2021-10-23
Polyurethane adhesives are adhesives containing carbamate group (-NHCOO-) or isocyanate group (-NCO) in the molecular chain.
Main features
It can be divided into polyisocyanate and polyurethane, because it contains isocyanate and carbamate groups with strong polarity and high chemical activity, so it can be excellent with materials containing active hydrogen, such as foam plastics, wood, leather, fabrics, paper, ceramics and other porous materials, as well as metals, glass, rubber, plastics and other smooth surface materials. Learn cohesion. The hydrogen bonding between polyurethane and the bonded material will enhance the molecular cohesion and make the bonding more firm.
The diversity of polyurethane adhesives provides solutions to many bonding problems, especially where other types of adhesives are not able to bond or where there are difficulties in bonding.
In addition, polyurethane adhesives also have good toughness, adjustability, simple bonding process, excellent low temperature resistance and excellent stability. It is precisely because of its excellent bonding performance and adaptability to various substrates that polyurethane adhesives have been widely used and become the fastest-growing adhesives at home and abroad.
Main Components
Polyurethane adhesives are mainly composed of ammonium isocyanate, polyols, polyethers containing alkyl groups, polyesters and epoxy resins, fillers, catalysts and solvents. It has many excellent properties, such as high reactivity, curing at room temperature, impact resistance and so on.
Polyurethane adhesives are generally divided into two basic types: one component is moisture curing type and two component is reaction curing type. One-component adhesives are easy to construct, but slow to solidify. Two-component adhesives have the characteristics of fast solidification and good performance, but they need to be prepared when used, and the process is more complex. Both have their own development prospects. Polyurethane adhesives can be divided into non-sagging and self-leveling according to their fluidity. The non-sagging type is used in vertical plane, inclined plane, ceiling and other occasions. Before curing, there will be no offset, sliding or flow due to the weight of the tape; while the self-leveling type is used in horizontal occasions. According to the properties after use, it can also be divided into non-drying type, semi-drying type and fully cured elastomer type.
Reference Formula
component
Percentage of mass
Composition description
Aliphatic polyurethane (PBA)
5-8%
Aliphatic Polyurethane (IPDI)
5-10%
Vinyl vinyl acetate copolymer (VAE)
25-30%
Hydrogenated rosin
0-1%
Sodium bicarbonate
0-1%
1,4-butanediol
1-3%
Bactericide
0-1%
silicone defoamer
0-1%
Sodium dodecylbenzene sulfonate
1-3%
acetone
1-3%
water
allowance
Main Applications
1. Bonding between composite materials and metal frames;
2. Adhesive filling of automobiles;
3. Bonding of glass fiber reinforced plastics to metals;
4. Sealing adhesives;
5. Reactive hot melt adhesive;
6. Subprime mortgage adhesives;
7. It can also be used in aerospace, electronics, electrical, metal materials, packaging materials, shipbuilding, textile, rubber, plastics, ceramics, construction, automobile and other industries.
8. it can be used for extruding polystyrene foam with steel plate, aluminum plate, calcium silicate and cement wall.
