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Alkyd resins
The corresponding alkyd resins are produced from native oils and/or fatty acids such as soybean oil, linseed oil, wood oil, sunflower oil, derizole oil and other oils or the corresponding fatty acids by condensation reaction of alcohols with acids. Depending on the raw materials used, these binders can be up to 100% based on renewable raw materials.
An important characteristic is the oil length and one classifies in
<40%: short oil alkyd resins,
40 - 60%: medium oil alkyd resins and
>60%: long oil alkyd resins.
In addition, a distinction is made according to the drying behavior:
air-drying alkyd resins
oven-drying alkyd resins
non-drying alkyd resins
Compared to native oils, alkyd resins dry more quickly by oxidation and exhibit greater hardness and resistance, e.g. to water.
These alkyd resins can be used in combination with other binders, stand oils, oils and hard resins such as maleic resins or resin esters to formulate coatings, e.g. wood coatings, painters' lacquers as well as parquet sealers, glazes, care systems and, of course, alkyd resin coatings. Alkyd resin emulsions are also produced for waterborne applications.
Abietic acid
If pine resin is heated to over 100°C, water and turpentine oil escape and a glassy mass remains after cooling, the rosin. The main component of rosin is abietic acid (C20H30O2) with various isomers such as dextropimaric acid and laevopimaric acid. The proportion of abietic acid in rosin is up to 90%. The aforementioned resin acids exist in a supercooled, amorphous state and tend to crystallize upon melting. Pure abietic acid is colorless and insoluble in water. Its solubility in organic solvents such as alcohols, acetone and ether, however, is good. Abietic acid can cause an allergy to rosin. Since rosin derivatives are also found in cosmetics, they can cause allergies in rare cases.
As the main component of rosin, it is the main reactant in all reactions of rosin with other reactants, such as with maleic anhydride and the subsequent reaction with polyalcohols to form synthetic resin polyesters.