Alkyd base coatings

Fig. 4.22 Elastic moduli vs. temperature obtained by AFM nanoindentation measurements on various alkyd-based coatings (a) effect of oil number, (b) time evolution of modulus after application of the coating. (Reprinted with permission from [47].)...

Uses Dispersant, defioccuiant, antifiooding agent for pigments in alkyd-based coatings... 

Alkyd-based coating Esterification Isophthalic acid Pentaerythritol Polymerization process... 

Petroleum solvent-based paints contain aliphatic and aromatic hydrocarbons, ketoximes, alcohols, free monomers and plasticisers. In a general purpose petroleum solvent-based paint the volatile components are aliphatic hydrocarbons and paraffin naphtha. Odourless solvents (isoparaffinic naphtha or petroleum distillate) used in some interior oil/alkyd-based coatings can pose a danger for hypersensitive persons. 

The manufacture of alkyd resins (qv), which are obtained by the reactions of polybasic acids or anhydrides, polyhydric alcohols, and fatty oils and acids, consumes about 17% of the phthahc anhydride demand. While materials such as maleic anhydride, isophthahc acid, and fumaric acid can also be used, phthahc anhydride is the most important. The resin provides a binder for coatings that are apphed for either protection or decoration. Ak quahty concerns have put alkyd resins under pressure from water-based coatings which do not emit organic vapors upon drying. 

These are the most important components of paint. Coatings can be either clear or opaque (containing pigments) and either solvent- or water-based. With solvent-based paints, after application, most of the solvent is lost through evaporation. These solvent-based coatings are mostly alkyds (name derived from alkyl/acid) or modified alkyd resins. Normally they contain 30% polymer solids higher solids content is limited by the increasing viscosity of the system. 

This isoindoline nickel complex pigment is mainly recommended for the coloration of metallics and effect coatings, especially for water based systems. P.R.271 affords yellowish to medium red shades, providing a bright flop in metallics. Alkyd/melamine resin systems may safely be overcoated and withstand exposure of 140°C for 30 minutes. The flow properties of P.R.271 in these systems and in polyester cellulose acetobutyrate base coat systems are good, but there is a certain tendency to flocculate. 

Fig.12. Comparison between a conventional high solid alkyd coating ( ) and an alkyd based on a hyperbranched aliphatic polyester ( ). Drying time as a function of molar mass [123]...

Other uses for alkyds are in general industrial coatings such as machinery and metal furniture. Alkyd resin-chlorinated rubber based coatings are used in traffic paints, but use is declining because of VOC concerns. Some alkyds are still used in refinish paints for automobiles. Uralkyds are used as a vehicle for urethane varnishes for the do-it-yourself market. 

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