The paint industry is raw material intensive. Approximately 60 to 70 per cent of the paint cost is accounted for by raw materials and packagings. The raw materials used are also of a wide variety. Some 300 to 400 raw materials are required to manufacture various kinds of paints.

The total annual turnover of paints is about Rs.15,000 million and, of this, raw materials and packagings together constitute about Rs.8,000 to 12,000 millions.

It is estimated that about 18-20% of the total raw materials used in the Indian paint industry are imported. The other major problem faced by the Indian paint industry in the raw material field pertains to packaging. The tin containers and CR sheets for packaging of paints are in short supply. The other aspect is the lack of standardisation of raw materials and inconsistency in their quality, which affect the overall quality of the paint system.

The major features of critical raw material used in the paint industry are as follows:

The function of pigments and fillers is not provides simply a coloured surface, pleasing to the eye and with an aesthetic appeal but the solid particles of paints reflect much of the destructive light rays and thus help to prolong the life of pigments is to reinforce the film structurally and, at the same time, serve special purpose of protection to the metal. The pigments are classified as organic and inorganic and could be further subdivided into synthetic and natural.

In India, both in the large as well as the small sector, a number of units are manufacturing organic and inorganic pigments. M/s. Sudarshan Chemicals is exporting over Rs.22 crores worth of pigment every year. The pigment industry in India is in a position to meet the requirements of the Indian paint industry except in the case of titanium dioxide (rutile) and certain proprietary pigments.

Organic pigments are being manufactured by 12 units in the DGTD sector and some 50 units in the small scale sector. The total installed capacity is around 8,000 tonnes.

The total production of organic pigments in 1988-89 was 4500 MT and the requirement of the paint industry is 1,200 tonnes, which is met indigenously. The import dependence is negligible.

India manufactures a full range of inorganic pigments including zinc chrome, lemon chrome, middle chrome, scarlet chrome, ultramarine blue, prussian blue, iron oxide, cadmium pigments, titanium dioxide, coated mica etc.

India is not only self sufficient in inorganic pigments but also exports the surplus production to different countries. The only pigment being imported into India is PG Red Oxide by the cement, paint and tile industries due to its peculiar colour, strength and fastness properties. Sudarshan Chemicals, a major pigment producer, is exporting over Rs.22 crores worth of pigments every year.

India has one of the largest reserves of Titanium minerals in the world The titanium mineral is processed by The Kerala Minerals and Metals Ltd., (KMML) and Indian Rare Earths (IRE). The mineral (ilmenite) found in Kerala is termed as the Q grade and containing upto 60% titanium dioxide is considered as one of the best grades in the world. Inspite of the best quality of ore available indigenously, the availability and prices of titanium dioxide (rutile) have been most unfavourabale to the Indian paint industry. At present, titanium dioxide (rutile) is being manufactured by M/s. Kerala Minerals & Metals Ltd., (KMML) with an installed capacity of 24,000 MT. M/s. KMML has technical collaboration with M/s. Kerr Mc Gee of U.S.A. to produce titanium dioxide rutile through the chloride process. Due to some problems, the average production of this plant has been ranging only between 6,000 to 7,000 TPA. Approximately 1600 MT of rutile titanium dioxide was imported into the country in the year 1990-91. A new titanium dioxide unit is likely to come in Chattarpur in Ganjam District in Orissa in collaboration with Industrial Promotion & Investment Corporation of Orissa Ltd., (IPICOL).

This is being manufactured by M/s. Travancore Titanium Products Ltd. (TPPL) though the sulphate based on the know-how from Titan Products. Although the installed capacity of this unit is 15,000 MT, annual production has been ranging only between 7,200 to 11,000 tonnes against the paint industry’s requirement of around 15,000 tonnes. The demand for anatase grade in India is limited as it is used in low grade paints. In the developed countries the anatase grade has been replaced by different grades of rutile titanium dioxide. In the year 1990-91, approximately 1900 MT of anatase grade titanium dioxide was imported into the country.

Synthetic iron oxide is used as a pigment and usually manufactured from steel scrap. The various colours available include red oxide, yellow oxide and black oxide. It is widely used in synthetic enamels, automotive primers etc. A number of units both in the small and the large sector are manufacturing these pigments. However, abroad, in addition to the above mentioned colours, different shades of brown and blue are also available.

There are five units in the organised sector and a number of units in the small scale sector making zinc oxide. The installed capacity in the organised sector alone is 12,000 MT and the annual production ranges between 8,000 to 10,000 MT. The paint industry consumes around 2,000 tonnes of zinc oxide including the capacity in the small scale sector, available for export of this product.

Pthallic anhydride is being manufactured in the country by certain manufacturers with a total installed capacity of 142,255 tonnes. Production is around 87,603 tonnes. Orthoxylene, the critical raw material for the manufacture of pthallic anhydride is currently in short supply.

Pentaerythritol is used for manufacture of synthetic resins, mainly alkyds. There are three grades of pentaerythritol available commercially viz. monopentaerythritol (explosive grade), technical grade and dipenta.

Over 80% of pentaerythritol manufactured goes into the surface coating industry for the preparation of alkyd resins and, to a smaller extent, for the preparation of other synthetic resins. The installed capacity of pentaerythritol is in the vieinity of 20,000 TPA and the production was 85,000 MT in 1989-90.

Vinyl acetate, esters of acrylic acid, etc. are some of the monomers, of which about 1,500 tonnes of vinyl acetate and 500 - 600 tonnes of acrylic monomers per annum, are requiered by the paint industry.

There is a manufacturing capacity of 20,000 tonnes of butyl acrylate ester set up by M/s. Colour Chem. Ltd., Rajprakash Chemicals, a small scale unit, has set up a plan to produce other acrylates, like ethyl acrylate, 2 ethyl hexyl amylate etc. Polymer Corporation of Gujarat has set up a plant to produce methyl methacrylate in collaboration with Mitsubishi, Japan.

In India, there are 19 units licensed to manufature glycerine while there are 6 units recovering only crude glycerine. The present total capacity is around 47,000 tonnes. Production of glycerine is around 15,000 tonnes.

Rosin is one of the major natural resins widely used in the paint and varnish industry. Rosin , a bright solid material is obtained from the exudation of pine trees. Commercial rosin consists of 90% free acid and 3% combined acids.

The production of oleoresin, the basic raw material for rosin, has been falling every year due to indiscriminate felling of pine trees.

Oils from the largest group of raw materials, consumed by the paint industry. Linseed Oil, soyabean oil and castor oil are among the major oils being used, while minor oils, like niger seed oil, tobacco seed oil, rice bran oil, fish oil, etc., are used to a smaller extent.

Currently the production of linseed oil is 1,20,000 tonnes, out of which the requirement of linseed oil by the paint industry is 15,000 tonnes. The current production of castor oil is 2,40,000 tonnes. The paint industry consumes castor oil in the ofrm of dehydrated castor oil (DCO). The requirement of the paint industry is estimated at around 5,000 tonnes. Tobacco seed oil is probably used only in the Indian paint industry since it is easily avalilable in India.

The production of soyabean oil is around 2,90,000 tonnes, out of which the requirement of the paint industry is estimated at around 10,000 tonnes.

Resins are primarily uses as binders and act as the main film, imparting durability and water proofness to the film. The resins are primarily divided into two groups, viz. natural and synthetic.

Resins and the derivatives, kauri, amber, copal, shellac, damar, ester, gums, manila, etc.

Alkyd, phenolic, maleic, amino, acrylic, polyester, epoxy, silicone, urea fromaldehyde, cellulose derivatives, polyurethane etc.

In India, most of the large and medium scale manufacturers produce certain resins in-house while, in the developed countries, the resins are usually bought from outside. The major resins used in the paint industry are detailed below:

Alkyd resins are widely used in India and a number of manufacturers have in-house facilities for manufacturing them. These are manufactured by condensation polymerization of esters formed as a result of reaction between polycarboxylic acids and polyhydride alcohols. Glycerol and phthallic anhydride are the main raw materials for alkyd resins. In the developed countries, certain polyols like trimethylol propane are used, while in India, due to its high cost on account of import, these polyols are not widely used. Abroad there is a choice to use isophthalic acid as a substitute to phthalic anhydride, while, in India, due to high landed cost of imported isophthalic acid, it is rarely used. Castor Oil, one of the major raw materials for alkyd resins, is easily available reasonable prices and has led to a wider usage of alkyd resins in India.

Amino resins are formed by condensation reaction between aldehydes and amines. Urea fomaldehyde and melamine fromaldehyde polymers are widely used amino resins. Butanol is used to modify these so as to make them soluble in common solvents.

There are few units in India manufacturing epoxy resins. Epichlorohydrin, on eof the important raw materials for epoxy resins, is being imported. The high landed cost of this raw material has led to high prices of epoxy resins in India. Due to this, the use of epoxy resins is somewhat restricted in India.

Though acrylic resins are available indigenously, the cost of production is high due to the high cost of monomers.

Isocyanate is an important raw material for polyurethane resins. Isocyanate is generally imported which results in the high cost of polyurethanes.

Polyester resins are made from esterification of polybasic acids and polyhydric alcohols. The reaction mechanism is similar to alkyd resins but polyester resins need no modification. Glycerol, neopentyl glycol or trimethylol propane are used a polyhydric alcohols. In the case of polybasic acid, isophthalic acid, phthalic anhydride and adipic acid are widely used as polybasic acids. Till recently polyester resins were imported in India but recently M/s. Ciba Geigy Ltd. have started production of polyester resins in the country.

These are thermoplastic resins obtained by the polymerization or copolymerization of acrylic and methacrylic esters. These resins along with melamine, epoxy, alkyd etc. provides a film with excellent resistance to wate, acids, alkalies, chemicals etc. These are widely used for wood, concrete, paper and metal.

Solvent based vinyl resins are usually the copolymers of polyvinyl chloride and polyvinyl acetate; though they are available as polymers of either one. The chlorides have excellent resistance to chemicals, acids and alkalies but they are difficult to dissolve. The acetates are not as resistant but it is easiser to dissolve them. The vinyl resins are mainly used as coatings in cables, swimming pool, cans etc.

The high styrene-butadiene latices are produced by the emulsion polymerisation technique. Polyvinyl methyl ether is used as a agglomeration promotor to produce high solid latices. These are used as flat wall paints, primers, concrete coatings, etc.

Coal tar resins have good water resistance, excellent adhesion and good chemical resistance. These are thermoplastic and tend to cold flow at moderate temperatures. The cold flow tendency is improved combining coal with epoxy, acrylonitrile or isocyanate resins. Acrylonitrile improves their oil resistance and reduces the water absorption capacity.

These are used extensively on the exterior of underground pipelines for oil and gas as well as on both the interior and the exterior water pipelines.

The chlorinated rubber resins is manufactured by chlorinating natural rubber. It is usually modified with alkyd resins while manufacturing protective coatings. These are high solids solutions. The unmodified chlorinated rubber coatings contain no alkyd resins and are outstanding protective coatings.

The solvents are added to the paint system in order to reduce the viscosity of the paint to a suitable consistency for smooth application. The solvent evaporates leaving behind non volatile matters (pigments, binders & additives). The rate at which solvents evaporate influences the application characteristics of the coating. In case the solvents are partially retained, it leads to premature failure of the paint film due to blistering or pinholing. Various organic solvents are widely used in the paint industry. Water is used as a solvent in the water based paints.

The sole source of solvents such as mineral turpentine (MTO), toluenes and xylenes in the country are from the public sector refinery units.

These are used as oxygen carriers. Driers accelarate the drying of paint films through oxidation, polymerization and condensation.

The commonly used driers are resinates, linoleates and naphthanates of cobalat, manganese and lead.

Plasticizers provide elasticity to the film, thus inhibiting the cracking of the films.

The various plasticizers used in paints include castor oil derivatives, resinous plasticizers, phthalates, phosphates, sebacates, hexoates, etc.

The additives are chemicals performing a specific function in the paint system. The classification of the additives is based upon the specific function of each, for e.g.:

a. Wetting and dispersing agents.

b. Anti-skinning agents

c. Anti-setting agents

d. Anti-floating agents

e. Anti-livering agents

f. Puffing agents

g. Flow control and levelling agents

h. Defoaming agents

Extenders not only reduce the cost but are also beneficial in adding resistance to the liquid paint so as to facilitate the covering of the edges. In the dried paint, extenders help in reducing the permeability to water and oxygen and provide a reinforcing structure within the film. Mica and talc are widely used exenders; other important extenders are barytes, china clay, blanc fine, paris white etc.

Various types of raw materials are used in different types of paints. The consumption norms vary from product to product and it is difficult to establish the exact raw material consumption norms because of the wide product range and properties and usage of substitute raw materials in many cases, for example the oil percentage in alkyd resins vary from 22% to 70% and, based on that, the composition of polyols, pthalic anyhydride, pentaerythritol, etc., also varies. Similarly the use of pigments particularly TiO2 varies a lot, depending on the colour of the paint, colour of the paint, from as low as 1.5-2% to 40-50% by weight. The total annual turnover of paints is about Rs.14,000 million and, of this, raw materials and packaging together constitute about Rs.8000 to 9000 millions.

With the increasing size of the paint industry and raw materials accounting for about 60% of the production costs, standardisation has assumed considerabale importance. The lack of standardisation of raw materials has adversely affected the quality of paints, particularly those manufactured by the small scale sector. It is recommended that a National Body of Standardisation of Raw Materials for the Paint Industry should constituted.

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