How to choose the potting polymer?
At present, there are three kinds of potting polymer commonly used for PCB circuit boards: polyurethane potting compound, silicone potting compound and epoxy resin potting compound. How to choose these kinds of PCB boards? Let's have a look!
POLYURETHANE POTTING
The temperature shall not exceed 100 ℃, and it needs to be carried out under vacuum conditions. Bubbles are easily generated after potting. The bonding strength is between epoxy potting adhesive and silicone potting adhesive.
The low temperature performance is excellent, and the shockproof performance is the best among the three. However, it is not resistant to high temperature and has poor toughness. After curing, the surface is not smooth enough and the chemical resistance is general.
Application: It is suitable for electronic components with low calorific value and indoor electrical appliances.
SILICONE POTTING
good impact resistance, aging resistance and physical resistance. Its performance can be maintained in both hot and cold environments. Good electrical performance and insulation performance, easy to repair. Silicone potting has low viscosity, good fluidity and easy potting. And can effectively improve the safety factor and heat dissipation of components.
But the adhesion is poor, the confidentiality is not good enough, and the price is high.
It is suitable for electronic components working in harsh environment for a long time.
EPOXY RESIN POTTING
high temperature resistance, excellent electrical insulation, stable before and after curing, excellent adhesion to a variety of metals and porous substrates, and simple operation.
It is not cold resistant enough and is not suitable for low-temperature environment. Cracks are easy to occur after cold and heat shock, resulting in device damage. The epoxy resin potting after curing has insufficient toughness, high hardness and brittleness.
It is applicable to electronic components in normal temperature environment, and has no excessive requirements for environmental mechanical properties.
Each of the commonly used potting adhesives for PCB circuit boards has different performances, advantages and disadvantages. It is necessary to select the appropriate one for operation. Do not blindly select and use it. Choose it according to the construction process and device requirements.
