Often, we are asked about the initiatives of using less fiber in our corrugated structures. Many times, these questions are asked by the investment communities. We are still overpackaging but not at the levels where we were before the pandemic.
Increases in strength ratios (i.e., Short Column Test [SCT]) versus basis weight offer greater opportunities. I have often been a proponent of access to on-site labs or sheet feeders willing to provide certificates of analysis for final key combined board properties, regardless of the basis weight of the components.
“Performance” grades of linerboard and medium are often overused terms like that often dreaded term “sustainability.” While the former description works smoothly in written marketing communications, it is not a real indication of variation in raw materials that we need to look toward for comparing stacking strength potential to basis weights to price. Look for a major research investment firm to bring to life a template for comparing packaging strength and costs per pound of fiber.
Additional production is brought on by the new containerboard or repurposed newsprint and printing and writing machines. Using 100% OCC, DLK, and/or mixed paper waste, opportunities abound: 18# can be used for low-strength corrugated boxes where there is primary interior packaging such as folding carton grades or products containing cores or tubes.
Also, one would expect that with extended producer responsibility legislation being enacted by a few states, users of single-use plastic containers would be investing in containerboard options. Although items such as clam sheets are the domain of lightweight kraft and recycled papers, corrugated still has a replacement option for many carryout and bakery containers. This is especially true with the continued development of oxygen, moisture, and grease barrier solutions that are also repulpable for recycling. This can be accomplished without the use of forever chemicals, such as per- and polyfluoroalkyl substances, which we discussed in the May/June 2023 issue and earlier issues of BoxScore.
The table below includes some statistics to explain the movements of basis weights over a 15-year period. Ranges in strength, as measured by the SCT, are also included in the far right-hand column. The data here reports the combination of recycled and kraft linerboards.
One must choose wisely knowing the downward shift in nominal basis weights and the variations in ECT and stacking strength potential of the corrugated box based on the compression strength potential of the raw material SCT. The table does not include all of the 140-plus containerboard machines in the U.S. and excludes Canadian production.
Observations and Conclusion
There are small increases in 26# and below-26# liners, as the newest recycled mills have introduced 23#, 21#, and 18# products for e-commerce and smaller lightweight boxes.
Of greater significance in the light category is the replacement of 33# with 31# and 29# facings.
The long-term mainstay 42# grade continues to fall to lighter liners combined with more substantial medium in the midweight category.
The four heaviest grades have all declined. What started 30 years ago with 56# compression-based SCT engineered liner replacing 69# Mullen boards continues now with 52# liners and more significant mediums to meet ECT combinations.
What I interpret as another movement to lighter-weight combinations and a move in the continued direction to reduce overpackaging is the large increase in 23# mediums.
Ralph Young is the principal of Alternative Paper Solutions and is AICC’s technical advisor. Contact Ralph directly about technical issues that impact our industry at askralph@AICCbox.org.