When I started selling tape years ago, the first type o […]
When I started selling tape years ago, the first type of tape I sold was carton sealing or box tape. I remember going into a large warehouse and talking about the tape they were using to seal the boxes going out the door every day.
The gentleman with whom I was speaking was very opinionated about the type of tape used there. I was very new to the industrial packaging industry and found this to PTFE Water Tape Manufacturersbe a good place to learn a thing or two about tape. He had many names for the tapes he had tested, one of my favorites was, "hundred miles an hour tape". This was a reference he used to describe a tape that unwound off itself too quickly. This was a tape he did not enjoy using.
So why do some tapes come off of the roll easier than others? Why do some tapes feel stickier than others?
These are all interesting questions. Simply stated, tape is made to stick to stuff. So why are we able to unwind the tape off of itself? The back side of the tape or the part that does not have adhesive is called the backing. The top side of the backing actually has a release agent on it to allow the tape to come off the top of the backing. The adhesive, backing and a few other factors determine how easily one can unwind the roll of tape. It really has no real effect on the adhesive, thus it will not tell you how well the tape is going to stick to whatever it is you want it to stick to.
Why does one tape feel stickier than another is a bit more difficult and technical question to answer. There are 3 factors that are considered when a tape is made including adhesion, cohesion and tack.
Adhesion can be defined as the attraction between the adhesive itself and the substrate. Cohesion is the inner strength of the adhesive. Tack is how sticky the tape feels, or technically, it is how well does the tape wet out onto the surface on initial contact.
Rubber based adhesives tend to feel more tacky when given the old "finger test". A tape that has an acrylic based adhesive may not feel as sticky as a rubber based adhesive, but don't be fooled by this. With a rubber based adhesive, what you feel is pretty much what you get. The bond of a rubber based adhesive generally doesn't get any stronger the longer it sits on the substrate. In fact, rubber based adhesives will break down faster with age.
Generally speaking, acrylic based adhesives do not feel as sticky to the touch. Acrylic adhesives will actually gain some holding power as they cure or dwell. This can take hours or even up to 3 days. If you had some pure acrylic adhesive laying around and picked it up to feel it, it hardly has any real tack to it. But if you let that same adhesive set up for a while... good luck removing it!
So, when you are looking to put some tape down on something, do not be too quick to judge the tape based on how sticky it feels to the finger. You may find that the one you found to be super sticky failed and the one you felt had very little tack rose to the top and became very permanent.