With long-term and high-quality sealing of joints and cracks, polyurethane two-component sealants are widely used. They have high deformation and elastic properties, so they can be used as butt sealants in the field of repair and housing construction.
Description
The material is versatile, but on store shelves is less common than a single-component counterpart. This is because skills will be required to prepare the material and apply it. In this regard, such a sealant is used mainly in the field of industrial construction.
Creature
Two-component polyurethane sealants consist of a paste with polyols and a hardener. Remaining in a separate state, they maintain a long shelf life, since they are not affected by the external environment. Two-component compositions have one important advantage - the ability to use at low temperatures. This is due to the fact that moisture in the air does not take part in the polymerization.
The mixture provides a strong elastic and durable seam. Polyurethane two-component sealants have one drawback, which is expressed in the fact that the mixing of the components is accompanied by the need to release additional time. Polyurethane cool mix should be used immediately after kneading. The quality of the composition will depend on how correctly the proportions were observed when mixing.
Main types and types
Bicomponent formulations can be classified as intended. They are represented by mixtures for indoor and outdoor use. Sealants are also divided into materials that must be used under the influence of vibration or without it. Among the main types, those that are applied outdoors or under water should be distinguished. You can also divide the compounds according to the material for which they are intended. It can be: wood, metal, stone, plastic.
Basic properties
Two-component polyurethane sealants have excellent properties and characteristics. They have high elasticity, which often reaches 100%. These materials adhere well: brick, metal, wood, plastics, glass ceramics. Application can be carried out on previously used sealant. Mixtures have high wear resistance. They undergo prolonged exposure to ultraviolet radiation, mechanical stress, high humidity, as well as temperature changes. The material provides waterproofing and reliable sealing for a long time.
Mixtures have a high thixotropy, which is expressed in the ability of the material to collapse under mechanical stress, and to increase viscosity at rest. For example, you can consider creating a seam, the length of which is 2 m. Its width is 2 cm and the depth is 1 cm. In this case, 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 suggests that the material has a low thixotropy.
Polyurethanes are able to maintain the shape of seams, the length of which reaches 6 m. Their depth can be equal to 1 cm or less, but some compounds are capable of more. Another rather useful property is minimal shrinkage after the completion of the polymerization process. Sealants are quickly cured and can be machined. This means they can be sanded.
Some cons
If we compare with silicone analogues, then the polyurethane mixture can be painted. However, the described compositions also have disadvantages. Although the sealant has high adhesion to many surfaces, there are materials that require primer or primer to increase adhesion. This is characteristic of some plastics.
Polyurethane compounds should not be used on wet surfaces. If the moisture content of the base is more than 10%, then without the use of primers sufficient adhesion cannot be achieved. Polyurethane sealants are not able to withstand severe temperature extremes from - 60 to + 80 ° C. If the temperature rises above + 100 ˚, the material begins to collapse and loses its performance characteristics.
Oxyplast: the nuances of application
Oksiplast two-component polyurethane sealant is used for sealing joints in reinforced concrete and concrete structures. The deformation should not be more than 25%. The material is suitable for sealing cracks, joints and cracks, as well as for repairing concrete roofs.
Only on previously cleared of dirt and dust, as well as on 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 ° C. The temperature can be lowered, while the time of use increases, because the composition gradually cures, it becomes inapplicable.
Dilution of the mixture is unacceptable. Leveling is done with a special spatula or a tool suitable for this. Avoid rain on freshly applied sealant. In order to comply with the design thickness, use adhesive pads.
Creation of Oksiplast sealant
This mixture is a gray or white thixotropic mass. The polymer is a two-component polyurethane composition, which acquires its properties in the process of cold curing after mixing the ingredients under the influence of natural moisture from the air.
The bulk is supplied in a plastic container where the hardener is located. The sealant is ready to mix in a ratio of 6 to 1 by weight. The total mass of the kit is 12 kg. The sealant lasts longer than 5 hours in the standard version. This is true at 23 ° C and a relative humidity of 50%. In the winter version, the viability of the mixture is 3 hours or more at the same temperature and humidity. The time to cure can be reduced if the temperature rises.
Description of the two-component sealant "Technonikol 2K"
The Technonikol two-component polyurethane sealant is marked 2K. It is used to seal cracks, 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 occurs, the result of which is curing. The speed of this process increases with temperature. After this, the sealant gains high adhesion to building materials.
The two-component polyurethane sealant Technonikol 2K has a wide range of operating temperatures. It varies from - 60 to + 70 ˚. The material is resistant to ultraviolet, highly elastic and can be painted with acrylic facade paints. The scope is sealing:
- expansion joints;
- vertical and inclined 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 premises, but their use is allowed only after the mixture has completely cured.