In our industrial production, in order to improve the service life and reliability of products, PCB circuit boards are often sealed and protected to prevent water, dust, and corrosion. Sealing adhesive is widely used in fields such as high-power electronic components, module power supplies, circuit boards, and LEDs.

There are three common classifications of sealant: polyurethane sealant, epoxy resin sealant, and silicone sealant.

1. Polyurethane sealant

1.1 Characteristics

• low-temperature resistance

• Good adhesion performance

• Wide range of hardness

• Waterproof, oil resistant, chemical resistant

• Low internal stress and fatigue resistance

1.2 Disadvantages

• The material is sensitive to water vapor, and strict moisture prevention is required during the dispensing process

• Poor high temperature resistance

1.3 Scope of Application

Widely applicable to non high temperature environments, such as automotive taillight wiring harness encapsulation, tire pressure sensor encapsulation, power module encapsulation, ballast encapsulation, micro switch encapsulation, transmission sensor encapsulation, etc.

2. Epoxy resin sealant

2.1 Characteristics

• High bonding strength

• Excellent insulation performance

• Easy to operate, very stable before and after curing, easy to store

• Widely applicable, with excellent adhesion to various metal substrates and porous substrates

2.2 Disadvantages

• After curing, the stress is high and it is easy to strain electronic components

2.3 Scope of Application

Suitable for applications with high requirements for insulation strength and adhesive strength, such as air conditioning controller potting, ignition coil potting, and power motor potting.

3. Organic silicon sealant

3.1 Characteristics

• Good weather resistance and aging resistance

• Good temperature resistance, able to maintain elasticity within the temperature range of -60 ℃ to 200 ℃ without cracking

• Excellent electrical and insulation performance

• Excellent waterproof and seismic performance

• Non corrosive, curing reaction does not produce any by-products

• Repackable

• Low stress after curing, excellent seismic performance

3.2 Disadvantages

• Poor adhesion

3.3 Scope of Application

Suitable forVarious electronic components that work in harsh environments have been encapsulated and sensitive components have been protected, such as coil encapsulation for communication equipment, LED power encapsulation, OBC encapsulation, DC-DC converter encapsulation, ECU encapsulation, PCU encapsulation, BDU encapsulation, and so on.