| accelerator |
A substance used to speed the curing time of a cyanoacrylate adhesive. |
| acetic acid |
A byproduct of the vulcanization reaction. Silicones cure through vulcanization. |
| acrylic adhesive |
A type of structural adhesive made from acrylic, a manufactured polymer. Acrylic adhesives set rapidly and are very strong due to heavy cross-linking. |
| acrylic adhesive |
A type of structural adhesive made from acrylic, a manufactured polymer. UV-curing acrylics typically cure in less than one minute. |
| active surface |
A surface with ample ions that leave the surface and react with an anaerobic adhesive. Active surfaces enable the fastest curing of an anaerobic adhesive. |
| additive |
An element often mixed with resin to assist in the curing of an adhesive. A toughening agent is an additive. |
| adhesion |
The measure of the bond strength between an adhesive and a surface. Adhesion assists in the curing of a PSA. |
| adhesive |
A nonmetallic material used to join two or more materials together. Adhesives are generally categorized as natural or synthetic. |
| adhesive bond |
The process of binding a material to a surface using any number of adhesive substances. |
| ambient temperature |
The temperature of the atmosphere. Urethane adhesives are sensitive to ambient temperature. |
| anaerobic adhesive |
A type of structural adhesive that can only cure in the absence of oxygen. Anaerobic adhesives are used to make parts that require a tight seal. |
| benzoyl peroxide |
A curing agent typically used to cure two-component acrylics. |
| blooming |
The condensation of evaporated adhesive on a part. Blooming occurs most often with cyanoacrylates. |
| carrier |
The backing material to which pressure-sensitive adhesives stick. The carrier acts as a mode of transport for the adhesive. |
| catalyst |
Also called the curing agent or hardener, the substance that hardens the adhesive when mixed with resin. |
| catalyst system |
The method by which acrylic adhesives cure. Most acrylics cure through a two part catalyst system. |
| chemical activator |
A substance that speeds the polymerization of a cyanoacrylate adhesive. |
| chemical resistance |
A material's ability to withstand exposure to chemicals. Several structural adhesives have strong chemical resistance. |
| chlorosulphonated polyethylene |
A toughening agent that typically assists in the curing of acrylics. |
| cohesive strength |
The internal strength of the adhesive. Epoxies have high cohesive strength. |
| creep |
The deformation of a material that occurs over time due to the presence of a constant load. A PSA must have the ability to resist creep. |
| cure |
To cross-link molecules permanently. Adhesives cure as they solidify. |
| curing agent |
Also called a hardener or catalyst, the substance that hardens the adhesive when mixed with resin. |
| cyanoacrylate adhesive |
A type of structural adhesive made form acrylic, a manufactured polymer. Cyanoacrylates bond with surfaces very quickly. |
| elastic |
Capable of resuming original shape after experiencing temporary deformation. Silicone adhesives are elastic once cured. |
| elasticity |
The measure of a material's ability to reshape itself after it has been stretched or deformed. A rubber band is an example of an object with high elasticity. |
| elastomer |
A formation of a thermoplastic or thermoset that can stretch and then return to its original shape without permanent deformation. |
| epoxy adhesive |
A type of structural adhesive made from epoxy, a manufactured polymer. Epoxy adhesives are strong and resilient and can bond with a variety of surfaces. |
| glass transition temperature |
Tg. The temperature at which a hot melt changes from a brittle, glassy condition to a soft, pliable condition. |
| hardener |
Also called the curing agent or catalyst, the substance that hardens the adhesive when mixed with resin. |
| heat resistance |
A material's ability to withstand heat. Several structural adhesives have strong heat resistance. |
| hot melt |
A thermoplastic, non-structural adhesive that flows when heated and hardens and strengthens as it cools. When applied as a melted liquid, a hot melt immediately adheres to a surface. |
| impermeable surface |
A surface that cannot be penetrated by any element. Urethanes can bond to impermeable surfaces. |
| inactive surface |
A surface that lacks sufficient ions with which to react. An inactive surface requires heat or a primer in order to cure the anaerobic adhesive. |
| inhibiting surface |
A surface with a cover that prevents ions from escaping from the surface and reacting. An inhibiting surface requires heat or a prime rto cure the anaerobic adhesive. |
| ion |
An atom or molecule that gains an electrical charge after it has either lost or gained electrons. Metal ions assist in curing anaerobic adhesives. |
| isocyanate resin |
The resin used to cure urethane adhesives. |
| joint |
The location where an adhesive layer holds two surfaces together. |
| LED |
Light emitting diode. A semiconductor device that emits a narrow spectrum of light in a forward direction. |
| load |
The overall force applied to a material or structure. |
| low-solvent formulation |
An adhesive dissolved in a small amount of petroleum-based solvent. The adhesive cures as the solvent evaporates. |
| melt temperature |
Tm. The temperature of a hot melt during application. |
| methyl methacrylate |
A type of monomer that is odorous and tends to behave unpredictably. Most acrylics are composed of methyl methacrylate monomers. |
| monomer |
A small molecule that joins with other molecules to form a polymer. An acrylic is composed of a monomer. |
| natural adhesive |
Also called an organic adhesive, an adhesive made from naturally occurring living sources, such as plants and animals. |
| nonstructural adhesive |
A synthetic adhesive ideal for applications that do not require high strength or permanent joining. Nonstructural adhesives can be easily unbonded from their surfaces. |
| one-component formulation |
A method used to make an adhesive in which the resin and curing agent are packaged together, already mixed. |
| organic adhesive |
Also called a natural adhesive, an adhesive made from naturally occurring living sources, such as plants and animals. |
| peel strength |
A material's ability to resist forces that attempt to pull an adhesive apart by separating flexible surfaces. |
| permeable surface |
A surface that can be penetrated by an element. Urethanes can bond to permeable surfaces. |
| photoinitiator |
A curing agent typically used to cure UV-curing acrylics. |
| polar attraction |
The process through which a PSA cures. Tack, shear strength, and adhesion enable a PSA to cure. |
| polymer |
A material made of very large molecules. Synthetic adhesives are derived from polymers. |
| polymerization |
A chemical reaction in which molecules are linked together to form large molecules. Most structural adhesives cure through polymerization. |
| pressure-sensitive adhesive |
PSA. A non-structural adhesive that provides instant tackiness to a variety of surfaces. PSAs require minimal pressure to stick to a surface. |
| primer |
A liquid material that is used to coat a surface before the adhesive is applied. Primers improve surface conditions and allow for stronger adhesive bonds. |
| properties |
The characteristics of a material that distinguish it from other materials. |
| PSA |
Pressure-sensitive adhesive. A non-structural adhesive that provides instant tackiness to a variety of surfaces. PSAs require minimal pressure to stick to a surface. |
| resin |
A solid or semi-solid organic material that tends to flow when subjected to stress. Resin is mixed with a curing agent to enable an adhesive to cure. |
| shear strength |
A material's ability to resist forces that can cause the internal structure of the material to slide against itself. |
| shear stress |
A force that can cause the internal structure of a material to slide against itself. A PSA must be able to resist shear stress. |
| shelf life |
The length of time an adhesive can be used for its intended application. |
| silicone adhesive |
A type of structural adhesive made from silicone, a manufactured polymer. Silicone adhesives are durable and have high elasticity. |
| solvent |
A chemical material that can dissolve another material. Adhesives generally are either low-solvent formulations or zero-solvent formulations. |
| structural adhesive |
A durable synthetic adhesive designed to endure the duration of the application without undergoing deformation or unbonding from its surfaces. Structural adhesives can withstand heavy loads. |
| surface moisture |
Water particles that accumulate on a surface. Silicone adhesives often turn yellow because they react with surface moisture. |
| synthetic adhesive |
A man-made adhesive derived from polymers. Synthetic adhesives are produced to have specific chemical characteristics. |
| Tg |
Glass transition temperature. The temperature at which a hot melt changes from a brittle, glassy condition to a soft, pliable condition. |
| Tm |
Melt temperature. The temperature of a hot melt during application. |
| tack |
The property of an adhesive that enables it to bond immediately to a surface. |
| tackiness |
The ability of an adhesive to form an immediate bond with a surface upon contact. Pressure-senstive adhesives provide instant tackiness when applied to a surface. |
| tensile strength |
A material's ability to resist forces that attempt to stretch it or pull it apart. |
| thermoplastic |
A plastic that may be repeatedly heated, shaped, and cooled without damage. Cyanoacrylates are thermoplastic adhesives. |
| thermoset |
A type of plastic that is permanently hardened by cooling. Synthetic adhesives are thermosets. |
| toughening agent |
An additive mixed with resin to assist in the curing of an adhesive. |
| two-component formulation |
A method used to make an adhesive in which the resin and curing agent are packaged separately and mixed prior to or during application. |
| ultraviolet light |
UV light. Light not visible to the naked eye because it consists of wavelengths shorter than those of visible light. Most acrylics used today cure with UV light. |
| urethane adhesive |
A type of structural adhesive made from urethane, a manufactured polymer. Urethane adhesives are highly flexible and are known for their versatility. |
| UV light |
Ultraviolet light. Light that is invisible to the naked eye because it consists of wavelengths shorter than those of visible light. Most acrylics used today cure with UV light. |
| viscosity |
A fluid's resistance to flow. The higher the viscosity, the greater a material's ability to resist flow. |
| vulcanization |
The process by which silicone adhesives cure. Acetic acid is a byproduct of vulcanization. |
| wetting |
The process of spreading an adhesive over a surface. Proper wetting occurs when the adhesive fills all crevices of the surface. |
| zero-solvent formulation |
An adhesive dissolved in a substance such as water. The adhesive cures as the water evaporates. |