T6 new generation calcium carbonate by k.k. mishra

NEW GENERATION OF CALCIUM CARBONATE

K.K.Mishra

20 Microns Ltd., Mumbai, India

GENERAL OUTLOOK

Paint, as an aesthetic and protective material, has undergone significant transformation over the years from

being just a colour to a performance specific composite material. With this change, the ingredients of paint

have evolved into more sophisticated functional raw materials. Extenders once considered as mere fillers are

today looked upon as functional input to the paint contributing to rheology, adhesion, gloss control, hiding and

PVC optimization. This situation necessitates up gradation of techniques and for the characterization of

extenders.

MANY paint makers still believe that fillers, (extenders, minerals) are of little importance, low cost and widely

available products. But extenders should no longer be viewed in such terms. They have a functional purpose

in the paint end product and their properties and qualities will substantially affect this product. Paint makers

must expand and modernize their production facilities to cope with increasing technological sophistication. In

trying to cut costs, raw materials will be a key consideration. Many paint makers have successfully decreased

the use of expensive titanium dioxide by partial replacement of white extenders which are properly ground to

the extent of sub-microns to 2microns average particle size.

FUNCTIONAL EXTENDERS

Extender pigment or simply extenders are also so called because such materials are used to “Extend” the

effect of expensive white and coloured pigments, so cheapening the paint formulation. However, it is now

recognized that extender pigments contribute much more to paint properties. Careful selection of the type and

quantity 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 colour

assessment, sieving, specific gravity, oil and water demand, pH and microscopic examination. These tests do

give very useful information to the paint formulator in deciding upon fundamental formulation parameters like

PVC, weight per liter, finish and the like. However, if one desires to establish the closer relationship between

characteristics of the extenders on one hand and various paint making, application and performance

parameters on the other, then the use of modern analytical techniques become unavoidable. These

techniques possess the capability to look at the micro structure of extenders in terms of size, shape, surface

chemistry and crystallography. Correlations established between different extender parameters and a paint

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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 incorporates

certain type of extenders.

While examining various modern techniques, it is important to take over view of various particle size analysis

techniques like, electron microscopy forms a very important tool for examination of particle shape which has

significant 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 to

the paint where as extenders have little or no hiding power themselves. The manufacturers of mineral

extenders are generally required to give high technical service back up, and bear above average the R&D

costs. The efficient processing is important, as is the ability to upgrade and modify products term as a “New

Generation Extenders” by using ultrafine grinding technology without any oversized particles (nib

free), calcining or surface modifications.

FUNCTIONAL PERPORTIES OF EXTENDERS

Selection of extenders by the paint maker depends on a number of factors:

GENERAL

The 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 pigment

extenders and medium, and on particle size and size distribution, particle shape and crystal habit. The opacity

or hiding power is a function of the difference between refractive indices of the pigment and dispersion

medium. Both pigments and extenders are opaque as dry powders, but when dispersed in media, pigments

are opaque in both organic and aqueous media, whereas the extenders are practically transparent in organic

media but opaque in aqueous media. This is because the refractive indices of extenders are very close to

those of oils and resins.

Extenders have a low refractive index, similar to that of binders and so are effectively transparent. They are

usually white or off-white and contribute either no color or an undesirable one to paint film. How, then, can

extenders increase the efficacy of pigments if they possess neither of the basic properties required. ? There

are 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.

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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 FIELD

In quantity terms calcite, dolomite and whiting are the most widely used carbonate extender minerals in

paints. Calcite is basically used as a pigment extender for the improvement of pigment efficiency because of

the spacing and refractive index. Paint makers may use any grade size from a coarser grade (400 Mesh) to a

micronized grade (20 Microns and 10 Microns). In general, the finer the particle size, the higher the gloss of

the paint.

Calcium carbonate does not contribute significantly to opacity in itself but a new generation calcium

carbonate is said to “bring out” the opacity of prime white pigments by spacing them correctly. High

brightness and proper micronisation is desirable to improve paint colour characteristics. Properly micronized

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carbonates may be used to improve film cohesion, higher gloss and higher loading (pigment volume

concentration).

In paints & coating, the endless opportunity for modifying the optical and mechanical properties with calcium

carbonate, make this mineral particularly popular main extenders which offer functional properties with

regards to high brightness low oil absorption, dispensability, weather resistance, low abrasiveness, low

electrolyte 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 Generation

Calcium Carbonates, mainly

1. 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.

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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

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-1

3. 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

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Tests M. Carb 2µ O Carb Vaporlite 90T Vaporcifier

Micronized

fine GCC

Superfine

CaCO3

Sub-micron

CaCO3

Modified CaCO3

Average Particle

diameter (d50%) on

Marven

2.6 ± 0.2 µm 1.8 ± 0. 2 µm 0.9 ± 0.2 µm 2.0 ± 0.3 µm

Top cut (d97%) 13±2µm 7±1 µm 4±1 µm 10±2 µm

Bulk Density loose

(gm/liter)

580±50 520±30 350±50 400±50

Brightness 94±2 94±2 92±2 90±2

Oil absorption

(gm/100gm)

20±3 27±5 35±5 75±5

Specific surface area

(BET) m2/gm

3-4 5-6 12-15 22-25

EXPERIMENTAL OBJECTIVE

The most widely used pigment in the paint industry is titanium dioxide. The rising titanium dioxide price and

tight supply situation is causing more and more paint manufacturers to seek means of extending this pigment

without loss of opacity or change in colour tone. Based on the experience and global trend in the industry, we

introduce a New generation calcium carbonate, and our product application center had carried out some

experiment which is subsequently fallowed by our esteemed paints & coating customers.

EXPERIMENT NO. 1

PARTIAL REPLACEMENT OF TITANIUM DIOXIDE IN EXTERIOR EMULSION PAINT BY VAPORCIFIER

AND “O” CARB NEW GENERATION CALCIUM CARBONATE

TECHNICAL DATA OF EXTENDERS:

Extender Top Cut D(97)

µm

Average particle

size D(50) µm

Brightness

%

Oil Absorption

gm/100gm

Talc 10 µ 20 6-8 94 55

Vaporcifier 10 ± 2 2.0 ± 0.3 90±2 75±5

“O” Carb 7±1 1.8±0.2 94±2 27±5

OBJECTIVE:- This experiment, an exterior emulsion paint formulation was taken and reformulated by

replacing 20% titanium dioxide on weight basis,

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EXPERIMENTAL INTRODUCTION

The standard formulation content 60% by weight of TiO2 and calcium carbonate extender with average

particle size of 2 µm. means “O” Carb in this experiment 20% TiO2were replaced by weight by Vaporlite 90T

as per Table no. 2

The paint was made using a high speed disperser.

Table no. 1

Raw Materials Standard formulation Reformulation with

Vaporcifier & “O”

Carb

Binder 306.3 312

TiO2 161.4 129.1

Talc 10 µ 161.4 102.3

Vaporcifier ----- 72.1

“O” Carb 110.2 120.8

Dispersing agent 2.8 2.9

Preservative 1.9 1.9

Defoamer 2.8 2.8

Wetting and dispersing agent 10.4 10.5

Thickener 100.6 101.8

Caustic soda, 10% aq. Sol. 1.9 1.9

Mineral spirit 9.5 9.6

Butyl diglycol acetate 7.6 7.7

Water 123.2 124.6

Total 1000.0 1000.0

Technical Data

PVC % 50.0 50.0

Solid content %wt. 58.4 58.0

Density (Liquid paint) g/cm3 1.45 1.43

Results

Brightness 89.3% 88.6%

Yellowness Index 1.6 2.4

Contrast ratio 94.3% 94.5%

Cost reduction

Weight % ---- 4.6

By volume % ---- 5.7

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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.

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EXPERIMENT NO. 3

REPLACEMENT OF SYNTHETIC ALUMINIUM SILICATE BY CALCINED CLAY, VAPORIFIER,

VAPORLITE 90T AND “O” CARB.


It is evident from the technical data of extenders both calcined clay and synthetic aluminium silicate have

much higher oil and hence binder absorptions than Vaporlite 90T. This means that the PVC can be increased

somewhat 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 DATA

Extender Top Cut

(µm)

Average

Particle size

(µm)

Brightness

(DIN 53 163,

C/2°) Ry

(Green

Filter)

Oil

Absorption

(Gm/100gm)

Specific

Surface

Area (BET)

(m2/gm)

Synthetic

agglomerated

aluminium

silicate

-- 0.2 95 160 100

“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

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Table No. 3

Raw Material Standard Formulation in

kg

Reformulation with


Copolymer vinyl acetate acrylate

emulsion, 50%

244 180

Titanium dioxide rutile 135 108

Calcined clay- Glazex 90 53.8 53.8

Synthetic aluminium silicate 36 ----

Vaporcifier ---- 142.6

“O” Carb / Vaporlite 90T 79.3 58.2

Talc 72 68.3

Water and additives 379.9 389.1

Total 1000.0 1000.0

Physical Properties

PVC % 55 65

Solids content vol. % 31.5 31.5

Solids content wt. % 49.5 52

Density gm/ml 1.36 1.43


Brightness % 89.1 88.7

Yellowness Index % 2.6 2.9

Opacity % 93.7 93.8

Sheen (85° angle) 6 7

Wet scrub resistance cycles >5000 >5000

Cost reduction

By Weight % ---- 30

By volume % ---- 8

CONCLUSION

Due to its special particle size distribution curve and low binder absorption, Vaporlite 90T can replace

extenders such as synthetic aluminium silicate and calcined clay.

The PVC of the paints containing Vaporlite 90T can be increased by 10 percentage points whilst maintaining

the volume solids content. The optical properties remain virtually unchanged. Substantial raw material savings

are possible. Using Indian price levels these are about 30% on weight basis and about 8% on a volume basis.

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EXPERIMENT NO. 4

REPLACEMENT OF REFINED CHINA CLAY BY VAPORCIFIER, VAPORLITE 90T AND “O” CARB.


In our countries, water washed china clays are used in emulsion paints of medium PVC. The technical data of

a widely used china clay and Vaporlite 90T are compared. The lower binder absorption of Vaporlite 90T

allows 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 90T

2. 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

(µm)

Average

Particle size

(µm)

Brightness

(DIN 53 163,

C/2°) Ry

(Green

Filter)

Oil

Absorption

(Gm/100gm)

Specific

Surface

Area (BET)

(m2/gm)

Refined China

clay

5 0.9 85 35 11.2

“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

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Table No. 4


kg

Reformulation with


Terpolymer vynil chloride

emulsion 55%

197 180

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



Brightness % 87.5 88.0


Opacity % 96.4 96.5

Scrub resistance (DIN 53 778, 1

week) cycles

>5000 >5000

Sheen (85° angle) % 2 2

CONCLUSION

By increasing the PVC by 3 percentage points and replacing china clay by Vaporlite 90T, the brightness was

improved 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 (using

European prices) were more than 3% when calculated by volume and more than 5% when calculated by

weight.

EXPERIMENT NO. 5

REFORMULATION OF A HIGH GLOSS AIR-DRYING ENAMEL BY VAPORLITE 90T AND “O” CARB.


The standard formulation contained 29% titanium dioxide and we found that we could replace 7.5% of this on

a volume basis by Vaporlite 90T and the resulting paint had the same optical and rheological properties as

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the 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


kg

Reformulation with


TiO2 %wt. 28.07 26.08

Vaporlite 90T %wt. --- 1.52

PVC % 20.3 20.3

Solid vol. %

Wt.%

48.6

66.8

48.6

66.6


Optical Properties ( After 2 days drying at 23°C)


Contrast ratio (45µm film) 97.9 97.4

Gloss

20° (after 2 days) %




85

81

91

90

86

82

92

90

EXPERIMENT NO. 6

PARTIAL REPLACEMENT OF TITANIUM DIOXIDE IN A STOVING ENAMEL BY VAPORLITE 90T AND

“O” CARB.


A further practical example involved high gloss short oil alkyd/melamine stoving enamel. The paint were made

using a high speed disperser. The initial formulation contained 29.5% titanium dioxide. We replaced 6% and

12% by volume. The paints were stoved at 120°C for 30 min. details are given in Table 6. The results indicate

that Vaporlite 90T helps to disperse the titanium dioxide better, allowing 5-10% of it to be replaced whilst

scarcely effecting the optical properties.

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Table No. 6

Raw Material Standard

Formulation in kg

Reformulation 1 with

Vaporlite 90T

Reformulation 2

with Vaporlite 90T

TiO2 %wt. 22.45 21.08 25.10

Vaporlite 90T %wt. --- 1.21 2.36

PVC % 20 20 10

Solid vol. %

Wt%

41.0

55.4

41.0

55.1

41.0

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 97

20 MICRONS LTD can set up on site WGCC (WET GROUND CALCIUM CARBONATE) manufacturing plant

in your premises of having any proposed capacity of 1000mt/month. WGCC will get supply in slurry form

having 70% - 75% Solid Content through pipe line to your plant.

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Fig 3.WET PROCESS PLANT

Fig 4.ON SITE SATELITE PLANT

20 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.

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ADVANTAGES OF WET GRINDING PROCESS

Wet ground calcium carbonate is superior to dry ground calcium carbonate.

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 CaCO3

this application particle size plays major role to achieve end product’s performance ,wet ground process

gives the particles of 50 to 98% below 2 microns and it act as a spacers between tio2 particles leading to

increase the efficiency of tio2 in paint and coating application Due to controlled & uniform particle size

distribution, 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 paint

CONCLUSION

Suitably new generation fine calcium carbonate extenders help to disperse pigments better, thus increasing

the efficacy. This allows the quantity of pigment used to be reduced without affecting the optical and

rheological 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 Oxide

ACKNOWLEDGEMENT

The 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 and

Head, Testing & Calibration Cell, CGCRI, Kolkata & Dr. Harendra Nath, IIT, Mumbai for providing valuable

guidance & necessary facilities.

REFERENCES

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1. Paper published on “ FUNCTINAL EXTENDERS AND THEIR ROLE IN MODERN PAINTS by Shree C.

S. Parikh (Chairman 20 Microns Limited).

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 Industry

6. Ciullo, P.A. (ed.), Industrial Minerals and Their Uses, Noyes Publications, Westwood, NJ, 1996

7. Adams Reg, Artikol Ltd., Journal on Alternative White Pigments and TiO2 Extender for Coatings, Paper

and Plastic by Intertech, USA on November 8 –10, 2000

8. 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

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Technology

T6 new generation calcium carbonate by k.k. mishra