Alkyd varnishes: types and their characteristics

Alkyd varnishes: types and their characteristics

Treatment with protective compounds is necessary for almost every material and surface, especially substrates that are exposed to mechanical stress or factors that negatively affect their condition and appearance. This issue is relevant both for wood and metal. There are many different products on the market recommended for such materials, among which alkyd varnishes can be distinguished..

What it is?

This composition is a mixture of synthetic resins and natural solvents. The components of the varnish provide it with a high level of adhesion and resistance to moisture.

The requirements for the quality of alkyd products establish certain standards that the composition must comply with – first of all, the varnish must be colorless, and form a glossy or matte protective layer on the surface. Some products may have a certain shade. The mixture allows to increase the aesthetic appeal of the base, emphasizing the depth of color, which is important, for example, for parquet floors.

As a result of use, the surface to be treated becomes more attractive. However, the choice of a particular product should be based on personal preference and the field of use of the surface. Alkyd varnishes differ somewhat in their specificity and chemical content, depending on their use for indoor or outdoor use..

Alkyd mixtures are widely demanded in comparison with their counterparts. This is due to the operational properties of the products, which are many times higher than the available indicators of oil compositions..

Specifications

The invariable and main component of varnishes is alkyd resin, which acts as a base. Among similar products, alkyd varnishes are out of competition in terms of resistance to temperature fluctuations..

Vibration loads do not in any way affect the quality of the applied alkyd composition, in addition, the adhesive qualities that many representatives of paint and varnish products have are not inherent in the varnish. The product is absorbed directly into the wood and does not penetrate into the genital crevices in the frame. Such characteristics of the products allow minimizing the squeaks of the floorboards when processing the floor with an alkyd mixture..

The first alkyd-based varnish, which began to be produced in Russia, is the composition of PF-231. The product is intended for use on all types of surfaces. It is possible to note the external attractiveness of the base obtained after processing with this composition – the film evenly and neatly covers the working surface.

In addition to the positive characteristics, the composition also has some disadvantages. The main disadvantage is the short service life of the coating due to its minimal hardness. Due to this, after 2-3 years, the surface of the wooden floor will have to be processed again. On other materials, the composition will last many times longer.

PF 283 forms a glossy layer, remarkable for its decorative properties. In fact, these products are a mixture of alkyd resins, fatty acids and naturally occurring solvents. In addition, there is a desiccant among the ingredients. Most often, such a varnish is sold in a can as an aerosol of 150 ml..

PF-170 includes resin in combination with specific additives and aliphatic hydrocarbons. The composition can be used on wood, wood-containing materials, metal and ceramic substrates. In addition, bases treated with paints, enamels and primers are very often covered with these very protective and decorative compounds. The products are allowed for indoor and outdoor use. The varnish is made according to GOST, is resistant to chemical detergents and aggressive environmental factors, allows the surface to “breathe” and is very economical in terms of consumption.

Benefit and harm

The advantages of alkyd varnishes include the following characteristics:

  • resistance to fluctuations in temperature and humidity;
  • vibration resistance;
  • lack of adhesive properties;
  • high decorative qualities of the resulting coating;

  • when using a brush, the composition is applied very quickly, since it has a thick consistency;
  • after drying, a glossy or matte film forms on the base;
  • resistance to mechanical stress;
  • the composition does not lose its properties upon contact with chemical compounds;
  • prevents the formation of mold or mildew on the material.

According to consumer reviews, the following disadvantages of alkyd compositions stand out:

  • It takes a long time for the mixture to fully polymerize, usually about a day. To eliminate this disadvantage, most manufacturers began to include hardeners in the composition, which help to reduce the time required for the mixture to dry..
  • An incompletely dried base, treated with alkyd varnish, has a pungent specific odor that is dangerous to human health. To eliminate the risk of vapor poisoning, the room should be well ventilated while the film solidifies..
  • An excessive amount of alkyd mixture will necessarily wrinkle on the base, therefore, when working with products, you must adhere to the instructions.

Views

There are several types of alkyd varnishes.

Two-pack

They consist of two components, the second component is the desiccant. Before application, the mixture must be combined into one composition in the ratio specified by the manufacturer. After that, you can start painting. Typically 2 or 3 coats are required for a durable, high quality finish..

An important feature of such formulations is the short shelf life of the finished mixture – the solution is suitable for operation for 8 hours. According to their characteristics, the compositions are distinguished by the highest rates. However, the varnish has a pungent odor, as well as a low index of resistance to sunlight..

Alkyd urethane

It becomes in demand due to the peculiarities of the mixture in which alkyds react with polyurethane. The mixture is improved due to a special component – toluene diisocyanate, due to which the drying process of the varnish is carried out in a slightly different way. First of all, the solvent evaporates, and after that the mixture hardens when exposed to oxygen. The drying time of the surface with this drying mechanism is reduced, in addition, the indicators of resistance to abrasion, temperature effects and high humidity are improved..

This pattern leads to an increase in the operational life of the coating, which is explained by the high demand for the product, as well as its high cost..

However, due to the fact that half of the alkyd-urethane varnish consists of an organic solvent, its toxicity increases. Also, products are unsafe in terms of fire, therefore, the operation of coatings requires additional safety measures. In addition, if the coating does not dry out completely, and the base is already in use, situations are inevitable in which the varnish is deformed, forming serious defects. You can only remove them with a grinder..

Matte and glossy

Compositions differ only in what texture the dried base has after processing. The matte composition forms a more practical surface, since dirt and traces are less noticeable on it, there are also semi-matte mixtures. Gloss is best used in rooms with minimal lighting, as it reflects light perfectly. In terms of the set of components, both products do not differ at all, which is why the choice of the mixture will be based only on the taste preferences of the consumer..

Yacht

Based on the name, the scope of use of the products becomes clear – the mixture is produced for coating wooden yachts, but in addition to processing ships, such a specialized composition can be used on bases that are operated in a humid microclimate. However, it should be noted that yacht varnish can only be used for outdoor work..

This limitation is explained by the chemical composition of the material – to increase the indicators of resistance to moisture during the production of varnish, toxins are included in its main set of mandatory elements, for example, toluene.

For metal

By its composition, it is a mixture of alkyds and polymers. The substances provide shine and attractive appearance to metal substrates. The mixture has high resistance to chemically aggressive substances, high humidity, thermal effect on the surface, in addition, adhesion to various types of material makes it possible to use the varnish inside and outside the premises.

To properly carry out the work on applying alkyd varnish, you need to prime or putty the surface. Also, before application, the base must be cleaned of dust and dirt and degreased..

To achieve a high quality result, it is better to use products from one manufacturer.. Parquet alkyd compounds can be classified as follows:

  • Water-based mixtures. The advantage of solutions is the absence of odor and environmental friendliness of the product. But such paints and varnishes are of high cost..
  • Two-component varnishes.
  • One-component formulations.

Based on the type of coating, alkyd varnishes are divided into the following subspecies:

  • glossy;
  • matte;
  • semi-gloss;
  • semi-matt.

To give the varnish color, some masters use colors that are selected taking into account the basis on which the composition is made and what kind of solvents are used. This option creates a tinted surface on the material.

Application

The main areas of use of alkyd varnishes can be identified:

  • end parquet processing;
  • heated parquet floor;
  • Floating floors;
  • parquet, for the manufacture of which very “capricious” wood species were used – their feature is susceptibility to the influence of environmental factors;
  • metalworking products.

Consumption

The level of consumption of alkyd varnish directly depends on the type of composition used, as well as the professionalism of the master performing the processing. Manufacturers and experts agree that the composition should be applied in several layers. Usually 2-3 coats are required. It is very important to start applying the next layer only after the previous one has completely solidified. Based on this, it can be understood that the work will take at least 2 days..

The average consumption rate of alkyd mixtures is 50-70 g / m2. Some types of alkyd varnishes need to be thinned before application..

How to dilute?

White spirit is used as a solvent for alkyd compositions, which begins to evaporate as soon as the composition has been applied to the surface. Then the composition is polymerized. It is caused by chemical reactions between resin molecules and other components..

To remove the varnish from the surface, a wash is used. It is a special chemical agent that destroys the varnish and lifts the film off the material. The varnish can be washed off with powder products, pastes of different consistencies, as well as by scraping or by heat treatment..

How much dries?

Alkyd varnish is similar to glue immediately after application. After about 10 hours, some varnishes with special hardeners in the composition will already harden. Usually it takes 24 hours for one layer to dry.

It is worth noting that the thickness of the varnish film after drying may become smaller, in this case it all depends on how much of the solvent has evaporated. Its content in alkyd mixtures can be different, and based on this indicator, the level of toxicity of the composition increases or decreases.

For more information on alkyd varnish, see below..

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