Does Mullen make or break the success of a box?

March 17, 2016

Justin asks,

As you may know I am a bit of a geek when it comes to board combinations. By picking and choosing what machines and what mill run our paper, we are now pretty consistently getting 38 ECT and above from 31-23-31. I confess that the 23# comes in at 24 or above, but the point stands. I have been doing much ruminating about all this.

We have a very long-time customer that went from 200# test to 32ECT, started having too many box failures due to stacking problems, and went back to 200# Mullen. Folklore at our company for years has been that this is an example of a customer use that better suits itself to Mullen than to ECT. Maybe there’s some Mullen magic? However, now I am coming around to the opinion that since our 42-23-42 generally tests a bit north of 44ECT, what we really had was success moving from 32ECT to 40 ECT. The Mullen probably had nothing to do with it.

Would you agree that it is probably rare that Mullen makes or breaks the success of a box?

Agreed.  I was just on a case with another member whose boxes made from 100% recycled fibre failed in trailer storage after about three weeks.  They performed in the past.  As best I could determine, the linerboard had a low level of size and was subject to more degradation through swings in relative humidity (RH)  and the box seemed to overhang one corner of the pallet.  It’s all about an engineered approach to each customer’s total packaging system.  Yours maybe more than Mullen verses ECT, are the recycled contents the same of the two sheets?  ECT 40 is always a good compromise, but I know you like to get to the bottom of opportunities.  Thanks for sharing the challenge.

Anyone one like to share their knowledge and experiences?

— Ralph


Does DOT Govern Recycled in DOT Certified Packaging

March 11, 2016

Kevin asks,

Does the DOT govern the amount of recycled content that can be present in a DOT certified UN Hazmat corrugated package?

Yes. The Department of Transportation ( ) governs the standards for UN Hazmat packaging.

— Ralph

Hazmat Paperwork Lifecycle

January 26, 2016

Tim asks,

How long do we need to keep our paperwork for boxes where we print the UN hazmat logo’s on?

I reached out to Lonnie Jaycox ( for some help on this topic. Below is Lonnie’s reply. Thank you Lonnie for your assistance.

— Ralph

If the Hazmat logo is the certification mark for specification packaging; it depends on the paperwork “who” (which person) the box plant is listed in the regulations.

If the box plant is both the fabricator of the box and the “manufacturer” of the packaging under 49 CFR (It is their name or symbol that appears in the certification string.). Then they will need to keep design qualification test reports for the period specified in 49 CFR 178.601(I) [see below]:

  • Record retention: Following each Design Qualification (DQ) test and each periodic retest on a packaging, a test report must be prepared. The test report must be maintained at each location where the packaging is manufactured, certified, and a design qualification test or periodic retest is conducted as follows:


Responsible Party Duration
Person manufacturing the packaging As long as manufactured and two years thereafter.
Person performing design testing Design test maintained for a single or composite packaging for six years after the test is successfully performed and for a combination packaging or packaging intended for infectious substances for seven years after the test is successfully performed.
Person performing periodic retesting

Performance test maintained for a single or composite packaging for one year after the test is successfully performed and for a combination packaging or packaging intended for infectious substances for two years after the test is successfully performed.

If the box plant is a fabricator (not the manufacturer), then is no need for them to retain a copy of the DQ report at all, since there is no requirement that they have it to begin with. In that case, the manufacturer simply gives the construction specification to the box plant to manufacture. However, because the person responsible for the specification and performance of the packaging is required to maintain records for two years after a packaging is no longer manufactured, I would recommend that the production records for boxes marked with a UN specification marking should be retained for two years. That way if there is any question as to the construction of the packaging, the fabricator could demonstrate from their records that the manufacturer’s specifications were followed.

If the “paperwork” mentioned above is not associated with the UN specification marking, I would need some clarification of what UN marking is being discussed.


Litho-label Score Cracking

December 2, 2015

Gary asks,

Could you tell me the key variables in the Litho Label and the Corrugate Board that will affect Label Fracturing. We are seeing fracturing variability in the litho label after laminating and scoring.

Moisture, paper grade and condition, glue/adhesive, scoring profiles, scoring rule, impression and the manufacturing process are some of the variables that can cause score cracking (fracturing) in both litho-label and corrugated. When a label is glued over a liner you’ve added another ply and basically reinforced that surface. Now, when that surface is scored and folded the label is stretched around the corrugated liner causing stress to the label causing it to tear.

Moisture may play one of the most key roles in score cracking. If the moisture level is too low, the paper loses its elasticity, the fibers become brittle and fail resulting in a cracked score. However, if the moisture level is too high, or there is too great a difference between the moisture levels of the corrugated and the label then you can risk warp and shrinkage issues.

In an earlier post on this topic Brian Tankersly from Lewisburg Printing offered insight through his experience with the affects of moisture on litho labels. Click here to read that post.

We tend to take great care of our litho-labels. We handle them so that are not damaged. We keep them in controlled environments to maintain moisture levels, cleanliness, etc, but do we take the same care to control and monitor the sheets to which the labels are being applied?

If the corrugated liner under the label tears, the result will most likely carry through to the label. So the condition and “conditioning” of both the corrugated and litho-label are critical to the quality of the score.

Then of course there is the paper itself. Every paper machine has its own unique profile and engineers each one of its products with its own DNA characteristics. As in life, there are tradeoffs to make: improving one property may diminish another. In the case of high graphic substrates as those typically used for labels, the formulas, combinations and engineering of the paper can be proprietary information. An example can be the hardwood to softwood fibre mix. The hardwood to softwood ratio is used to improve the coating application. However, enhancing the “coatability” of the paper can increase the incidence for score cracking. Also some types of coating can be more prone to cracking than others.


I hope this provides some help and variable to consider. If you have any further questions, or there is anyone out there that has information to contribute, please don’t hesitate to comment or contact us.

— Ralph


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