Tests for Quality of Board

August 14, 2019

Harendra asks,

We are in the process of evaluating the quality of OCC grade 11 & 12. Can you suggest what specific test should be performed for quality evaluation of these two grades for production of container boardpaper?

I would suggest contacting Bill Moore at Moore Associates in Atlanta. He is an expert in this area.

Moore & Associates
Phone: (770) 518-1890
www.marecycle.com/

— Ralph

Convert European Board Specs to ECT

August 14, 2019

Jeff asks,

We have a customer that is based in Germany and is opening a branch in Tennessee.

They gave us some specs with the below board grades:

2.91BCB (alternative 2.91 AC)

2.70BC

2.91ACA

2.30BC

1.40C

We need to convert them to ECT values.

Do you have any information on how I can convert them?

 

Jeff, usually the metric equivalent to our pounds force per linear inch is expressed in kN/m but in this case I believe we are looking at kg-f/in so you need to divide their requirement by 0.038 to obtain the equivalent Imperial value. We have compiled a list of conversions that you may find helpful. (English Metric board conversions)

Conversions for grades listed above would be,

2.91BCB (alternative 2.91 AC)   — 76 ECT BCB Triplewall or AC Doublewall

2.70BC — 71 ECT BC Doublewall

2.91ACA — 76 ECT ACA Triplewall

2.30BC — 61 ECT BC Doulbewall

1.40C — 37 ECT C Singlewall

— Ralph

Measuring Force to Break PDQ Perforation

April 10, 2019

Pete asks,

We have been working with several different perf styles to provide ease of opening for retail ready PDQ style trays. There is a variety of different sizes and the majority of the items are earmarked for Walmart stores. While our execution has been successful we do not have an effective process to measure the force required to open the boxes to ensure consistency. Are there any tests to can recommend or any laboratories capable of testing the variables we are trying to measure?

Very good question Pete! You might review TAPPI T-813 which discusses the tensile test for the manufacturer’s joint. There are also jigs for compression testers that will measure the force necessary to bend a crease through a certain distance, usually to a 90 degree angle.  Also check TAPPI 577 and 829 for ideas.

Another option may be to use a burst test at the point of the perf. TAPPI T-810 describes the burst testing method. The question would be whether conventional equipment would have a satisfactory range of operation/measure or would the bursting strength of the perforation be below the recommended operating range of the equipment.

Now let’s toss this one out to our readers to see what their thoughts and experience may be. Has anyone done this type of testing, or is anyone aware of a specific method for testing the force necessary to break a perf?

– Ralph

Corrugated Shelf Life, Storage and Usage Temps, Toxicity?

April 9, 2019

Chris asks:

Do you have any resources for the following information regarding corrugated containers?

As the answers would appear to be specific to the material composition, these would be for plain C-Flute kraft containers.

  • Shelf Life
  • Service Temp Range
  • Storage Temp
  • Toxicity

These questions are asked quite often on Ask-Ralph. This may not be a complete answer to your question, but it is a start to the dialogue.

Corrugated under compression (loaded and stacked) ages/deteriorates at a different rate than KD boxes on a pallet. Environment, fill load, stacked load, potential crush during converting all contribute to the deterioration rate of a loaded box.

Ideally, whether loaded or stored as knock downs, corrugated should be stored at 72 degrees and 50% RH.  That’s a perfect world and few of us live in a perfect world. Any fluctuations in these conditions can reduce the fibre to fibre bonding and strength of the adhesive bond. Temperature does effect stored corrugated, but it’s the combination of temperature and humidity that has the greatest effect. High temps (90 plus degrees F) and low humidity and you’re likely to start to see score cracking and brittle paper issues. High temps and high humidity and you’re likely to start seeing bond breakdown and an increase of the compressive creep rate leading to increased chances of failure under load.

At extreme low temps and you may start to experience recharacterizations of adhesive that can lead to failures at joints and even at the liner to medium bonds. Same holds true here with humidity though it may not be as severe as with high temps.

General rule of thumb, if it is comfortable to work in, it’s probably good for corrugated. We don’t like to be hot and sweaty or numb from cold… neither does corrugated.

As far as toxicity, corrugated is considered an indirect food additive by the FDA and is detailed in 49 CFR.  Therefore, no toxicity for plain kraft. If there are inks or coatings involved, then you have to look that them on an individual basis.

Now there’s a start to the discussion. What input do our readers have?

— Ralph