Adhesive Terms

Adhesive Terms

Term	Definition
Adhesion	The power of an adhesive layer to hold the parts of an assembly together.
Adhesive layer	The layer of adhesive between the parts to be stuck together.
Adhesive sealant	An adhesive that also acts as an elastic sealant.
Aerobic adhesive	Adhesive that sets on contact with the air.
Anaerobic adhesive	Adhesive that sets when air is excluded, by catalytic effect (of a metal).
Application	Coating the surfaces to be stuck together with the adhesive.
Base	The basic ingredient of an adhesive, on which its properties largely depend.
Binder	In multi-component reaction adhesives, components that form the basic part of the adhesive.
Bonding	The fixing of an adhesive (setting) by means of physical or chemical processes.
Bonding time	The period of time taken for the assembly to achieve sufficient firmness to bear the load exerted on it.
Catalyst	A substance that triggers a chemical reaction without itself being altered.
Cement	A paste-like sealant; depending on its composition, it may be either rigid or elastic once it has set, and may have adhesive properties in addition to its sealant properties.
Cohesion	The holding power within the layer of adhesive.
Cold adhesive	An adhesive that sets at room temperature (20°C).
Contact adhesion time	The period of time when using a contact adhesive during which the dry adhesive layers may still be bonded together (= open time).
Contact pressure	When using a contact adhesive, the pressure applied to the assembly to achieve a bond.
Creep	The effect of strain and/or time on the shape of polymer layers; even under little stress the adhesive layer changes shape. When stress is exerted, the adhesive layer gradually changes shape as a result of creep.
Dispersion	Solid particles suspended (not dissolved) in a liquid.
Evaporation time	When using a contact adhesive, the period of time necessary for the solvent to evaporate from the adhesive applied to both sides of the assembly, so that when the parts are placed together they bond immediately.
Final firmness	Maximum firmness after the adhesive has set; expressed in newtons per square centimetre (N/cm_). 10 N corresponds to 1 kg.
Fixing	Holding the parts to be assembled together (using clamps, collars, presses, etc) while the adhesive sets.
Flashpoint	The lowest temperature at which a substance (solvent) may evaporate and produce a flammable compound.

Glue	Originally an adhesive based on egg white. Now used indiscriminately to mean an adhesive, mainly in connection with woodworking. The word now includes adhesives on an animal, plant or synthetic base.
Hardener	Components that affect the hardening of multi-component reaction adhesives.
Indicator	A substance that indicates a chemical reaction by changing colour.
Initial bond	State of bonding achieved after a certain amount of time when the fixings holding the assembly together can be removed, although the final load cannot yet be exerted on the assembly.
Joint gap	The space between the parts to be assembled.
Joint thickness	The average distance between the parts to be stuck together (= thickness of the layer of adhesive).
Mixing ratio	The ratio in which the components of two- or multi-component adhesives and any fillers used must be mixed together in order to achieve the desired adhesive result.
Natural resin	Semi-liquid substance exuded by conifers, used as a basic ingredient in adhesives, paints and cements.
Open time	The period of time when using a contact adhesive during which the dry adhesive layers may still be bonded together.
Polymerisation	In polymerisation, small molecules (monomers) combine to create giant molecules (polymers), without changing their composition to any great extent.
Polymers	Macromolecules that affect cohesion; a basic ingredient of adhesives.
Resin	Base for adhesives.
Setting time	Period of time taken by a reaction adhesive to polymerise and form a completely set plastic layer. For single-component adhesives, the setting time starts when the adhesive is applied to the surfaces to be stuck together; for adhesives with two or more components, it starts when the components are mixed.
Shelf life	The period of time during which an adhesive stored according to the manufacturer's instructions (packaging, temperature, humidity) retains its expected properties.
Solvent	Volatile (i.e. evaporates readily) liquid added to adhesives to keep them in usable condition. Usually readily flammable. The adhesive bonds when the solvent evaporates.
Synthetic resin	A synthetic adhesive agent in adhesives and components of reaction adhesives (phenolic, epoxy and polyester resins).
Warm-setting	Setting at an (artificially) raised temperature.
Wet adhesion time	The period of time during which wet adhesion is possible
Working life	The period of time between the mixing and setting of two- or multi-component adhesives, i.e. the period of time during which the mixture can be worked. Most cold-setting adhesive systems have a short working life (minutes or hours), whereas most warm-setting systems have a long working life (hours or days)