by various techniques, which include injection moulding, blow moulding, rotomoulding, and film extrusion. However, since the bulk of the processed material is used as film in the area of packaging, the discussion in this chapter focuses mainly on processing behavior and the ultimate properties of tubular blown film. 

This review is concerned with the engineering thermoplastic uses of polyamide materials in injection moulding and extrusion applications. Types of polyamides are described, and their key properties are considered. Commercial applications in the automotive, electrical/ electronic, engineering and construction, and packaging industries are discussed. Polyamide processing is... 

Packaging materials which have a smooth, impervious surface, free fi cm crevices or interstices, such as cellulose acetate, polyethylene, polypropylene, poly vinylchloride, and metal foils and laminates, all have a low surface microbial count. Cardboard and paperboard, unless treated, carry mould spores of Cladosporium spp., Aspergillus spp. md Penicillium spp. and bacteria such 2 Bacillus spp. sn.dMicrococcus spp. 

Additives are needed not only to make resins processable and to improve the properties of the moulded product during use. As the scope of plastics has increased, so has the range of additives for better mechanical properties, resistance to heat, light and weathering, flame retardancy, electrical conductivity, etc. The demands of packaging have produced additive systems to aid the efficient production of film, and have developed the general need for additives which are safe for use in packaging and other applications where there is direct contact with food or drink. 

Many analytical techniques are in use for the qualitative and quantitative evaluation of monomers and oligomers extracted from PA6 (GC, differential refrac-tometry, IR, PC, SEC, HPLC, RPLC, etc.). FTIR has been used for quantitative analysis of caprolactam oligomer content (extract %) in polyamide-6 [113], The method, which involves a 3h extraction in boiling methanol, is suitable for process control and plant environment. Kolnaar [114] has used FTIR characterisation of fractional extracts with pentane, hexane, and heptane of HDPE for blow moulding applications. Vinyl acetate in packaging film has similarly been determined by quantitative FUR. 

Drying out can be prevented in one of two ways, either by packaging or by lowering the water activity of the product. Starch retrograda-tion can be inhibited by using a starch complexing emulsifier with or without the addition of fat. Mould growth is inhibited by a low water activity. 

Polystyrene can be moulded, cast or extruded in sheets, rods and tubes. It can be easily pigmented. It finds wide, application in making household goods, lenses, plastic moulds, toys, wood laminates, films, battery boxes and electrical components. Expanded polystyrene is used as thermal insulating material and packaging. It is also used in lifejackets and floats. 

Blow-moulded containers have various and diversified applications from small bottles to drums for packaging of foods and beverages, chemicals, motor oils, cosmetics, toiletries, drugs and pharmaceuticals. Table 2.24 displays some examples for industrialized countries. The use of bottles and other containers depends on several growing markets, for example ... 

Blow-moulded drugs, cosmetics toiletries packaging 129 7... 

Lightweight mats of fibres, which can be die-cut and thermally moulded, can be applied behind any interior trim panel, door panels, headliners or package shelves as superior sound absorbers. 

TPS are used in the footwear, automotive, construction, hygiene, packaging, sports and leisure, consumer durable and disposable sectors for various moulded and extruded technical goods, soft-touch overmoulding, etc., SEES satisfying more stringent specifications than SBS particularly versus heat and weathering. 

TPO skins for low-pressure injection moulding. .. insulation of electric wires, connectors... workbench feet, appliance feet, supports and pads... returnable packaging, totes and bins... handles, soft-touch overmoulding. .. profiles, tubes, pipes, sheathing. .. toys... 

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