[article]
| Titre : |
The importance of particle sizing in the coatings (paints, pigments) industry |
| Type de document : |
texte imprimé |
| Auteurs : |
Nick Grantham, Auteur |
| Année de publication : |
1996 |
| Article en page(s) : |
p. 19-39 |
| Note générale : |
Bibliogr. |
| Langues : |
Anglais (eng) |
| Index. décimale : |
667.9 Revêtements et enduits |
| Résumé : |
The importance of controlling the particle size of materials used in the paint industry is a relatively new phenomena. In the past mediaeval European painters decorated churches and palaces with a mixture of pigment (e.g red lead, lapis lazuli) mixed with an animal glue (e.g egg white) and ground into water. Later (13th centry) linseed oil was added to the mixture.
By 1900, products were still largely based around white lead or zinc oxide, linseed oil and turpentine, but new organic and inorganic pigments were starting to be developed. Zincoxide (refractive index 2.0) was still used up till about 1945, when titanium dioxide (refractive index 2.7) came into the use. This material still has not been superseded as a white pigment (see th section on Pigments).
However, despite these recent developments, the paint industry has only emerged from the "witchcraft" era in the last thirty years or so, when science started to play a part in paint formulation. Some would say that it is still in the witchxraft era!
Particle size controls a number of properties important to the paint chemist: - Optical properties including opacity - Tinting strength - Viscosity - Sedimentation
Improved quality methods mean that paint companies now need to control the performance of their paints at the manufacturing stage. This need has stemmed from increased pressure from the large paint consumer especially industries like the automobile industry. These users have required tighter tolerances and specifications on their suppliers and the paint manufacturers have had to respond.
Traditionnaly the paint industry has not been a manufacturer of any chemicals - it buys the chemicals it needs, formulates them packages the material.
This article attempts to explain the importance of particle size to the modern paint compagny and to illustrate it with relevant examples. |
| Note de contenu : |
WHAT IS PAINT ? : Binder - Pigment - Solvent - Additives
- PIGMENTS
- WHAT IS A PARTICLE ? : The particle size conundrum - The equivalent sphere (Equivalent spherical diameter of cylinder 100x20µm, Equivalent spherical diameter of cylinders of various ratios) - Different techniques - D(4,3) etc - Different techniques give different means (To show that the volume and weight equivalents of a particle are identical, Volume equivalent, Weight equivalent) - Number et volume distibutions) - Interconversion between number length and volume/mass means - Measured and derived diameters - Which number do we use ? - Mean , Median an Mode - basic staistics
- WHY IS PARTICLE SIZE SO IMPORTANT IN PAINTS : Opacity - Colour hue - Tinting strength - Gloss - Durability - Viscosity - Sievers - Sedimentation - Electrozone sensing (Coulter Counter) - Microscopy - Laser diffraction
- APPLICATION TO THE COATINGS INDUSTRY : Carbone black - Powder coatings - Metal powders
- THE RANGE OF AVAILABLE PRODUCTS : The Mastersizer range (MSX) - The Autosizer range |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=13408 |
in PAINTINDIA > PAINTINDIA 96 (02/1996) . - p. 19-39
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The importance of particle sizing in the coatings (paints, pigments) industry in PAINTINDIA, PAINTINDIA 96 (02/1996)
