Box Closures

A manufacture’s joint is an even piece of corrugated fiberboard that has been cut, slotted, and scored, for the purpose of holding the two ends of a box blank together. When assembled, the joint forms a tight seal with tape, staples, or glue. An important aspect to protect your product during packaging and shipping, these joints are crucial that can either make or break the structural integrity of your box.

Not all boxes have manufacturer’s joints; for example, the bliss box does not. However, most widely used box styles have a manufacturer’s joint.

There are four main ways to close a corrugated box: Taping, Stapling, Strapping and Gluing.

A very common question asked by many of our customers that use packaging tape is “What is the difference between PVC and Polypropylene packaging tapes?” …which is usually followed by “Which kind of packaging tape should I be using?”

PVC (polyvinylchloride) and Polypropylene are the base materials used to make a packaging tape’s backing.

Adhesives – Natural rubber, acrylic or Hot Melt – are then applied to the PVC or Polypropylene backing to provide the ‘sticking’ power.
In general, most people find that PVC packaging tape is superior to Polypropylene in every area except price and recyclability. Don’t worry – both tapes work well in most situations.

The following illustrations show the most efficient method of stapling the tops and bottoms of corrugated boxes. Note that the number of staples required in each case depends on several factors, including board quality and test, contents, staple type etc.

Stapling has several benefits;

1. Cost Effective – The more cartons you close, the more you’ll save by stapling. Strapping and taping can be up to 50% more expensive in terms of material and labour costs. Furthermore, many packaging designs can be simplified to use less material when staples are used for closing – and less material means lower packaging costs.
2. Strong, Stable & Secure – Stapling is ideal for packaging heavy items and for long distance shipping. They also hold well in all weather and environmental conditions. A stapled box is always a safe package, whether damp, dusty, hot or cold.
3. Attractive and ‘Pilfer-Proof’ – A stapled box leaves a clear, unmarred surface; no part of the box is obscured (especially print) and the box achieves its function as a messenger. And because a stapled box is difficult to re-close, the staples act as a deterrent to the thief. Traces of the crime are obvious; thus a break-in during transport can be detected before the package reaches the customer.

Gluing is an effective way to adhere and the most common, but it is also more costly than tape or staples. Liquid adhesives are most often used to join the two surfaces. Often there is a glue tab, extending along one end of the box blank. The tab is scored and folded to form one corner of the box when joined. The tab can be joined to either the inside or the outside of the box.

Strapping is another method to close a corrugated box. Strapping materials can be PVC or metal depending on your needs.