Glossary of Terms

Bulk Density
Mass per unit of volume including the air filled voids in the bulk material
Caking
Agglomeration of individual powder particles or sticking of powder to walls or components of equipment
Cartridge Filter
A filter construction containing one or more cartridges that function as a filtering element
Catalyst
See accelerator
Chalking
Degradation of a coating due to UV exposure, which results in loss of color and gloss
Chromatation
Preparation process for metal substrates, in the form of a conversion coating using chromium and forming an inert chromate coating film, prior to the application of powder coating material.
Classifier
An equipment to separate particles from another fluidum, much like a cyclone, whereby the separation cut is adjustable, within a range, with an additional device.
Clean Air Act
Act which empowers the EPA to improve the quality of air through enforcement of the developed pollution standards.
Clear Coat
A non-pigmented coating applied on a base material such as aluminium or over a previously applied pigmented coating.
Coating Powder
Powder material being a mixture of resin, pigment filler, and additives, for application on substrates with the objective to form a coating film thereafter.
Compatibility
The capacity of coating powders from either different sources or of different compositions when combined and applied which yield no visible or mechanically measurable differences in the cured film or application properties.
Composition
The parts of a mixture, formulation or recipe, usually expressed as percentages.
Contamination
Any foreign material, such as soil, dirt, or unwanted chemicals that deteriorate the quality of the coating film.
Contrast Ratio
A value related to the hiding powder of a coating which must be reported at a specific film thickness; the ratio of the reflectance of a coatings is measured over black and white backgrounds at the same film thickness; the results are measured as a numerical value-in general, a 0.98 contrast ratio is visually opaque; directly related to product pigmentation; minimum film thickness with full coverage of the substrate is critical.
Conversion Coating
Preparation process for metal substrates, with the help of iron, chromium, or zinc, prior to powder coating application.
Conveyor
A chain mechanism that transports the parts to be coated, in a hanging position, through all steps of the application process.
Corona Charging
The induction of powder particles exposed to an electrostatic field generated by a high voltage device.
Corrosion
Decomposition or reaction with oxygen, water, or other chemicals, when exposed to a particular environment.
Coverage (Calculated)
Determines the m2 /kg @ 1.0 mil; adjust accordingly for other film thickness.
Cracking
The arising of crevices or cuts in the surface of a coating film by chemical or mechanical influences.
Cratering
The appearance of tiny pitts (like mini craters) visible to the trained eye without enlargement at the surface of a powder coating film, usually due to some form of incompatibility.
Cross Contamination
The deterioration of a coating film occurring when powders are used in mixed forms when they are not compatible.
Cross Hatch
A testing method to investigate the adhesion properties of a coating film.
Crosslinking
The multi-directional linking together of resin molecules through chemical reactions, stimulated by a curing agent.
Cure Schedule
The time at temperature necessary for a coating to develop specific properties.
Curing
The hardening or cross-linking process.
Curing Agent
A crosslinker or hardener that stimulates the curing of a binder system.
Curing Oven
An oven in which the powder coated parts are exposed at the required temperatures so that the cross-linking reaction can take place for a pre-determined time.
Cyclone
A cylindrical type of equipment for separating particles from another fluidum applying centrifugal forces.
De-ionized Water
Water which has been treated such that it does not contain water foreign ions
Delamination
Separation between two layers of coating, or a coating and the substrate.
Dielectric Strength
Property of an insulated material where electrical breakdown occurs under specific conditions of test, expressed in volts per mil.
Disbondment or Blistering
The effect, usually at the scribe, or blisters formed under a cured powder film.
Dispersion
A suspension or mixture of particles in another fluidum.
Distinctness of Image (DOI)
The sharpness of an image reflected by a coating's surface.
Dry Crosshatch Adhesion
Determines the relative adhesion of a coating to the substrate.
DSC
A differential Scanning Calorimeter can measure several thermodynamic properties of chemicals.
Dust
Particular matter which is, or has been, airborne with a particle size below 75 micron.
Dust Explosion
The confined rapid combustion of dust particles which are airborne causing strong expansion effects.
Dwell Time
The length of time a part is in an oven.
Edge Coverage
The ability of a coating inits cured state to flow, build, and adhere to sharp corners, angles, and edges.
Electrostatic Charging
The process of transferring a static electric charge on powder particles.
Electrostatic Spray (Corona) Method
The induction of powder particles exposed to an electrostatic field generated by a high voltage device.
Emmaqua
Weathering test performed in Arizona where panels placed in a special apparatus are exposed to a brief water spray and magnified sunlight; ambient humidity is fairly low.
EPA
The Environmental Protection Agency is a USA Government institute which regulates and controls organizations influencing the environment
Epoxy Resin
A thermosetting resin, produced on the basis of epichloro-hydrin, which can be further polymerized by the addition of a hardener.
Etching
Surface preparation of metal by a chemical process; removal of a layer of the base material.
Extender
A type of pigment which also transmits special properties to a powder coating material.
Extrudate
The resulting product coming out of an extruder, be it in the initial molten form or the solidified state thereafter.
Extruder
A machine that mixes soli particles by using mechanical kneading and the subsequent heat-development until a molten fluidum is created of a homogeneous composition.
Faraday Cage Effect
The lack of penetration of powder particles into cavities or recessed areas of a substrate due to its configuration.
Fatty Edge
Thicker than usual coating film found along edges of a flat substrate.
Ferrous
Metal containing an amount of iron
Field Lines
Imaginable lines of force in an energy field.
Filiform
Corrosion or creep resembling a thread-like formation.
Filler
Inorganic inert material; also extender or certain pigments.
Film Thickness
Height of a cured coating film measured in microns.
Fines
Small powder particles, usually less than 10 microns.
Flash Off
The process-step in liquid coating application of allowing the solvents to evaporate prior to curing.
Flash Rust
A molecular film of rust appearing on a steel surface within minutes after pre-treatment.
Flexibility
Measures coatings' bend capability over a given shape.
Flop
A characteristic of metallic coatings to change color when viewed at different angles.
Flow
Measure of self-levelling; the nature of a coating which allows it to level or spread into a smooth film of uniform thickness before hardening.
Fluidity
The degree to which powder coating material can be brought to fluidization.
Fluidized Bed
Container in which powder is kept suspended in air continuously.
Galvanized steel
Steel coated with a thin layer of zinc.
Gel Time
The interval of time at a given temperature required for a material to be transformed from a dry solid, through a liquid state, to a gel-like condition; measured in seconds at a given temperature.
Glass Plate Flow/Hot Plate Melt Flow
A measurement on an inclined surface when powder is in a molten state, usually measured in millimetres at a given temperature and angle.
Gloss
Surface reflection of directed light, measured in units; the most common angle of measurement is 60°; a 20° angle should also be considered for certain full gloss formulations and an 85° angle for low gloss products.
Grounding
The principle of bringing the electrical potential in equilibrium with a neutral mass.
Hardener
See curing agent.HardnessThe ability of a cured powder coating film to withstand the penetration of a standardized object.
Hazardous
A condition of contact or case of presence in which a risky, dangerous or less healthy or toxic situation is created.
Hiding Power
The extent to which a powder coating masks the color and pattern of the surface to which it is applied at a given film thickness.
Humidity Resistance
Measures a coating's ability to wit stand exposure to 100% relative humidity at various temperatures.
Hybrid
A polyester or acrylic powder coating material which has been epoxy-modified.
Hygroscopic
The tendency of a substance to attract or absorb moisture from the air.
Impact Fusion
The tendency of powder particles to fuse with other particles at points of impact in the application equipment during the application process.
Impact Resistance
Measures a coating's ability to withstand a force expressed in Nm; results can be affected by type of substrate, film thickness, or diameter of indenter.
Incompatibility
The impossibility of powders to be used and applied in a mixture of any composition, without any visible or mechanically measureable differences of the resulting powder coating film when compared to the virgin materials.
Infrared (IR) Cure
A method of curing powder which utilizes direct exposure to light energy in the IR region of the light spectrum.
Infrared Radiation
Energy in the infra-red region of the electromagnetic spectrum just above the visible light range.
Inhibitor
An additive used to delay or neutralize a chemical reaction.
Inorganic
The sort of materials not containing carbon compounds such as metals and its derivatives.
Intercoat Adhesion
The ability of a coating to adhere to previously applied films.
Karl Fisher Test
Chemical testing method to determine the moisture content of powdery materials.
LEL
The lower Explosive Limit is the lowest concentration of organic powder suspended in air which can be brought to explosion when ignited by a standardized energy source.
Levelling
A powder's ability to flow into a smooth, uniform thickness (free from defects)
Mandrel Bend Test
A mechanical method for testing the flexibility of a coating film applied of a standardized sample plate.
Mar Resistance
A coating's ability to withstand contact without blemishing.
Metal Temperature
The temperature of a part at any time during the cure cycle; varies based upon mass of part and dwell time.
Metamerism
A definition applicable to a coating film when its color appears different when viewed in light of varying wavelengths.
Micron
Standard unit of measuring a coating film thickness (1/1000 of 1mm)
Micronizing
Grinding powder to the range of microns.
Monomer
A molecule that has the ability to chemically react with another monomer by forming a long chain of identical section, the so called polymer.
MSDS
A Material Safety Data Sheet provides the hazardous components, other safety and health hazards, protection equipment and first-aid procedures.
NFPA
The National Fire Protection Association is a USA organization that indicates the health, reactivity, and flammability of hazards of chemicals.
Nonferrous
A material containing no iron.
OEL
The Occupational Exposure Limit relates to the exposure limit by inhalation and refers to the concentration of hazardous materials in the atmospheric air.
Opacity
The ability to hide underlying substrate at a given film thickness. (See also Contrast Ratio or Hiding Power)
Orange Peel
A surface appearance which has an irregular appearance similar to the skin of an orange and is generally caused by restricted the limited flowing ability of the powder coating material.
Organic
The sort of materials containing carbon compounds such as manyresins, certain pigments and additives, etc.
OSHA
The Occupational Safety and Health Administration is a USA organization for the control of safety and health issues.
Out-Gassing
Air or gas that escapes from the sub-surface beneath or within the coating and causes blisters, bubbles, or small holes; frequently occurs with zinc or aluminium castings or galvanized steel.
Over-bake
The application of heating using more time and/or temperature than is required for cure which often causes the coating to become too brittle; color and gloss may be adversely affected.
Overcuring
The application of higher than recommended curing-values (temperature, time or both)
Overspray
Material not deposited on the part or rack; it may be recovered with the appropriate equipment.
Particle Size Distribution
The overall range of particles (from coarse to fine) resulting from the grinding process; measured in microns; varies with product.
Passivation
Chemical treatment of a metallic surface with the objective to make it less reactive.
Pencil Hardness
Relative rating of a coating's ability to resist scratching; measured as mar and/or gouge.
Penetration
Ability of particles to penetrate towards and onto the surface of Faraday cage like areas such as cavities and recesses.
Phosphating Preparation
Process for metal substrates, in the form of a conversion coating using iron (chromium) or zinc, and forming an inert phosphate coating film, prior to the application of powder coating material.
Pickling
A cleaning step of hot rolled steel plate, usually carried out in the steel mill, to remove the milling scale before the metal is oiled to protect from corroding.
Pinhole
The appearance of tiny holes (like from a needle) visible to the eye without enlargement at the surface of apowder coating film, usually due to the insufficient ability of gasses to escape from the molten film during curing.
Plate Flow
A test to measure the ability to flow during the curing powder during which a compressed pile of powder is placed on an inclined plate that is subject to a preset temperature.
Polyester
A thermosetting resin, saturated carboxyl or hydroxyl terminated, which can be further polymerized by the addition of a hardener.
Polymer
A long molecule that has been formed out of a large series of monomers by a chemical reaction.
Polymerization
The reaction in which a large molecule (polymer) is formed by chemically binding identical sections (monomers) to a long chain.
Post-formability
The ability of a cured coating to withstand severe bending without the appearance of cracks.
Potable
Suitable for drinking.
Powder Coating
The application of powder coating material on substrates in order to form a coating film thereafter.
Powder Coating Material
The ultimate dry solid compound including all necessary ingredients, ground to powder and ready to be applied as a coating material on a given substrate.
Powder Pump
A lifting and moving device that applies air for transporting either powder from one container to another or towards an operating device.
Premixing
The mixing and size reduction of all necessary raw materials for the production of powder coating material prior to feeding them to the extruding step.
Pretreatment
The preparation of a part prior to the application of a coating powder in order to improve adhesion and corrosion resistance.
Primer
A coating applied to a surface to improve adhesion of a topcoat and/or improve corrosion resistance.
QUV
Accelerated weathering test performance at elevated temperatures in which coated panels are exposed to regular cycles of intense UV light alternated with dark cycles where water is allowed to condense on the panels.
Radiation Curing
The application of energy-rays of a particular range of the electromagnetic spectrum for curing of a coating layer.
Reclaim
Any material not deposited onto parts; usually mixed with virgin material for future applications.
Recoatability
A cured coating's ability to accept another coat.
Recovery
The entire process step of the powder application process in which the non-deposited powder is reclaimed, recycled and added to the virgin powder for re-use.
Recycling
The action in the powder recovery step of the powder application process by which the reclaimed powder is fed back.
Reflectance
The percent of light reflected at a given wavelength the illuminant, degree of observer and the wavelength must be specified; color (not gloss) dependent-whites will have the highest values.
Reflectivity
The reflectance of a coating at a film thickness such that any further increase in thickness will not affect the amount of light reflected.
Resin
A thermosetting resin is an organic material, be it from a natural or a synthetic source, can be further cross-linked or polymerized by the addition of a hardener.
Respirator
Safety breathing face mask.
Rework
A correction procedure to correct shortcomings on a powder coated article.
Salt Spray Test, acetic
The degree of corrosion determined at the scribe based upon a prescribed time period; should be tested with a control.
Scale
Rustlayer on steel originating from the hot roll steel-milling process.
Seal Rinse
A step in the pre-treatment process where the metal surface is passivated to prevent corrosion prior to the powder coating of substrates.
Service Temperature (continuous or intermittent)
The temperature which a finish is able to withstand for an extended period of time or number of cycles with degradation.
Shelf Life
The period of time a coating retains its application and appearance properties if stored according to the manufacturer's recommended conditions.
Sieve
A screening mechanism applying a wire mesh to separate a certain portion out of too coarse or contaminated material.
Softening Point
The temperature at which a resin or a powder coating material first starts to melt.
Soil
Any foreign material that adheres to a substrates surface prior to the pre-treatment.
Solvent
A liquid of one or more components often applied in the liquid paint industry to dissolve paints.
South Florida Exposure
Exposure to typical heat, humidity and sunlight conditions at southern latitudes; measurements are generally the change in gloss and/ or color (Delta E).
Specific Gravity
The density of a formulation relative to water.
Spray Booth
A special cabin in which powder coating material is sprayed, manually or automatically, onto substrates under strictly controlled conditions.
Stripping
The procedure to remove a coating film from a substrate in order to be recoated.
Substrate
The article or product to be powder coated.
Surfactant
Chemical additive to control the surface tension of a material.
Taber Abrasion
Resistance to water.
Temperature Stability
Appearance and adhesion after a period of time at a prescribed temperature and film build.
TGIC
Triglycidyl Isocyanurate is a curing agent for carboxyl terminated resins.
Thermoplastic
A powder coating which will repeatedly melt when subjected to heat and solidify when cooled.
Thermoset
A powder coating which, when subjected to heat, undergoes an irreversible chemical reaction during the cure cycle.
TLV
The Threshold Limit Value is the concentration of chemicals in air to which persons may be daily exposed without harm.
Touch-up
The repaid of small damages on a coating film or the paint to be used for that purpose.
Toxic
Poisonous.
Transfer Efficiency
The amount of powder attracted to the part compared to the amount of powder sprayed; measured as a percentage.
Triboelectric Spray Method
Powder particles receive anelectric charge through the use of frictional contract with a nonconductive material.
UEL
The Upper Explosive Limit is that concentration of organic powder suspended in air above which the mixture will not explode if ignited by a standardized energy source.
Ultraviolet Stabilizer
A chemical additive that absorbs part of the UV radiation in the sunlight.
Ultraviolet Radiation (UV)
Light energy from the UV region of the light spectrum which can break certain chemical bonds and contributes to the fading and wearing of coatings.
Undercured
The application of an insufficient curing temperature, time or both.
Urethane
A thermosetting hydroxyl functional resin, usually reacted with an isocyanic curing agent.
Venturi
A special shaped restriction in a powder pump body.
Vibratory Box Feeder
A moving device that applies vibration for transporting powder from abox container to another hopper.
Virgin Material
Powder which has not been mixed with reclaim material.
Virgin Powder
Fresh powder coating material directly from the supplier not containing any reclaim.
Volatile Organic Compounds (VOCs)
Carbon compounds which can undergo an atmospheric photochemical reaction, contributing to air pollution and causing ozone depletion.
Washer Zone
The immersion or recirculating spray cleaning step of the pre-treatment system.
Water Resistance
A coating's ability to withstand immersion in water at prescribed temperatures for specified time periods.
Weatherability
Degradation caused by humidity, temperature, and exposure to sunlight.
Weld Splatter
Contaminations left behind on a metal surface after welding such as slag or beads.
Wrap
A characteristic of coating powders during electrostatic application to seek out and adhere to areas of the substrate not in the direct line of sight of the delivery system end point.
Yellowing
Development of a yellow color or cast of a coating dueto aging or cure variables; more evident in light colored formulations.