Consumers often desire controlled easy access to packages. Perforations in a packaging material might be one solution but these sometimes weaken the material too much, resulting in premature opening during distribution or retail display. Tear strip products are often an effective means to focus tearing on the desired area of a package without weakening it.

Background

One of the common forms of tear strip products is a narrow tensilized film such as polypropylene. Some film tear strip tapes have ribs, which provide additional resistance to cross tape tears when the edge of the tape is nicked. A pressure sensitive adhesive allows easy application without any heat or extra processing.

A tab in the package allows the user to initiate the tear through the packaging material, tearing it along each side of the tear strip tape.

Conventional Tear Strip Function

This is common in corrugated boxes, paperboard cartons, and some film overwraps. Some examples of paperboard uses follow:

Most narrow width tear strip tapes are applied from long yardage level wound rolls. These may be several thousands of meters long.

Tape is most often applied continuously to a package surface, prior to die-cutting and forming, sometimes at high production speeds. Another option is to apply short strips to a package form; this requires more specialized tape application equipment. One example of an unwind stand for level-wound rolls of tear strip tape is shown below (photo courtesy of Straub Design)

Conventional narrow width tear strip tapes are functional on some thin film packaging materials such as cellophane and BOPP. They often have problems tearing tough or stretchable films such as LDPE, LLDPE, or their coextrusions. These thicker and tougher films have been difficult to provide easy access to without weakening them with perforations.

New Advances

A recent development is the use of a wider ribbed tape to the inside surface of a tough packaging film. A die-cut tab directs the tear to the inside of the ribbed tape. The ribs control the direction of the tear and help keep it internal within the ribbed tape. Opening is controlled and easier because the ribs prevent excessive stretching of the tough film while tearing.

Internal Tear

This internal tear characteristic allows easy access to tough shrink films and overwraps which previously could not easily be opened. This tear strip application does not weaken the package film as perforations do.

A few packaging films are extremely tough and may need a two-tape system for easy opening. Several combinations are possible. The example below uses the ribbed tear tape on the inside surface and a film cover tape, such as BOPP, on the outside surface. These ribbed tapes might be 12 mm wide and applied from long planetary wound rolls, 1828 meters long. An example of this is Scotch® Reinforced Strapping Tape #8640, available from 3M. There is also the potential for longer level wound rolls.

Two Tape System

Uses of New Easy Opening Technologies

Easy Open Poly Mailers

One use for the new internal tear tape is in “poly mailers”. The tough films have been notoriously difficult to open without a knife or scissors and they present a risk of cutting or damaging the contents. Perforations have been available but these significantly weaken the flap, particularly for bulky products such as clothing. Premature opening and subsequent product losses are an unfortunate possibility.

The easy open poly mailers have a strip of ribbed tape applied to the inside of the flap as shown below:

Easy Open Poly Mailers

An additional advantage of having controlled easy-access to a poly mailer is the viable option of a returnable poly mailer. These have two adhesive strips with liners and one 12 mm wide ribbed tape applied to the inside surface of the flap. Perforations have been tried here but, again, they have unpredictable openability. Conventional narrow width tear strips often do not function with tough films.

Easy Open Shrink Wraps

The internal tear of a ribbed tape is also very useful on shrink wraps. For example, books might be shrink wrapped to a corrugated pad and placed in a box for shipment. Customers might find this difficult to open without tools, which may damage the contents. A ribbed tape with internal tear characteristics allows the tough film to be easily opened without the film being weakened.

This easy access system may be applicable to many other types of shrink wrapped items.

Easy Open Handle for Multipacks

Shrink wraps are also used on multipacks of beverage bottles or cans. The use of a ribbed tape with internal tear allows for some extra benefits to the packager and to consumers. The same tape can function as an easy opening device and as a package handle.

A shrink overwrap can be printed for sales impact and also to block the UPCs of the internal containers. It provides a different UPC for the multipack. This can yield cost savings to bottlers over ring carriers because of simplified and reduced inventory.

A 24 mm wide ribbed transparent tape could be in rolls 1828 meters long. Tape would be applied to the inside of the shrink film. Die-cuts would be made to form handle slits and to form the initiating pull-tab.

There are four functions provided by this:

The tape would be applied to the inside surface of a shrink film prior to die-cutting and being wrapped around the items. The tape could be applied continuously but may also be cut to precise strips and applied to the film. Equipment can be custom tailored to specific application needs. The taping head below is one option for application of tape strips (photo courtesy of Straub Design).

With these advancements in easy opening technology, additional options are now available for controlled opening of tough tear-resistant films. Packagers can offer improved convenience and accessibility to their customers.

References:

US Patents 6,354,739, 6,513,657 and other patents pending

Sheehan, R L, Tape, Pressure Sensitive, Encyclopedia of Packaging Technology, second ed, Brody and Marsh editors, John Wiley & Sons, 1997, pp 883 - 887