[article]
| Titre : |
Formulating principles of paint |
| Type de document : |
texte imprimé |
| Auteurs : |
M. Veeramani, Auteur |
| Année de publication : |
2017 |
| Article en page(s) : |
p. 100-104 |
| Note générale : |
Bibliogr. |
| Langues : |
Anglais (eng) |
| Index. décimale : |
667.9 Revêtements et enduits |
| Résumé : |
SO FAR we have seen the manufacturing process, testing and application techniques of water-based paints. Now let us turn our attention to a very important part of the paint chemistry, Formulation Water-based paints. In the earlier chapters I had dealt with in detail all the constituents that go into the manufacture of water-based paints and their functions in the paint. Now I will deal with a very important chapter on "how to formulate water-based paints ?" This includes all the products like Acrylic Washable Distemper, Water-based Primer, Interior and Exterior Paints and Hight end, and Prenimum Paints which are used in day to day application.
One must know that broadly paint contains various constituents like Water, Additives, Pigments, Extenders and Binders. The effects of the physical properties of the components include, for instance, the role of the external phase viscosity on emulsion stability. These effects are well know or easy to ascertain in most cases and may be handled in a corrective or complementary fashion. they will not be discussed in detail in this chapter, which is dedicated to clarifying the coupled effects of the three other types of variables. Physichochemical formulation refers to intensive variables, whiwh are characteristics of the nature of the components, along with temperatiure and pressure. They determine the affinity or negative of the standard chemical potential of the different species-particularly the surfactant-in all phases at equilibrium. They determinate the phase behaviour, as well as interfacial properties such as tension or natural curvature. Although emulsions are systems out of mechanical equilibrium because they would finally end up in a separated two-phase system, the formulation is of paramount importance during the formulation of the emulsion and its useful lifetime. This is probably due to the emulsion persistence is large enough to attain physicochemical equilibrium between the phases.
The main practical problem in formulation is the large number of components present in the paint. As a consequence a typical emulsion could contain scores of different chemical species; each of them is able to influence the formulation in a way not necessarily proportional to its concentration. Thus, even for a common place practical case, a systematic study could require thousands of research hours to be completed. This is why formulation has been considered an art rather than a science. This assessment has been changing with the growth of surface science in the past half-century and the uncovering of an extraordinarily rich variety of phenomena and structures in surfactant, polymer, and colloidal chemistry. However, most of the available knowledge is still too specific, simplistic, or naive to be useful to deal with the intricacies of even very simple practical cases. This is why a rational approach based on cause-and-effect trends has been favoured by formulators of emulsions and other systems involving surfactants, oils, and water when numerical relationships are not available. As proposed 50 years ago, the empirical hydrophilic- lipophilic balance (HLB) method has still its supporters because of its extreme simplicity, although it falls short of taking into account many factors.
Now let me take you to the actual Formulation procedure and the grammar rules attached to it. First of all before proceeding to formulate a product one has to decide the parameters of the paint which is to be formulated. Main parameters are: PVC, Specific Gravity, percentage of principle raw material like Rutile and Emulsion etc. These parameters will determine the quality of the paint whether it is a primer or mid end or high end paint and so on. Once these parameters are specified the formulator proceeds further.
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| Note de contenu : |
- Major formula component calculations
- Other raw material functions and quatity
- Critical pigment volume concentration (CPVC)
- The PVC/CPVC ratio |
| En ligne : |
https://drive.google.com/file/d/1ZlxdKF45XAY0whKcZzofLooVqJSAuy8T/view?usp=drive [...] |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=29754 |
in PAINTINDIA > Vol. LXVII, N° 11 (11/2017) . - p. 100-104
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Formulating principles of paint in PAINTINDIA, Vol. LXVII, N° 11 (11/2017)
