Paint Formulation

Paint driers Paint formulations Painting Paint removers... 

Paint Formulations. Tables 1 and 2 provide examples of generic water-based latex and solvent-based alkyd oil paints. These formulations exhibit typical proportions of the paint ingredients discussed. 

PyCis usuaHy expressed in percentage, but the % sign is often omitted. Although many additives in the paint formulation are nonvolatile, they are often omitted from this calculation, because they represent a smaH fraction of the volume of a newly formed paint film and, in exterior paints, are often water-soluble materials leached out by rainfaH, and therefore wHl probably not factor into the long-term performance of the paint film. 

The characteristics of interior paints that require testing and analysis include hiding and appearance, package stabiHty, adhesion, spatter resistance, flow and leveling, color and sheen uniformity, touch-up, stain removal, burnish resistance, and block and print resistance. A popular test that assesses the wet abrasion resistance of an interior paint is to measure its scmb resistance. A mechanical device is used to scmb a paint film of a specified thickness with a standard bmsh and abrasive cleanser suspension. The number of scmb cycles (back and forth movements of the weighted bmsh) at various end points (first cut through, or 50% removal of the film) is then recorded. Scmb resistance usually holds steady or decreases slightly as PVC is increased, but drops quickly once the CPVC is exceeded in a paint formulation. 

J. BoxaE and J. VonPraunhofer, Paint Formulation, Industrial Press, New York, 1981. 

Part 446 paint formulating point source category... 

The acids are converted to peroxy esters for use as polymerization initiators. The metal salts are used as driers in paint formulations (see Carboxylic acids, TRIALKYLACETIC ACIDS). 

The ultrafine siUcon carbide produced in an electric arc is used as an insulation in cryogenic appHcations (152) (see Cryogenics). It generally increases the wear resistance of the paint film when added to paint formulations. 

Paint Driers and Polymer Additives. Paints based on alkyd resins (qv) dry by the oxidation and cross-linking of unsaturated side chains. Metal catalysts are included in paint formulations to promote this drying. Cerium carboxylates, eg, the naphthenate, are used as through driers, ie, to promote drying in the body of the paint film rather than at the film s surface (44). 

Eor water-based alkyd paints, greater (0.2% cobalt on a resin basis) concentrations of drier are required than for other systems because the reaction of the drier with water decreases the activity of the catalyst. The cobalt content of oil-based paint formulations is usually 0.01—0.05% cobalt. Although the concentration of cobalt in the formulations is small, the large volume of paints, inks, and varnishes constitute a significant use for cobalt chemicals. 

Polyvinyl chloride (PVC) is one of the most widely used thermoplastics. It can be extruded into sheets and film and blow molded into bottles. It is used in many common items such as garden hoses, shower curtains, irrigation pipes, and paint formulations. 

Although formulation is an art, science finds its place in the characterisation of the raw materials, in the design and testing of the series of experimental formulae and in the interpretation of the results. In addition to possessing an intimate knowledge of pigments, binders and solvents, the paint formulator must also be well acquainted with raw material costs and availability, paint making machinery, and the market s performance requirements. 

The most important component in the majority of paints is the binding medium, which determines the physical and chemical properties of the paint. Blends of binding media are often used to impart specific properties to the dry paint film or to suit a particular application method. The compatibility of chemically different types of binders is an important factor to be taken into account by the paint formulator. These properties will be modified, however, to a greater or lesser extent by the nature and quantity of the other components, more especially the pigment. The general characteristics of various binding media are given in Table 14.2. 

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