Applications of Hot Melt Adhesive

Hot-melt adhesives mainly include hot-melt adhesive blocks, granules, strips, powders, films, and sheets.

　　a. Hot-melt adhesive strips are primarily used in the electronics, handicrafts, glass, packaging, and luggage industries.

　　b. Hot-melt adhesive powder is primarily used in the apparel industry.

　　c. Hot-melt adhesive pellets are primarily used in air filters and for edge banding and veneer application in furniture.

　　d. Hot-melt adhesive blocks are primarily used in the luggage and bag industry.

　　The specific requirements depend on the application and the hot-melt adhesive machine used.

　　3. The following section primarily introduces hot-melt adhesive strips and hot-melt adhesive pellets, along with the common problems encountered in their applications and the corresponding solutions.

　　First, hot-melt adhesive strips often exhibit dripping, primarily due to two reasons:

　　a. The colloid itself has a melting point that is too low; it is recommended to switch to a product with a slightly higher melting point.

I.

1.1 Definition of Hot-Melt Adhesive

Hot-melt adhesive is the abbreviated term for hot-melt adhesives and represents an important category of adhesives. It is characterized by 100% solids content, the absence of solvents, environmental friendliness and non-toxicity, and rapid curing. Typically, it exists in a solid state at room temperature; upon heating to a specific temperature, it melts into a viscous liquid. After being applied and wetting the substrates, the bonded materials are pressed together and then cooled to room temperature, completing the bond within a few seconds.

Widely used in industries such as automated packaging, hygiene products, label and tape applications, healthcare and pharmaceuticals, automotive interiors, building waterproofing, furniture manufacturing, printing and binding, footwear, and apparel.

1.2 Classification of Hot-Melt Adhesives

Based on the base material, hot-melt adhesives can be classified into ethylene-vinyl acetate (EVA)-based, polyamide (PA)-based, polyurethane (PU)-based, polyolefin (PO)-based, and block copolymer (SBC)-based types, among others.

Based on form, hot-melt adhesives can be classified into hot-melt adhesive pellets, hot-melt adhesive sticks, hot-melt adhesive blocks, hot-melt adhesive films, hot-melt adhesive powders, and so on.

Based on application, hot-melt adhesives can be categorized into filter-element hot-melt adhesives, automated packaging hot-melt adhesives, automotive interior hot-melt adhesives, label hot-melt adhesives, tape hot-melt adhesives, medicated-plaster hot-melt adhesives, and so on.

Other classifications: whether it is reactive, its color, whether it is natural, whether it exhibits pressure sensitivity, and so on.

1.3 Application Areas of Hot-Melt Adhesives

Hot-melt adhesives have been integrated into every aspect of daily life, spanning the realms of food, clothing, housing, daily necessities, transportation, and leisure. Whether it’s enjoying a bowl of instant noodles, sipping a bottle of water or a glass of wine; wearing clothes, shoes, and hats; living in buildings and homes; traveling by car, train, or airplane; using appliances such as refrigerators, color TVs, and washing machines, as well as everyday items like toilet paper, toothpaste, and soap; or decorating living spaces with handicrafts, decorative paintings, artificial flowers, children’s toys, and gifts—hot-melt adhesives are present in all these applications. In short, hot-melt adhesives are ubiquitous in modern life.

1.4 Characteristics of Hot-Melt Adhesives

Technical Specifications:

It cures rapidly—within just a few seconds—and exhibits the characteristic of melting upon heating and becoming adhesive upon cooling, which facilitates continuous, automated high-speed operations, thereby enhancing production efficiency while reducing costs.

100% solids content, solvent-free, environmentally friendly and non-toxic, energy-efficient, and does not cause secondary environmental pollution.

Non-reactive hot-melt adhesives can be repeatedly melted and re-applied for bonding, making them particularly suitable for bonding components that require specialized processing techniques, such as the restoration of cultural relics.

It exhibits broad substrate compatibility, providing both adhesion and sealing, with an exceptionally wide range of applications; it delivers excellent bonding performance on materials such as paper, plastics, metals, and ceramics.

Easy to construct, with a small footprint and reduced labor requirements; it can be applied by spraying, rolling, scraping, spot coating, line coating, and more.

Market characteristics:

In the application of hot-melt adhesives in customer products, the adhesive itself accounts for only a small fraction of the overall product value; however, its impact on the customer product can be profound. In many cases, it is precisely poor bonding provided by the hot-melt adhesive that results in the loss of the customer product’s overall value.