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PAINT PRODUCTION
Paint was first used as a protective coating by the Egyptians and Hebrews, who applied pitches and balsams to the exposed wood of their ships. During the Middle-Ages, some inland wood also received protective coatings of paint, but due to the scarcity of paint, this practice was generally limited to store fronts and signs. Around the same time, artists began to boil resin with oil to obtain highly miscible (mixable) paints, and artists of the fifteenth century were the first to add drying oils to paint, thereby hastening evaporation. They also adopted a new solvent, linseed oil, which remained the most commonly used solvent until synthetics replaced it during the twentieth century.
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AIMS OF THE STUDY
The aim of this work is to make use of available raw materials in the production of Emulsion Paint. 1.3
OBJECTIVES OF THE STUDY
The objectives are as follows 1. To facilitate the manufacturing process. 2. To enhance the products stability and durability 3. To enhance the product performance, which include application and film quality so as to achieve all the desirous goals of the coating. 1.4
THE SCOPE OF PROJECT RESEARCH
Paints is classified according to its application and functions such as Varnishes, leaguers, fillers etc. Emulsion paint which is a water based paint is principally used for external and internal surface coatings, mostly in building for appearance and as a surface protector. Apart from their
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protective action, vanishes and leaguers increases the protective action of manufactured goods. 1.5
SIGNIFICANCE OF STUDY
On considering the high cost of imported raw materials for the production of paint in the paint industry, which at the end of the production affect the market price, likewise causing economy constrain, there is need to lookout for those locally raw materials, e.g. calcium carbonate which will give such desirable qualities and properties as those of imported raw materials e.g. titanium dioxide). It will be interesting to note that chemical Engineering have some of possible solutions towards reduction of high cost of emulsion paint production and also this research project work is directed towards the vital needs for the used of local pigments and extenders as raw materials for the production of paint of high quality and standards which will stand the test of time and also compete with those emulsion paints produced with imported raw materials. Finally, this research project work will be of more importance to the paint manufacturers in the country, who spend lots of money for importations of raw material, while they are blessed with much raw materials as pigments and extenders for emulsion paint production in their country, it will also be of help to students researchers, and also reveals the importance of research among producers for future betterment and economy improvement.
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CHAPTER TWO LITERATURE REVIEW
Paint is a mixture of insoluble particles of pigment suspended in a continuous organic or aqueous vehicle. It is most commonly used to protect, colour or provide texture to objects. Paint can be made or purchased in many colours and in many different types. It is typically stored, solid, and applied as a liquid, but dries into a solid. With a branch, a roller, or a spray gun, paint is applied in a thin coat to various surfaces such as wood, metal, or stone. Samples of the first known paintings made between 20,000 and 25,000 years ago, survive in caves in France and Spain. Primitive painting tended to depict humans and animals, and diagrams have also been found. Early artists relied on easily available natural substances to make paint such as natural earth pigments, charcoal, berry juice, blood, lard, and milk-weed sap. Later, the ancient Chinese, Egyptians, Hebrews, Greeks, and Romans used more sophisticated materials to produced paints for limited decoration, such as painting walls. Oils were used as vanishes, pigments such as yellow and red ochres, chalk, arsenic sulfide yellow, and malachite green were mixed with binders such as gun Arabic, lime, egg albumen and beeswax.
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The twenty-first century has seen the changes in paint composition and manufacture. Today, synthetic pigments and stabilizers are commonly used to mass produce uniform batches of paints. New synthetic vehicle developed from polymers such as polyurethane and styrene-butadiene emerged during the 1940s. Alkyd resins more synthesized, and they have dominated production since. Before 1930, pigment was ground with stone mills, and these were replaced by steel balls. Today sand mills and high-speed dispersion mixers are used to ground dispersible pigments. Perhaps the greatest paint-related advanced has been its proliferation. 2.1
COMPOSITION OF PAINTS
Generally speaking, components of paints can be discussed under the following: 1. Pigments 2. Binders (Resins) 3. Solvents 4. Additives
Pigments:
pigments can be defined as a substance used for coloring (hiding) purpose. However, more technically, pigments can be defined as finely powdered solid substance, essentially insoluble in the medium in which they are dispersed (if any) and are used in paints to provide the dried film and such properties as, hiding and colour. There are different kinds of pigments used in making paints like basic white pigment (titanium dioxide) selected for its excellent concealing properties, black pigments commonly made from carbon black. Others are iron oxide and cadmium sulfide for
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reds, metallic salts for yellow and oranges, iron blue and chrome yellows for blues and greens.
Binders (Resins):
Simplistically, a binder is anything that binds, while technically, a binder is a non volatile potion of the vehicle of a paint, it binds or cement the pigments particles together and also the paint film as a whole to the material it is applied. Examples of binders are thickener (Nitrosol) and Acrylic.
Solvents:
solvents are various low viscous, volatile liquids. The aid flow and applicability of the paint products. Solvents can commonly be divided into two, via: polar solvents and non polar solvent. Polar solvents are known to contain OH group (alchanol group) whereas non polar solvents do not contain the OH and are mostly organic in nature. In the surface coating industry, i.e. paint industry, the universal solvent is water. Water is found common and generally used in the water based-paint. In the same way, it can be said that the non polar solvents are used in the oil based paint.
Additives:
additives are those components of paint system other than the primary components (pigments, binders, and solvents) which are introduced to serve special purposes.
2.2 TYPES OF PAINT
Paint is a fluid, or semi-fluid material which may be applied to surfaces in relatively thin layers, and which changes to a solid coating with time. The change to solid material may or may not be reversible, and many occur by evaporation of solvent b chemical reaction, or by a combination of the two.
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There are many types of paint, which include oil based paints (gross paints), emulsion paints (water based paint), textured paints (texcote), cellulose paints, bituminous paints and rubber-based paints.
Gross paints (oil based paints):
These are paints that may be classified according to whether the drying mechanism is predominantly solvent evaporation, oxidation or some chemical reaction. Gross paints which dry essentially by solvent evaporation, reply on a fairly hard resin as the vehicle. Paints which dry by oxidation, the vehicle is usually an oil or an oil-based varnish, these usually contains driers to accelerate the drying of the oil. Paint based essentially on oil with suitable pigment such as titanium dioxide, extenders, and usually zinc-oxide and white lead, are conventional outside house paint because these materials give the combination of properties which meet this requirement. Oil paint is a type of slow drying paint that consist of particles of pigments suspended in a drying oil, commonly linseed oil. The viscosity of the paint may be modified by the addition of a solvent such as turpentine or white spirit, and varnish may be added to increase the glossiness of the dried oil paint film. It is the oldest and most traditional of the types of paint, generally suitable for all surfaces, but not the most economical for all occasions. Oil paints have been used in Europe since the 12
th
century for simple decoration but were not widely adopted as an artistic medium until the early 15
th
century. Common modern applications of oil paint are in finishing and protection of wood in buildings and exposed metal structures such as ships and bridges. Its hard-wearing properties and luminous colour make it desirable for both interior and exterior use on wood and metal. Due to its slow drying properties, it has recently been used in paint-on-glass animation. Thickness of coat has
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considerable bearing on time required for drying. For those instances when oil based paint would traditionally be preferable, but you desire a water
based product, a number of companies have introduced “waterborne enamels” or “waterborne alkyds. “These paints look and behave
much like oil-based options because they have good leveling qualities for a smooth finish.
ADVANTAGES OF OIL BASED PAINTS
Attractive gloss
Good “leveling” (brush strokes fill themselves in to create a smooth
finish)
Hard durable finish
EMULSION PAINTS (WATER BASED PAINT)
These are paints with water-soluble vehicle and they include, calcimines, in which the vehicle is glue and case- in paints, in which the vehicles is casein or soya-bean protein. This project research study is directed towards producing and formulating of emulsion paint (water
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thinned paint) from local pigments and extenders as raw materials. The high demand for emulsion paint for protective and decorative purposes has encouraged the development of different equipments for the manufacturing operation. This piece of research work is due to reducing the high cost of emulsion paint formulation and production, because of the imported raw materials. (E.g. Titanium dioxide), and thereby disclosing a local raw material from our natural domain which could also be used for the same purpose.
