Polypropylene film tapes

Monoaxially oriented polypropylene film tapes have been widely used for carpet backing and for woven sacks (replacing those made from jute). Combining strength and lightness, oriented PP straps have gained rapid and widespread acceptance for packaging. 

An important application for polypropylene is film tape. This is made by slitting unoriented film (cast or blown) into tapes 2 or 3.5 mm wide and stretching under heat about seven-fold. With cast film the orientation is more completely monoaxial and there is a tendency for the film to split along its length (fibrillate). Tubular film does not self-split so easily and also has a somewhat softer feel. Such tapes may be woven into sacks and these have... 

Zirconium propionate is a polymeric zirconium carboxylate its structure is illustrated in Fig. 10. Use of zirconium propionate markedly increases the adhesion of an ink applied to treated polypropylene film. Figure 11 compares zirconium propionate with titanium acetylacetonate, which is commonly regarded as the industry standard. The standard test method used in the ink industry is the so-called tape test . Sticky tape is placed on the printed film and pressure is applied by the operator s thumb. The tape is then pulled off, by hand, and the amount of ink removed is visually assessed. Although extremely crude, it can be, and is, used for control in the ink industry. 

The formulations in Table 14 were examined using treated, oriented polypropylene film as the tape substrate. These formulations might be useful as... 

Fibrillated tape yarns are produced from narrow width polypropylene films that are converted into relatively coarse filaments using special cutters and pins. These yarns find only limited use in filtration, mainly as coarse, open weave structures to provide support or drainage fabrics behind finer grade filter cloths. 

Medical. Medical tapes often have cloth or cloth-like backings for comfort and breathability. Numerous synthetic breathable, conformable nonwovens (eg, spunlaced polyester such as Sontara, a trademark of DuPont creped polypropylene) have been developed for such purposes. In some instances, film tapes are preferred to provide a barrier for wound coverage or to increase hydration to speed transdermal drug delivery. Electrically conductive adhesives are used for electrode applications. 

Polypropylene films are used in a variety of packaging applications. Both oriented and non-oriented films are used. Film tapes are used for carpet backing and sacks. Foamed sheet is used in a variety of applications including thermoformed packaging. Fibers are another important apphcation for polypropylene, particularly in carpeting, because of its low cost and wear resistance. Fibers prepared from polypropylene are used in both woven and nonwoven fabrics. 

If the sheet has been subjected to biaxial orientation during extrusion (see Section 14.2), heating above the deformation temperature will cause the sheet to shrink. A tight package can be made by wrapping an article in a biaxially oriented sheet followed by a brief heat treatment. Such shrink packaging with polypropylene film is widely used for everything from lettuce and meats to books and video tapes. 

Plastic. A plastic bag usuaUy consists of a single heavy waU of plastic film, woven sheets of plastic tape, or laminates. Principal materials of constmction are polyethylene and polypropylene (see Fibers, olefin). Both transparent and opaque sheeting are used, and printabUity usuaUy is exceUent. Plastic bags can be fiUed and closed with conventional equipment beat-sealing is essential for open-mouthed bags to effect a moisture barrier. 

Fibrillated tape, again particularly successful with polypropylene, in which oriented film is stretched so much that fibrillation occurs. 

Plastic films represent the largest worldwide market for plastics with practically all extruded (6). They are used to meet different performance requirements particularly for its major packaging market. Worldwide just for biaxial oriented (Chapter 8) polypropylene consumption is about 5 /2 billion lb. Their use includes tape, food, tobacco, and confectionery. Thermoforming film (and extruded sheets) is a major processing technique producing all kinds of products. 

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