Adhesion: The state of two surfaces held together by interfacial forces, to be stuck or clinging together.
Adhesive: A substance that holds or bonds together two surfaces by mechanical or chemical forces.
Ambient Temperature: The temperature surrounding or in the room where an object rests.
Bleed-Through: The migration of an adhesive through a surface so that it becomes visible.
Bond: The attachment of an adhesive to a surface or surfaces.
Bond Strength: The force or load that can be applied to a bonded joint before it will fail or break.
Catalyst: A substance added in small amounts to an adhesive to speed up the cure time.
Cement: Another word for adhesive.
Cohesion: The state in which the particles of the adhesive are held together.
Cohesive Failure: A term used to describe bond failure within the glue line without failure of either bonded surface.
Cold Flow: Dimensional change of a material under load at room temperature. Also known as Creep.
Contact Adhesive: An adhesive which when coated on two surfaces for bonding and dried will adhere only to itself. May be solvent or waterborne.
Coverage: The amount of adhesive required to cover a specific square foot area for proper bonding.
Crazing: The creation of fine cracks or dull haze in substrates caused by solvent or adhesive compounds attacking a surface. The effect may also appear in the adhesive.
Creep: A change in size of a material under load. Movement at room temperature is often called creep.
Cross Linking: The union of two large molecules by means of chemical reaction resulting in a random network of molecules which no longer have mobility.
Cure: The change in physical property of an adhesive caused by a chemical reaction which may be by condensation, polymerization or vulcanization. This is usually produced by the action of heat and a catalyst alone or in combination with or without pressure. In common terms, it is the process in which an adhesive dries or changes to bond two substrates together.
Cure Temperature: Ideal temperature for maximum cure to take place for a specific adhesive.
Delamination: The separation of layers of a laminate to failure within the adhesive itself or the bond between the adhesive and the substrate.
Dry: The change in state of an adhesive by loss of evaporation, absorption or both.
Elastomer: A material which, at room temperature, can be stretched repeatedly beyond its original size and when released return to its former size. (Rubber)
Emulsion: A suspension of particles of liquid or solid in a normally incompatible liquid.
Fatigue: The internal weakening of a dried or cured adhesive resulting from constant static or dynamic force acting on it.
Flash Point: The temperature at which the vapors of an adhesive or other chemical will ignite when exposed to an open flame.
Full strength or full cure: The time an adhesive takes to build up to its full, final strength. Remember with all these terms, figures quoted on technical datasheets will vary depending on temperature, gap and surface reactivity, so exercise caution with these figures.
Green Strength: The amount of strength in an adhesive before achieving full curing or drying.
Handling Time: After the adhesive has been applied and the joint assembled and clamped, the handling time is the point at which the clamps can be removed and the joint is strong enough to hold itself in position. The bond strength after the handling time is often understood as approximately 100 psi.
Hardener: Added to an adhesive to promote or control curing. See Catalyst.
Latex: A very fine particle size emulsion.
Non-Structural Bond: A bond that is required to bear little or no load other than to hold two parts together.
Open time: The time between the application of an adhesive to a surface and the assembly of the two parts.
Pot life: The period of time during which an adhesive may be used satisfactorily after being mixed or exposed to drying air (also known as Working time or Work time).
Shelf life: (Same as storage life) The period in which an adhesive may be stored in its original, unopened container at a specific temperature and still be usable.
Substrate: The material surface to which an adhesive is to be spread for bonding.
Tack: The stickiness or ability of an adhesive to cling to an object.
Thermoplastic: A material that will repeatedly soften when heated and harden when cooled.
Thermoset: A material that after being exposed to heat will remain in a fixed or infusible state.
Thixotropic: A property in which a chemical’s viscosity will lessen after being agitated such as in stirring or pumping.
Viscosity: The thickness or heaviness of a liquid and its resistance to flow, such as the difference between a 10-weight oil and a 40-weight oil.
Wetting: The ability of an adhesive to adhere to a surface immediately upon contact.
Working Time: See “Pot life”
