What is polyamide hot melt adhesive?

Polyamide hot melt adhesives are mainly thermoplastic hot melt adhesives with polyamide resin as the main matrix.

Polyamide resin is a linear thermoplastic resin with many repeating amide groups on the molecular backbone. Compared with other thermoplastic resins, polyamide resin has a remarkable feature, that is, when it is heated and cooled, the melting and solidification of the resin are both Occurs in a narrow temperature range. This feature enables the polyamide hot melt adhesive to be quickly solidified when it is heated, melted, and coated after a little cooling. It can also make it have better bonding performance at a temperature close to the softening point.

Because the hydrogen on the amide group of the polyamide resin can combine with the electron-donating carbonyl group on the other amide group to form a strong hydrogen bond, the melting point of the resin is increased, so it has good flexibility, oil resistance and Bonding performance. These properties increase with the increase of the molecular weight of the resin.

Compared with the ethylene-vinyl acetate copolymer hot melt adhesive, the polyamide hot melt adhesive has a higher softening point, so the heat resistance is better.

The molecular weight of the polyamide resin currently used as the matrix of the heat-resistant hot melt adhesive is generally in the range of 1000-9000. The polyamide resin used as the matrix of the hot melt adhesive is mainly composed of dimers of unsaturated fatty acids (such as linoleic acid, soybean oil acid, tungoleic acid, etc.) and diamines (such as ethylene diamine, propylene diamine, and ethylene diamine). Amine, etc.) obtained by polycondensation reaction.

When the polyamide resin is synthesized, different diamines are selected, and the molecular weight of the obtained resin is also different, so the softening point is also different. At present, the method of mixing ethylenediamine and hexamethylenediamine is often used.

Conventional polyamide resin has strong high temperature resistance but poor low temperature resistance. Spiderbond polyamide hot melt adhesive is different from conventional polyamide resins. It has both high temperature resistance and low temperature resistance, and has good high and low temperature cycle resistance. Flex+ series products can withstand low temperatures to -40°C, and can withstand high temperatures of 120°C. While providing high and low temperature resistance, they also provide super strong adhesion to plastics, metals and other materials.