Two-component sealants: features and scope of their application

It is almost impossible to carry out most types of construction work without the use of a sealant. It is an irreplaceable material for hydro, heat and vapor insulation, as well as for connecting various fragments. The two-component version of the sealant is mainly used in industry.

A special feature is the need to mix the two components before starting work.


Two substances of a two-component sealant are combined in certain proportions according to the instructions, then mixed. After vulcanization, the mass is a rubber-like material capable of elongation in the event of rupture..

The most common two-component option is polyurethane. The product contains a polyol-containing paste and a special hardener. These substances do not interact with the environment, and therefore have a long shelf life before mixing..

Another variety is polysulfide sealant. The composition of the material includes a thiokol, which can be compared in structure to rubber. One of the components contains a polymer, a plasticizer and a filler, and the second contains a structuring agent, a plasticizer and a pigment. The sealant is a synthetic rubber with good adhesion properties. Often used in shipbuilding.

Special attention should be paid to a two-component silicone sealant, since it is he who is the most common of all options..

Its versatility is due to its wide range of applications.

Can be used:

  • when installing double-glazed windows;
  • for working with polycarbonate structures, wall panels;
  • for sealing the seams of formwork and air ducts;
  • when installing industrial and street lighting equipment, gaskets in engines and radiators;
  • for sealing units of household appliances, electronic devices and boards;
  • in the manufacture of aquariums and glass products;
  • for sealing artificial reservoirs.


As noted, two-component sealants have a long service life..

This is not the only benefit – there are other benefits:

  • the possibility of using at low temperatures;
  • strength, elasticity and durability of the seams;
  • excellent adhesion properties;
  • indicative physical and mechanical qualities;
  • exact time of vulcanization;
  • UV resistance;
  • the possibility of staining with organic and water-based paints;
  • wide scope.

The main advantage of two-component polyurethane sealants is reliable frost resistance. This is due to the fact that the moisture contained in the atmosphere does not participate in the hardening process of the material, and therefore this option is perfect for outdoor work..


Despite the large number of advantages, some disadvantages of two-component sealants cannot be ignored:

  • due to mixing of components, the operating time increases;
  • care must be taken when mixing the composition;
  • glue should be applied immediately after preparation – delays and “smoke breaks” are unacceptable.

Areas of use

Before purchasing a two-component sealant pay attention to the options recommended by the craftsmen in the field of construction and renovation.

  • “Neftezol” NF 88 (16 kg) – bitumen-polyurethane glue. Scope of application – gluing materials from metal, blocks, foam glass. Also suitable for sealing joints.
  • Ecoroom PU-20 designed for sealing expansion joints, cracks and crevices on the facade. Characterized by excellent adhesion to concrete, metal and wood surfaces.
  • “Tektor” 201 is a two-component mastic for sealing joints of fencing structures, panel slabs, during construction and repair work.

  • “Germotex” used for sealing expansion joints and cracks on concrete floors and slabs. Contains synthetic rubber for good adhesion, reliability and structural integrity.
  • “Sazilast 22” provides sealing of expansion joints, joints and cracks in the facade coating. Suitable for concrete, polymer concrete, foam concrete, brick. Differs in light gray color.
  • Polikad M – a good means for sealing double-glazed windows. Contains polysulfide, plasticizer, pigment, fillers. Considered an effective vapor barrier.

Shore hardness

The most important indicator specified in the list of technical characteristics of the sealant is Shore hardness. It is a method for measuring the hardness of a composition. The results obtained are presented as a numerical value with a letter corresponding to the scale. High hardness is determined by a large number. The letter A denotes softer indicators, the letter D denotes harder.

The result is achieved by detecting the resistance of the material to the indentation of a tip of a certain shape under the action of the force of the pressure of the spring..

For example, Germet, a popular construction company. pro offers two-component polyurethane sealants with Shore hardness already in the name: Germet. Pro 20 has a 20A rating, respectively, Germet. Pro 40 – 40A.


For operation, the components of the sealant, which must be stored in special separate containers before use, must be mixed using a special technology. Care must be taken that the environment does not negatively affect the product. During storage, it is necessary to protect the container with the hardener from moisture..

For cooking, use a special mixer, which is a construction mixer or electric drill. A nozzle is put on the device, then you need to use a spatula or a special pistol.

When working with a two-component sealant, there are a few more tips to consider:

  • observe all proportions indicated in the instructions;
  • watch the air temperature during operation – it should not be lower than indicated on the package;
  • thoroughly clean and wipe the surface well before work;
  • mix only the right amount – no more, as the sealant hardens very quickly;
  • do not take breaks and delays, as the prepared material, again during its inactivity, can harden;
  • in the case of an unsuitable consistency, one of the components cannot be added – a new composition must be made.

Thus, two-component sealants have a wide range of applications., and the modern market offers many options from various manufacturers. However, in order to get the highest quality result from the use of two-component varieties, it is necessary to comply with all preparation conditions.

For how to use a two-component sealant, see the following video.

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