Natural oil - advantages and disadvantages
One of the main advantages of drying oil, almost 100% of vegetable oil - absence of solvents, due to which there is practically no characteristic sharp odor. Rapid drying of this material is achieved by the fact that its main component, that is, oil, undergoes heat treatment, which can last up to 12 hours at a temperature reaching 300 degrees. In addition, the content of this base component is still not 100%, of the total mass of 3% is accounted for by desiccants, that is, the metals introduced into the composition that promote the oxidation of oils and the formation of a rapidly hardening film.
Let's find out what is good for coloring natural, the technical characteristics of which is very different from oxal, combined and alkyd solutions - all those liquids, a considerable percentage of which is white spirit. Firstly, the smell is specific, corresponding exactly to the oil that forms the basis of the liquid. There are quite a few types of drying oil, each of which contains some kind of natural vegetable oil.
How can varnishes differ based on this or that
oil? Impregnation of wood or metal surface treatment( priming), adding to paints for better congealing and plastering - only linseed oil is suitable for all this. Interestingly, not all natural oils under the influence of air and heat form a hard film as it hardens, some remain a viscous substance. The linseed oil dries faster and best, and the reason for this is the highest content of polyunsaturated fatty acids, as indicated by the high iodine number( 175-204) of the .Almost the same indicators have hemp oil with iodine number 145-167.
Additives in drying oil are the following metal compounds: lithium, cobalt, iron, lead, strontium, zirconium, manganese.
As for the drying oil, which contains walnut, sunflower or poppy( this also happens) oil, they would dry out without driers for a very long time. It is logical that the content of fatty acids in these extracts from seeds of plants with the corresponding names is relatively small. Even worse with rustic and olive oil, they practically do not dry up, only gradually thickening. A castor oil without the addition of siccatives in general would never freeze, so negligible is the iodine number of its constituents. In addition, it should be borne in mind that this indicator decreases as it dries.
Application of natural oil-based drying oils
To the greatest extent drying oils, both natural and alkyd, are necessary in paint and varnish production, since this component is needed for the production of thick oil paints. The reason for this - and the composition of the above liquids, and the requirements for the rate of solidification of coloring products. At the same time, it is more popular to use alkyd drying oils, as cheaper ones, which is why you have to inhale the sharp smells of evaporating solvents during the finishing works. On the basis of natural oils are obtained more expensive paints, which are used by artists.
For the treatment of various surfaces, for example, priming of wood and metal, drying oils suit as well as possible. Actually, it was for this purpose that they were invented in ancient times, however, the component compositions of these "boiled oils", according to old recipes, also contained amber, as well as other resins that are more similar to varnishes. Natural linseed oil is designed exclusively for domestic work, outside it can cover the wooden parts under the canopies and canopies. In this case, regardless of the place of treatment, it is desirable then to cover the surface with paint or plaster.