Acrylic Emulsion Paints
Paints and coating materials normally consist of a physical mixture of binders, pigments, extenders, additives, and solvents. Depending on the method of application and area of use, the solids content may reach 80 wt%, the proportion of pigment may reach 60% of the solids content. The technologically most important component is the binder (or binder mixture). Binders may be classified as physically or chemically drying according to their film-forming mechanism.
Physically drying paints are solutions of thermoplastic polymers with molecular masses exceeding 20,000 on account of their low solubility they have a high solvent content (> 60%) and low solids content. Chemically drying paints have a fairly low solvent content (30 - 60%) and high solids content because the polymer network is formed by cross-linking of the binder (Mr Ca. 800-10,000) to form thermosetting coatings. Oxidative drying paints contain alkyl groups and reactive double bonds, and cross-link by absorbing oxygen and forming ether bridges.
Normally paints are also classified according to the nature of the principal binder and its associated film properties; e.g., alkyd, acrylic, polyester, nitrocellulose, epoxy, and oil-based paints. The method of application, surface properties, and intended use are also utilized for classification. Since the beginning of the 1980s environmental requirements have become increasingly important for two main reasons, especially in the case of paints with low material transfer (application) efficiencies
(1) Avoidance of the use of toxic, carcinogenic, mutagenic, or teratogenic organic solvents.
(2) Drastic and in some cases legally imposed reduction of solvent contents.
Legal regulations have resulted in a sharp rise in the solids content and a reduction in the solvent content of the most important paints systems. Among solvent borne paints, high-solids paints have enjoyed the largest growth rate ; in the Federal Republic of Germany production of this type of paint rose by 32% between 1988 and 1989, whereas the production of all solvent borne paints increased by only 3%. A sharp drop in high-solvent paints is to be expected in the United States and Europe. The definitions of "low" and high-solids" paints differ. For example, the verb and der Deutschen Lackindustrie (Association of the German Paint Industry) defines "high-solids" paints as paints with a no aqueous (i.e., organic) solvent content of less than 30 wt%, whereas the Environmental Protection Agency (EPA) in the United States defines "high-solids" paints as having volatile organic contents of < 2.8 pounds/gallon (336 g/L).
Typical examples of low-solids paints (solvent content usually > 60 wt%) are :
(1) Metallic (effect) base paints for mass production of automobiles and touch-up finishes
(2) Thermoplastic coatings
(3) Coatings for the electronics and opt-electronics industries
Of these three groups metallic basecoats are quantitatively the most important. Technical reasons for the high solvent content of these paint systems include the need for thin layer thickness (e.g., when applying paint with a spin coater). Secondly, binders such as polyamides for electrical insulation coatings and thermoplastic acrylic resins have low solubility. Finally, in some cases (e.g., in metallic basecoats) a high solvent content is needed to optimize rheological behaviour. Rheological factors limit the reduction of the solvent content, particularly when coatings vertical surfaces. Significant improvements can often only be achieved by replacing organic solvents with water. For example, the solvent borne metal effect paints used in the automobile industry are increasingly being replaced by waterborne paint systems with a reduction in the solvent content in the paint to ca. 10% based on 25% solids.
General Properties of Acrylic Paints
General Properties: Paints containing acrylic resins as binders have been known since the 1930s. They are now one of the largest product classes in the paint and coatings sector.
Polyacrylates as binders consist of copolymers of acrylate and methacrylate esters. Other unsaturated monomers (e.g., styrene and vinyl toluene) may also be incorporated, but usually to a lesser extent. Copolymers formed exclusively from acrylates and/or methacrylates are termed pure acrylics. The co monomers differ as regards the alcohol residues of the ester group, which also allow incorporation of additional functional groups. Choice of suitable monomers allows wide variation of the physical and chemical properties of the resulting polymer. Hydrophilicity, hydrophobicity, and acid-base properties can be adjusted; resins containing hydroxyl, amine, epoxy, or isocyanate groups can also be produced.
The resin product may be solids, solutions in organic solvents or water, emulsions, or dispersions.
Acrylate resins have several advantages over other paint binders:
(1) Polyacrylates are only slightly attacked by chemicals, and confer a high degree of resistance to paints.
(2) Polyacrylates are colourless, transparent, and do not yellow, even after prolonged thermal stress.
(3) Polyacrylates do not absorb above 300 nm and are therefore not degraded by UV radiation (as long as they do not contain styrene or similar compounds).
(4) Polyacrylates do not have unstable double bonds.
(5) Polyacrylates have outstanding gloss and gloss retention.
(6) Acrylates, and especially methacrylates, are stable to hydrolysis.
The following properties of the coatings can be ascribed to individual monomers. Methyl methacrylate promotes weather resistance, light fastness, hardness, gloss, and gloss retention. Styrene increases hardness and resistance to water, chemicals, and salt spray, but reduces light fastness and gloss retention. Alkylacrylates and alkyl methacrylates impart flexibility and hydrophobicity, while acrylic acid and methacrylic acid improve adhesion to metals.
The increasing importance of environmental considerations places new requirements on paint resins and has broadened the range of paint systems. Paints are now required that have a low solvent content (medium-solids, high-solids coatings) or are solvent-free (powder coatings), that can be adjusted by dilution with water (waterborne paints), and that are thermoplastic or capable of undergoing cross-linking. All of these properties must be obtained via the polymer structure of the binders. Important parameters are described below.
The glass transition temperature (Tg) affects adhesion, flaking and peeling from the substrate, crack formation, and resistance to impact shock. In acrylates adjustment of Tg is achieved relatively easily via the ratio of methyl methacrylate (Tg of the homopolymer + 105º C) to n-butyl acrylate (Tg of the homopolymer-54ºC). The Tg also influences properties of dispersions and the viscosity of solutions. A high Tg value is associated with a faster drying rate. In the low molecular mass range (< ca. 6000), which is of interest particularly for high-solids paints, the Tg depends on the cross-linking density.
The styrene content in the binder reduces resistance to yellowing and weathering, but improves resistance to chemicals, hydrophobic properties, adhesion, and pigment wetting. Styrene is therefore largely avoided in topcoat paints for exterior use and in clear coats.
The development of low-solvent (high-solids) paints requires resins with a very low viscosity. The principal viscosity-determining parameters for such binders are the molecular mass and molecular mass distribution. Oligomers with a molecular mass of ca. 1000-3000 are required for high-solids paints. An acrylate binder with a molecular mass of 1,00,000 can be processed to form a paint with 12.5% solids content at the application viscosity; a molecular mass of ca. 6000 results in a paint with 50% solids content. A narrow molecular mass distribution is beneficial in achieving low viscosity. However, the mechanical properties of paint are favoured by a high molecular mass. Low molecular mass binders that cross link after application are therefore used exclusively for high-solids paints. When it is applied, the paint contains low-viscosity oligomers; a highly polymeric system is formed after cross linking and curing. Further possibilities of reducing the viscosity include specific interactions between the binder molecules and choice of a low-viscosity solvent that does not interact significantly with the resin. The melt viscosity is an especially important criterion in powder coatings; acrylic resins have disadvantages in this respect when compared with polyesters.
Incorporation of functional groups in the polymer skeleton is necessary for the production of dispersions. Most free carboxyl groups. Water thin ability is achieved by neutralizing the acid groups with aqueous alkali or amines. Binders may also contain basic nitrogen-containing groups; dispersion can then occur after neutralization (e.g., with acetic or lactic acid). Since the viscosity of dispersions is very low irrespective of the molecular mass, polymers of very high molecular mass, polymers of very high molecular mass are generally used; dispersions are therefore ideal for physically drying coatings.
Solvent emission from paints can be reduced without lowering the molecular mass by using non aqueous dispersions (NAD). Acrylates have been described as binders for NADs, but apart from a low viscosity they offer few advantages over conventional coatings and moreover must complete with high-solids paints and powder coatings.
Application and Uses of Acrylic Paints
Acrylic paints are used in many different areas and applied by all commonly used methods. Recent developments (low-solvent paints and aqueous dispersions) require special formulation. The largest application sector of acrylate binders are emulsion paints for ceilings, walls, and building fronts. These emulsion paints are generally physically drying and only contain a small amount of binder; the main constituents are pigments and extenders. Acrylate dispersions for paints have a good water vapor permeability and good water resistance.
Acrylic resins have been used in the automotive sector since 1957. They are now important binders in automotive finishes and topcoats, and have replaced alkyd resins in many cases. Advantages for automotive finishes and coatings are high transparency, weather resistance, gloss retention, and yellowing stability. Automotive finishes are always cross-linked; melamine resins are generally used as hardeners, polyisocyanates are being increasingly used for clear coats. Automotive fillers and metallic basecoats may be formulated with acrylate dispersions to reduce solvent emission. Solvent-containing system are, however, still indispensable in the topcoat sector.
Properties and Testing
Anyone wishing to test the quality of paint or coating quickly realizes that only a few properties can be accurately scientifically defined. In many cases there is a good correlation between defined physical properties and the behaviour of interest to the scientist or practitioner. In some cases, however, it is impossible to obtain such a correlation. A large number of laboratory testing methods have therefore been developed for paints and coatings that are intended to simulate in-use conditions. These testing methods are often similar but their results are not fully comparable. Standard manuals provide a good overview of available test methods.
for further detail, please contact....
M/S. Bureau of Indian Standards,
9, MANAK BHAVAN,
B.S. ZAFAR MARG,
NEW DELHI - 110 002.
Tel: (091) (11) 23230131, 23233375, 23239402.
Fax: 011-23234062, 23239399
Note: The use of the Standard Mark is governed by the provisions of the Bureau of Indian Standard Act - 1986 and the Rules and Regulation made there under. The Standard Mark on products covered by an Indian Standard conveys the assurance that they have been produced to comply with the requirements of that standard under a well defined system of inspection, testing and quality control which is devised and supervised by BIS and operated by the producer. Standard marked products are also continuously checked by B.I.S. for conformity to that standard as a further safeguard. Details of conditions under which a license for the use of the Standard Mark may be granted to manufacturers or producers may be obtained from the Bureau of Indian Standards.
Basic Raw Materials Required:
2. Acrylic Acid or Ester or Acrylate
3. Aluminium Oleate
4. Hydrogenated Castor Oil
5. Ethylene Glycol
6. Propylene Glycol
7. Tributyl Phosphate
8. Potassium Tripolyphosphate
9. Zinc Phosphate
11. Printed Metallic/Plastic Containers
Basic Plant and Machineries Required:-
3. Pre mixer, Dissolver
4. Movable Container
6. Ball Mill
7. Paste Mixer
8. End Product Mixer
11. Container/Storage Tank
12. Automatic Filling Weighing and Packing Machine
13. Mixing Machine
Most Probable General Formula of Acrylic base Emulsion paints
Acrylic Acid 10%
Aluminium Oleate 5%
Hydrogenated Castor Oil 5%
Ethylene Glycol 25%
Propylene Glycol 25%
Tributyl Phosphate 2%
Potassium Tripolyphosphate 2%
Zinc Oxide 1%
Take above all the materials from store by weight. Keep all the materials separately with their serial use.
Take pigments by weight and put it in the ball mill to ground it and pass it through the shifting sieve and make powder below 300 meshes. Store it in the storage tank. Now put Acrylic Acid in the premixer. Add ethylene glycol and propylene glycol in the premixer and agitate the premixer at 200 rpm, such that acrylic acid mixes homogeneously in the solvent. Now add aluminium oleate in the premixer and mix it at 200 rpm, such that a homogeneous mixed solution formed. Now add Zinc oxide to the premixer and agitate continuously such that a homogeneous mixed product formed. Now keep on mixing another hour after last product addition.
Take water in the premixer where add potassium tripolyphosphate and agitate the mixer till it form uniform homogeneous mixed product. After that add tributylphosphate to the water and mix it till it forms a homogeneous mixed product. Heat the mixed product to 90°C and add hydrogenated castor oil to it with agitation 200 rpm, till a homogeneous mixed product formed.
Now put both the mixed product (solvent base and water base mixed product) in the dispenser and agitate the dispenser at 400 rpm, such that both the product mixed together and formed homogeneous mixed product. Now add slowly pigments in the mixer with the agitation of 400 rpm, till the complete addition of the pigments. After complete addition of pigment agitate the mixed product another 12 hours such that it will form optimum viscosity. Check the product quality then fill in the printed packing material according to required weight. It may be vary from 1 Kg to 20 Kgs by automatic filling and sealing machine. Store the product for marketing.
Raw Materials Suppliers
M/s. Alka Minerals & Chemicals
25, DSIDC Sheds,
Jhilmil Industrial Area,
G. T. Road, Shahadara,
Ph.: 011-22271104, 22285830.
Fax: 011-25719220, 25756148.
M/s. Indian Aluminium Co. Ltd.
1, Middleton Street,
Jeevan Deep Building,
Ph.: 033-22402210, 22809710.
Fax: 033-22473808, 22884808.
M/s. Taurus Chemicals (P) Ltd.
318, Swapnalok Complex,
92/93, S. D. Road,
Ph.: 040-27814501, 27814502, 27811022.
M/s. H. K. Finechem Ltd.
201, Aniket, C. G. Road,
Ph.: 079-26468752, 26402429.
Opp. Sion Fort Garden,
109, Sion (E),
Ph.: 022-24073221, 24073222, 24030802.
Fax: 022-24091554, 24073771.
M/s. Acme Synthetic Chemicals
Next to Ram Mandir,
Ram Mandir Road,
Ph.: 022-28724258, 28722581, 28785753.
M/s. Naren Chemicals
Plot No. 562, Phase II,
Opp. Railway Station,
G.I.D.C. Industrial Estate,
Vatva, Ahmedabad-382 445.
M/s. Rita Corp.
21, Chewool Wadi, 1st Floor,
Dr. M. B. Velkar's Street,
Ph.: 022-22056895, 28894226.
Ph.: (R) 022-28899598.
M/s. Hydrochem Chemicals P. Ltd.
Hydrochem House, Gautam Nagar,
U. S. Nagar, Kashipur-244 713.
Ph.: 05947-274874, 278496.
M/s. Aamaan Industries
D-4, 549, Marmik Society,
Sector 5, Charkop,
Rated Plant capacity = 10.00 MT/day
= 3000.00 MT/annum
ACRYLIC EMULSION PAINTS
No. of working days = 25 days/month
= 300 days/annum
No. of shifts = 3 per day
One shift = 8 hours
LAND & BUILDING TOTAL Rs. 259 Lakh
PLANT & MACHINERY
1. Ball Mill
2. Moveable Balance (Electronic
3. Automatic Filling Weighing and Packing Machine
4. Conveyor Belt with driving motor, pully,
5. Close Dispensers
6. Jacketed Close Premixer
7. Moveable Containers
8. Storage Vessels
9. Mixing Machine Containing Alfa blade as agitator inside volume of the mixer
10. Driving motors and reducing Gear.
11. Filtration Unit. Notch type filter Surface area
12. Sifter Sieves (Containing 300 mesh Sieve)
Boiler 2 MT Capacity Steam
Effluent Treatment Equipments
Miscellaneous Machinery TOTAL Rs. 150 Lakh
1. LAND & BUILDING Rs. 259 Lakh
2. PLANT & MACHINERY Rs. 150 Lakh
3. OTHER FIXED ASSETS Rs. 112 Lakh
TOTAL Rs. 521 Lakh
WORKING CAPITAL REQUIREMENT/MONTH
2. Acrylic Acid
3. Aluminium Oleate
4. Hydrogenated Castor Oil
5. Ethylene Glycol
6. Propylene Glycol
7. Tributyl Phosphate
8. Potassium Tripolyphosphate
9. Zinc Oxide
10. Printed Packing Material
11. Lab Chemicals
12. Miscellaneous Chemicals TOTAL Rs. 315.6 Lakh
TOTAL WORKING CAPITAL/MONTH
1. RAW MATERIAL Rs. 315.6 Lakh
2. SALARY & WAGES Rs. 9.69 Lakh
3. UTILITIES & OVERHEADS Rs. 1.1 Lakh
TOTAL Rs. 326.39 Lakh
COST OF PROJECT
TOTAL FIXED CAPITAL Rs. 326.39 Lakh
MARGIN MONEY Rs. 2.41 Lakh
TOTAL Rs. 328.8 Lakh
TOTAL CAPITAL INVESTMENT
TOTAL FIXED CAPITAL Rs. 326.39 Lakh
TOTAL WORKING CAPITAL FOR 3 MONTHS Rs. 9.67 Lakh
TOTAL Rs. 336.06 Lakh
TURN OVER/ANNUM = 908 Lakh
PROFIT SALES RATIO = 25.06%
RATE OF RETURN = 34.92%
BREAK EVEN POINT (B.E.P) = 33.36%