Glossary
As part of our S Walsh Painting Promise, we are dedicated to providing information and education to our clients.
One of the most important terms a client should be familiar with when having any project done on their property is, VOCs. What are they?
VOCs are solvents that get released into the air as the paint dries. (Other products emit solvents, including adhesives, cleaning supplies, and even some home furnishings.) VOCs can cause acute symptoms, including headaches and dizziness. The federal government caps the VOC content in paint at 250 grams per liter (g/l) for flat finishes and 380 g/l for other finishes (low-luster, semigloss, etc.). However, some manufacturers have opted to comply with more stringent limits—50 g/l for all finishes—set by California’s South Coast Air Quality Management District. Benjamin Moore’s Aura is one such paint.
(The Ozone Transport Commission, a multistate organization created under the Clean Air Act, also has a model rule that limits flat coatings to 100 g/l and non-flat coatings to 150 g/l. It has been adopted by the District of Columbia and Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, Pennsylvania, Rhode Island, Vermont, and Virginia. Any paint sold in these places must be OTC-compliant.)
The following glossary contains commonly used terms and phrases in the paint and coatings industry to describe the characteristics, usage and components of paints and coatings.
Abatement
Involves either removal of the painted surface, covering the painted surface with an impermeable surface, or covering surface with heavy-duty coating (encapsulant).
Alkyd
Synthetic resin modified with oil. Coating that contains alkyd resins in the binder.
Acrylic
A synthetic resin used in high-performance water-based coatings. A coating in which the binder contains acrylic resins.
Amide
A functional group which can act as an epoxy resin curing agent.
Adhesion
The ability of dry paint to attach to and remain fixed on the surface without blistering, flaking, cracking or being removed by tape.
Anti-fouling Paint
Paints formulated especially for boat decks and hulls, docks and other below-water-line surfaces and structures to prevent the growth of barnacles and other organisms on ships’ bottoms.
Aerosol
A product that uses compressed gas to spray the coating from its container.
Historical Note: Aerosol paint products have not contained chlorofluorocarbons–CFCs–since 1978.
Binder
Solid ingredients in a coating that hold the pigment particles in suspension and attach them to the substrate. Consists of resins (e.g., oils, alkyd, latex). The nature and amount of binder determine many of the paint’s performance properties–washability, toughness, adhesion, color retention, etc.
Air Cure
One method by which liquid coatings cure to a dry film. Oxygen from the air enters the film and cross-links the resin molecules. Also called “Air Dry” and “Oxidizing.”
Blistering
Formation of dome-shaped projections in paints or varnish films resulting from local loss of adhesion and lifting of the film from the underlying surface.
Body
The thickness or viscosity of a fluid.
Chroma
A measurement of color. The degree of saturation of a hue. A color at its full intensity has maximum chroma.
Boiled Oil
Linseed (sometimes soya) oil that was formerly heated for faster drying. Today, chemical agents are added to speed up the drying process.
Clear Coating
A transparent protective and/or decorative film; generally the final coat of sealer applied to automotive finishes.
Butadiene
A gas which is chemically combined with styrene to create a resin used in latex binders, styrene-butadiene.
Coalescent Aid
The small amount of solvent contained in latex coatings. Not a true solvent since it does not actually dissolve the latex resins, the coalescent aid helps the latex resins flow together, aiding in film formation.
Catalyst
Substance whose presence increases the rate of a chemical reaction, e.g., acid catalyst added to an epoxy resin system to accelerate drying time.
Coating
A paint, varnish, lacquer or other finish used to create a protective and/or decorative layer. Generally used to refer to paints and coatings applied in an industrial setting as part of the original equipment manufacturer’s (OEM) process.
Chalking
Formation of a powder on the surface of a paint film caused by disintegration of the binder during weathering. Can be affected by the choice of pigment or binder.
Cohesion
A bonding together of a single substance to itself. Internal adhesion.
Colorant
Concentrated color (dyes or pigments) that can be added to paints to make specific colors.
Cure, Curing
The process whereby a liquid coating becomes a hard film.
Colorfast
Non-fading in prolonged exposure to light.
Dead Flat
No gloss or sheen.
Color Retention
The ability of paint to keep its original color. Major threats to color retention are exposure to ultraviolet radiation and abrasion by weather or repeated cleaning.
Diluent
A liquid used in coatings to reduce the consistency and make a coating flow more easily. The water in latex coatings is a diluent. A diluent may also be called a “Reducer,” “Thinner,” “Reducing Agent” or “Reducing Solvent.”
Corrosion Inhibitive
A type of metal paint or primer that prevents rust by preventing moisture from reaching the metal. Zinc phosphate, barium metaborate and strontium chromate (all pigments) are common ingredients in corrosion-inhibitive coatings. These pigments absorb any moisture that enters the paint film.
Driers
Various compounds added to coatings to speed the drying.
Creosote
A liquid coating made from coal tar once used as a wood preservative. It has been banned for consumer use because of potential health risks.
Dry Colors
Powder-type colors to be mixed with water, alcohol or mineral spirits and resin to form a paint or stain.
Drying Oil
An oil that when exposed to air will dry to a solid through chemical reaction with air: linseed oil, tung oil, perilla, fish oil, soybean oil.
Enamel
Broad classification of paints that dry to a hard, usually glossy finish. Most equipment-coating enamels require baking. Enamels for walls do not.
Earth Pigments
Those pigments that are obtained from the earth, including barytes, ocher, chalk and graphite.
Epoxy
Extremely tough and durable synthetic resin used in some coatings. Epoxy coatings are extremely tough, durable and highly resistant to chemicals, abrasion, moisture and alcohol.
Eggshell
Gloss lying between semigloss and flat.
Extender
Ingredients added to paint to increase coverage, reduce cost, achieve durability, alter appearance, control rheology and influence other desirable properties. Less expensive than prime hiding pigments such as titanium dioxide. Examples: barium sulphate, calcium carbonate, clay, gypsum, silica, talc. May also improve coating performance.
Emulsion
A mixture of solids suspended in a liquid.
Film Build
Amount of thickness produced in an application. Millimeters (mils) of dry film per mils of applied wet film.
Emulsion Paint
Coating in which resins are suspended in water, then flow together with the aid of an emulsifier. Example: latex paint.
Film Thickness
Depth or thickness of the dry coating in millimeters.
Fire Resistance
The ability of a coating to withstand fire or to protect the substrate to which it is applied from fire damage.
Gloss
The luster or shininess of paints and coatings. Different types of gloss are frequently arbitrarily differentiated, such as sheen, distinctness-of-image gloss, etc. Trade practice recognizes the following gloss levels, in increasing order of gloss: flat (or matte)– practically free from sheen, even when viewed from oblique angles (usually less than 15 on 60-degree meter); eggshell– usually 20-35 on 60-degree meter; semi-gloss–usually 35-70 on 60-degree meter; full-gloss–smooth and almost mirror-like surface when viewed from all angles, usually above 70 on 60-degree meter.
Fire Retardant
A coating which will (1) reduce flame spread, (2) resist ignition when exposed to high temperature or (3) insulate the substrate and delay damage to the substrate.
Gloss Meter
A device for measuring the light reflectance of coatings. Different brands with the same description (such as semi-gloss or flat) may have quite different ratings on the gloss meter.
Flat
A surface that scatters or absorbs the light falling on it so as to be substantially free from gloss or sheen (0-15 gloss on a 60-degree gloss meter).
Hardener
Curing agent for epoxies or fiberglass.
Forced Dry
Baking the paint between room temperature and 150ø F to speed the drying process.
HEPA Vacuum
High-efficiency particulate air-filtered vacuum designed to remove lead- contaminated dust.
Galvanizing
Process in which a thin coating of zinc is applied to iron or steel to prevent rust.
Inert
A material that will not react chemically with other ingredients.
In-place Management
A series of steps used as an alternative to lead-based paint removal. Improves condition of intact lead-based paint to reduce and/or eliminate hazards without total removal.
Linseed Oil
Drying oil made from the flax seed. Used as a solvent in many oil- based paints. “Boiled” linseed oil can be used to protect wood from water damage. Sometimes used as a furniture polish.
Intumescence
A mechanism whereby fire-retardant paints protect the substrates to which they are applied. An intumescent paint puffs up when exposed to high temperatures, forming an insulating, protective layer over the substrate.
Liquid Driers
Solution of soluble driers in organic solvents.
Lacquer
A fast-drying usually clear coating that is highly flammable and dries by solvent evaporation only. Can be reconstituted after drying by adding solvent.
Lithopone
A white pigment of barium sulfate and zinc sulfide.
Historical Note: Lithopone was once a primary substitute for lead carbonate or “white lead” pigments; it has been largely replaced by titanium dioxide.
Latex-based Paint
General term used for water-based emulsion paints made with synthetic binders such as 100% acrylic, vinyl acrylic, terpolymer or styrene acrylic. A stable emulsion of polymers and pigment in water.
Marine Paint
Coating specially designed for immersion in water and exposure to marine atmosphere. (See also Anti-fouling Paint)
Lead
A metal, previously used as a pigment in paints. Discontinued in the early 1950s by industry consensus standard, and banned by the Consumer Products Safety Commission in 1978 because of its toxicity.
Material Safety Data Sheet (MSDS)
Information sheet that lists any hazardous substance that comprises one percent or more of the product’s total volume. Also lists procedures to follow in the event of fire, explosion, leak or exposure to hazardous substance by inhalation, ingestion or contact with skin or eyes. Coatings manufacturers are required to provide retailers with an MSDS for every product they sell to the retailer. Sales clerks should make MSDSs available to retail customers.
Mineral Spirits
Paint thinner. Solvent distilled from petroleum.
Oil Paint
A paint that contains drying oil, oil varnish or oil-modified resin as the film-forming ingredient. The term is commonly and incorrectly used to refer to any paint soluble by organic solvents.
Monomer
Substance composed of low molecular weight molecules capable of reacting with like or unlike molecules to form a polymer.
Oleoresin
A natural plant product that contains oil and resins. Turpentine is an example.
Naphtha
A petroleum distillate used mostly by professionals (as opposed to do-it- yourself painters) for cleanup and to thin solvent-based coatings. A volatile organic compound (see VOC).
Oxidation
Chemical reaction upon exposure to oxygen. Some coatings cure by oxidation, when oxygen enters the liquid coating and cross-links the resin molecules. This film-forming method is also called “Air Cure” and “Air Dry.” (Oxidation also causes rust on bare metals.)
Natural Resins
Resins from trees, plants, fish and insects. Examples: damars, copals.
Paint
A coating including resin, a solvent, additives, pigments and, in some products, a diluent. Paints are generally opaque, and commonly represent the portion of the industry known as “architectural coatings.”
Nonvolatile
The portion of a coating left after the solvent evaporates; sometimes called the solids content.
Paint Remover
A chemical that softens old paint or varnish and permits it to be easily scraped off. Also called “stripper.”
Paint Thinner
See Mineral spirits
Polyvinyl Chloride
A synthetic resin used in the binders of coatings. Tends to discolor under exposure to ultraviolet radiation. Commonly called “vinyl.”
Penetrating Finish
A finish that sinks into the substrate, as opposed to settling on the surface.
Primer
First complete coat of paint of a painting system applied to a surface. Such paints are designed to provide adequate adhesion to new surfaces or are formulated to meet the special requirements of the surfaces.
Pigment
Insoluble, finely ground materials that give paint its properties of color and hide. Titanium dioxide is the most important pigment used to provide hiding in paint. Other pigments include anatase titanium, barium metaborate, barium sulphate, burnt sienna, burnt umber, carbon black, China clay, chromium oxide, iron oxide, lead carbonate, strontium chromate, Tuscan red, zinc oxide, zinc phosphate and zinc sulfide.
Propellant
The gas used to expel materials from aerosol containers.
Polymer
Substance, the molecules of which consist of one or more structural units repeated any number of times; vinyl resins are examples of true polymers.
Resin
Synthetic or natural material used as the binder in coatings. Can be translucent or transparent, solid or semi-solid. Examples: acrylic, alkyd, copal ester, epoxy, polyurethane, polyvinyl chloride, silicone.
Polymerization
The interlocking of molecules by chemical reaction to produce very large molecules. The process of making plastics and plastic-based resins.
Rosin
Natural resin obtained from living pine trees or from dead tree stumps and knots.
Semi-gloss Finish
Finish that has a low luster sheen. Semi-gloss paints are formulated to give this result (usually 35-70 degrees on a 60-degree meter).
Solvent
Any liquid which can dissolve a resin. Generally refers to the liquid portion of paints and coatings that evaporates as the coating dries.
Shellac
A coating made from purified lac dissolved in alcohol, often bleached white.
Historical Note: The word lacquer is derived from the word lac, which describes the secretions of the lac beetle. This insect, found mainly in Asia, deposits its secretions on branches of trees and this crop is later harvested. The resin developed by the insects, in its original state, contains a red dye. This dye is separated from the resin by boiling in water. Next the residue resin, known as seed lac, is melted, strained, cooled and flaked and then becomes shellac.
Source Reduction
Steps taken to reduce waste generation and toxicity at the source through more effective utilization of raw materials and reformulation.
Silicone
A resin used in the binders of coatings. Also used as an additive to provide specific properties, e.g., defoamer. Paints containing silicone are very slick and resist dirt, graffiti and bacterial growth, and are stable in high heat.
Specular Gloss
Mirror-like finish (usually 60 degrees on a 60-degree meter).
Solids
The part of the coating that remains on a surface after the vehicle has evaporated. The dried paint film. Also called Nonvolatile.
Substrate
Any surface to which a coating is applied.
Urethane
An important resin in the coatings industry. A true urethane coating is a two-component product that cures when an isocyanate (the catalyst) prompts a chemical reaction that unites the components.
Titanium Dioxide
White pigment in virtually all white paints. Prime hiding pigment in most paints.
Vehicle
Portion of a coating that includes all liquids and the binder. The vehicle and the pigment are the two basic components of paint.
Turpentine
Distilled pine oil, used as a cleaner, solvent or thinner for oil-based and alkyd coatings.
Vinyl
See Polyvinyl Chloride
Volatility
The defining quality of a liquid that evaporates quickly when exposed to air.
Viscosity
The property of a fluid whereby it tends to resist relative motion within itself.
Volatile Organic Compound
Organic chemicals and petrochemicals that emit vapors while evaporating. In paints, VOC generally refers to the solvent portion of the paint which, when it evaporates, results in the formation of paint film on the substrate to which it was applied.
VOC
See Volatile Organic Compound
Volume Solids
Solid ingredients as a percentage of total ingredients. The volume of pigment plus binder divided by the total volume, expressed as a percent. High-volume solids mean a thicker dry film with improved durability.
Water-based
Coatings in which the majority of the liquid content is water.
White Lead
Lead carbonate
