Oxidatively drying paints

Methyl isobutyl ketone has become increasingly important as a chemical feedstock. The oxime is used as an antiskinning agent in oxidatively drying paints, and the peroxide is used to cure unsaturated polyester resins. Methyl isobutyl ketone is an intermediate in the preparation of imidazolones and acetal esters. It is also used to block amines (ketimines) that act as moisture-initiated latent epoxy resin hardeners. Finally, alkaline autocondensation at elevated temperature yields higher molecular mass products that are employed as fragrances and perfumes. 

Uses Antiskinning agent for oxidatively drying paints in the can Features Min. drying retardation exc. yellowing resist, in light and heat Properties Nearly water-wh. low-vise, liq. dens. 0.91-0.93 g/cm (20 C) ... 

The initial drying of currently applied alkyd paints is accomplished by evaporation of solvent (physical drying). Subsequently, the eventual curing of the alkyd paint is completed by the formation of a polymer network, which is mainly formed by chemical crosslinks (oxidative drying) but in some cases also physical interactions between the fatty acid side chains occur, such as crystallization or proton-bridge formation [129]. Efficient network formation is crucial in the formation of dry films with good mechanical properties. Due to the presence of unsaturated units in the investigated LOFA- and TOFA-PHA bin-... 

Like other manganese lakes, P.R.58 4 accelerates the drying process of oxidatively drying systems, which rapidly thickens the paint. This clearly precludes its use in such systems. 

The most important ingredient of a white paint used to be lead oxide. This was objectionable, as it could be swallowed by infants and lead to brain damage. Other white powders with strong covering properties were needed, and the current material of choice is titanium dioxide. Many painters still prefer lead oxide-based paint, as it has a more desirable warmer shade of white and it dries much faster than titanium oxide-based paint. When a mistaken stroke is made by a painter, lead paint that dries quickly can be covered up by another stroke, but titanium paint needs 3 days to dry before it can be covered up by another stroke. A solution is available in quick-drying additives to the titanium paint. 

Cobalt(ll) oxide is used as a pigment for ceramics and paints for drying paints, varnishes and oils for coloring glass as a catalyst and for preparation of other cobalt salts. The commercial product is a mixture of cobalt oxides. 

Mn-MeTACN complexes have been studied extensively by ESI-MS in the oxidation of a variety of organic substrates using hydrogen peroxide (MeTACN = 1,4,7-trimethyl-l, 4,7-triazacyclononane). An assortment of binuclear and mononuclear species has been observed [7,33,34]. One such example focused on the use of these complexes for the oxidative drying of alkyd paints. The binuclear... 

On account of these disadvantages and the relatively long drying time, oil paints have almost completely lost their former importance over the last 30 years in favor of oxidatively drying alkyd resins. Being naturally-based paints , renewed interest has, however, recently been shown in oil paints owing to ecological reasons. 

C, polyurethane 0 C, oxidative hardening paints 0°C. If it is strictly necessary to paint in cold weather, physically drying paints (i.e. those drying by evaporation of the solvent) should preferably be used, since these dry relatively fast also at low temperatures. 

Traditionally, in alkyd paint preparation, vegetable oils are transesterified to polyols (e.g., pentaerythritol or trimethylolpropane) at high temperature (270°C) to become part of the binder system. Upon (oxidative) drying, the double bonds in the alkyd chains are cross-linked to form the final coating network. Therefore, agricul-... 

Iron Oxide, Red (Indian Red and Bright Red) (Pigment, dry, paint)... 

Uses Drier for waterborne oxidatively drying alkyd resin paints, esp. externally emulsified alkyd resin emulsions Features Lead-free, barium-free nonylphenol ethoxylate-ffee Properties Violet liq. water-emulsifiable dens. -1.09 g/cm (20 C) dynamic vise. 150-1000 mPa s flash pt. = 66 C 5% Co, 0.22% Li, 7.5% Zr Use Level 1-3% (on solid resin)... 

This merging of particles will not take place unless the polymer molecules in the particles have freedom of movement. Either the glass temperature of the particle must be below room temperature, or heat must be applied. In the former event, this will mean that the final film will be relatively soft, unless the droplets contain a solvent that evaporates later, or unless the polymer can harden by chemical reaction, e.g. by oxidative drying. In practice then, there are three possible types of paint ... 

The paints in this chapter all dry by the second mechanism discussed in Chapter 7 and, in particular, by the same form of that mechanism. This is known as oxidative drying and occurs when the film-former becomes cross-linked as a result of a chemical reaction with oxygen in the atmosphere. 

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