Pin Adhesion Test (PAT)

August 30, 2019

Sam asks,

Do you have any formal reference of what the ideal pin adhesion test result should be.   For agro boxes (vegetables) we currently use values of 55 to 60  (pound/inch) and in industrial 40 and higher.

We have a particular customer that has experienced some delamination failures. The PAT test value is 27 (pound/inch) which we believe to be too low. However, we are lacking established information to back up our opinion.

I could not agree with you more.  I prefer a minimum, not average, of 45 for industrial application.  My technical associates at TAPPI like this 45 value while I would rather have 55 on all corrugated bonds.  It is most important to know where the failure is occurring: linerboard, medium, or in the starch itself.  Under ideal conditions we want 100% liner failure. As you can see in these photos a very low PAT value can have disastrous results. There is very little liner pull and very little glue with a poor bond.

A good reference for the PAT is the most recent version of TAPPI document TM 821 (TM 821-0M 17 at this writing), Pin adhesion of corrugated board by selective separation.

— Ralph

Pin Adhesion Test sample Pin Adhesion Test sample Pin Adhesion Test sample

Insulating Properties of Corrugated

August 15, 2019

Rich asks,

I have a question about the insulating properties of corrugated and the impact of vent holes in dairy applications. I have a dairy customer who is looking to pack sour cream in cartons. It is filled at 100 degrees F and put into 35 degree refrigeration. What is the difference in how long it will take to get down to 40 degrees if there are no vent or hand holes in an RSC against if there are some? Is there a formula that exists for the cooling time? This would be an ECT48 DW RSC. Thank you as always for your guidance.

Here is a link to a research paper (Overall Effective Thermal Resistance of Corrugated Fiberboard Containers) complied by the US Dept. of Agriculture and the Forest Products Laboratory. Pages 4 – 6 of this report contain information regarding the affect of vent holes.

The location and area of the vent holes as well as the velocity of the circulating air will also have an affect on the thermal transition time.

Would it be possible to perform an experiment using a grill or meat type thermometer to determine when the core of a loaded box with vents and a loaded box without vents reached the desired 40 degrees F?

— Ralph

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