Laminator Glue Recipe

December 1, 2017

David asks,

I have just installed a Flute laminator Mounting machine here in UK that I purchased from China. While I was there they said that most of the machines in China would be using Starch Glue. I wanted to try some so they sent me about 25kg of the components to try with the idea of buying from China if it works. However there are problems with importing it, so I have started to look at buying materials here.

We are either mounting uncoated paper to Test corrugated board or to Unlined grey-board our speeds are not much more than 70 metre/min max but much lower for most jobs around 45mtrs/min

The recipe from China is as below. The problem is that they are saying the Calcium Carbonate has other additives in it. I guess they want me to buy from them and won’t say what those additives are nor are the instructions to prepare the glue very clear.

The recipe I have is as follows

  • 5kg Corn Starch
  • 5kg Calcium Carbonate + whatever there may be in it
  • 16kg water
  • 300gm Caustic soda
  • 150 gm Borax

I was told to mix the starch and the calcium carbonate and then add the Caustic soda and Borax.

My question is:

Does the above recipe look viable? I think it’s possible that the calcium compound is just with that nothing added. I have seen recipes for starch glue including all of the other contents and I have also seen that the Calcium can be a filler which might make it more viscous?

The cost of all of these chemicals is much cheaper than the PVA based adhesives we have available here and I understand that Starch glue has been used in corrugated for many years.

If you are able to advise if this recipe will work or if there is a different combination of chemicals it would be very helpful.

PVA adhesives are recommended for laminating because their elastic properties reduce the extent of score cracking. Yes they are more expensive, but the finished product is typically of a much higher quality.

I do believe that the calcium carbonate is nothing more than a filler and increases the viscosity of the mixture.

I have copied some of my network contacts here in the States for their expertise.

Let’s also toss this out to our readers and see what their experiences have been.

– Ralph

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Letters of Compliance regarding chemical migration

November 20, 2017

Jeff asks,

We have received three requests from customers in the last month, asking for letters of compliance regarding chemical migration testing of corrugated packaging. They are saying this is a requirement for their SQF 2000 audits.

Is there a statement we can make to our food manufacturer customers that would generally satisfy their requirements?

The world has not agreed yet on what the general statement or regulations will look like. The Global Harmonization Standard or GHS is still in committee as they work to iron out the specs.  We do not have issues with mineral oil migration in the USA. Ask your sheet supplier for the letters that you can provide to your customers. They know the process and materials going into the manufacture of the sheets and should have a reasonable understanding their product as it corresponds to your customers’ requests.  Also, placing the responsibility of compliance on your supplier may be beneficial to you in the long run. I’ll keep my ear to the ground on the GHS and update when if I hear of any changes.

Has anyone else had experience on  this subject that they can share? Let us know what your experiences and thoughts may be.

— Ralph

Regulations on box storage for food related boxes

November 17, 2017

Tim asks,

Ralph, are you aware of any regulations regarding the storage of secondary packaging for food related boxes? We make secondary packaging for a customer and they received some of our boxes that were covered with stink bugs. Apparently there was a small hole in the wall, which we have repaired, where the boxes were stored. Being that they are secondary boxes it does not required us to be AIB certified.

Those little insects get everywhere! There should not be any regulations for reasonable storage of secondary packaging. Below is a link for recommended practices for the storage of corrugated. https://www.pmmi.org/sites/default/files/PMMI-B155-TR2.3.pdf

I would also suggest that you walk through 21 CFR 110 for the “Current Good Manufacturing Practice in Manufacturing, Packing, or Holding Human Food.”  You may also consider an overview of the Food Safety Modernization Act.

However, regardless of whether there are regulations or not, your customers don’t want any little six-legged stowaways in their shipments. Perhaps you could bag or stretch wrap the entire pallet to protect against further infiltration or contamination from dust or other elements that me be present in the atmosphere.

– Ralph

Peeling white liner issue

October 24, 2017

Khuram asks,

We are experiencing a peel off issue with white 135gsm test liner. This issue is random and the top layer of white liner gets peeled off in the cross direction during conversion. (See the picture below for examples.) We have our own vertically integrated board mill which is providing this white test liner and as far as ply bond strength is concerned we have tested it different lots (using method TAPPI-569) and its average values are >250J/m2.

This issue can have several root causes.

One is that the ink is too tacky and it is pulling the white fibre from the brown base sheet.  It can also be that the ink is drying on the printing plate or otherwise not releasing properly from the plate.

Second is that there could be a poor bond between the white fibre top sheet and the brown base sheet.  This is usually caused by poor fibre developing during the pulping process.  It could also be an issue of poor water drainage in the board making segment.  There could be a contaminated water system, or there may not have been enough starch between the two layers to hold them together.

Sometimes closure tapes can be used in the box plant to predict the ply separation.

So there are a few things that you can look at. Let’s toss this out to our followers and see what they have experienced and information they can offer.

— Ralph