Classification And Properties Of Packaging Adhesive Materials

Packaging adhesives are classified into organic and inorganic adhesives based on their chemical composition. Organic adhesives include natural organic adhesives such as starch, protein, and natural rubber, as well as synthetic organic adhesives such as epoxy resin, phenolic resin, and polyurethane. Inorganic adhesives include silicates and phosphates. They are also classified into liquid and solid adhesives based on their physical form. Liquid adhesives include solution-type, emulsion-type, and paste-type. Solid adhesives include hot melt adhesive sticks and tapes.

Packaging adhesives are mainly used to make pressure-sensitive tapes and labels, bonding the surfaces of packaging materials such as paper, plastic, and metal. Adhesives for paper packaging materials are polyvinyl acetate emulsions. Adhesives for plastic and metal packaging materials include polyacrylic acid emulsions, VAE emulsions, polyurethane adhesives, and cyanoacrylate adhesives.

Hot melt adhesives, depending on the raw materials, can be classified into EVA hot melt adhesives, polyamide hot melt adhesives, polyester hot melt adhesives, and polyolefin hot melt adhesives. Currently, EVA hot melt adhesive is the main type produced and used in China. EVA hot melt adhesive is composed of basic resin, tackifiers, viscosity modifiers, and antioxidants, and is solid at room temperature but melts upon heating.

Instant adhesives are single-component, fast-curing adhesives. They contain tackifiers, thickeners, stabilizers, toughening agents, and polymerization inhibitors, synthesized through advanced production processes, and are used for instantaneous and rapid bonding.

The bonding principles include mechanical theory, adsorption theory, and chemical bonding theory.

Performance indicators include bond strength, temperature resistance, chemical resistance, and curing time.