My World of Moisture

Category: My Moisture Technical Page 2 of 3

Thinking Humidity Outside The Box

So much stuff being ordered online and delivered. Like me, you most likely have had a few boxes not arriving in a good condition. Here is an article on cardboard boxes I wrote before lockdowns drove us into online ordering madness!

So there I was, standing in front of an audience, wearing a headset and my voice booming out through large speakers, when suddenly, two minutes into my talk, the screen goes blank! I was giving a presentation called “Fidelity of Moisture Status in the Pharmaceutical Supply Chain” at a conference in Dublin. Nothing else for it, with no slides to show, I switched to talking about “Moisture Matters”. After a few minutes talking about the way materials interact with moisture, I brought my talk back towards the theme of my presentation. With about five minutes left, the screen came back on and I flicked through the key slides at speed, highlighting the points I had just talked about. A further twist in events was that the next speaker, who was talking about getting the right packaging for transporting products, started showing pictures of cardboard boxes and mentioned that magic word to my ears “humidity”.……..

Damaged packaging

Nothing surprising in mentioning humidity when choosing packaging, as we know some products need to be protected from moisture. The really interesting bit for me was the speaker talking about humidity and the problems it causes with “adhesives” used to stick cardboard boxes together. Obviously, if the adhesive doesn’t work, your cardboard box carrying your product falls apart. This does not inspire confidence in the product, especially if you’re the customer.

Storage of cardboard boxes
Damaged cardboard boxes

Making cardboard

Naturally, when I got home, I started researching adhesives used for cardboard boxes and effects of humidity. Some information that popped up is similar to the effects of moisture on paper. I talked about storage of paper and the printing facility environment in my previous blog. Since the raw material for cardboard and paper is wood fibres then it can be expected that both react in much the same way when exposed to changes in humidity.

Ripped cardboard
Exposed layers of cardboard – liner ripped off to show flute

Most of the information offered by my Google search was about how cardboard is made. I never thought about this before, but then, why would you? Cardboard is made using flat sheets of paper as “liner” and a shaped paper sheet called the “flute”. Each layer of cardboard consists of a flute sandwiched between two liners. Of course these layers have to be stuck together and that is done using adhesive. In the picture you’ll see where part of a liner has been removed showing the flute below. Because the liner has been forcibly torn off, the surface of the flute is rough where the adhesive attached the two layers.

Any, or all of these parts (liner, flute and adhesive) can be affected by moisture depending on the humidity at the time of making the cardboard. But, as interesting as this may be, it is a diversion from my search to find out about adhesives and cardboard boxes falling apart.

Adhesives

At this point in my search I was struggling to find a simple report or studies on moisture affecting adhesives or glues used for cardboard boxes. However, there are some detailed published scientific studies and online resources describing moisture reducing the bonding strength of adhesives. Also, people have investigated adhesives used for bonding wood. Two wood adhesives with increasing popularity are polyvinyl acetate (PVAc) and polyurethane (PUR).

Why the popularity of PVAc and PUR? They do not contain formaldehyde which is volatile, banned for use in food containers and best avoided anyway. These two adhesives are also used for gluing the edges of cardboard boxes. If you think about it the fibres in cardboard that are bonded by the adhesive are the same as in wood.

What I discovered

To summarise, what I’ve discovered in my searching, and taking out scientific jargon such as “interfacial bonding”, the effect of humidity and moisture on the adhesive, causing the edges of the cardboard box to become unstuck, is on three levels:

  1. When cardboard is stored at high humidity, moisture uptake happens and this weakens the bonding strength of the adhesive when applied to form the edges of the box.
  2. Even when a strong bond is formed along the edges, high humidity causes moisture to enter the adhesive and can change it chemically and physically weaken its bonding.
  3. High humidity drives moisture between the adhesive and the surface of the cardboard, breaking down the bond.
Humidity and cardboard boxes
From UPS: “Air Freight Packaging Pointers”

There is a fourth level but nothing to do with the glued edges. The courier company UPS have done studies that show a 60% reduction in the strength of cardboard itself at high humidity. This is important because if a cardboard box has been exposed to high humidity it should not be reused but sent for recycling. UPS provide a cold storage transportation service and if you read the first two chapters of my eBook you will understand why the reduced temperature has a big impact on humidity.

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Welcome to my world of moisture

Printing and the Birth of Air Conditioning

It’s been two months since my last blog article. That sounds like a confession of a sin and in some ways it is, as I have deliberately stayed away from blogging over the past weeks. I was told by Sophie who set me up for blogging, that I “must” write one, or better two articles, a week. Sorry Sophie but two articles a week is just too tough for me. My reason for the recent lapse is I had to focus, even over Christmas, on my company Relequa. We are at a very exciting and very busy stage of developing and launching a new instrument for looking at the way moisture interacts with materials. During this activity I visited a printing company in Belfast. The owner of the printing company asked what Relequa was about and when I explained he said “air conditioning was invented for the printing industry”. Immediately that comment was lodged in my brain with a label “must investigate if that’s true”.……..

Quality: Fuelling Growth – Reducing Risk

Fuelling Growth - Reducing Risk

Fuelling Growth – Reducing Risk

A bit of a departure from my moisture related topics this week. I attended a conference in Sheffield with the title “Quality: Fuelling Growth – Reducing Risk”. Of course, I cannot write on my blog without at some point mentioning humidity, and Sheffield nicely obliged with a humid conference room. In this post for my blog I thought I would quickly run through the speakers and topics at the conference. My reason for writing about the conference is simple. All the presenters and the people organising the conference gave their time for free to support a local charity “The Children’s Hospital Charity”. I really liked the idea of hosting a conference and giving the proceeds from the conference to an excellent cause. Over £5000 was raised for the charity.

Flying around humidity

Drosophila_melanogaster_-(aka) - Wikimedia

Drosophila_melanogaster_-(aka) – Wikimedia

I’m always on the lookout for moisture related stories. Part of this is about testing my own knowledge and asking myself if I can make sense of the story. Last week I was following stuff on Twitter seeing if anything caught my eye. Suddenly out jumps what I would call a little gem of a story.  Actually it was not a story as such but a research paper that had just been published. However, the content was very much part of my story in My World of Moisture ….

Relaxing with a Gin in Edinburgh

Differnt Edinburgh Gin Bottles

Edinburgh Distillery Gin

Just had another trip to Edinburgh. This was a pre-booked visit to see my mum, but if you have been reading my blog, you will know she died in early March. So we had two full days in the beautiful city of Edinburgh to relax and enjoy what Edinburgh has to offer. Two things-to-do were planned in the days before setting off to Dublin for our flight to Edinburgh. A favourite attraction for me is the National Museum of Scotland in Chamber’s Street and that was put on the agenda. Picking inside locations fitted with the weather forecast, which was possibly snow! Another event chosen was more of a touristy venue, the Edinburgh Gin Distillery that is amazingly slap bang in the city centre. We booked this online for the day after our arrival. You may be thinking at this point that I’ve run out of things to say on moisture and turned my blog into a travelogue. Not so, it was at the Edinburgh Gin Distillery that the subject of moisture jumped out at me, but not directly….

My Damp Sheet of Paper Mystery

I was feeding sheets of paper into a paper shredder and stopped suddenly when I felt a piece that seemed to be damp. The other sheets of paper in the same pile were dry, so how is it that this one sheet appeared to have picked up moisture? As far as I could see, this “damp” sheet came from the same place as the others, which was a stack of various documents, flyers from the post and envelopes with their plastic windows torn out. Curious is it not, to have just the one damp sheet in a pile, how can this be?

Moisture in Transformer Oil

 

“Oil and water don’t mix” is a common saying and a scientific fact. But oil and moisture do mix! So how is it that moisture, which is also water, can mix with oil?

Why do I mention this?

Because I tuned into a webinar last week with a title that caught my attention, “Moisture in Transformer Oil”, to find out this is something that is very important to know about, if we want to keep our lights on!

Saving money on kitchen appliances (and save a bit of the environment)

Tricity Bendix Dishwasher

Dishwasher Controller Box

Having one of those years when everything electrical goes wrong? I’m pretty sure most of you have had at least one of these in your lifetime. Ours was over the past 12 months. I confess at this point that this article has little to do with moisture, only to say “it never rains but it pours”. Dishwasher only running for a few minutes on a run then stopping; Fan oven tripping out all the electricity when turned on; TV screen with a line down the left hand side; A burning smell when the electric shower is on. Honestly, I’m not making this up, all these things happened in the past year. Sounds like an expensive time?

Wearable technology for temperature and moisture

My second Guest Article from Sensirion

Imagine this, if you are young, or remember this, if you are not so young, a world without mobile phones! Awful, how on earth did we communicate? We managed somehow but now we are virtually in constant communication with our world. A vast choice of Apps takes us to a whole new level of interaction with our mobiles. This article by Sensirion on wearable devices talks about the next step in our relationship with the technology that we carry around with us every day. Getting this to work for measuring the moisture around our body, we are talking “State-of-the-Art” technology.

Guest Article – Automatic Climate Control in Vehicle Seats Increases Comfort

My first guest article

Here is the very first guest article on Moir’s Moisture Matters blog. It is reproduced below by kind permission from Sensirion, an innovative Swiss company that I’ve known for many years and had the pleasure of visiting over ten years ago. They gave me a present of a small temperature and humidity measuring device that I used to take with me to my early moisture interaction talks and pass around my audience. My point was that our bodies are much more sensitive to temperature than humidity changes. Most of the time you simply cannot guess the humidity and so are unaware that a change has happened and therefore have no feel or warning of its impact on the things around you. An area where this is important and even critical is handling and working with materials that react to moisture, which is the main topic of my talks.

By some strange quirky coincidence, my first guest article from Sensirion talks about temperature and humidity control in vehicles and at my first school talk the teacher told me that he used the misting up of windows when travelling in a car as a way of introducing the students to humidity. Recently Sensirion have released the world’s smallest humidity and temperature sensor and I mean really small. Their article below talks about how these sensors go way beyond just measuring humidity and are integrated into rapid feedback systems to make the vehicle’s environment more comfortable for the driver and passengers.

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