Paint is a liquid substance, typically consisting of pigments suspended in a solvent and oil. The purpose of the paint is to protect or decorate various surfaces such as wood, metal, stone, concrete and plaster.
In addition to colouration and protection from wear and tear, paints often provide other functions: for example, they can be used as sealants or surfactants. Of course, the specific process depends on the type of paint it is - some are designed for use on floors while others are made specifically for walls or ceilings. In addition, some colours will only cover items like furniture; essentially, any object you want to give a new coat of paint can be covered with it!
The Main Ingredients of Paint
The main ingredient found in paint is pigment, which gives the paint its colour. There are three types of pigments: organic pigments, inorganic pigments and artificial pigments. Organic pigments have been used since prehistoric times for artwork and decoration.
However, many of these organic dyes have a brief life span and fade quickly. Inorganic pigments are made up of minerals, while synthetic pigments are chemicals derived from petroleum processing.
Types of Pigments
Organic pigments are derived from animal, vegetable or mineral sources. They include the following:
- Animal-derived colours include browns; yellow colours come from compounds made by insects, which can be found in nature.
- Vegetable—the carmine lake is a red colour obtained from carminic acid found in cochineal.
Inorganic pigments are compounds of various metals or semi-metals. They include the following:
- Iron oxide colours—red, yellow and orange
- Ultramarine blue—derived from a natural mineral
- Lead chromates—used in the past but have been replaced with more colourfast alternatives
These are made of chemical compounds derived from petroleum processing. Some examples are as follows:
- Cadmium colours—have been banned due to health risks
- Dioxazine purple—derived from coal tar, this pigment has a long-life span and is known for its good transparency. This means that it is also used in paints for car bodies.
Another main ingredient found in paint is the solvent, which serves several purposes: it dilutes the pigment to prevent it from being too intense, carries the pigment through to the surface, and evaporates once there to provide a durable finish. The most common solvents used in today's paints are water-based (aqueous) or organic solvent-based (organic).
Properties of Solvents
The solvents used in paints are usually water or organic solvent-based. The main properties of these are as follows:
- Water-based—less toxic, easy cleanup, fast-drying but have less covering power.
- Organic solvent-based—more challenging to clean up but can be more difficult for bugs or rodents to penetrate, slower drying but have better-covering power
The binder is another essential ingredient found in paint that holds the pigment particles together. The binder helps the colour retain its strength and adhesion to surfaces. Binders are typically made from resins or plasticizers but may also be made from natural materials such as cement or vegetable oils.
Top 3 Binders Used in Painting
Acrylic: Made from a polymer resin and water, acrylics are the least toxic of all paints. They produce less odour when drying and come in an array of bright colours to choose from.
Epoxy: This type of binder can be used in both interior and exterior applications. It is incredibly durable, making it the preferred choice for items that will take a lot of abuse.
Alkyd: Alkyd paint is oil-based and perfect for use on surfaces that need to stay flexible, such as wood or concrete. When exposed to sunlight, the colour may become slightly translucent.
Paint is a multi-layered material created from various ingredients for specific purposes. The main components of paint are pigment, solvents and binders. Pigment gives the paint its colour properties, while solvents evaporate to produce a drying effect on the dried paint film.