Films shrink-wrap

Polyethylene shrink film wrapping of cormgated ftberboard trays is in common use outside of the United States. Equipment erects the trays, fills the trays with primary packages such as cans or jars, wraps the grouping in shrink film, and heat shrinks the combination. Shrink film wrapping keeps primary and secondary packaging materials clean and dry. 

See also Polyethylene polymer entries Polyethylene shrink film wrapping, 18 37 Poly(ethylene-stal-a-olefin), glass... 

Oriented polypropylene film (OPP) may be classified as heat-set and non-heat-set, blown and tentered, coextmded and coated. Orientation improves the cold-temperature resistance and other physical properties. Heat-set biaxially oriented polypropylene film (BOPP) is the most widely used protective packagiag film ia the United States. It is used to wrap bakery products, as lamination pHes for potato and com chips, and for pastas and numerous other flexible pouch and wrapping appHcations. Nonheat-set OPP is used as a sparkling, transparent shrink-film overwrap for cartons of candy. 

Further, they can be used for medical purposes, such as press-through packages, disposable syringes, liquid medicine vials, and infusion bags. They are suitable for electric or electronic materials, such as wire coating. In addition, packaging films, such as wrapping films, stretch films, shrink films, and blister packs can be produced. 

The term film is also applied to sheets of cellophane, polyethylene, polyvinylidene chloride, etc., used for wrapping and packaging of food products, meats, and poultry (especially shrink films that are stretched before application). These function as a moisture vapor harrier. Plaslic lilms are also used as slip surfaces in concrete structures such as airstrips, ice rinks, and highways. Photographic film is made from cellulose acetate. 

Plastic Paper-Based Packaging Shrink Film Stretch Wrap Polyolefin Fabric Products Industrial Specialty Tape Flexible Bulk Containers... 

Plastic Suppliers Inc., a US extruder of blown film for labels and envelopes, has produced the world s first blown film from NatureWorks PLA. It was hitherto thought that PLA was unsuitable for blown film extrusion. Plastic Supplies claims that its EarthFirst film is 100% compostable, has high gloss, optimum clarity and transparency, high moisture vapour transmission rate, flavour retention, odour barrier, is breathable and is US Food and Drug Administration (FDA) compliant. Areas of application for EarthFirst include window carton film for food packaging, label film, floral wrap film, shrink film and envelope film. 

Sidaplax has added Plastic Supplies EarthFirst PLA film to its product range. EarthFirst is used in label face stock, shrink sleeve, wrap around shrink, floral and over wrap, window carton, packaging and envelope window film applications. 

SBC film is growing into more and more film applications. It is proving to be well suited for fresh cut produce packaging, candy twist wrap, shrink films, flexible medical and decorative films. SBC can be extruded into either cast or blown film for use in flexible packaging applications. While some applications employ a monolayer SBC film, many films are co-extruded with SBC along with several layers of other materials in order to bring a combination of properties to the final application. 

Shrink films, like stretch films, use the tendency of a film to try to return to a smaller dimension after deformation to provide a tight wrap around a packaged object. In shrink film the product is loosely packaged, and when it is exposed to heat, the film shrinks. The resistance of the product on the film provides the holding force. 

Shrink wrap materials include PE, PP, and PVC, among others. Some shrink wrap is used for pallet-loads of goods, but that market is dominated by stretch him, due in part to its lower energy requirements. Most shrink-wrap is used for individual packages or small bundles of products. A nonpackaging use of shrink film is window insulation, where the film is placed on the inside of a window and then shrunk using a hair dryer. 

Freezing in of orientations is made use of with what are called heat-shrink films Heat-shrink films are stretched or drawn biaxially, and these films are used to solidly encapsulate mold components. The wrapped goods are then warmed, whereby the film expands slightly below the glass transition temperature (for amorphous polymers) or the melting temperature (for crystalline polymers). At the transition temperature, however, the molecular segments become mobile the molecules tend to assume their unperturbed dimensions and the film shrinks in upon itself. 

Stresses are often frozen-in in processing films. The stresses are released on reheating, whereby the film shrinks and encloses wrapped material. Such shrinking films are especially interesting in the packaging industry when the shrinking process can be carried out in hot water baths. 

Polyethylenes Tough, low cost, versatile. Used for aU types of packaging trash bags, bread wraps, shrink film, antistatic film, etc. 

There are two different kinds of wrapping material, stretch film and packaging paper. Shrink film is hardly ever used for wrapping paper rolls, since the creases formed on the faces of the wrapped rolls do not allow one to store the rolls in a vertical position. Shrink wrap is only found in special apphcations, e. g. for holding finished paper rolls on pallets. 

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