Introduction of polyurethane sealant

The main application of polyurethane sealant is civil engineering and construction industry, transportation industry and so on. For example, in Japan, about 75 to 80% of polyurethane sealants are used in construction, 15% are used in automobiles, machinery manufacturing, etc., and 5% are used in civil engineering and other areas.
Specific applications in construction include: the connection of prefabricated concrete and other building materials and the filling and sealing of construction joints, the sealing and caulking around the wooden frames of doors and windows and the concrete between the walls, and the pasting of lightweight structures (such as curtain walls) on buildings. Caulking, waterproof caulking of balconies, swimming pools, bathrooms and other facilities, sealing of air-conditioning and other system connections, sealing of insulating double glazing, and insulating window frames, etc.
The applications of polyurethane sealants in automobiles include: assembly and sealing of windows (mainly windshields), and assembly of car bodies and other parts.
Polyurethane sealant can also be used for flexible joints of cables (such as underground cables) and potting of electronic components to prevent dust and shock; for thermal insulation systems such as refrigerated trucks, cold storage insulation layers and low-temperature container bonding and sealing, etc.

Polyurethane sealants are generally divided into two basic types, one-component and two-component, one-component is moisture curing type, and two-component is reaction curing type. The one-component sealant is easy to construct, but the curing is slow; the two-component has the characteristics of fast curing and good performance, but it needs to be formulated during use, and the process is more complicated. Both have development prospects.
According to whether there is fluidity, polyurethane sealants can be divided into non-hanging type and self-flowing parallel. The non-hanging type is used for vertical surfaces, inclined surfaces, ceilings and other occasions, and will not shift, slide or flow due to the weight of the rubber strip before curing; while the self-leveling type is specially used for horizontal occasions. According to the properties after use, it can be divided into non-dry type, semi-dry type and fully cured elastomer type.

1. Use cotton yarn to remove the dust, oil and water on the surface of the glued part. If the surface is easy to peel off and rust, it should be removed with a metal brush in advance. If necessary, you can also wipe the surface with organic solvents such as alcohol and acetone.
2. According to the shape of the construction part, cut the tip of the sealant into a certain shape and size, and apply the glue to the construction part with a manual or pneumatic glue gun.
3. Carry out surface leveling and finishing work within the surface drying time. The parts with particularly strict surface requirements should be covered with protective tape on both sides of the glued part, and peeled off after scraping. If you accidentally contaminate the non-construction part, wipe it with a cotton cloth dipped in alcohol.