Polyurethane adhesive refers to the adhesive containing the carbamate group (-nhcoo -) or isocyanate group (-nco) in the molecular chain.
The main features
Divided into two major categories of isocyanate and polyurethane (pu), because it contains strong polarity, chemical active high isocyanate and carbamate groups, so it can and containing active hydrogen material, such as foam plastic, wood, leather, fabric, paper, ceramics and other porous materials, and the smooth surface such as metal, glass, rubber, plastic materials have excellent chemical bonding strength.
Hydrogen bonding between polyurethane and the bonded material will enhance the molecular cohesion, thus making the bond more firm.
The diversity of polyurethane adhesives provides solutions to many bonding problems, and is especially suitable for other types of adhesives can not be bonded or bonding difficulties.
In addition, polyurethane adhesive also has good toughness, adjustable, easy bonding process, low temperature resistance and excellent stability.
It is because of the excellent adhesive performance and the adhesive adaptability to a variety of substrates that polyurethane adhesives have become a rapidly developing adhesive at home and abroad.
The main ingredients
Polyurethane adhesives are mainly composed of ammonium isocyanate, polyols, alkylated polyethers, polyester and epoxy resins, fillers, catalysts and solvents.
With high reactivity, room temperature curing, impact resistance and many other excellent properties.
Polyurethane adhesive is generally divided into two basic types, one component and two components, the single group is divided into moisture consolidation type, the two groups are divided into reaction consolidation type.
The one-component adhesive is convenient for construction but slow for curing.
The two components have the characteristics of fast curing and good performance, but they need to be prepared when used, and the process is more complicated.
Each has a future.
Polyurethane rubber can be divided into non-sag and self- drooping according to whether there is fluidity.
Non-sag type is used for vertical plane, inclined plane, ceiling and other occasions. Before curing, it will not be offset, slide or flow due to the self-weight of rubber strip.
The self-leveling type is designed for horizontal applications.
According to the properties after use can also be divided into dry type, semi-dry type and fully solidified elastic body.
The main application
1. Bonding between composite material and metal frame;
2. Adhesive and caulking of automobile;
3. Bonding of glass fiber reinforced plastic with metal;
4. Sealing adhesive;
5. Reactive hot melt adhesive;
6. Subprime adhesive;
7. It can also be used in aerospace, electronics, metal materials, packaging materials, shipbuilding, textile, rubber, plastics, ceramics, construction, automobile and other industries;
8. It can be used for extruding polystyrene foam and bonding with steel plate, aluminum plate, calcium silicate and cement wall.