Polyurethane adhesive: characteristics and features of the application

The modern market offers a wide range of adhesives that allow you to get a strong and reliable connection of various items. But many of them are designed for specific actions and materials that are not “to the liking” of the buyer. Popular is the polyurethane composition, which is characterized by its versatility and is used to work with any materials.

Virtually the entire composition of polyurethane glue is solid synthetic resin, which distinguishes this mixture from all analogues. In them, the resin - it is only a small part of the composition, everything else - water. A feature of the polyurethane product is its hardening.Upon contact with water vapor, it enters into a chemical reaction, resulting in a strong film. Also, during the reaction, carbon dioxide and bubbles are released, which makes the polymerization process similar to the drying of the foam.

There are two-component and one-component polyurethane adhesive. The second consists of prepolymers of isocyanates, is easy to use and allows you to quickly do a lot of work. It has a high viscosity, thanks to which any material is instantly glued to the required surface.

The bicomponent has two substances in its composition, which in an unmixed state have a low viscosity. And only after mechanical mixing, the glue takes up its working condition. The procedure of mixing components requires certain temperature conditions and specific proportions.

Polyurethane composition has several advantages, so that he and demand among buyers.

• resistance to high humidity - this mixture can be used even on the streets for garden furniture, which is used all year round in any weather;
• reliability and durability - the glue guarantees a quality bond when combining different materials, even wet wood or covered with all sorts of antiseptics;
• open time - when working with polyurethane glue, you don’t need to hurry at all, you can carefully apply the composition for about 20 minutes and apply all the details with precision;
• comfort during work - glue ensures sliding of lubricated elements, which is convenient when assembling tight structures;
• It is appropriate to use for laying parquet - the mixture firmly fixes the tree with the floor and does not allow the material to swell.

Polyurethane hot melt glue is a viscous liquid that is gray, white or amber. Complete with a two-component mixture has a container with a hardener. Glue is sold in plastic or metal buckets up to 5 kg. The mixture based on polyurethane has excellent mechanical properties.

You can work with the mixture in conditions with temperatures ranging from 0 to +40 degrees, and after pasting the composition maintains from -50 to +120 degrees. Please note that for good adhesion, the surface must be thoroughly cleaned from dust and dirt and must be degreased before applying glue.

The properties of the glue also include preventing the formation of fungus and mold. During application, the mixture foams a little, so that the space between the two materials is completely filled with the composition. Solvents are not used for the production of glue, it does not smell, which has a positive effect on human health and the environment.

Consider the most popular polyurethane compositions.

• Soudal - this option is sold in an aerosol, it is easy to use. The adhesive qualitatively fixes foam panels and plasterboard plates. The mixture dries in just an hour and is consumed economically.
• Polynor fixo - heat-insulating glue, used to join the plates of polystyrene foam, polyurethane foam and mineral wool in the insulation of the building.It is sold in an aerosol can therefore it is easy to use.
• "Moment Crystal" - glue of the domestic company, designed to work with plexiglass, rubber, metal and other materials. Resistant to moisture and alkalis.

• "Desmokol" - solution of polyurethane rubber in organic solvents. With it, you can get a strong seam that will not be afraid of moisture and temperature changes. The undeniable advantage is that this composition dries very quickly.
• Mapei - tile adhesive from the Italian manufacturer.

These mixtures are offered at different cost, the choice of composition depends on the operating conditions, as well as on the materials that it must glue. Experts recommend buying the mixture in large hardware stores, where you can compare prices from different manufacturers, study the composition of the glue and the conditions of its operation.

When buying an adhesive, not only polyurethane, special attention should be paid to its characteristics. Even the smallest details cannot be overlooked.

• The time that the applied adhesive retains its elasticity — during this period, you can neatly apply the composition, remove excess material, and fit the glued elements of flexible metal or wood with high quality.That is why novice professionals are encouraged to choose formulations with the highest rate. Quick-drying materials will cause a lot of trouble.
• Indicator of spreadability - this property is important to consider in two situations: when gluing tiles on vertical surfaces, or if there is a base with a lot of flaws, such as pits or bulges. Too dense composition does not spread on the material, respectively, it does not fall into all voids, and high-quality adhesion is not guaranteed, no matter what it will be - PVC, CIP panel, polystyrene foam or ceiling plinth.

• Expiration date to drawing - this property is considered when buying two-component adhesives. After mixing the two substances for several hours, the adhesive retains its properties. From the time after which the composition loses its characteristics, depends on the amount of the prepared solution.
• Sphere of operation - some solutions are best used for aerated concrete or parquet, and some - for sandwich panels or stone. Some mixtures are suitable for molding on curved surfaces, gluing curtain rods to the ceilings, and others - for high-quality insulation from inside or outside the room.

In order to achieve high-quality and reliable bonding of surfaces, it is necessary to follow all the rules and recommendations of specialists. All elements should be thoroughly cleaned of dust, dirt and treat them with a degreasing agent. The application of glue is carried out with a thin layer with a brush, spatula, sprayer or special equipment when it comes to manufacturing plants.

Note that excess glue can get on a clean surface. In order not to worry later about how to remove the dried composition, it is better to remove it immediately with a special solvent.

You can glue different materials using different technologies.

• Hot method - it is used with Desmokol glue, the solution is applied to both objects and left for half an hour. The properties of the substance are activated under the influence of high temperature (approximately 85 degrees) within a few minutes. After that, the surface must be strongly pressed to each other.
• Cold method - to glue the objects, it is necessary to apply the mixture on both surfaces, after 10 minutes, re-apply the adhesive with a thin layer, dry and combine the elements for a few minutes.
• Humidification of the surface - for high-quality adhesion, the elements to be glued are sprinkled with water and pressed against each other.This method is appropriate to use when there is a special press, as it requires the most powerful compression.

It is necessary to work with glue in special clothes, a respirator and goggles.

In winter, the polyurethane composition does not lose its characteristics, but becomes more viscous, therefore, it is more difficult to work with it. Many believe that it can be diluted or constantly heated, but experts do not recommend this. The optimum temperature for working with glue is +20 degrees. Therefore, if you work at low temperatures, it is better to heat the barrel once and pour the glue into small containers that close tightly.

Note: container with glue can not be kept near an open flame, and even more so to heat on the fire. To save the optimum temperature, it is recommended to store the glue in a thermos. Do not heat the medium above +40 degrees, and also do not glue hot surfaces. If the glued items have a temperature above +80 degrees, the glue will harden faster and its adhesion will increase.

If, upon completion of the work, you still have the composition in the container, squeeze the bottle and close tightly so that all the air escapes.This will prevent the rapid deterioration of the substance, and it can be used more than once.

For information on how to use polyurethane glue, see the next video.