Hot Melt adhesives are a type of high-performance adhesive produced in a 100% solid form without the use of solvents. As atommek , we are capable of providing turnkey Hot Melt adhesive production lines along with custom formulations.
Thanks to its flexible formulation, properties like open time, softening point, and adhesion can be precisely designed to meet the specific demands and needs of customers. There are various types of Hot Melt adhesives:
- EVA-based Hot Melt adhesives
- Polyolefin-based Hot Melt adhesives
- Block copolymer-based Hot Melt adhesives (PSA-Pressure Sensitive Adhesive)
- Polyamide-based Hot Melt adhesives
Hot Melt adhesives are widely used across various industries and are environmentally friendly and safe for human health. The main application areas include:
- Printing
- Automotive
- Labeling
- Packaging
- Hygiene
- Bedding
- Footwear
Hot Melt adhesives contain no solvents or water. They are characterized by heat loss, which gives them a very fast setting time. They can bond two non-porous materials. Polymers provide adhesion strength and a certain degree of flexibility. Resins enable immediate adhesion when the adhesive is hot. Wax is used to thin the adhesive. Antioxidants help protect the adhesive at high temperatures.
How do Hot Melt adhesives work?
Hot Melt adhesives are applied to a material in a molten state. The time between applying the adhesive and bringing the second material into contact is called “open time.” When the second material contacts the adhesive, it cools and solidifies very quickly. At this stage, compressing the materials is crucial.
What affects adhesion?
Hot Melt adhesives work based on the temperature at which they are applied. The adhesive must be liquid (molten) enough to wet the surfaces and hot enough for assembly before it cools. If the adhesive is not hot enough, it may form a “cold bond” that will fail at a later stage.
On the other hand, if the adhesive is applied at too high a temperature, it will remain molten for too long and may still be soft when the compression stage is reached. Any pressure on the bond afterward can cause it to fail or create a weak bond that will fail later.
Application Tips:
- The materials to be bonded should be clean, dry, and free of dust, oil, and grease.
- Hot Melt adhesive should be applied at the correct temperature.
- The temperature of the materials and the environment can affect adhesion:
- If too hot, the adhesive may take too long to set.
- If too cold, the adhesive may solidify before the materials are fully bonded.
- The amount of adhesive applied significantly affects the bond:
- Too little adhesive may cool too quickly, preventing proper bonding.
- Too much adhesive can delay cooling, leading to a weak bond.