Thermoplastic Adhesives: Hot Melt Adhesives

Hot melt adhesive is a plastic solid adhesive made of thermoplastic resin as the main component, plasticizer, tackifying resin, antioxidant, flame retardant, filler, etc., and is melted and mixed.

Hot melt adhesive is non-toxic, solvent-free, easy to transport and store, and has fast bonding speed and high viscosity.

According to relevant data, the output of hot melt adhesive in 2010 accounted for about 40% of the total production of adhesives, occupying a very large share of the market.

Characteristics of hot melt adhesive

Compared with cold adhesives such as paste and polyvinyl acetate (PVAC), hot melt adhesive is solid at room temperature. When it is heated to a certain temperature, it melts and becomes a fluid adhesive. After leaving the heating device, it quickly cools and solidifies, and the bonding speed is fast.

Hot melt adhesives are usually colorless, transparent, or translucent. Tan or colored hot melt adhesives may have lower viscosity. Hot melt adhesives usually appear in sticks, granules, and films.

Classification of hot melt adhesive

The base resins used in traditional hot melt adhesives include polyurethane (PU), polyamide (PA), polyethylene (PE), ethylene/vinyl acetate (EVA) and other varieties.

Biodegradable hot melt adhesives can be divided into polylactic acid type, polyester amide type, polyhydroxyalkanoate type, natural polymer type, etc.

1. PA hot melt adhesive uses polyamide as the main raw material. It has very strong bonding strength to textiles and fibers, is washable, and is widely used in the clothing adhesive lining industry.

2. PES hot melt adhesive uses low molecular weight polyethylene as the resin raw material. It is cheap and is mainly used for carton packaging, carpet splicing, car carpet backing, clothing lining bonding, etc.

3. EVA hot melt adhesive (English: Ethylene Vinyl Acetate) is a copolymer of ethylene (E) and vinyl acetate (VA). The higher the vinyl acetate content (VA content), the higher its transparency, softness, and toughness.

Application of hot melt adhesive

Hot melt adhesive can be used to bond a variety of materials, including wood, plastic, metal, etc. To use hot melt adhesive, simply melt the glue block or stick, then apply it to the object to be bonded, and it will solidify after a few seconds.