Strapping

Strapping, also known as bundling and banding, is the process of applying a strap to an item to combine, stabilize, hold, reinforce, or fasten it. The strap may also be referred to as strapping. Strapping is most commonly used in the packaging industry.

Strap is a flexible flat material, most commonly made from steel or various plastics.

Steel is the oldest and highest tensile strength strapping. It is available in a variety of widths and thicknesses as well as variations in the grade of steel. Steel is used for heavy duty holding where high strength and minimal stretch are desired. Surface finishes for steel strap include: paint, paint and wax, bluing or zinc and wax. The wax is used to better transmit the tension around the bundle and for use with certain types of tensioners. Common applications include steel coils, bundles of metal, baling wire, bricks and pavers, and roll end-binding.

Polypropylene strap (oriented or tensilized) is an economical material designed for light to medium duty unitizing, palletizing and bundling. It is available in various widths, thicknesses, and polymer variations (e.g., copolymers). Most polypropylene is embossed, some of which is also printed. This product offers higher elongation at break but tends to have irrecoverable dead stretch with constant stress. What is not generally known to end users is that polypropylene strapping will lose about 50% of the applied tension within one hour, and that this tension loss is accelerated with increases in ambient temperature, consequently although suitable for packs with a degree of stored energy that will take up any relaxtion that occurs in the strap, unacceptable strap slackness may occur after time if used on product that is 'Solid' such as bricks or concrete. Further more polypropylene strapping is susceptible to UV degradation and can quickly degrade if left outside exposed to the elements. The sensible choice of colour will retard the process, such as specifying black strap. Similarly, a UV inhibitor can be specified.

Polypropylene strapping may be printed, either during production and pre-embossing for the highest quality and precision, or post production over the embossing for a reduced quality. Both offer security and marketing advantages to the strapped product.

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