Drying oil oxidation

The mode of drying is as varied absorption (non-drying oils) oxidation (drying oils) evaporation of solvent (resin-solvent solutions) cold-set (resin-wax combinations) quick-set (resin-oil combinations) heat-set (resin-oil-solvent combinations). 

Oxidation. Inks that dry by oxidation behave much like oil paint films and dry by means of the reaction of drying oils (qv) with oxygen. They contain metallic driers, which catalyze the absorption of oxygen by the drying oil (see Driers and metallic soaps Paint). 

Driers. These are generally soaps of cobalt, manganese, and other metals formed with organic acids such as linoleic, naphthenic, and other organic acids. They catalyze oxidation of drying oils (qv), and thus are used in inks that dry by oxidation (see Driers and metallic soaps). 

Oxyd-chlorid, n. oxychloride, -einschluss, m. oxide inclusion, -faden, m. Elec.) oxide-coated filament, -firms, m. oxide varnish (thickened drying oil). 

Alkyds These are the most widely used of all air-oxidizing coatings and have the broadest use both industrially and domestically. They are usually classified according to the proportion of drying oil to synthetic resin (known as oil length ). The oil length influences all properties (e.g. chemical resistance, viscosity, flexibility and hardness). 

Air-drying aikyd resins Alkyds capable of air drying do so through the oxidation of the drying oils that they contain. Such alkyds are consequently... 

Unsaturated (drying) oils, like linseed oil, etc., will rapidly heat and ignite when distributed on active carbon, owing to the enormous increase in surface area of the oil exposed to air, and in the rate of oxidation, probably catalysed by metallic impurities [1]. A similar, but slower, effect occurs on fibrous materials such as cotton waste [2],... 

The product of cross-linking and oxidation processes in drying oils is described as a porous polymeric fraction with a wide range of molecular weight. The chemical structure that can be influenced by age, thickness and the presence of pigments, while nonbonded species are present in the interstices free mono- and dicarboxylic acids, mono-, di- and triglycerides, aldehydes, ketones, etc. 

High amounts of a,co-dicarboxylic acids (mainly suberic, azelaic and sebacic) in a paint sample are indicative of the presence of an aged drying oil. This is because dicarboxylic acids, of which azelaic is the most abundant, are produced during the auto-oxidation of the polyunsaturated acylic chain present in drying oils. 

Development of the third class, i.e. unsaturated polyester resins, remained rather slow until the late 1930s, but after commercial production of maleic anhydride by catalytic oxidation of benzene began in 1933, maleic anhydride and fumaric acid rapidly became the most important sources of unsaturated groups in polyesters. The mechanism of drying of these resins on their own and with the addition of drying oils (i.e. unsaturated compounds such as linseed oil) was... 

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