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Abrasion resistance
Ability of a coating to resist degradation due to mechanical wear by hard and rough objects (mechanical erosion) thanks to the ability to dissipate the applied mechanical energy. Abrasion resistance can be enhanced by incorporation of surface modifying additives (see Surface conditioner and Surface modifier).

Abrasive media
Material used in abrasive blasting to remove surface contaminants. Examples of abrasive media are sand, iron shot, crushed iron slag, glass beads, or ground nutshells.

Accelerating agent
Syn. Vulcanizing agent

Accelerator (extended definition)
Compounding material used in small amounts with a vulcanizing agent to increase the speed of vulcanization, of a chemical reaction. Accelerators are often used in the coating industry to hasten the curing of a coating system.
Syn. Catalyst

Acid absorber/acceptor
Additive neutralizing and absorbing hazardous acid spills.

Acrylic latex
Aqueous dispersion of acrylic resins.

Acrylic resin
Resin made by the polymerization of acrylic monomers such as acrylates (Methyl, Ethyl, Butyl) or acrylic acid.

Activator
Curing agent of a two pack coating system.

Adhesion
Degree of attachment between a coating film and the underlying material to which it is in contact. The two surfaces are held together by interfacial forces which may consist of valence forces or interlocking action.
Syn. Adherence

Adhesion promoter
Material used to improve adhesion between materials. May be used in two different modes: by pre-treatment of a substrate, and as a component in coating formulation capable of enhancing adhesion durability due to the improvement in substrate wetting and formation of chemical bonds across the film/substrate interface.
Syn. Bonding agent

Adsorption
Not to be confused with absorption, adsorption is the build up of a molecule at a surface. Adsorption generally occurs because different parts of a molecule have an affinity for the two different phases on either side of the interface.
Syn. Physical adsorption

Aging
Change of a material with time under defined environmental conditions, leading to improvement or deterioration of properties. Addition of Antioxidants, UV / Light stabilizers, and so on, allows an improvement of aging properties.
Syn. Weathering

Aggregate stability
Ability to resist to various changes without flocculation and coagulation. This stability can be improved by using emulsifiers or dispersing agents which create repulsion forces.

Air cap
Perforated housing for directing the atomizing air at the head of a spray gun.
Syn. Air Nozzle

Air drying
Form of curing a coating (the most common one) by oxidation or solvent evaporation by simple exposure to air without heat or catalyst. Velocity of air-drying depends on the concentration and structure of double-bonds in the binder, the right selection of the drier (or drier system), temperature, and film thickness.

Air entrapment (extended definition)
Paint defect due to the incorporation of air bubbles into applied coating films during the application process and holding air bubbles inside the film due to a sufficiently high film viscosity. Air entrapment can be suppressed by introduction of substrate wetting agents or by the reduction of application viscosity.

Airless spray
System of applying paint by passing the paint, under high pressure, through a nozzle and by atomizing it (broking into droplets) when it enters the lower pressure atmosphere.

Alkali
Aqueous liquid which has a pH value of between 7 and 14.
Syn. Base or Caustic material

Alkyd resin
Resin formed by the condensation of polyhydric alcohols with polybasic acids. May be regarded as complex polyester (thermoset). Widely used in general purpose coatings.

Alligatoring (extended definition)
Coating defect: surface defects of a coating film having the wrinkled appearance of alligator skin.

Ambient temperature
Room temperature or the existing temperature of the surroundings.

Amide resin
Organic compound that contains a carbonyl group bound to nitrogen. -CON- (C double bonded to O)

Amino resin
Thermosetting resin manufactured from amino compound and formaldehyde. Amino resins are often used as curing agents for epoxy coatings.

Anti-blocking agent
Additive used to lessen the adhesion of coated surfaces to another surface. Acts by producing a slight roughening of the surface. Are typically finely divided, solid minerals, but some are waxes.
Syn. Surface conditioner

Anti-crater aid
Additive used to prevent crater formation on the paints film.

Antidegradant
Compounding material used to retard deterioration caused by oxidation, ozone, light and combinations.
Note: Antidegradant is a generic term for such additives as Antioxidants, Antiozonants and UV / Light stabilizers.

Anti-flex cracking agent
Compounding material used to retard cracking caused by cyclic deformations.

Anti-floating/flooding agent
Additive preventing floating/flooding defects in coating applications.

Anti-foaming agent (foam suppressant)
See Foam control agent and Defoamer

Antifreeze
See Freeze/thaw stability controller

Anti-gelling agent
Additive used to prevent gelling in solvent or water-based coatings. Anti-gelling agents can be metal-organics, polyphosphates, active organic solvents... .

Antioxidant
Compounding material used to retard deterioration of coating films caused by oxidation, heat exposure... Usually based on molecules that will scavenge free radicals as they are formed.
Different types are available: phenolic compounds, primary and secondary amines...

Antiozonant
Additive used to protect a polymer against the effects of ozone-induced degradation.

Anti-sagging agent
Rheological additive used to prevent sagging in wet coatings where it increases the viscosity.

Anti-settling agent
Additive that impedes sedimentation of pigments, extenders and fillers by imparting increased low shear viscosity or a small yield value to liquid paints.

Anti-skinning agent
Substance added to a material to prevent or retard the processes of oxidation or polymerization which result in the formation of an insoluble skin on the surface of the wet coating.

Anti-slip agent
Additive which decreases the slip of surfaces. Used to eliminate the sliding of parallel film surfaces over each other or the sliding of film surfaces over substrates.
Syn. Surface conditioner

Anti-static agent
Additive which increases the surface conductivity of coatings and which minimizes static electricity (charge build-up, dust collection).
Main families of antistatic agents are: Fatty acid esters, Ethoxylated amines, Quaternary ammonium compounds...

Architectural Coating
Coating used in applications for interior or exterior surfaces of buildings.

Asphalt
Black resinous material of petroleum origin.

Assisted Airless
Airless system that uses small amounts of air to help atomize the paint in conjunction with airless spray. Used to get rid of the nagging problem of "Rabbit Ears".

Atomization
Formation of tiny droplets of liquid as in the paint spraying process.

Auxiliary drier
See Secondary drier