ADHESIVE BONDING TERMINOLOGY

The following list of technical terms will help in understanding the adhesive bonding process.

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, when 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 the 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. 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 do 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.

GREEN STRENGTH: The amount of strength in an adhesive before achieving full curing or drying.

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 assembly of the two parts.

POT LIFE: The period of time during which a adhesive may be used satisfactorily after being mixed or exposed to drying air.

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 stiring 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.