Paint, coating, water-based paint, water-based coating... For professionals in the coating industry, have you noticed this interesting phenomenon? People use the terms "paint" and "coating" interchangeably in different contexts. Are they just different expressions, or do they refer to two distinct substances? When can they be swapped, and when must they be strictly differentiated? If you find this confusing, you're not alone. After researching, we found key similarities and differences. Let's dive into the distinction and relationship between these two terms.
Firstly, the relationship can be summarized as: Coating ≥ Paint. This means coatings include paint, but coatings are not entirely synonymous with paint. Let's look at their definitions.
- Definition of Coating
A coating is a material applied to a surface to protect it, decorate it, or impart unique functionalities (like insulation or corrosion resistance).
- Definition of Paint
Paint is a chemical mixture coating that firmly adheres to a surface for protection, decoration, marking, or other special purposes. It traditionally refers to coatings using an organic solvent as the medium, or high-solid, solvent-free oil-based paints.
In summary, Coating ≠ Paint; they have distinct definitions. Historically, "paint" ( literally 'oil paint') was named for its use of vegetable oils. Now that synthetic resins have largely replaced oils, the term "paint" is often considered a subset of the broader category "coatings."
- Differences Between Coating and Paint
① Different Scope
Coatings encompass paint. Coatings include water-based paints, solvent-based (oil-based) paints, and powder coatings. Paint is a category within coatings. The term "coating" has a wider meaning and scope. Coatings are organic chemical polymer materials forming polymeric films and are classified as fine chemical products.
② Different Composition
The film-forming agents in paint are mostly organic high-molecular compounds like natural resins (rosin, lacquer), drying oils (tung oil, linseed oil), or synthetic resins, blended and formed through high-temperature reactions. Some paints may use inorganic compounds.
Paint contains resins, additives, pigments/fillers, and solvents.
Coatings, however, include the four components above and more. For instance, some solid resins don't require organic solvents and can be used as powders. These resins, mixed with additives and pigments/fillers, form powder coatings. There is no such thing as "powder paint."
③ Different Classification
Classified by the primary solvent or carrier, coatings are broadly divided into:
Solvent-based (Oil-based) Coatings
Water-based Coatings
Powder Coatings
Paint is generally understood to mean solvent-based (oil-based) coatings. Historically, the public often uses "paint" to refer to most surface coating materials (i.e., coatings). However, the popular water-based coatings are often mistakenly called "water-based paint," influenced by traditional habit.
To clarify their relationship, see the equation below:
As evident from the above, a coating is a material (liquid or solid) applied to surfaces to form a solid film offering protection, decoration, insulation, anti-corrosion, or other special functions. It is a fine chemical product. Paint specifically refers to coatings that are oil-based or use organic solvents as a medium. We hope this article helps you distinguish between coatings and paint.