Two-component polyurethane sealant: definition, creation, types and types, characteristics, properties and nuances of application

2024 Author: Howard Calhoun | [email protected]. Last modified: 2023-12-17 10:16

With long-term and high-quality sealing of seams and cracks, polyurethane two-component sealants have found their wide distribution. They have high deformation and elastic properties, therefore, they can be used as butt sealants in the field of repair and housing construction.

Description

The material is versatile, but it is less common on store shelves than a one-component counterpart. This is due to the fact that the preparation of the material and its application will require skills. In this regard, this sealant is mainly used in the field of industrial construction.

Creation

Two-component polyurethane sealants consist of a paste with polyols and a hardener. Remaining in a separate state, they retain a long shelf life, since they are not affected by the external environment. Two-component compositions haveone important advantage - the ability to use at low temperatures. This is due to the fact that the moisture in the air does not take part in the polymerization.

The blend provides a strong elastic and durable seam. Two-component polyurethane sealants have one disadvantage, which is that the mixing of the components is accompanied by the need to release additional time. Polyurethane adhesive mixture should be used immediately after mixing. The quality of the composition will depend on how correctly the proportions were observed when mixing.

Main species and types

Two-component formulations can be classified according to purpose. They are represented by mixtures for indoor and outdoor use. Sealants are also divided into materials that must be used with or without vibration. Among the main types, one should single out those that are applied outdoors or under water. You can also subdivide the compositions according to the material for which they are intended. It can be: wood, metal, stone, plastic.

Basic Features

Polyurethane two-component sealants have excellent properties and characteristics. They have high elasticity, which often reaches 100%. These materials bond well: brick, metal, wood, plastics, glass ceramics. Application can be carried out on previously used sealant. Mixtures havehigh wear resistance. They undergo prolonged exposure to ultraviolet radiation, mechanical stress, high humidity, and temperature changes. The material provides waterproofing and reliable sealing for a long time.

Mixtures have high thixotropy, which is expressed in the ability of the material to break down under mechanical action, and at rest to increase viscosity. Using an example, we can consider the creation of a seam, the length of which is 2 m. Its width is 2 cm, and its depth is 1 cm. Some kind of sealant was used. 20 minutes after its application, it may be found that the material has slipped down from the top of the seam. This indicates that the material has low thixotropy.

Polyurethanes are able to retain the shape of seams up to 6 m long. Their depth can be 1 cm or less, but some compounds are capable of more. Another rather useful property is the minimum shrinkage after the completion of the polymerization process. Sealants are fast curing and can be machined. This means they can be sanded.

Some cons

When compared with silicone counterparts, polyurethane mixtures can be painted. However, the described compositions also have disadvantages. Although the sealant has strong adhesion to many surfaces, there are materials that require the application of a primer or primer to increase adhesion. This is true for some plastics.

Polyurethane compounds should not be used on wet surfaces. If the moisture content of the base is more than 10%, then sufficient adhesion cannot be achieved without the use of primers. Polyurethane sealants are not able to withstand severe temperature changes from -60 to + 80 ˚С. If the temperature rises above + 100 ˚С, the material begins to break down and loses its performance.

"Oxyplast": application nuances

Two-component polyurethane sealant "Oksiplast" is used for sealing joints of structures made of reinforced concrete and concrete. The deformation should not be more than 25%. The material is suitable for sealing gaps, joints and cracks, as well as repairing concrete roofs.

Only pre-cleaned from dirt and dust, as well as a dry surface, it is necessary to apply 2K polyurethane sealant. The two-component composition should be used in such a way that a syringe or spatula is involved in the work. Mastic is produced within 6 hours at a temperature of 23 ˚С. The temperature can be lowered, while the use time increases, because the composition gradually vulcanizes, it becomes inapplicable.

Dilution of the mixture is unacceptable. Leveling is done with a special spatula or tool suitable for this. Avoid rain on freshly applied sealant. Release pads must be used to maintain design thickness.

Creation of Oxyplast sealant

This mixture is a gray or white thixotropic mass. The polymer is a two-component polyurethane composition, which acquires its properties during the cold curing process after mixing the ingredients under the influence of natural moisture from the air.

The bulk is supplied in a plastic container containing the hardener. The sealant is ready to be mixed in a ratio of 6 to 1 by weight. The total weight of the kit is 12 kg. The pot life of the sealant is more than 5 hours in the standard version. This is true at 23°C and 50% relative humidity. In the winter version, the pot life of the mixture is 3 hours or more at the same temperature and humidity. The time to cure can be reduced if the temperature is increased.

Description of the two-component sealant "TechnoNIKOL 2K"

Two-component polyurethane sealant "TechnoNIKOL" is marked "2K". It is used for sealing gaps, interpanel joints and cracks in the repair and construction of all buildings and structures for industrial and civil purposes. After the components are mixed, a chemical reaction takes place, resulting in curing. The rate of this process increases with increasing temperature. After that, the sealant acquires high adhesion to building materials.

Two-component polyurethane sealant "TechnoNIKOL 2K" has a wide range of operating temperatures. It varies from - 60 to + 70 ˚С. The material is resistant toUV resistant, highly elastic and can be painted over with acrylic facade paints. The area of use is sealing:

• expansion joints;
• vertical and oblique joints;
• building structures;
• prefabricated and monolithic reinforced concrete structures.

Deformation of the seams can be 25%. This two-component polyurethane joint sealant can be used in residential areas, but should only be used after the mixture has fully cured.