Recently, with the rise in temperature, some customers with special needs have reported that the heat resistance of hot melt adhesives is insufficient. Of course, this is related to the choice of adhesives, but hot melt adhesives are not all-purpose adhesives.
Hot melt adhesive is a type of adhesive that is applied after being melted by heating to 60-180℃. It achieves bonding through physical solidification when cooled, with no chemical reactions occurring during the process. Its main components include polymers and tackifying resins. It is commonly used in fields such as automotive, home furnishing, and packaging, and can bond common materials like paper, plastic, and metal. However, its bonding strength and application range are limited.
The limitations of hot melt adhesives are quite obvious. Firstly, their weather resistance is insufficient: they tend to soften and deform in high-temperature environments (above 70℃) and become brittle and crack at low temperatures (below -20℃). Therefore, they cannot be used in scenarios that are exposed outdoors for a long time or subject to alternating high and low temperatures. Secondly, they have poor adhesion to special materials: hot melt adhesives struggle to form a strong bond with materials with extremely low surface energy such as silicone, rubber, and polytetrafluoroethylene (PTFE), or with metals and glass that have oil stains or moisture on their surfaces. Forced bonding may lead to easy detachment. Thirdly, their mechanical properties are limited: compared to structural adhesives such as epoxy resins and acrylates, hot melt adhesives have lower tensile and shear resistance, and cannot withstand long-term pulling by heavy objects. Fourthly, their applicable scenarios are limited: due to their extremely fast curing speed, they are not suitable for precision assembly that requires repeated position adjustments, nor can they fill large gaps.
Therefore, when choosing an adhesive, a comprehensive judgment should be made based on the material, environment, and strength requirements. Hot melt adhesive is only an "efficient tool for specific scenarios" rather than a "universal solution".