Yeast & Mold Standard

December 1, 2017

Reul asks,

We recently had a batch of doublewall boxes held at the port because it was mishandled by the shippers and delayed for about two weeks. The dry container van was stored at the Customs Yard. Maybe the two weeks of exposure to cyclic condition, high humidity at night time and occasional rainfall may have resulted in a favorable condition for spore to develop into molds.

Do you know a standard or allowance of presence of yeast/molds in a corrugated box? We have this analysis of 1500 CFU from the swab test conducted on the samples coming from a certain batch of corrugated boxes that we produce.

This has been a concern for us since one of our customers complained the boxes they received had some dusty matter on its surfaces. We sent samples to an independent lab for microbial analysis and it was confirm to have that reading mentioned above. Is this value alarming?

That’s a tough question. We have no threshold count for molds and yeasts. It would not come with the containerboard except where the relative humidity or liquid water is present with the spores. Certainly the conditions you described could have had an impact on the condition of the boxes and the growth of molds if spores were present. Depending on what the contents are and what the end user environment is these conditions could very well be unacceptable.

— Ralph

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Dual Arch Medium

December 1, 2017

Bruce asks,

I am searching for a company that manufactures corrugated sheets with dual arch medium capability. Our location is Dalton Ohio, is there anybody you could refer me to please? I know there is a supplier in Florida that does this medium, but freight is too costly.

I have reached out to some industry contacts. I’m awaiting a phone call. Also a search within the iDirectory revealed no information.

While we’re waiting to hear back, let’s toss this one out the readers too! Is anybody near Ohio running double arch?

— Ralph

What the #1W?!

December 1, 2017

Steve asks,

I have a customer asking me to interpret and explain this call out “ 200E #1W”.

The 200E part is easy. It’s the #1W is a bit more ambiguous…I don’t believe it is industry standard expression. Could it be a designation for coated SBS?

Oh yes. A long history here.

# 1 could be Kemi, Coated SBS, or Coated label stock

#2 does not exist anymore or a lightly coated white top or uncoated SBS

#3 is what we refer to today as uncoated white top.

— Ralph

Hot Melt Glue Separation

December 1, 2017

Mike asks,

I have a customer that runs case make up units using a solid set hot melt. As of late we have an issue with the appearance of the seal on the bottom of the carton. When we are using light weight single ply liners the customer is not seeing fibre pull when breaking the bottom flaps apart to check for a bond. They are now considering this test to be a fail. Even though we can do a shake test and it passes. When pulling the cartons apart by hand the strength feels the same if you have fibre pull or not. When we are not seeing fibre pull what you see is the hot melt glue lines on each flap that is stuck to the paper so it looks like the glue came apart in the middle.

Anyway, is there is a tool that we can measure the bond strength on the bottom of a carton?

If glue is remaining on both flaps and is not separating from the paperboard, then the bond between the paperboard and the glue would appear to be good. If we take a lesson from the corrugator, too much glue can be as bad as too little glue. Too much and you risk shear within the glue itself. I’m not positive if the same ‘holds’ true (pun intended) in hot melt. I know too much hot melt can cause a variety of problems, but I’m not sure if shear within the glue is one of them. I’ve reached out to some of my industry contacts and I’m awaiting their input. I’ll update this post as when received.

I’m not sure if here is an official measuring device. However, I would think that if the box was to hold, say 25 pounds, you could get 25 pounds of weights at the local sporting goods store, place them in the bottom of the box and then somehow suspend the box so the full weight was on the bottom flaps. Perhaps do a few jerk tests where you would quickly lift the box with the weights in it. This would simulate the additional forces of acceleration. If it supports the weight, perhaps your customer would accept this as proof that the bond is sufficient to hold the prescribed weight. Be careful when you are testing.

Okay readers, has anyone else seen this type of separation with hot melt? Do you have any experience or suggestions to pass along?

— Ralph