What is Hotmelt?

Hotmelt is a type of thermoplastic adhesive that is solid at room temperature and becomes liquid when heated. In the hotmelt process (Hotmelt Moulding), the adhesive is heated and melted, then applied to the surface in its hot, liquid state. After cooling, the adhesive forms a connection with the material. The melting points range between 100 and 180°C.

Where is Hotmelt Used?

The application is utilized across many industries, including packaging, automotive, manufacturing, construction, and printing. Typical applications in electrical engineering include cable assembly, such as for cable end encapsulation, connectors, or potting other electronic components. The hotmelt process is particularly suited for small to medium quantities and is applicable to almost all materials.

Advantages of the Hotmelt Process

The hotmelt process offers several advantages compared to other injection molding techniques. Hotmelt is cost-effective to process due to lower material prices and can be stored almost indefinitely. Additionally, it is more environmentally friendly as it does not contain solvents. Thanks to the low-pressure process and low temperatures, hotmelt can be applied directly to sensitive electronic components, such as circuit boards or relays. Aluminum molds can also be used. The adhesive does not require curing, allowing for immediate production of solid connections.

The Different Types of Hot Melt Adhesives

Hot melt adhesives come in various forms, including blocks, granules, sticks, or pillows. The most common types of hot melt adhesives are:

EVA Hot Melt
EVA (Ethylene Vinyl Acetate) is considered the first form of hot melt adhesives and falls under thermoplastic adhesives. It typically consists of three components: EVA polymer, wax for processing, and resin for better bonding. The melting point is around 110°C, and it is used at approximately 160°C.

PSA Hot Melt
PSA stands for "Pressure Sensitive Adhesive" and refers to pressure-sensitive adhesives. These adhesives remain tacky even after cooling and are commonly used in the production of labels and adhesive tapes.

PUR (Polyurethane)
PUR hot melts are reactive adhesives that continue to cure during the cooling phase after the initial bonding. They are primarily used in the wood and construction industries.

Polyolefin
Polyolefin adhesives offer better adhesion at both low and high temperatures. The main representatives are polyethylene (PE) and polypropylene (PP).