Wednesday, December 16, 2015

New Package Testing Results Reveal Tape Closure is Superior For Compression Performance

By: Rob Kaszubowski, Sr. Packaging Engineer

Our original blog post on edge compression test (ECT) vs. box compression test (BCT) in box performance metrics prompted Sajith Pallippuram to write: “…Won’t the method of sealing the box also make an impact on the BCT value? We [have] seen that if we hot melt glue the box, that provides 30 percent more BCT value in comparison to taping the flaps. Can you please throw some light on this?”

Great question, Sajith! Chainalytics’ packaging engineer geeks are here to answer all your questions, so let’s jump in.

corrugated secondary shipper box
Tape closure with tape extending minimum of 2"
 into the body of the box
corrugated cardboard box
Adhesive closure with 6 adhesive bead lines
per minor flap.

The Set Up: Testing the Combatants
Over our many years of packaging engineering and testing we had not specifically tested this scenario to evaluate the difference in compression strength of taped flaps or adhesive closures. We were curious about this hypothesis ourselves and decided to conduct some compression tests to compare the two variables and evaluate this hypothesis:
  1. We designed an RSC (14" x 11" x 8") in Artios and cut out 6 samples of each box variable on our Kongsberg sample table in 32C Kraft material
  2. We set up the boxes and conducted the compression per ASTM D-642 using our LAB Compression table.
corrugated cardboard package testing
Tape (left) and adhesive flap closures
corrugated testing
Glued flap box in the compression tester.

The Contest Results 
The results showed the tape closure boxes with 8 percent more strength on average.
Minitab comparative data on compresion strength performance

What We Learned 
Even though this was a smaller sample set of only six boxes, our test data set shows the boxes with tape closure were stronger than the adhesive closure boxes. While there may be certain circumstances where the adhesive closure boxes may provide better compression strength (different box size, horizontal clamp forces, supply chain conditions, etc), our initial testing indicates otherwise. 

This initial data has definitely intrigued us and we will plan to pursue additional testing on this hypothesis to better evaluate these scenarios.

As a team of packaging engineering consultants, we’re constantly exploring questions like this, to challenge ourselves to help our clients find ways to optimize their packaging, save money and add to their bottom line. If you have a question or a cost savings hypothesis, drop us a line at or give us a call at +1 612.260.7845.

Rob Kaszubowski is a Manager in Chainalytics Packaging Engineering practice. His track record of success ranges from delivering packaging cost savings and damage reduction projects to optimizing packaging throughout clients’ entire supply chains.


  1. Your description of the test method is incomplete; for the taped closure, are you securing the minor flaps per requirements of Tappi T804? I think the test results are valid but the different is not likely due to the method used to close the major flaps, but rather what's happening inside the box with the minor flaps. By using adhesive to secure the major and minor flaps together you're preventing the minor flaps diving down inside the box and squaring it up from inside. If the boxes you're testing are empty, the vertical panels will tend to buckle inwards as the box deflects. Free floating minor panels shore-up the panels from inside and maintain their vertical load-carrying capabilities longer.

  2. Hi Pourlefun- thank you for your comment. We agree that this initial testing is a very small sample set. Our initial goal of the testing was to garner some high level results in response to a previous inquiry we received from our blog reader, Sajith, in regards to the performance of adhesive closures.
    We plan to perform additional tests utilizing a larger sample set, as well as securing minor flaps with box clips per Tappi T-804 methods.

  3. Hi Rob
    Thank you for your article. I am glad that you have taken the pains to test something based on my question. Really appreciate your passion,
    I would like to share my further learning on this topic (As I had just started this research when I popped the first question to you)
    1. There need not be any difference in the BCT value of the same box between two methods of sealing used - namely gluing and taping
    2. The difference of 8% could be attributed to the two different boxes of the same lot having a slight difference in the BCT value
    3. The reason why they will not be different - is BCT is simply measuring the strength of the strongest part of the box : its walls. So the type of sealing need not matter
    4. Now comes the question - what happens when the boxes are not stacked in a columnar fashion - and instead in an interlocking fashion ? What happens if there is a point load on the box. Now the method of sealing will come in to play. And thankfully as shown by your picture - the surface area to share the load will be much higher in the case of gluing. We have conducted transit trials with such simulations and found the glue box to sustain these challenges better.
    I can share more information and some videos if needed.

    thank you once again


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