Everyone has had liquid glue in their hands at some point – and adhesive tape as well. But what are the adhesive properties that make them differ from each other? What advantages does adhesive tape have over liquid glue? We have compared them.
Liquid glue differs fundamentally from adhesive tape. The name says it all: it is liquid. One-component adhesives are described as "physically bonding" when they contain solvents on a base of organic chemicals (alcohol, esters ..) or water. Adhesives on a water base are also described as "solvent-free", although water is used as a solvent here. The products in this group include, above all, universal glue (multipurpose glue), paper glue and glue sticks. The second group of liquid adhesives includes reaction glues such as so-called instant glues and two-component glues (consisting of resin and hardener). Reaction glues mostly have a polyurethane and epoxy base and are solvent-free.
The actual strength of liquid adhesives is only achieved when they have become hard. This is because the actual adhesive is mixed with a solvent so that it does not bond immediately. In the tube, the solvent cannot leak out and the adhesive remains liquid. Only when it is applied to the surface does the solvent evaporate, the adhesive becomes hard and a solid bond is achieved. That can take two seconds or hours.
On tapes pressure-sensitive adhesives are used. Such adhesives are always gluey and ready for use. This brings new meaning to the concept of holding fast. As soon as the protective and separating layer is removed and you press the adhesive tape to the surface, it bonds. No chemical reaction or drying time are needed. This is how double-sided adhesive tape holds the emblems on cars, printing plates on printing cylinders or components of the smartphone in place.
Adhesive tape is able to unveil its strengths in industry above all. Simple, flexible handling and quick adhesion accelerate the processes and even optimize the end products. Uneven surfaces may be evened out with adhesive tape. The entire process goes very quickly, since there is no drying time as we have with liquid adhesives. There is also no poisonous evaporation. In addition, adhesive tape is clean. Follow-up work in order to remove the remains of the adhesive is not necessary.
The bond is also hardly perceptible since adhesive tape can be as thin as you can imagine. This allows for entirely new product designs and combinations of materials. Screws have no space and disrupt the optics in a small area. Welding and rivets destroy the surfaces of materials and create intermittent stress points. Not a problem with an adhesive bond that distributes the forces that arise from impacts or bumps over the entire adhesion surface. Moreover, some materials cannot be combined in any other way than by adhesive tapes or glues: carbon and aluminum, for example, in the car industry. And as opposed to liquid glue, adhesive tape can help balance out different degrees of expansion with distinct materials in heat or cold thanks to special backings and adhesive masses. Pretty solid, wouldn't you say?