In many areas such as electronics manufacturing, home appliance assembly, automotive electronics, LED lighting, and industrial packaging, the choice of “adhesives” is critical. Two common adhesive materials – Potting Compound and Hot Melt Adhesive – often appear in the same factory or even the same production line. But many engineers and procurers confuse their properties and scope of application when selecting.
Today, we will analyze in detail: what is the difference between sealant and hot melt adhesive? What applications are they suitable for? How to choose the right type of adhesive to improve product reliability and production efficiency?
- What is sealant?
Sealing glue is an adhesive material used for the overall sealing protection of electronic components or modules. It is liquid before curing, easy to flow and cover complex structures. After curing, a dense protective layer is formed, with excellent insulation, water resistance, moisture resistance, corrosion resistance, high and low temperature resistance and mechanical strength.
Common Type:
Epoxy sealant
Polyurethane sealant (PUR)
Silicone
Main Applications:
Power Module Filling
LED drive circuit sealing
Automotive Sensor/Controller Seal Protection
Solar Inverter
Smart Home Appliance PCBA Filling
Features:
Deep filling of complex structures
Strong shell protection after curing
Strong electrical insulation performance
Adjustable hardness and thermal conductivity
Suitable for harsh working conditions (-60°C to 200°C)
Second, what is hot melt adhesive?
Hot melt adhesive is a thermoplastic adhesive that is formed by heating and cooling after melting. Its advantages are fast adhesion speed, easy construction, no solvent and environmentally friendly. It is mainly used for structural adhesion, packaging sealing, quick assembly, etc.
Common Type:
EVA hot melt adhesive (most commonly used)
Polyolefin hot melt adhesive
Polyamide hot melt adhesive
PUR reactive hot melt adhesive (curable, with higher temperature resistance)
Main Applications:
Lamp border adhesion
Electronic Housing Assembly
Toys, Paper, Packaging
Household appliance internal components bonding
Features:
No mixing and short curing time
Suitable for automatic spot glue / spray glue
Processing temperature range 120℃~200℃
Fast bonding speed, high production rate
Generally does not have sealing protection capability
Three, the core difference between filling adhesive and hot melt adhesive
Comparison Dimensions Sealing Glue Hot Melt Glue
Physical form Liquid, need to be mixed, need to be cured Solid state, after heating melt use
Adhesion method Intrusion into the gap, whole wrap or fixed spot glue / wire glue, surface fit
Curing mechanism Chemical reaction curing (heating/constant temperature/humidity) Physical curing after cooling, no chemical reaction
Temperature range High, up to 200 ℃ or even higher Medium to low temperature, generally ≤ 120 ℃ (except PUR hot melt adhesive)
Weatherproof / electrical performance Strong, with excellent insulation, moisture resistance, corrosion resistance Weak, generally not used for electrical insulation or sealing protection
Typical applications Circuit board sealing, power module packaging, sensor sealing protection Housing assembly, structural bonding, packaging sealing
High construction complexity, need to mix, defoaming, heating / baking, process control requirements high low, easy operation, suitable for large-scale rapid production
Material cost High, generally 2-5 times of hot melt adhesive Relatively low, the unit cost advantage is obvious
How to choose the right glue according to the application?
✅ Choose a sealant if you care about:
Electrical insulation, waterproof and moisture-proof
Long-term reliability, chemical resistance
Use in high temperatures or extreme environments
Precision modules, sensors, power supplies, etc. require total sealed protection
Recommended application: LED drive sealing, power module, automotive controller, PCB sealing, etc.
✅ Choose hot melt adhesive if you need:
Fast positioning and initial adhesion
Simplify the process and increase the pace
Adhesive plane structure or border
Scenarios without high insulation and protective performance
Recommended application: lamp shell assembly, toy bonding, household appliance structural parts fixation, packaging sealing box, etc.
Can sealant and hot melt adhesive be replaced?
From a technical point of view, the two cannot be completely replaced. Hot melt adhesive does not have sealing protection, electrical insulation, deep mobility and other characteristics; and sealing adhesive, although strong performance, is not suitable for high-speed rapid assembly lines, and the cost and process are complex.
Some high-end scenarios (such as camera modules, automotive radar, industrial controllers) may even combine two types of adhesive: hot melt adhesive for structural fixation and filling adhesive for electrical protection and seal enhancement.
Summary: master the key differences, choose the right glue
Sealing adhesive and hot melt adhesive as two completely different performance and use adhesive materials, widely used in electronics, automotive, lighting, industrial and other fields. In practical use, it should be combined with structural complexity, use environment, reliability needs, production process and other factors, scientific selection.
ELAPLUS is specialized in electronic adhesive solutions, offering a full range of products from hot melt adhesive, structural adhesive, sealing adhesive to conductive thermal adhesive, UV adhesive. Welcome to contact us for one-to-one adhesive recommendations and test solutions!
Tags: sealant · Difference between sealant and hot melt adhesive · What is sealant · Hot melt adhesive use · Can hot melt adhesive be sealed · Circuit board sealing recommended
