Drying oil types and purpose. Drying oil: technical characteristics of species

Drying oil - liquid film-forming compositions, which are products of processing of vegetable oils or fatty alkyd resins with the addition of desiccants to speed up drying. Drying oil is intended for the manufacture of thick, ready-to-use oil, alkyd paints, as well as for diluting these paints and bringing them to working viscosity before use. Drying oil has some use for impregnation, priming wooden surfaces before coloring.

Drying oil production

To improve the properties of drying oil, rosin, low molecular weight rubbers, and other additives are introduced into them, this explains their name - "composite".

Insofar as vegetable oils are a valuable food raw material, and the properties of drying oil as film formers are not so high, the main directions for the development of the industry of varnishes and paints provide for the replacement of drying oil with more advanced materials.

What is natural drying oil made of?

natural drying oil is produced by heat treatment (seal) at a temperature of 270-280°C (with or without air purge) of drying oils with the addition of desiccants.

For the manufacture of natural drying oil, linseed, hemp and other drying refined oils are used. Lead-manganese or manganese-lead-cobalt linoleates, as well as naphthenates, are usually used as driers for natural drying oil. Oil polymerization is carried out in stationary steel reactors equipped with fittings for introducing liquid desiccants.

Natural oxidized drying oil is obtained by compacting linseed, hemp or other drying oil by heating with air purging in the presence of a desiccant.

Production of combined drying oil

Combined linseed oil and oksol linseed oil of different grades are produced by successive heating of oil (drying, semi-drying or mixtures thereof), oxidation of the oil by blowing with air at a temperature of 150-160 ° C in the presence of a desiccant to the required viscosity and dilution with white spirit to a given content of non-volatile substances .

Production of castor oil

Castor drying oil is made by dehydration and polymerization of castor oil, followed by its esterification with glycerol (to reduce the acid number below 10) and dissolving the obtained prepared oil in white spirit with the addition of a desiccant. Castor drying oil contains ~ 46% (wt.) prepared castor oil, ~ 50% (wt.) white spirit, ~ 4% (wt.) (calculated as metal) desiccant - a mixture of linoleates: lead 1.4% (wt. .), manganese 1.6% (wt.) and calcium - 1.0% (wt.).

Obtaining alkyd drying oil

Alkyd drying oils (glyphthalic, pentaphthalic and xifthalic) are obtained by diluting the corresponding fatty alkyd resins of a certain viscosity with white spirit and introducing a desiccant.

Production of other drying oils

Other drying oils are being prepared different ways. So, rubber drying oils are obtained by heat treatment of sunflower oil and its modification with liquid rubber of the SKDP-N brand, dilution with white spirit and the addition of a lead-manganese desiccant.

Synthetic drying oils

There is a group of materials that are conditionally called synthetic drying oils. These are various by-products of petrochemical industries that can form films when dried. As a rule, these are low-quality materials, which, however, can be used for non-critical work, impregnation of porous surfaces, temporary protection, etc. Such materials include, for example, polydiene drying oils.

Due to the lower quality of synthetic drying oils compared to natural ones, a negative attitude has been formed in everyday life towards all synthetic materials as inferior substitutes, surrogates.

Therefore, chemists involved in the development, manufacture paintwork materials, must, on the basis of a deep study of the properties of raw materials, objectively evaluate its positive, negative sides and give the consumer recommendations on the use and operation of these materials. Consumers should strictly follow these recommendations, since synthetic drying oils are less versatile. The scope of synthetic drying oil is limited.

The introduction of desiccants (sikkativirovanie) in drying oils

In the process of obtaining drying oil, it is necessary to introduce the optimal amount of driers. At the same time, a small amount of desiccant may be ineffective to ensure the required drying rate, and an excessive amount of desiccant may not only not accelerate, but even reduce the rate of oil drying. In addition, the use of a desiccant, including 2 or 3 metals (polymetallic desiccants), provides an increase in the drying speed of drying oils.

At the enterprises of the oil and fat industry, in the manufacture of drying oil, linoleates of lead, manganese, and cobalt are most often used.

Precipitated naphthenate driers are most widely used in the production of drying oils, as they are more economical than melted resinates and linoleates.

drying oil drying speed

The drying speed of drying oil is determined both by the quality of the feedstock and by the type and amount of desiccant introduced.

Drying oil containing polymetallic desiccants has a drying rate significantly higher than drying oil containing monometallic desiccant. For example, when a lead or manganese desiccant is introduced into linseed drying oil, it dries out in 20 hours and 12 hours, respectively, and when a lead-manganese desiccant is introduced, it dries out in 7.5 hours; with the introduction of a calcium desiccant or lead-manganese-calcium desiccant, linseed oil dries out in 32 hours and 6 hours, respectively.

Drying oil is largely affected by temperature and relative humidity. With an increase in temperature from 17 to 25 ° C, the drying speed of drying oil with cobalt desiccant increases by 1.3 times, and with manganese - by 3.9 times. Drying oil containing 0.05% (wt.) manganese dries at a relative humidity of 70%, twice as fast as at 97% humidity.

The use of wood as a building material is back in fashion - having become saturated with the plastic of the most different types, synthetics and substitutes, people begin to appreciate the natural purity, safety and incomparable appearance. That's just the tree needs serious processing. Should I use drying oil or give preference to more modern materials?

Natural materials - in search of safe!

If you have chosen a tree for finishing your house, guided, first of all, by its environmental friendliness, then it will certainly be important for you to comply with this condition to the end. After all, an environmentally friendly tree can be covered with such an amount of chemistry with your own hands that any sense of using this material is lost.

And here a slightly forgotten drying oil enters the arena. Of all the film-forming materials that are on the market today, it is objectively the most natural. This statement is easily confirmed by the fact that most drying oils consist of natural oils (hemp, linseed, sunflower, etc.) - the percentage of the natural component is from 45 to 95%.

Drying oil or, as it was called in the old days, "boiled oil" was known to master painters several centuries ago. Already in the 17th century, every artist used this material. Today, the technology for making natural drying oils practically does not differ from the methods known in antiquity. There are different types of this film former, the properties of which differ quite strongly.

Oil drying oils - what you need to know?

No matter how many manufacturers, but the production technology as a whole is the same for all - vegetable oil, subject to heat treatment, after filtration, mixed with desiccants. Desiccants are metal compounds that accelerate the process of polymerization of the oil film. Cobalt, lead, manganese, iron, lithium, strontium - the very name of these metals raises serious doubts about the safety of the compounds obtained. It should be noted that GOST, which regulates the production of this material (GOST 7931-76), was developed back in the USSR, and has long required a thorough revision.

If you choose a composition, then look for the necessary information on the label, which particular desiccant was used - cobalt desiccant is considered relatively safe. According to GOST, it should be from 3 to 5%. Exceeding this figure leads to a too high rate of drying oil polymerization, and the process does not stop even after drying, which further leads to darkening and cracking of the layer. That is why artists today use oils and paints without desiccants.

Is it possible to do without desiccants? Of course you can. Although this is a rarity, if you wish, you can still find such compounds, or compounds with a minimum content of this component. In fact, it is they who are best able to protect wooden structures from rot. Ordinary drying oils with driers completely harden in 24 hours, and even faster in hot and windy weather, while compositions without driers can harden up to 5 days. If you dissolve the oil paint with such a composition, then its curing time will also increase.

Such a long polymerization period allows the oil component to penetrate as deep as possible into the wood fibers, due to which the wood will better repel moisture and resist fungus, woodworms.

In the case of desiccants, the oils do not penetrate as deeply in 24 hours. The film formed on the surface of the tree can peel off and collapse over time, because of which all your efforts will go down the drain. That is why the old wooden buildings, treated with drying oils without desiccants, have been perfectly preserved to this day, while modern wooden buildings need constant maintenance with their own hands.

The natural rate of polymerization of natural vegetable oils depends not so much on the production technology, but on the quantitative content of glycerides of polyunsaturated fatty acids, such as linoleic and linolenic. Linseed (GOST 5791-81) and hemp (GOST 8989-73) oils can boast the highest content of glycerides - 80% and 70%, respectively. For comparison, sunflower oil, which is also often used for inexpensive drying oils, contains about 30% linolenic acid glycerides, and therefore, even in the presence of desiccants, it dries several times slower. Olive oil is practically devoid of the ability to harden, over the years it will only thicken, and castor oil does not thicken at all.

According to the existing GOST, natural drying oil must consist of 97% natural vegetable oil. However, manufacturers often violate this rule in an effort to improve the setting speed. It is easy to determine this with the knowledge gained - if drying oil in sunflower oil, according to the manufacturer, hardens faster than in 24 hours, the amount of driers in its composition clearly exceeds the 3% established by GOST. And therefore, from the point of view of environmental safety, it will be more harmful than drying oil in linseed oil, which hardens in the same period.

Requirements for production technology are also described in GOST 7931-76 and have not been revised for a long time. During cooking, vegetable oils undergo languishing at high temperatures - at a temperature of about 300 ° C, they are heated and kept for about 12 hours. Further, the technology may differ - drying oil obtained by heat treatment without air blowing is called standard (polymerized), and the compositions that have been blown are called oxidized, or oxidized. Natural oil drying oil has a sweetish aroma of vegetable oil, its color varies from light brown to dark brown, almost black, it dries for a long time.

Not natural - drying oil drying oil strife!

The closest to natural drying oil is combined - these compositions contain about a third of the solvent, often white spirit. This reduces the cost of production and offers the buyer a product that dries at a faster rate. The use of drying oil on solvents fits perfectly into the repair from the outside - both quickly and reliably, and the smell will quickly disappear.

If you dilute vegetable oils even more, you get the so-called oxol, the production of which is regulated by GOST 190-78. - these are the obligatory 55% of natural oil, the remaining 45% are divided among themselves by solvents and desiccants. Oxol dries much faster due to the active evaporation of the solvent, and therefore it is convenient to use it in outdoor work with your own hands. In internal use, as in the case of the combined one, it is not recommended - due to the solvent, the composition has a sharp, bad smell, which can be preserved even after the layer has hardened.

The low cost of oxoli makes it popular among the masses. Oksol is used to dilute oil paints and enamels, since by itself it cannot adequately protect wooden structures. If you choose oxol, then we recommend giving preference to more expensive formulations based on linseed oil- they create a strong and elastic film on the surface of the tree, and such drying oil dries faster.

Alkyd drying oil is a film-forming composition, the main component of which is alkyd resin (glyphthalic, xyphthalic or pentaphthalic), as well as modified oils and solvents. Objectively, this is the most acceptable combination of price and quality - alkyd compounds perfectly withstand temperature extremes, endure the effects of atmospheric phenomena and are little susceptible to ultraviolet radiation. Is post-processing necessary? Necessarily! Such drying oil dries for about a day, after which at least two layers of varnish or paint should be applied.

Composite drying oil occupies the last place in terms of the quality of the coating being created and its characteristics. However, it is difficult to call it drying oil - it is a product of oil refining, which has a similar purpose, for example, to dilute paint. There is not even an appropriate GOST for the manufacture of such compositions. In appearance, such compositions are easy to distinguish by a high degree of transparency. Composite drying oil dries longer and is poorly absorbed into the wood surface. This material should be used only for covering temporary structures or to dilute inexpensive paint.

Natural drying oil is easy to identify by its dark brown color and the characteristic sweetish aroma of heat-treated vegetable oil. If there is a pungent smell of chemistry, this is no longer natural drying oil, but combined or oxol. There should not be any sedimentary formations, spots or lumps inside the jar in all cases. You have full right ask the seller for a certificate of conformity.

With composite drying oil, you should be doubly careful, since such compounds can be toxic, and therefore high-quality drying oils are accompanied by a hygiene certificate. Different shades in the composition may indicate the presence of a residue of oils (fuza) - composite drying oils should not have any color at all. Fuzz is the reason that drying oil takes a very long time to dry. If the so-called osprey (a product of oil refining) penetrated into the composition, then the drying oil will simply never dry out. The presence of such inclusions can also give out a pronounced odor.

It should be remembered that all drying oils are fire hazardous. Their use and storage should be away from sources of fire and heat. While the drying oil dries, do not use electronics or smoke indoors. Be sure to purchase a fire extinguisher and other safety equipment.

1. What is drying oil
2. Selection Guide
3. We make drying oil ourselves
4. Storage

Since ancient times, to protect wood from negative influences: moisture, oil impregnation was used - drying oil. Finished surfaces wooden structures acquired lasting protective properties. market today building materials offers a wide range of impregnations.

What is drying oil

Film-forming liquid agent is a product of thermal processing of oils of vegetable origin with the use of additives. Drying oil can be called boiled butter. There are other types of impregnation created from artificial components.

With the advent effective materials protection of wooden structures outside houses and structures, drying oil began to be used only to cover the finish of wood fences indoors.

The principle of operation of oil impregnation

The mass of natural oil in the open space under the influence of warm sunlight and oxygen acquires a thick consistency. The substance applied in a thin layer begins to dry slowly, and as a result of polymerization, the coating turns into a high-density film. Drying is promoted by polyunsaturated fatty linoleic and linolenic acids (glycerides).

Among a large number oils of vegetable origin, hemp oil also has the highest ability to quickly dry. Sunflower, poppy, walnut, colza, castor and other raw materials almost do not thicken due to the low content of glycerides. They are not subject to complete polymerization.

To significantly reduce the drying time, vegetable oils are heated by adding a desiccant (metal compound). As a result of heat treatment, chemical compounds that slow down the polymerization process are broken down into inert substances. With the help of this technology, wood is impregnated - drying oil. Various compositions applied in a thin layer on wood, or, drying (from 6 to 36 hours), form a hard elastic coating. On average, the compositions dry out within a day.

Means impregnates upper layer wood, creating a film with high adhesion. It is used for surface treatment before painting with oil compositions, which significantly reduces paint consumption. Processing is also carried out before the subsequent coating of wooden surfaces with wax.

Kinds

Building materials factories fill the market with many types of impregnations with different characteristics. They are classified as:

• natural;
• semi-natural - oksol;
• combined;
• synthetic;
• alkyd and composite.

natural

Natural drying oil is produced in accordance with GOST 7931-76. The product is obtained by thermal processing of natural hemp and linseed oils. The oil must not be diluted with solvents or other chemicals. The use of sunflower oil is excluded. A desiccant is added to the prepared mass - with manganese, cobalt or lead in the amount of 3% of the total mass of the material.

V industrial production heated raw materials are languishing (+300 ˚C) in special tanks for 12 hours. The resulting mass is a polymerized or standard impregnation. Sometimes the cooking process is accompanied by air blowing. Such an impregnation is called an oxidized or oxidized agent.

Impregnation looks like an oily translucent substance of different shades. The liquid product has a slight sugary smell of vegetable oil. Linseed drying oil is much more transparent than its hemp counterpart. Therefore, its quality is awarded the highest grade. All natural liquids reach complete drying within a day.

Semi-natural - oksol

The composition of oxoli includes natural oils or their mixtures (sunflower, soybean, corn, etc.), occupying up to 60% of the total volume. A prerequisite for the manufacture of oxoli is the use of up to 40% petroleum polymer resins mixed with desiccants. In the manufacture of semi-natural impregnation, it is allowed to use (GOST 190-78) driers of petroleum origin containing manganese, cobalt, lead or mixtures thereof.

The composition of oxoli includes the following components in% ratio:

• oils and resins - 55%;
• white spirit or turpentine - 40%;
• desiccant - 5%.

Unlike natural products, oxol has a sharp bad smell, which can persist for a long time. The advantage of the tool is the low price. Linseed oil oxol is considered the highest quality drying oil. Impregnation differs in durability, the increased elasticity, water resistance and hardness.

Combined

The combined compositions are similar to oxol in terms of the production method. The difference lies in the proportions of the mixture of oils (70%) and solvents such as white spirit (30%).

The purpose of impregnation is protection, coloring of wood, dilution of thick oil paints. The liquid coats the plaster before oil painting. Dries completely in 24 hours.

Combined drying oils are produced in two grades: K-2 and K-3. Each comes in 2 varieties.

Means brand K-3 is used for surface treatment both indoors and outside buildings and structures. They are covered with street poles and wooden buildings to protect against precipitation and the appearance of negative organic formations. The second grade K-3 is slightly darker than the 1st grade, which is completely transparent.

K-2 does not have a pungent odor and gives wooden structures a noble pale shade, which is used before varnishing surfaces. Impregnation does not withstand negative atmospheric phenomena, so it is used only indoors.

Synthetic

This type of drying oil contains inorganic substances. They are a product of oil refining. Popular synthetic impregnations are slate drying oil and Ansol artificial drying oil.

Shale impregnations are made from petroleum film-forming components. A special catalyst is added to the mixture, and then the mass is diluted with shale gasoline. This tool contains:

• raw material from diesel shale oil;
• shale gasoline;
• raw material from shale generator oil;
• solvent.

The manufacturer adds natural vegetable oils to the impregnation in the amount of up to 20%. A modified drying oil is prepared by mixing all the ingredients, followed by heat treatment. Drying time - 24 hours.

Ansol is a fully synthetic product without the inclusion of vegetable oils. Impregnation is prepared from refined petroleum products. Petroleum polymer drying oil for bringing to technical condition diluted with a solvent. Because of this, the drying oil has a sharp unpleasant odor. To quickly get rid of this, you need to ventilate the premises well. Over time, treated surfaces cease to spread an unpleasant odor.

The undeniable advantage of synthetic impregnation is low price. Due to intolerance to sunlight, Ansol is used only for internal works. The tool shows itself well at the end plastering works. Drying oil reliably impregnates the porous surface of the plaster and strengthens it before painting. If we compare the economic benefits from the use of different types of drying oil, then Ansol claims the first place.

Several factors influence the choice of impregnation type. This list may include the following items.

1. For the treatment of surfaces made of expensive wood species, impregnations made from linseed and hemp oil are used.
2. It is better to treat the surfaces of enclosing wooden structures from the outside with oxol or combined compositions.
3. Synthetic fluids are applicable for coating wooden surfaces in non-residential premises. They process the wood of the supporting structures of the roof.
4. Treating large areas with Ansolyu brings significant savings.
5. It is better to take drying oil in a transparent or translucent container. If sediment is found, then it is better not to buy such a product.
6. Of considerable importance is the cost and type of solvents. When using an airbrush, the impregnation is diluted with a solvent in a ratio of 1:1.
7. When buying, it is better to contact a building supermarket, where you can get information about drying oil from professionals.

The cost is from 200 rubles per liter. V retail Containers up to 10 liters are available.

We make drying oil ourselves

If you have a home workshop, drying oil can be prepared independently. Drying oil good quality obtained from linseed oil. But if there is nowhere to get it, they cook home-made impregnation from natural sunflower oil - this is a publicly available and cheap raw material.

The impregnation process includes three stages:

• oil base preparation;
• preparation of a desiccant;
• final production of drying oil.

Oil base preparation

The container is half filled with oil and placed on the stove. When the base is heated to 110–120 ˚C, water will evaporate and foam will begin to appear.

Then the foam will subside. Continue cooking for 3-5 hours, increasing the heating temperature to 270 ˚C. If the edges of the pigeon feather wrap in oil, then the heat level is sufficient.

Preparation of the desiccant

A desiccant is an auxiliary reagent that drastically reduces the drying time of drying oil. The substance is also added to oil paints.

You can make a desiccant like this:

1. 100 weight parts of rosin are melted at a temperature of 150 ˚C in a separate container.
2. 5 parts of manganese peroxide are gradually added to the molten mass after the next settling of the foam.
3. The mixture is brought to 200 ˚C and incubated for 3 hours. The material should become transparent.

Final production of drying oil

A desiccant is carefully introduced into the oil base over low heat, monitoring the level of foam. After the final decline of the foam, the mixture is boiled for 5-10 minutes. Then the container is removed from the stove and the mixture is left to cool.

Storage

Storage conditions for viscous impregnation are simple. Drying oil is stored in open areas for no more than 3 days. Impregnation must be contained in a closed container. In conditions warehouse drying oil retains its qualities for about three years. If during this period a precipitate appears at the bottom of the vessels, then the product becomes suitable only for ignition. Temperature regime drying oil storage ranges from -40 to +40 ˚C.

One of the main advantages that drying oil has, almost 100% consisting of vegetable oils, is the absence of solvents, due to which there is practically no characteristic pungent odor. The rapid drying of this material is achieved by the fact that its main component, that is, oil, is subjected to heat treatment, which can last up to 12 hours at temperatures reaching 300 degrees. In addition, the content of this basic component is still not 100%; of the total mass, 3% falls on desiccants, that is, metals introduced into the composition that contribute to the oxidation of oils and the formation of a rapidly hardening film.

Let's find out how natural drying oil is good for coloring, specifications which is very different from combined and alkyd solutions - all those liquids, a considerable percentage of which is white spirit. Firstly, it has a specific smell, corresponding to exactly the oil that forms the basis of the liquid. There are quite a few types of drying oils, each of which contains one or another natural vegetable oil. Linseed drying oil is considered the best, it forms the strongest and most durable film on the surface of the processed material.

How drying oils differ based on a particular oil

Impregnation of wood or processing of a metal surface (priming), adding to paints for their better solidification and plasters - only suitable for all this. Interestingly, not all natural oils, under the influence of air and heat, form a solid film as they solidify, some remain a viscous substance. Linseed oil dries fastest and best, and the reason for this is the highest content of polyunsaturated fatty acids, as evidenced by a high iodine number (175–204). Hemp oil with an iodine value of 145–167 has almost the same performance.

The driers added to drying oils are compounds of the following metals: lithium, cobalt, iron, lead, strontium, zirconium, manganese.

As for drying oils, which contain walnut, sunflower or poppy (this also happens) oil, they would dry out extremely long without driers. It is logical that the content of fatty acids in these pomace from the seeds of plants with the corresponding names is relatively low. The situation is even worse with rapeseed and olive oils, they practically do not dry out, only gradually thickening. And castor drying oil without the addition of desiccants would never have frozen at all, the iodine number of its component is so negligible. In addition, it should be borne in mind that this figure decreases as it dries.

The use of natural oils

To the greatest extent, drying oils, both natural and alkyd, are needed in the paint and varnish industry, since it is this component that is needed for the manufacture of thickly grated oil paints. The reason for this is the composition of the aforementioned liquids, and the requirements for the speed of solidification of coloring products. At the same time, it is alkyd drying oils that are more popular, as they are cheaper, which is why during finishing works you have to inhale the pungent odors of evaporating solvents. Based on natural oils, more expensive paints are obtained, which are used by artists.

For processing various surfaces, for example, priming wood and metal, drying oils are the best fit. Actually, it was for this purpose that they were invented in antiquity, however, the component compositions of these “boiled oils”, according to old recipes, also contained amber, as well as other resins, which is more similar to varnishes. Natural drying oil is intended exclusively for interior work, outside it can be used to cover wooden parts under awnings and visors. In this case, regardless of the place of processing, it is desirable to then cover the surface with paint or plaster.

During some construction and repair work often used material such as wood. The tree has a porous structure and therefore more than others needs additional processing.

In order to protect this valuable and not entirely cheap material, Oksol drying oil is used.

What it is?

Drying oil is a thick oily liquid mainly Brown, consisting of a mixture of different components, is intended for painting wood and preparing plastered surfaces for painting, and is also used as a solvent for oil paints.

Like any other product intended for processing, drying oil consists of basic and auxiliary substances. The basis of drying oil "Oksol" is vegetable oil, the share of which is in the range of 54-55% of the total mass.

Different oils can be used to make the product: linseed, hemp, sunflower, grape, soybean, corn or camelina. The base contains either one type or a mixture of several oils.

The share of additional components in the composition of "Oxol" accounts for 45% of the total mass, of which 40% is occupied by a solvent (white spirit is most often used), and the remaining 5% are desiccants. Each of them has certain properties that affect the composition as a whole.

The solvent gives the drying oil the desired consistency, and the desiccants contribute to the rapid drying of the composition on the surface. Salts of various metals, and, more precisely, compounds of iron, cobalt, lead, lithium, strontium and many others with organic acids are called driers.

The film formed on the surface does not allow paint or varnish to penetrate deep into the wood structure, which means that less material is required. In addition, the use of drying oil as a preparatory layer for painting improves the adhesion of varnish or paint to a wood surface.

In order to understand how and due to what the film is formed on the surface, it is necessary to consider the principle of operation of drying oil, based on the properties of the components. Many types of vegetable oils used as a base, under certain conditions (oxygen, heat, light) are able to thicken, and when applied to the surface in a thin layer, polymerize (dry).

The formation of a semi-solid mass occurs due to polyunsaturated fatty acids present in some oils of vegetable origin. The rate of solidification on the surface is directly dependent on the value of glycerides of unsaturated fatty acids and such an indicator as the iodine number. The higher the percentage of fatty acids in the oil and the higher the iodine number, the faster the polymerization process.

But natural process oxidation occurs slowly, and therefore the drying oil is subjected to heat treatment along with driers added to its composition. Heating of this composition leads to the decomposition of substances that slow down the formation of the film, and due to the presence of metal salts, the oxidation process is faster.

Desiccants affect the composition not only during the drying process, but also after it. It lasts all the time while the layer remains on the surface, their share should not exceed 5%, a higher percentage of their content in the composition leads to darkening, and then the destruction of the film coating.

The formation of an elastic film on the surface usually occurs within 6-36 hours. Such a run-up in time is due to many factors: composition, preparation technology, the presence of additives. Almost all drying oils known today dry for about a day..

Kinds

To date, manufacturers produce several varieties of oil-based drying oils, differing in the presence of additional components and the percentage of basic substances.

Natural drying oil is the basic basis for "Oxoli", but differs from it in the percentage of components and the absence of additional substances in the composition. The share of oil, most often linseed or hemp, accounts for 97%, and the remaining 3% are desiccants.

This type of drying oil is suitable for processing surfaces that are only indoors., in connection with which it is used infrequently, and the cost of this type is quite high due to the large percentage of oil in the composition and its initial price.

Drying oil "Oksol" it is much cheaper than natural, because the share of oil in its composition is only 55%. But the reduced proportion of oil and the solvent included in the composition do not make this type of drying oil worse than natural. It is in no way inferior in properties and appearance natural analogue and even surpasses it in some ways.

"Oksol" can be used to cover wooden structures and plastered surfaces not only indoors, but also outside, which is its undoubted advantage.

On the treated surface a stable coating with a gloss effect is formed no later than a day. It is characterized by elasticity, water resistance and maximum durability compared to other types. The only disadvantage of Oxoli is its harsh smell compared to its natural counterpart due to the presence of a solvent, which is most often white spirit.

The division of "Oxoli" into brands is due to the use of different oils that make up the basis. For Grade B, either hemp or linseed oil is used. The best drying oil is considered to be made on the basis of linseed oil., it is it that forms a more durable coating on the surface.

The composition of the brand "PV" is based on other types of oils (soybean, sunflower, camelina, grape, corn).

A surface treated with a sunflower oil based composition is less resistant to various influences compared to a linseed oil base.

Combined drying oil unlike other types, it contains several types of oils that undergo various processing. In particular, if cheaper and poorly drying rapeseed oil is added to the composition, then it is preliminarily subjected to oxidation. This process is necessary in order for drying oil with cheaper oils used as a base to approach the original version in terms of properties.

The composition of the combined drying oil also includes synthetic substances and a solvent. Such drying oil is marked with the letter "K", and the number following the letter indicates for what types of work the composition can be used. Even numbers indicate drying oils intended for surface treatment indoors, and odd numbers mark compositions that can be worked with outside.

Alkyd drying oil has some similarities with Oksol. Vegetable oils are present in the composition of alkyd species, but their share is insignificant. This type of drying oil is produced on the basis of alkyd resins, which are diluted with solvents, most often with white spirit. In addition, the composition includes desiccants.

Specifications

Drying oil "Oksol" is produced in accordance with GOST 190-78, which prescribes the norms of various indicators for grades "V" and "PV". There are eight basic standards by which drying oil is determined to belong to one or another species.

They vary depending on the type of oil used and the brand of drying oil itself:

• The color index is listed first in the table.. For both grades, this value is identical, the color should not be darker than 800 mg J / cm³ (according to the iodometric scale). But there are exceptions for drying oil, where camelina oil (PV brand) acts as the basis, this indicator has a different numeric expression. The color of such drying oil should not be darker than 1800, and for drying oil made on the basis of soybean oil, this figure is 1100 J / cm³.

• Conditional viscosity indicators, measured with a viscometer, differ slightly for the two grades. For brand “B”, the drying oil flow time through a funnel with a diameter of 4 mm (at t = 20 ° C) is within 18-22 seconds, and for brand “PV” - within 19-25 seconds.

• Acid number, measured in mg KOH / g, differs for different brands. For brand "V" this indicator should be no more than 6, and for brand "PV" it is slightly higher - 8. If sunflower oil is used as the base in drying oil, in which the acid number ranges from 8-15 mg KOH / g, the total acid number should not exceed 10.

• Mass fraction of non-volatile substances, measured in%, for both brands should be in the range of 54.5-55.5. If there is a petroleum polymer resin in the drying oil mixture, the mass fraction of non-volatile substances can vary between 55-59%, provided that the viscosity index corresponds to the standards specified by GOST.

• Indicators such as sludge by volume and transparency both brands have the same size. Sediment by volume - 1%, transparency - full. The flash point in a closed cup for both grades should not exceed 32 ° C.

• There is another important indicator characterizing drying oil by drying time. For brand "B" a stable coating (up to degree 3) is formed no later than 20 hours from the moment of application, and for brand "PV" - no later than 24 hours.

According to GOST 190-78, there are strict requirements prescribing which containers can be filled with drying oil, at what temperature the liquid can be safely stored, and what precautions to take when opening a can with a composition. All safety requirements are described in detail in this document.

When buying drying oil, sellers must have a quality certificate.

Consumption per 1m²

There are norms for the consumption of drying oil per 1 m². As a rule, these indicators are not very different from the consumption of oil paints. To apply drying oil in one layer per 1 m², it will take from 80 to 130 g. This run-up is due to factors such as the type of surface being treated (wood or plaster), the porosity and hardness of the material, the type of mortar, as well as the effect of temperature and humidity.

For fresh wood, the consumption can be increased up to 200, and in some cases up to 250 g per 1 m². According to some sources, the average consumption of drying oil for a single-layer coating ranges from 150-200 g per 1 m².