T6 new generation calcium carbonate by k.k. mishra


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T6 new generation calcium carbonate by k.k. mishra

  1. 1. NEW GENERATION OF CALCIUM CARBONATE K.K.Mishra 20 Microns Ltd., Mumbai, India GENERAL OUTLOOKPaint, as an aesthetic and protective material, has undergone significant transformation over the years frombeing just a colour to a performance specific composite material. With this change, the ingredients of painthave evolved into more sophisticated functional raw materials. Extenders once considered as mere fillers aretoday looked upon as functional input to the paint contributing to rheology, adhesion, gloss control, hiding andPVC optimization. This situation necessitates up gradation of techniques and for the characterization ofextenders.MANY paint makers still believe that fillers, (extenders, minerals) are of little importance, low cost and widelyavailable products. But extenders should no longer be viewed in such terms. They have a functional purposein the paint end product and their properties and qualities will substantially affect this product. Paint makersmust expand and modernize their production facilities to cope with increasing technological sophistication. Intrying to cut costs, raw materials will be a key consideration. Many paint makers have successfully decreasedthe use of expensive titanium dioxide by partial replacement of white extenders which are properly ground tothe extent of sub-microns to 2microns average particle size. FUNCTIONAL EXTENDERSExtender pigment or simply extenders are also so called because such materials are used to “Extend” theeffect of expensive white and coloured pigments, so cheapening the paint formulation. However, it is nowrecognized that extender pigments contribute much more to paint properties. Careful selection of the type andquantity of extenders can affect such features in paints & coating as:1. Opacity or hiding.2. Gloss or sheen.3. Flow, leveling and smoothness.4. Durability and appearance of the paint film.5. Pigment settlement on storage.6. Barriers effect and water permeability etc.Conventionally, extenders have been characterized employing simple techniques like visual colourassessment, sieving, specific gravity, oil and water demand, pH and microscopic examination. These tests dogive very useful information to the paint formulator in deciding upon fundamental formulation parameters likePVC, weight per liter, finish and the like. However, if one desires to establish the closer relationship betweencharacteristics of the extenders on one hand and various paint making, application and performanceparameters on the other, then the use of modern analytical techniques become unavoidable. Thesetechniques possess the capability to look at the micro structure of extenders in terms of size, shape, surfacechemistry and crystallography. Correlations established between different extender parameters and a paint -1-
  2. 2. performance property enables the technologist to diagnose the cause of the quality or performance problem.More importantly, it provides predictive capability to envisage performance of a paint which incorporatescertain type of extenders.While examining various modern techniques, it is important to take over view of various particle size analysistechniques like, electron microscopy forms a very important tool for examination of particle shape which hassignificant bearing on RHEOLOGY, GLOSS AND OPACITY AND SURFACE FINISH.For the sake of simplicity the term “Extenders” will be retained in this article, but it is used in the widest sense.The main difference between a pigment and an extender is that pigments impart colour and hiding power tothe paint where as extenders have little or no hiding power themselves. The manufacturers of mineralextenders are generally required to give high technical service back up, and bear above average the R&Dcosts. The efficient processing is important, as is the ability to upgrade and modify products term as a “NewGeneration Extenders” by using ultrafine grinding technology without any oversized particles (nibfree), calcining or surface modifications.FUNCTIONAL PERPORTIES OF EXTENDERSSelection of extenders by the paint maker depends on a number of factors:GENERALThe colour should be bright, clear, intense and reproducible. It depends on the mineral, chemical composition,the brightness, the cleanliness and the intensity on the difference between the refractive indices of pigmentextenders and medium, and on particle size and size distribution, particle shape and crystal habit. The opacityor hiding power is a function of the difference between refractive indices of the pigment and dispersionmedium. Both pigments and extenders are opaque as dry powders, but when dispersed in media, pigmentsare opaque in both organic and aqueous media, whereas the extenders are practically transparent in organicmedia but opaque in aqueous media. This is because the refractive indices of extenders are very close tothose of oils and resins.Extenders have a low refractive index, similar to that of binders and so are effectively transparent. They areusually white or off-white and contribute either no color or an undesirable one to paint film. How, then, canextenders increase the efficacy of pigments if they possess neither of the basic properties required. ? Thereare five aspects to consider:1. PARTICLE SIZE DISTRIBUTION. The particle size is very important and it is one of the properties which can be altered substantially by the processor. Hiding power and tinting strength are both related to the particle size. The particle size also influences gross consistency and settlement. Particle sizes have directly co-relation with surface area of the particle which effects viscosity, flow characteristics, dispersion stability and oil absorption. Particle shape effects flow characteristics settlement and film durability. -2-
  3. 3. 2. HIGH BRIGHTNESS. They should be as bright as possible so that no pigment is, as it were, wasted covering the unwanted colour of the extender. The brightness depends on the chemical composition of the deposit. Sometimes the colour can be improved by washing or flotation.3. HINDER RE-AGLOMERATION. This is done by introducing sufficient physical barriers so that the likelihood of two pigment particles colliding and re-agglomerating in the liquid paint system is reduced.4. IMPROVED PIGMENT DISPERSION. They help to break down the pigment agglomerates. It has been calculated that if all the titanium dioxide used were perfectly dispersed, the world demand for titanium dioxide would fall to about 14% of the present usage. It is evident that extender producers can help a lot here. The extender must itself be easy to disperse. The individual particles collide with pigment agglomerates, breaking them up. The extender must be fine since if it is too coarse it encourages “crowding” thus defeating the objective. Ideally, the pigment particles should be half the wave length of light in diameter and the distance between them should also be half the wave length of visible light. Please note that we no longer speak of spacing extenders. This theory has been proved wrong by simple experiment. If the pigment and extender are disperse separately in half of the binder and then subsequently mixed, there is only a slight increase in opacity and much less than when the extender and pigment are mixed together in the first place. The slight increase in opacity is caused by hindering re-agglomeration as mentioned above.5. DECREASE CRITICAL PVC. They can decrease the critical PVC to below that of the paint so that there is insufficient binder to completely coat each organic particle. Tiny pockets of air are trapped on the surface of some of the particles, increasing the amount of light diffracted and hence the opacity or hiding power of the paint film. Of course, this also lowers the scrub resistance and increases the tendency of the film to pick up atmospheric dirt. The extender must have a high absorption. Suitable ones are calcined clay or synthetic aluminium silicate. This usage is only practical for interior paints and even then it is limited due the poorer scrub resistance.A NEW GENERATION CALCIUM CARBONATES – LEADING THE FIELDIn quantity terms calcite, dolomite and whiting are the most widely used carbonate extender minerals inpaints. Calcite is basically used as a pigment extender for the improvement of pigment efficiency because ofthe spacing and refractive index. Paint makers may use any grade size from a coarser grade (400 Mesh) to amicronized grade (20 Microns and 10 Microns). In general, the finer the particle size, the higher the gloss ofthe paint.Calcium carbonate does not contribute significantly to opacity in itself but a new generation calciumcarbonate is said to “bring out” the opacity of prime white pigments by spacing them correctly. Highbrightness and proper micronisation is desirable to improve paint colour characteristics. Properly micronized -3-
  4. 4. carbonates may be used to improve film cohesion, higher gloss and higher loading (pigment volumeconcentration).In paints & coating, the endless opportunity for modifying the optical and mechanical properties with calciumcarbonate, make this mineral particularly popular main extenders which offer functional properties withregards to high brightness low oil absorption, dispensability, weather resistance, low abrasiveness, lowelectrolyte content, pH stabilizing effect, and improved anti-corrosion and rheological properties.a. Decorative coating Interior emulsion paint is the most important application of the calcium carbonate of the coating industry, and calcium carbonate also provide economical advantages and optimize properties performance in exterior emulsion paint and decorative enamel, where calcium carbonate filler loading is comparatively lower.b. Industrial Coating Industrial coatings are generally formulated with lower filler content, primarily use for protection, where durability is a main paint film property against environmental condition. Application Extenders Content Interior emulsion paints Up to 65% Exterior emulsion paints Up to 45% Brushing enamels Up to 10 -15% Powder coatings Up to 5 -20% Industrial coatings Up to 5 -20% Road marking paints Up to 30 -50% Primer Up to 5 -20% Inks Up to 15%To meet the challenging demands of its customers, 20 Microns Limited now produces New GenerationCalcium Carbonates, mainly1. O Carb Purest, ultra white and closely controlled superfine narrow particle size calcium carbonate from world best deposit. O Carb is white, closely controlled, micronized purest, natural calcium carbonate selected from world best deposit, specially developed for Paints-Coating, adhesives and sealants industry ‘O’ Carb narrow particle size distribution optimizes particle packing leaving less void space to be filled by expensive resin, which leads to enhance opacity with gloss in all type of premium water base formulation.2. Vaporlite 90T Sub-micron calcium carbonate produced by new engineered wet – milling techniques, which act as a spacers between prime pigment and contribute to batter coating opacity and high gloss. Vaporlite 90T is an ultra fine sub-micron natural calcium carbonate. The sub-micron particles of Vaporlite 90T can act as spacers between TiO2 particles leading to increase the efficiency of TiO2 in the paints and coating application. The size and numbers of Vaporlite 90T particles enable efficient separation at TiO2 particles and inhibit re-agglomeration after dispersion whereas agglomerates are less -4-
  5. 5. efficient at scattering light when compared to the fine primary particles. As light beams are refracted at the particle surface it follows that smaller and more numerous fine particles offer more opportunities for refraction and thus lead to better coating OPACITY and HIGHGLOSS.Fig 1. SPACING EFFECT OF VAPORLITE 90T WITH PRIME PIGMENT TiO2 Fig-13. Vaporcifier Modified calcium carbonate for partial replacement of Titanium Dioxide (TiO2) Vaporcifier is a new and innovative product designed especially for emulsion paints. Vaporcifier is a natural calcium carbonate where particle structures are modified by physical and chemical process which creates particle with an amorphous structure to offer excellent opacity of the paint and lower overall cost by extension of TiO2. Vaporcifier display a very amorphous structure which leads to the assumption that in addition to the external surface an internal surface also exists which significantly increase a specific area and oil absorption whereas micronized GCC shows a compact surface structure.Fig 2. S.E.M. OF VAPORICIFIER – LOW COST OPACIFIER CALCIUM CARBONATE Fig 2.TYPICAL PHYCICAL PROPERTY OF NEW GENERATION CALCIUM CARBONATE Tests M. Carb 2µ O Carb Vaporlite 90T Vaporcifier Micronized Superfine Sub-micron Modified CaCO3 fine GCC CaCO3 CaCO3 Average Particle 2.6 ± 0.2 µm 1.8 ± 0. 2 µm 0.9 ± 0.2 µm 2.0 ± 0.3 µm -5-
  6. 6. diameter (d50%) on Marven Top cut (d97%) 13±2µm 7±1 µm 4±1 µm 10±2 µm Bulk Density loose 580±50 520±30 350±50 400±50 (gm/liter) Brightness 94±2 94±2 92±2 90±2 Oil absorption 20±3 27±5 35±5 75±5 (gm/100gm) Specific surface area 3-4 5-6 12-15 22-25 (BET) m2/gmEXPERIMENTAL OBJECTIVEThe most widely used pigment in the paint industry is titanium dioxide. The rising titanium dioxide price andtight supply situation is causing more and more paint manufacturers to seek means of extending this pigmentwithout loss of opacity or change in colour tone. Based on the experience and global trend in the industry, weintroduce a New generation calcium carbonate, and our product application center had carried out someexperiment which is subsequently fallowed by our esteemed paints & coating customers.EXPERIMENT NO. 1PARTIAL REPLACEMENT OF TITANIUM DIOXIDE IN EXTERIOR EMULSION PAINT BY VAPORCIFIERAND “O” CARB NEW GENERATION CALCIUM CARBONATETECHNICAL DATA OF EXTENDERS:Extender Top Cut D(97) Average particle Brightness Oil Absorption µm size D(50) µm % gm/100gmTalc 10 µ 20 6-8 94 55Vaporcifier 10 ± 2 2.0 ± 0.3 90±2 75±5“O” Carb 7±1 1.8±0.2 94±2 27±5OBJECTIVE:- This experiment, an exterior emulsion paint formulation was taken and reformulated byreplacing 20% titanium dioxide on weight basis, -6-
  7. 7. EXPERIMENTAL INTRODUCTIONThe standard formulation content 60% by weight of TiO2 and calcium carbonate extender with averageparticle size of 2 µm. means “O” Carb in this experiment 20% TiO2were replaced by weight by Vaporlite 90Tas per Table no. 2The paint was made using a high speed disperser.Table no. 1Raw Materials Standard formulation Reformulation with Vaporcifier & “O” CarbBinder 306.3 312TiO2 161.4 129.1Talc 10 µ 161.4 102.3Vaporcifier ----- 72.1“O” Carb 110.2 120.8Dispersing agent 2.8 2.9Preservative 1.9 1.9Defoamer 2.8 2.8Wetting and dispersing agent 10.4 10.5Thickener 100.6 101.8Caustic soda, 10% aq. Sol. 1.9 1.9Mineral spirit 9.5 9.6Butyl diglycol acetate 7.6 7.7Water 123.2 124.6Total 1000.0 1000.0Technical DataPVC % 50.0 50.0Solid content %wt. 58.4 58.0Density (Liquid paint) g/cm3 1.45 1.43ResultsBrightness 89.3% 88.6%Yellowness Index 1.6 2.4Contrast ratio 94.3% 94.5% Cost reductionWeight % ---- 4.6By volume % ---- 5.7 -7-
  8. 8. CONCLUSION The partial replacement of titanium dioxide by Vaporcifier and “O” Carb in exterior emulsion paint offers cost savings without affecting the optical or weathering properties adversely. EXPERIMENT NO. 2 REPLACEMENT OF SYNTHETIC ALUMINIUM SILICATE AND PRECIPITED CALCIUM CARBONATE BY VAPORLITE 90T AND “O” CARB Table no. 2 Raw Material Standard Formulation Reformulation with Vaporlite 90T & “O” Carb TiO2 123.5 120 “O” Carb/Micron Carb 2µ 200.1 193 Ppt. Calcium Carbonate 96.6 ------ Vaporlite 90T ------ 169.1 Aluminium Silicate 24.1 ------ Talc 100.8 93.3 Styrene acrylate (50% solids) 148.5 110 Water and additives 306.4 314.6 Total 1000.0 1000.0 Physical Properties PVC % 72.54 79.54 Volume solids content % 40.22 40.22 Optical properties of Finished Paint Film Covering power % 94.8 95.2 Brightness (green filter) 88.8 87.8 Gilsonite porosity 16.5 12.8 CONCLUSION Aluminium silicate can be replaced by an ultrafine, white, natural calcium carbonate as “O” Carb and Vaporlite 90T. The lower binder absorption of the Vaporlite 90T allows the PVC to be increased so that the final paint has the same optical properties as the original. This offers substantial financial savings. -8-
  9. 9. EXPERIMENT NO. 3REPLACEMENT OF SYNTHETIC ALUMINIUM SILICATE BY CALCINED CLAY, VAPORIFIER,VAPORLITE 90T AND “O” CARB.EXPERIMENTAL INTRODUCTIONIt is evident from the technical data of extenders both calcined clay and synthetic aluminium silicate havemuch higher oil and hence binder absorptions than Vaporlite 90T. This means that the PVC can be increasedsomewhat when they are replaced by Vaporlite 90T without fear of mud-cracking.The steps taken in such a reformulation are given below:.1. Replacement of the extenders with higher binder absorptions e.g. synthetic aluminium silicate and calcined clay by Vaporlite 90T.2. Increasing the PVC by 10 percentage points whilst maintaining the volume solids content by increasing the Vaporlite 90T content and reducing the binder volume.3. Measurement of the brightness, opacity and porosity comparing these values with the standard formulation.4. Fine tuning by mixing the paints.TECHNICAL DATAExtender Top Cut Average Brightness Oil Specific (µm) Particle size (DIN 53 Absorption Surface (µm) 163, C/2°) (Gm/100gm) Area (BET) Ry (Green (m2/gm) Filter)Synthetic -- 0.2 95 160 100agglomeratedaluminiumsilicate“O” Carb 7±1 1.8±0.2 94±2 27±5 5-6Vaporlite 90T 4±1 0.9±0.2 92±2 35±5 12-15Vaporcifier 10 ± 2 2.0 ± 0.3 90±2 75±5 22-25 -9-
  10. 10. Table No. 3Raw Material Standard Formulation in kg Reformulation with Vaporlite 90T & “O” CarbCopolymer vinyl acetate acrylate 244 180emulsion, 50%Titanium dioxide rutile 135 108Calcined clay- Glazex 90 53.8 53.8Synthetic aluminium silicate 36 ----Vaporcifier ---- 142.6“O” Carb / Vaporlite 90T 79.3 58.2Talc 72 68.3Water and additives 379.9 389.1Total 1000.0 1000.0Physical PropertiesPVC % 55 65Solids content vol. % 31.5 31.5Solids content wt. % 49.5 52Density gm/ml 1.36 1.43Optical properties of Finished Paint FilmBrightness % 89.1 88.7Yellowness Index % 2.6 2.9Opacity % 93.7 93.8Sheen (85° angle) 6 7Wet scrub resistance cycles >5000 >5000 Cost reductionBy Weight % ---- 30By volume % ---- 8CONCLUSIONDue to its special particle size distribution curve and low binder absorption, Vaporlite 90T can replaceextenders such as synthetic aluminium silicate and calcined clay.The PVC of the paints containing Vaporlite 90T can be increased by 10 percentage points whilst maintainingthe volume solids content. The optical properties remain virtually unchanged. Substantial raw material savingsare possible. Using Indian price levels these are about 30% on weight basis and about 8% on a volume basis. - 10 -
  11. 11. EXPERIMENT NO. 4REPLACEMENT OF REFINED CHINA CLAY BY VAPORCIFIER, VAPORLITE 90T AND “O” CARB.EXPERIMENTAL INTRODUCTIONIn our countries, water washed china clays are used in emulsion paints of medium PVC. The technical data ofa widely used china clay and Vaporlite 90T are compared. The lower binder absorption of Vaporlite 90Tallows the PVC to be increased by from 3-5 percentage points whilst maintaining the volume solids content.The reformulation should take place in a number of steps:-1. Replacement of the natural china clay by Vaporlite 90T2. The PVC is increased by between 3 and 5 percentage points whilst maintain the volume solids content by increasing the amount of Vaporlite 90T and reducing the volume of binder.3. The brightness, opacity and wet scrub resistance are measured and compared with the standard formulation.4. Fine tuning by mixing the corresponding formulations.TECHNICAL DATA Extender Top Cut Average Brightness Oil Specific (µm) Particle size (DIN 53 Absorption Surface (µm) 163, C/2°) (Gm/100gm) Area (BET) 2 Ry (Green (m /gm) Filter) Refined China 5 0.9 85 35 11.2 clay “O” Carb 7±1 1.8±0.2 94±2 27±5 5-6 Vaporlite 90T 4±1 0.9±0.2 92±2 35±5 12-15 Vaporcifier 10 ± 2 2.0 ± 0.3 90±2 75±5 22-25 - 11 -
  12. 12. Table No. 4 Raw Material Standard Formulation in kg Reformulation with Vaporlite 90T & “O” Carb Terpolymer vynil chloride 197 180 emulsion 55% Titanium dioxide rutile 148 146.5 “O” Carb/ Vaporlite 90T 175 167.5 Pigment 55 54.3 Refined China clay 100 ----- Vaporcifier ----- 124.5 Water and additives 325 327.2 Total 1000.0 1000.0 Physical Properties PVC % 63.1 66.1 Solids content vol. % 38.0 38.0 Solids content wt. % 58.5 59.1 Density gm/ml 1.51 1.53 Optical properties of Finished Paint Film Brightness % 87.5 88.0 Yellowness Index 5.1 4.2 Opacity % 96.4 96.5 Scrub resistance (DIN 53 778, 1 >5000 >5000 week) cycles Sheen (85° angle) % 2 2CONCLUSIONBy increasing the PVC by 3 percentage points and replacing china clay by Vaporlite 90T, the brightness wasimproved and also the yellowness index.The opacity, scrub resistance and sheen remained unaltered.Although the density of the finished paint increased by about 1%, savings in raw material costs (usingEuropean prices) were more than 3% when calculated by volume and more than 5% when calculated byweight.EXPERIMENT NO. 5REFORMULATION OF A HIGH GLOSS AIR-DRYING ENAMEL BY VAPORLITE 90T AND “O” CARB.EXPERIMENTAL INTRODUCTIONThe standard formulation contained 29% titanium dioxide and we found that we could replace 7.5% of this ona volume basis by Vaporlite 90T and the resulting paint had the same optical and rheological properties asthe standard. The improved dispersion of the titanium dioxide by Vaporlite 90T resulted in a higher initial 20°gloss than in the standard formulation. The paints were made using a high speed disperser.Table No. 5 Raw Material Standard Formulation in kg Reformulation with Vaporlite 90T & “O” Carb - 12 -
  13. 13. TiO2 %wt. 28.07 26.08 Vaporlite 90T %wt. --- 1.52 PVC % 20.3 20.3 Solid vol. % 48.6 48.6 Wt.% 66.8 66.6 Density gm/ml 1.26 1.26 Optical Properties ( After 2 days drying at 23°C) Yellowness Index 2.9 2.9 Contrast ratio (45µm film) 97.9 97.4 Gloss 20° (after 2 days) % 85 86 20° (after 28 days) % 81 82 60° (after 2 days) % 91 92 60° (after 28 days) % 90 90EXPERIMENT NO. 6PARTIAL REPLACEMENT OF TITANIUM DIOXIDE IN A STOVING ENAMEL BY VAPORLITE 90T AND“O” CARB.EXPERIMENTAL INTRODUCTIONA further practical example involved high gloss short oil alkyd/melamine stoving enamel. The paint were madeusing a high speed disperser. The initial formulation contained 29.5% titanium dioxide. We replaced 6% and12% by volume. The paints were stoved at 120°C for 30 min. details are given in Table 6. The results indicatethat Vaporlite 90T helps to disperse the titanium dioxide better, allowing 5-10% of it to be replaced whilstscarcely effecting the optical properties. - 13 -
  14. 14. Table No. 6 Raw Material Standard Reformulation 1 with Reformulation 2 Formulation in kg Vaporlite 90T with Vaporlite 90T TiO2 %wt. 22.45 21.08 25.10 Vaporlite 90T %wt. --- 1.21 2.36 PVC % 20 20 10 Solid vol. % 41.0 41.0 41.0 Wt% 55.4 55.1 54.9 Density gm/ml 1.26 1.25 1.24 Optical Properties Yellowness Index 2.4 2.3 2.2 Contrast ratio % 98.8 98.7 98.4 Gloss at 25% 99 97 9720 MICRONS LTD can set up on site WGCC (WET GROUND CALCIUM CARBONATE) manufacturing plantin your premises of having any proposed capacity of 1000mt/month. WGCC will get supply in slurry formhaving 70% - 75% Solid Content through pipe line to your plant.Fig 3.WET PROCESS PLANT - 14 -
  15. 15. Fig 4.ON SITE SATELITE PLANT20 Microns Scope:-  Providing Un-interrupted supply WGGCC in slurry form as per the specification attached.  Provide the slurry at the dosage point in the 75% Solids.  Installation of the requirement Plant/Machinery and testing instruments at the site.  Regular running and maintenance of plant.  Storage tank for slurry.ADVANTAGES OF WET GRINDING PROCESS  Wet ground calcium carbonate is superior to dry ground calcium carbonate. - 15 -
  16. 16.  In wet process-due to floatation method it improves:  Colour of the material  Reduces impurity level  It helps to produce ultrafine mineral where uniform particle size distribution takes place which helps to dispersion in the end use.Advantage of wet ground CaCO3 over dry ground CaCO3this application particle size plays major role to achieve end product’s performance ,wet ground processgives the particles of 50 to 98% below 2 microns and it act as a spacers between tio2 particles leading toincrease the efficiency of tio2 in paint and coating application Due to controlled & uniform particle sizedistribution, it -Improves Following Properties:* Excellent opacity with high gloss* High brightness of end product* Spacing TIO2 and color pigments* Efficient extenders to white pigments* Outstanding dispersion properties in water and solvent based paintCONCLUSIONSuitably new generation fine calcium carbonate extenders help to disperse pigments better, thus increasingthe efficacy. This allows the quantity of pigment used to be reduced without affecting the optical andrheological properties but allowing interesting raw material cost savings.INOVATIVE PRODUCTS IN-TRANSIT 1. Low specific gravity Calcined Kaolin – We are in process to lunch low specific gravity with value of 2.0 -2.1 calcined kaolin compare with exciting specific gravity of 2.6. 2. Inorganic co-thickener – Hydrogel 90T a white inorganic co-thickener which having brightness of 85% against exciting trend of 65% brightness. 3. Low cost synthetic Red OxideACKNOWLEDGEMENTThe authors wish to express their gratitude to Dr. Atul Joshi, Reader, Dept. of Geology, M.S.Univ. Baroda,Gujarat, Dr.V.S.Patel, Director SICART, S.P.Univ.,V.V.Nagar, Anand, Gujarat, Mr.T.K.Dan,Scientist andHead, Testing & Calibration Cell, CGCRI, Kolkata & Dr. Harendra Nath, IIT, Mumbai for providing valuableguidance & necessary facilities.REFERENCES1. Paper published on “ FUNCTINAL EXTENDERS AND THEIR ROLE IN MODERN PAINTS by Shree C. S. Parikh (Chairman 20 Microns Limited). - 16 -
  17. 17. 2. Paper published on “CHARCTERISATION OF EXTENDERS BY MODERN TECHNIQUES AND ITS CORRELATION WITH PROPERTIES by V. M. Natu ( Paint Consultant).3. Paper published on “ IMPORTANCE OF EXTENDERS IN PAINT AND COATING FORMULATION” by Dr. K. Srinivasan (Ex-ICI india Limited)4. Experiment and formulations details provided by 20 Microns technical center.5. Product performance details provided by Indian Major Paint Industry6. Ciullo, P.A. (ed.), Industrial Minerals and Their Uses, Noyes Publications, Westwood, NJ, 19967. Adams Reg, Artikol Ltd., Journal on Alternative White Pigments and TiO2 Extender for Coatings, Paper and Plastic by Intertech, USA on November 8 –10, 20008. Hocken Jorg, Sachtleben Chemie GmbH, Journal on Alternative White Pigments and TiO2 Extender for Coatings, Paper and Plastic by Intertech, USA on November 8 –10, 2000, PP 1 – 10 - 17 -