What is Barium Sulphate? and why it is using in paint?

 Barium Sulphate: 
Barium Sulphate is one of the most common and important Functional fillers/Pigments in manufacturing

paint.
Colour Index — Barytes, CI Pigment White 22; blanc fixe, CI Pigment White 21.
Formula — BaSO4.
The Natural Barium Sulphate is very inert, insoluble and stable to light and heat. The natural form is obtained as the mineral ‘heavy spar’. After being crushed, washed and dried it is usually micronized, reducing its particle size from 25 µm to 2–10 µm, thus aiding its dispersibility. 

Specification 

MATERIAL PROPERTIES
Appearance		White Powder
Barium Sulfate (%)	min	92+
Whiteness  (%)		82-84
Mean Grain Size D50 (um)		8
Moisture (%)	max	0.3
Sieve Residue On 325 Mesh   (%)		0
Oil Absorption g/100g		13-15
pH Value		7±0.5
Loss on ignition (%)	min	1.2

Application

Paints and coatings	Automotive paint systems	For use in extender systems, due to gloss retention and excellent mechanical properties.
	High Solids Paints	Partial substitution of blanc fixe micro for other pigments achieves significant reduction of volatile matters (VOC)
	Pigment pastes	Greater colour intensity and brilliance due to improved dispersion of coloured pigments (using 10% blanc fixe micro, for example)
	Powder-coating systems	Particularly suitable for high-gloss brilliant thin-film coatings.
	Marine coatings	As a filler in anti-corrosion paints/coatings used for marine application

The synthetic Barium Sulphate is made by reacting available barium compounds with sulphuric acid or soluble sulphate salts, and has a finer texture than the natural grades, giving it a higher oil absorption.

Its Refractive index (1.64) is higher than other extenders, which gives it some pigmentary properties. 

It improves many remarkable properties including weathering resistance, aging resistance, chemical resistance, brilliance in coloured systems, mechanical strength, etc. It is one of the most used conventional functional filler and inorganic additive worldwide.

Specification:

BaSO content (%)                                          99+

Colorimetric index L* (%)                            99+

Median value D50 (µm)                                 1.0                              

 pH value                                                        6.5-9

 Oil Absorption (g/100g)                                15-19 

Volatiles (@105⁰C, %)                                    0.2

 Sieve residue on 325 mesh (%)                    0.01

Electrical conductivity (µS/cm)                     150

Application: Coatings Can coating, coil coating, wood coating, anti-corrosive/marine coating, powder coating, automotive coating, etc

Picture: Natural Barium Sulphate(Left hand side) is max.10% soluble in water 

Synthetic Barium Sulphate(Right hand side) is completely insoluble in water. 

THANKS FOR YOUR ATTENTION