Polyamide hot melt adhesive, also known as dimer acid polyamide hot melt adhesive, is produced by the high-temperature condensation reaction of dimer acid and polyamine. It exhibits excellent heat and cold resistance, electrical properties, oil resistance, chemical resistance, and media resistance. It is odorless and colorless, cures quickly, and can bond a variety of metals and non-metals. It also has good compatibility with other resins.
It can be used for bonding materials such as fabrics, leather, wood, plastics, metals, and ceramics, as well as for bonding and protecting electronic components, bookbinding, low-pressure injection molding, and tape production.
High molecular weight polyamide hot melt adhesive: It has good fluidity, high bond strength, and is resistant to dry cleaning and washing.
Low molecular weight polyamide hot melt adhesive: It has good strength and toughness, and most properties are superior to EVA hot melt adhesive.
Typically, the softening point of polyamide hot melt adhesive ranges from approximately 100°C to over 200°C. It can withstand temperatures as low as -40°C and temperatures as high as 200°C. At room temperature, its specific gravity is typically 0.97. The basic color of polyamide hot melt adhesive is amber (yellow), but it can often be changed to black by adding carbon black, white by adding titanium dioxide, and, less commonly, other colors by adding other pigments. Color-changing polyamide hot melt adhesives are often used in specialized applications such as low-pressure injection molding.
Because polyamide hot melt adhesives are produced by an acid-amine polymerization reaction, they are typically measured by both acid and amine values. Acid-amine polymerization reactions typically terminate when one end reacts with the other, which is near completion. Therefore, in terms of acid-amine values, a high acid value typically indicates a low amine value, and vice versa. In rare cases, when these two values are close, equilibrium is reached, and the reaction terminates.
