How Well Will The Glue Stick?
It’s not all chemistry!
It is a common misconception that the ability of a glue to bond or not, rests with how well it sticks to the surface. If gluing was that simple, I would not have spent the past thirty odd years fixing glue problems!
But seriously, bonding is a very complicated process. In gluing any materials together, we depend on two major types of bonding, chemical bonding and mechanical bonding.
Chemical (covalent) bonding occurs, when the glue forms chemical bonds with the surface of the materials. The glue actually reacts with the surface of the material being glued. As an example of this, in bonding technical textiles, we have developed several waterbased glues which chemically bond to the fabric surface.
This chemical bonding gives us an indestructible laminate, with exceptionally high peel, shear and water resistance. One of our Chinese customers, uses one of our waterbased polyurethane glues, to make recreational watercraft.
Mechanical bonding is totally different. In this type of bonding, the glue literally grips onto the surface being glued. Very few surfaces are perfectly flat. The glue takes advantage of this fact by anchoring into the surface irregularities on the material, these irregularities only being truly seen under a high power microscope.
There are also two other types of bonding. The first is hydrogen bonding, primarily used to bond materials with a polar surface. In these applications, there is always strong electrical attraction between the adhesive and the material being glued. Finally we have thermodynamic bonding.
Again principally seen in textile gluing, the glue swells the top later of a coated industrial textile, enabling it to mechanically lock into the textile fibres.
The above gives you an introduction to bonding mechanisms. As always, both myself and our technical team are always available to provide the best of technical service. It’s what we do!