ADHESIVE TYPES

Wet adhesives are only applied to one of the parts to be joined, which is then immediately glued to the second part. The parts must be fixed together as adhesion only occurs when the solvents have evaporated. In case of so-called (solvent-free" adhesives, water is the carrier substance. Open-poured materials encourage the drying of wet adhesives. 

Glues with solvents are used for a wide range of jobs. In particular these include jobs involving a particularly fast application sped, when paper curling must be avoided or when non-porous materials are being glued. These adhesives consist of resins or rubbers that are converted to liquid form using traditional solvents e.g. alcohol, acetone or methylacetate. The glue sets as a result of the evaporation of the solvent. The solvent must therefore be able to escape through the material. This is the case with wood, cardboard and leather. In the case of non-permeable, airtight materials such as metal, porcelain or hard plastics, the glued surface must be as long and narrow as possible so that the solvent can escape out the sides. Many plastics are, to varying extents, corroded or even dissolved by solvents. Therefore, when glueing plastics you must always note the corresponding instructions on the packaging.

Contact adhesives are applied to both parts to be joined. After the flash-off time, which varies depending on the solvent, the parts to be joints are pressed together with a high level of force. The parts to be joined bond immediately. Loads can be applied to the workpiece after a short period of time. 

UHU contact adhesives, such as UHU All Purpose Adhesive Power or UHU greenit, are applied using the double-sided bonding method. They are particularly well-suited to the glueing of thick materials that are solvent-permeable. Contact adhesive enable the creation of instant bonds, that become very strong after a short period of time. They remain elastic even once dry, and are therefore particularly suitable for materials that must remain flexible at the glued joint (e.g. soles of shoes, leather belts). Contact adhesives are also used in large surface processing (e.g. the veneering of tables). Solvent-free UHU contact adhesives are also available.

Reactive adhesives are adhesives that set by means of chemical, physical or catalytic processes. Depending on the reactive behaviour, they can have one or two components.

Single-component reactive adhesives
Single-component reactive adhesives react with air humidity, UV light or atmospheric oxygen (aerobic adhesives), or with the exclusion of air, e.g. with metal ions (anaerobic adhesives) Single-component adhesives are applied onto one of the surfaces to be glued. The reaction starts immediately as a result of the second reactive component in the atmosphere or on the surface to be glued. 

Two-component reactive adhesives
Two-component reactive adhesives consist of components in liquid, paste or powder-form, which must generally be precisely mixed in the stated proportions. The processing time (pot life) is limited, with setting commencing immediately. The glued joint must be fixed in place until fully set, with the setting time dependent on the type of adhesive and the ambient temperature.

High-performance bonding with reactive adhesives
(fast, strong and versatile)

Reactive adhesives are adhesives that set by means of chemical, physical or catalytic reactions. They are generally used when a high level of strength is required. These reactive adhesives generally have two components (binder and hardener). Binders and hardeners are always packaged separately. If the two components come into contact with one another, a reaction begins that sets the glue, causing it to reach its final strength.
Single-component reactive adhesives contain a non-active hardener, which does not reactive while in the packaging under normal conditions. A reaction only begins when the hardener comes into contact with the second reactive component. Depending on the type of adhesive, the reaction is started by air humidity, UV light or atmospheric oxygen (aerobic adhesives).