The type applied on the wall of a building is called decorative, domestic or home paint while that applied to an iron surface, wood, metal or stone is called industrial or paint or coating. In either case, the application can be made with a brush, a roller, or a spray gun. This article will concentrate on the domestic paint category.
Raw materials
Early artists relied on easily available natural substances to make paints, such a natural earth pigments, charcoeal, berry juice, lard, blood, and milkweed sap. Later, more sophisticated materials were used to produce paints for limited decoration, such as painting walls. Oils were used as varnishes, and pigments such as yellow and red ochres, chalk or kaolin, arsenic sulfide yellow, and malachite green were mixed with binders.
However, today, synthetic pigments and stabilisers are commonly used to mass produce uniform batches of paint while sand mills and high-speed dispersion are used to grind easily dispersible pigments. Although some shrewd house owners in the villages still adopt the old traditional paint-making methods, such people dig the earth to scoop out kaolin which they directly formulate into paints that they use in painting their new buildings.
For commercial purposes especially, it is however not advisable for a prospective manufacturer to think of adopting this rudimentary method. Offenders face the danger of incurring the wrath of Regulatory agencies. Both agencies periodically raid the market to identify products that do not conform to standards, confiscate them and prosecute offenders.
This article would not be complete without describing the group of raw materials employed in paint production. Paint is entirely composed or pigments, solvents, resins, and various additives. The solvent or dilutant is the material with which the binder and pigment is mixed in order that the paint may be of the correct consistency. Vehicle is the name given to the liquid portion of the paint, because it carries the pigment. It is composed of a binder which is either dissolved in liquid solvent or dispersed in diluents which do not dissolve. The binder is the portion of the dry paint film which binds the pigment particles together with the paint surface. The binder gives the film many necessary properties such as gloss, adhesion, hardness, toughness, flexibility, durability and speed of drying. Additives are materials which are added to the paint, usually in small quantities to help it dry more quickly or flow out evenly to remove brush marks and to stop skinning in the can.
One example is silicone, this makes the surface of the paint film more resistant to marking and scratching. All the various raw materials for paint manufacturing are found in the markets. Hundreds of different pigments, both natural and synthetic exist. The basic white pigment is titanium dioxide selected for its excellent concealing properties. Other pigments used to make paint include iron oxide and cadmium sulfide for reds, metallic salts for yellows and oranges, and iron blue and chrome yellows for blues and greens.
Solvents are various volatile liquids of low viscosity. They include petroleum mineral spirits and aromatic solvents such as benzol, alcohols, esters, ketnones, and acetone. The natural resins most commonly used are linseed, coconut, and soyabean oil, while alkyds, acrylics, epoxies, and polyurethanes number among the most popular synthetic resins.
Additives serve many purposes, some like calcium carbonate and aluminum silicate are simply fillers that give the paint body and substance without changing its properties. Other additives produce certain desired characteristics in paint such as the thixotropic agents that give paint its smooth texture, driers, anti-settling agents, anti-skinning agents, defoamers, and a host of others that enable paint to cover well and last long.
Manufacturing Process
During paint manufacturing, the pigment and vehicle undergo the following changes:
- Wetting of the pigment surface by the vehicle;
- Grinding of the pigment aggregates to small primary particles;
- Stabilisation of these small particles to prevent re-aggregation.
The process flow for paint manufacturing however consist of
- Dispersing the pigment
- Thinning the paste
- Canning the paint
Paint manufacturing is a small but very important sector of the manufacturing industry. While some sectors are particularly sensitive to market forces, the paint industry has proved itself a reliable avenue of investment, come boom, come meltdown. Almost every nation is constructing houses for its citizenry. This is a lucrative target market for this product. The greatest fascination of this venture is that low-cost, local but functional machinery are available.
Any prospective investor(s) who want to invest in paint making without appropriate knowledge should contact me by posting a comment on this post.
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