Corrugated Performance In Sub-Zero Temps

January 28, 2020

Jeff asks,

I have a client who is asking for specific information about corrugated performance at low temperatures (-20 degrees Celsius) for extended periods of time (up to 6 months).  I have not been given specific information about the contents of the boxes, but I suspect it to be clinical trial materials or something similar.  I expect them to be looking for some sort of performance guarantee.  Current board grade is 32 ECT C Flute.  Outside liner would be virgin paper.  The remainder of the box (medium and inside liner) is recycled paper.

Anything you can provide to help me with this?  Or can you direct me to the right place?  Thanks in advance for any help you can offer.

There just is not much out there. Here is a Link to the last industry wide study on freezer storage which is over 70 years old, but still relevant. Note the added box strengths in the chart. Also here is a link to the most recent report from the PMMI on the storage of Corrugated Packaging.

As you stated, the contents of the box is critical and also is the introduction of any moist air from repeated open and closing of the storage unit. Use of aqueous or UV coatings will certainly provide extended resistance to moisture on the boxes’ surface. However, what generally happens is the glue line is attacked by changes in atmospheric conditions. This is where we often see failure under these conditions.

Does any of our other followers have any knowledge or experiences they can care to share on this subject? How about adhesives and sub-zero temperatures? How does temperature affect the difference adhesives we use in the corrugated industry?

— Ralph

Can ECT board be used for UN tested cartons

October 28, 2019

Randy asks,

I asked this question a number of years ago but I was wondering if ECT Board can be used for UN Tested cartons or is Mullen tested board still the only thing that can be used?

That’s probably a yes and no answer. ECT is allowed as long as the packaging can pass an ISTA testing protocol and the liner weights do not vary by more than 5%. A wider 10% range has been approved and included in the most recent version of the 49CFR.

Don’t forget about the maximum Cobb test.

—Ralph

Analyzing the cost of corrugated boxes

September 17, 2019

Amine asks,

I would like to analyze the spend I have to my corrugated box suppliers across more than 1000 type of references.

I got the specifications for the references ( type of box ( Fefco, RSC, etc),fluting, the dimensions, the different liners and their Gsm, MOQ, volumes, etc).

I have calculated the area of each reference and the weight of each box. Then, I have calculated the price per sqm and the price per gram.

From there I would like to understand the cost drivers that influence the prices and identify the references that are priced too high.

How would you proceed?

Ultimately every corrugated shipping container is made to a physical and graphic specification that can endure the distribution environment. Since you are an international company shipping from and through different systems your analysis becomes very difficult to evaluate. Universally we must look to the minimum compression strength necessary to survive transport. This is best determined by ISTA testing protocols.

What you really need is to determine cost to strength ratios. Containerboard is a global commodity and yet strength to gsm ratios vary greatly.

There are differences between virgin and recycled fibre costs. Secondary fibre prices have been falling, but both products are often traded in the same range. You would also have to look to the financial returns of publicly traded companies to ascertain their margins over time. It is considered a very supply and demand driven packaging system.

Of course, order size and frequency of order can play a large part in the final cost of a box as well. The finish of the box is another thing you need to take into consideration. Are they all one-color boxes, or are they two, three, four or more colors.

The manufacturing regions can affect the product price. Material prices and manufacturing costs can vary—sometimes significantly—from one region/market to another.

Here are links to a couple documents that you might also find helpful.

How Does One Relate ECT and Basis Weight2

Selecting Components to Engineer a 44# ECT Corrugated Structure Combining For Strength with the Least Cost Containerboards

—Ralph

 

UPDATE:

Vann comments,

Amine, I recommend that you have some performance testing of your boxes that relates to your various applications.  I think that this could help you rationalize your supply of boxes with the objective of reducing the very large number of different boxes but still cover the critical needs of each of the applications. In other words, find out what current boxes can handle multiple applications in order to reduce the number of different boxes.

Is Burst and Puncture Testing Performed on Triplewall?

August 30, 2019

Bobs asks,

Is burst testing and puncture testing done on triple-wall boards? I’m having trouble interpreting the minimum fiberboard requirements issued by NMFC Item 22 and UFC Rule 41. Specifically 1100 triple-wall, does the 1100 represent minimum burst strength of 1100 lbs. per square inch? Or does 1100 represent a puncture test value?

That’s a really good question. It is Mullen burst and not a Beach puncture. It is really based on the additive Mullen values of the liners. So if you were experimenting with low Mullen yet high SCT liner and strong mediums, it would be better to go to an ECT standard.

— Ralph

UPDATE

Miranda comments,

TAPPI T810 Section 1.2 states mullen burst is not applicable to triplewall board. If the test is being performed on triplewall it would not be clear what the results would mean.