Polyurethane primer: types and properties

How to apply to the surface correctly

The method of applying primers with polyurethane is simple, it is almost no different from the application of other primers, only its structure is not suitable for using a spray gun. You can apply the solution:

1. Rollers of various sizes. They can quickly and evenly paint a large area.
2. Tassels. It is better to use them as an aid for painting over hard-to-reach places - processing large areas with them takes a lot of time.

The primer-mixture is allowed to be applied to an uncleaned surface, but for better "setting" the treated area is desirable:

• clean from dust and remnants of old finishes;
• wash;
• dry and degrease;
• to close up large cracks, small ones can be left - the polymer mixture will evenly fill them, leveling the surface.

After this preparation, you can prime:

1. The solution is evenly distributed over the entire area using a roller.
2. After complete drying (after 3-5 hours), a second layer can be applied. It should be remembered that you need to work crosswise, that is, if during the first priming the direction of movement was vertical, then when applying the second layer the roller should move in a horizontal direction, this will ensure the most uniform impregnation. As a rule, no third layer is required, and after drying, you can proceed to the decorative finish.

Advantages and disadvantages

Thanks to the primer, the concrete acquires a flawless surface, in addition, the mixture helps to make adhesion with subsequent decorative coatings - varnish, paints, enamels - more reliable.

Primers based on polyurethane are considered the best for priming because they have many advantages over other formulations.

• Polyurethane primer combines well with any substrates that have a porous structure with high absorbency. Therefore, it is used not only for priming concrete, but also for surfaces made of wood, metal, brick.
• Polyurethane can be used on floors with heating switched on.
• This material is not a hindrance, even if there are dust-like particles on the base. The primer can be applied to a slightly cleaned surface, and dust particles will be bound during the curing process.
• One of the important positive qualities of the primer is the possibility of interior and exterior finishing.
• When compared with compounds of the same purpose, polyurethane is a more economical material. Of course, the consumption depends on the depth to which it penetrates into the thickness of the product, but in any case, by 1 square meter. m of surface is spent from 200 to 500 grams of polyurethane mixture, and other compounds - 2-3 times more.

The primer mix has small drawbacks, but they are not so critical:

• the drying time for most of these compositions is 2 hours, and polyurethane will take from 3 to 5 hours to cure;
• the application procedure is carried out manually, since it is not possible to use a sprayer;
• polyurethane has a relatively high price (but we must not forget that the coating is distinguished by good wear resistance and durability, and a long service life is quite worth the money).

Varnishing

After staining, in most cases, it is also necessary to varnish the product. The first layer of varnish, prepared for use, is applied according to the same calculation as the primer (150 g per 1 sq. M).

The second layer is applied after the first layer is completely dry. Then, when this paint dries up, you need to sand the MDF panel again.First, coarse-grained sandpaper is passed over its surface, and then fine-grained sandpaper is used. To prevent the lumps from rolling, the treated area is periodically moistened with water.

A week later, the MDF must be additionally polished with a grinder and abrasive paste. This is the most correct technology, although at home, working with your own hands, it is sometimes not followed, limited to ordinary varnishing.

What are they?

Epoxy primer mixes have some differences in composition, which affects their main technical characteristics.

The following factors influence soil classification:

• material from which the structure to be processed is made: concrete or metal;
• temperature regime at which the mixture begins to solidify;
• components that are included in the composition as a hardener;

• the ability to use with various paints and varnishes;
• in composition, one-component and two-component types are distinguished;
• manufacturer.

One-component

Epoxy based primer is most often available as a two component mixture. The exception is epoxy mixtures, which are applied as a pre-coat to the car body. Basically, one-component primer is produced in the form of an aerosol.

In many respects, the material is inferior to two-component mixtures, so it is not very popular among car owners.

One-component mix for concrete, in addition to its main purpose, can be used for wood processing. Epoxy coated wood structures gain good moisture resistance.

In addition, one-component mortars are used for difficult concrete substrates and to improve the level of adhesion with materials such as:

• ceramic tile;
• wood;
• linoleum.

Two-component

Two-component mixtures are the most popular for metal and concrete work. It is believed that such a composition has better quality and higher performance than a one-component primer.

Car owners prefer this particular type of primer. In addition to the excellent protective properties of the coating, two-component compounds for cars can be painted with special pastes to improve the color of the final paint layer.

For metal

Epoxy primer for metal surfaces, above all, has good anti-corrosion properties. In addition to epoxy resins, this mixture contains elements such as zinc and phosphoric acid, due to which the primer prevents the formation of corrosion. Epoxy based metal primer is mainly available in two component form.

If necessary, you can cover the epoxy layer with an acrylic primer.

Zinc-filled

A two-component zinc-rich epoxy resin mixture used as a coating for subsequent painting with epoxy and polyurethane paints. This material can also be used as a topcoat for metal structures that are subject to negative environmental influences.

Due to the high content of zinc elements, such a primer perfectly protects steel surfaces from corrosion. This coating will last more than ten years as a base layer and more than twenty years in combination with other protective compounds.

For concrete

An epoxy primer for concrete floors and walls. In turn, concrete mixes have their own classification:

Different types of compositions

There are the following types of polyurethane-based formulations:

• one-component, which consist of a main component and a solvent.Mainly a one-component polyurethane primer, such as vl, is used for interior priming, for treating wood and MDF boards, as well as for coating concrete substrates. Its main purpose is to increase the adhesion rate, strengthen the base, level the surface before applying the finishing;
• This two-component polyurethane primer comes in two different containers, one containing the polyurethane compound and the other with a hardener. Both components must be mixed with each other before use. Polyurethane primers, consisting of two components, are more durable, but have little flow due to the fact that the composition contains a hardener. This type is mainly used for priming outside premises, and this polyurethane primer is also used for concrete, floors that withstand daily high stress. If the primer is zinc-rich, then it protects metal products from corrosion and rust.

Two-component primers are very rarely used for coating wood and MDF boards. In cases where priming is the only way to protect the surface, for example, floors in a workshop, it is advisable to use a primer enamel to strengthen the concrete base and protect it from destruction.

Soil 1101

1101 Polyurethane Primer is a one-component formulation containing organic solvents. Hardens on contact with air. The main properties of this polyurethane primer:

• deeply penetrates the surface of materials;
• makes the connection of the base with the topcoat very strong;
• significantly increases the adhesion properties of polyurethane products to the surface;
• after the soil has dried, the material becomes resistant to mechanical stress, as well as the influence of technical fluids and water;
• it is applied very easily and quickly, the material is completely safe for humans.

Primer 1101 is used for the treatment of porous substrates, can be applied to concrete, plaster, cement-sand surfaces, wood, shrinkage and expansion joints of concrete floors, before the polyurethane sealing products are applied.

Primer pu 01

Polyurethane primer-primer PU 01 is a one-component product that reliably fills small pores, significantly increases the adhesion of the base with a polyurethane finish, makes the surface much stronger, and removes dust from the base. It is used for priming surfaces in front of self-leveling concrete floors, applying protective materials, enamels with a polyurethane or epoxy base.

This type of polyurethane primer has the following advantages:

Paints that can be applied

For self-painting MDF boards, it is best to take enamels, since they form a strong opaque film, they are glossy and matte. The following materials can be used:

• enamels on alkyd, alkyd-urethane or oil base;
• based on polyurethane resins;
• acrylic enamels;
• nitro paints of the NTs series;
• professional two-component polyurethane enamels;
• specialized enamels for MDF;
• car enamels.

Each of these materials has its own characteristics. But, perhaps, the last two items of the list have the best properties.

It is especially worth noting that in industrial conditions today, powder coating of MDF facades is often used. This method is extremely economical, making it possible to achieve high mechanical and chemical costs. The method is based on the ability of opposite charges to be attracted to each other. It was originally used for ceramics, metals and other materials that can withstand high temperatures.

It is now almost impossible to paint MDF facades in standard home conditions using a powder method.For such painting, special expensive equipment is needed, which can pay for itself only with constant frequent use, and it is unlikely that it will be possible to place it at home.

Primer under the self-leveling floor. Types and application

In general, all types of primer can be divided into two categories:

• dry, which require preparation of a mixture before use;
• liquid, can be used immediately after purchase, do not require special preparation, except for mixing.

Universal primer

In turn, these mixtures can be divided into several more types.

Table. Types of primers for self-leveling floors.

mineral primer

Floor priming

Apart from this classification, primers can be divided into:

• reinforcing, which are used for loose types of bases. They have high penetrating abilities;
• regular or standard;
• deeply penetrating, ideal for plastered surfaces, concrete substrates. They perfectly increase the adhesion rate.

Deep penetration acrylic primer

There are several other types of primers. This is a biocidal primer, polyurethane, silicone, concrete contact and a material with increased adhesion properties.

Concrete contact

concrete contact

Biocidal primer has the ability to negatively affect various microorganisms, fungus and mold, protects the floor surface from them. It penetrates deeply into the base structure and has a long-lasting protective effect.

A primer based on polyurethane copes well with chemical influences - the surface treated with it will be protected from the appearance of oil, gasoline stains, and is not afraid of solvents. This is an economical option in terms of costs, but far from the cheapest.

Preparation of the primer mixture

There are also silicone primers that are not afraid of moisture at all. They penetrate very deeply into the surface of the base, while managing to displace excess moisture from it and close access to a new portion of liquid. Silicone primer can be applied to wet screed and also has bactericidal properties.

Concrete Contact is a crystallizing primer with enhanced adhesion properties. But it can only be used in rooms with a certain microclimate. The material does not interfere with the penetration of water, therefore it is not used in bathrooms and saunas.

The pigment provides a high-quality treatment of the entire floor

Primers with enhanced adhesion properties (or hydrophobic primers) have excellent adhesion rates, but are afraid of the effects of various alkaline substances, including those contained in concrete. Because of this, they require periodic updating of the layer.

Dispersion primer Uzin PE 360

RTM Polyurethane Floor Primer

Starting work on the device of a multilayer polymer coating, it is necessary to prepare the base before applying polymer layers.

Preparation of a concrete base includes:

• grinding the concrete surface;
• repair of the base or installation of cement screeds, if necessary (for these purposes, RTM offers MAX RS repair mortars and MAX TOP polymer cement screeds);
• cutting of structural joints;
• dedusting of concrete;
• application of a primer to remove dust, increase the strength of the concrete and improve the adhesion of the substrate and subsequent layers.

RTM company produces and sells a one-component polyurethane primer MAXFLOOR 105. This material is moisture-cured. It is used as an impregnation primer on mineral and porous substrates (concrete, cement screed, asbestos cement, wood), to prepare a concrete base for applying polymer floor coverings.

MAX One-Component Polyurethane Primer can also be used as a stand-alone coating to increase wear resistance, strength and dust control of mineral surfaces.

Application features

A one-component polyurethane primer RTM is applied to the concrete base before installing the polyurethane flooring.

When installing self-leveling polyurethane floors, priming is carried out in two or more layers, achieving complete closure of the pores of the base.

Material consumption:

• 1st layer: 150-250 g / m2
• 2nd layer: 150-200 g / m2

It is impossible to apply the material with a consumption of one layer more than indicated above, because this can lead to the formation of defects in the coating (bubbles and pores).

It is also necessary to protect the surface from precipitation during the entire curing cycle. The best conditions for work are air temperature: + 5 ° С… + 25 ° С and air humidity 30-80%.

MAX polyurethane primers have a number of advantages:

• high adhesion to the base;
• curing in the shortest possible time;
• chemical resistance.

For more detailed information and advice on the selection of the optimal polyurethane flooring system, please contact the specialists of the RTM company through the feedback form or by phone numbers indicated on the website.

Types of primers

As building technologies improve, new types of primers are constantly emerging, serving to prepare and strengthen surfaces before finishing. Each composition is distinguished by a special formula, which determines the purpose. The wide range of primers can be divided into several types:

• penetrating and strengthening soils;
• compositions for the regulation of porosity;
• materials that form a flat and maximally smooth surface;
• mixtures that improve adhesion.

You can also highlight universal formulations for internal and external use, as well as specialized products - for external or internal use only. Specialists recommend choosing specialized products, since they are much better withstand stress and harmful influences. Universal materials do not differ in the presence of special qualities - the characteristics are very mediocre.

By composition

The screed primer can differ in the type of substrate. So, there are four main types of primers:

Emulsion or acrylic primers. It is one of the most popular and versatile materials that can be combined not only with concrete surfaces, but also with bricks, wood, and clay.Among the main advantages is a fast speed of complete drying, usually produced in a concentrated form. The surface treated with these soils dries completely after 3-4 hours under normal conditions.

Alkyd soils. If the concrete screed will be laid on a wooden base, then prime with just such a composition. The material dries for a very long time, but its main plus is that it loosens the wood. Due to this property, the concrete screed sticks very strongly to the wooden surface, does not crack from thermal vibrations. After the alkyd primer is absorbed into the wood, it begins to protect the wood from putrefaction, the formation of fungus and mold.

Related article: Choosing paint for linoleum and staining technology

Epoxy primer. It is also called polyurethane primer. It is a pigmented solvent based compound that is ideal for concrete flooring. Epoxy primers are used primarily for the treatment of screeds prior to coating with self-leveling compounds.

Polystyrene based primer. Often, this primer is used to treat wood floors before screed. But the composition is widely used for concrete - it has good adhesion and high strength.

By depth of penetration

Concrete floor primers also differ in penetration depth. There are surface primers and deep penetration formulations. So, surface materials are widely used for finishing well-prepared solid bases - here the depth for soil penetration does not exceed 1-2 cm. The soil of deeper penetration is able to penetrate the concrete floor up to 10 cm, gluing the layers of concrete screed and strengthening it.

Cement screed primer: making the right choice

Depending on the type of room, its functionality and the microclimate present in it. Therefore, you need to figure out how to prime the self-leveling floor.

When repairs are made in an apartment or a private house, the main source of aggressive effects is moisture, therefore, the floor primer must have water-repellent properties.

Biocidal primer for cement screed

Biocidal and polyurethane primer

When there is a basement in the house, and a room that will be renovated is located above them, then there is a high percentage of mold and mildew on the floor surface. Therefore, for surface treatment, a biocidal primer should be used, it has dual properties, namely:

• Deep penetration and protection against moisture penetration;
• Antiseptic properties (protection against mold and mildew).

Polyurethane primer and epoxy paint

If a self-leveling concrete coating is created in a garage, then various aggressive agents (oils, solvents, gasoline, etc.) will act on its base. In this case, a primer for self-leveling floors based on polyurethane will be simply irreplaceable. And when the floor covering, in addition to protection, needs to be given a decorative look, then epoxy paint can be used.

Primers with enhanced adhesion and hydrophobic properties

Hydrophobic primers have excellent adhesion properties, but they do not tolerate the action of alkalis contained in concrete. Therefore, a place not processed after priming will have to be re-primed for a certain period of time. It is rather difficult to answer the question of whether it is necessary to prime the self-leveling floor with hydrophobic mixtures, because there are a huge number of them and, moreover, with different characteristics.

Silicone primers

Silicone Primer and Concrete Contact

This type of waterproofing primer has excellent moisture resistance due to its properties.The applied composition penetrates deep into the concrete coating, displaces the moisture present there and protects against reappearance, and also prevents the development of mold and mildew.

Primer "Betonokontakt"

This type of primer is crystallizing and has excellent adhesion properties. But, unfortunately, its use is limited only to rooms with a normal microclimate, because it does not have protective properties against moisture penetration and the formation of mold and mildew. The purpose of this type of primer is to create a special bonding film on the concrete surface.

With the correct selection and application of the primer, the self-leveling floor will serve "faithfully" for decades, so its use is mandatory, especially in rooms with a special microclimate.

You cannot save on primers, because the final result of the repair depends on this, and in which case it will be much more expensive to redo the entire coating. Therefore, you need to remember the saying "The miser pays twice" and start renovating the premises.

We also recommend that you learn about epoxy self-leveling floors, areas of application and how to fill with your own hands.

Features of applying a primer after screed

The priming of the finished screed must be done after the concrete surface is completely dry and hardened. Cement mortars can dry for three weeks or more. Before applying the primer, the concrete floor is thoroughly cleaned of sand and dust - it is best to use a vacuum cleaner. The cleaner the surface, the better the adhesion will be.

Then a solution is prepared. If the primer is acrylic, it is recommended to mix it thoroughly. If the composition is epoxy, then the two components are mixed (the proportions are indicated on the packaging). If an acrylic concentrate is used, then it is diluted with water according to the manufacturer's recommendation and mixed thoroughly.

Related article: Quick-drying floor varnish: what are the advantages and which one is better to choose?

As for the application, the first step is to process all areas adjacent to the walls. It is quite problematic to process there with a roller.

It is important to cover each area with soil - there should not be left untreated areas. Then the primer is applied to the main surface

At first, it is carried out several times over the surface - the composition should get on it, then several more times it is carried out over an already damp place in order to distribute the material as evenly as possible.

After a day, the primer will dry out, and you will get an ideal, protected base, fully prepared for the subsequent finishing. Tiles, ceramics, and other finishing floor coverings can be laid on such a floor. After the primer has dried, the floor will not become dusty. Also, with any adhesives, there will be good adhesion.