Main indexes affecting the performance of insulation materials such as FR4 fiberglass sheet

Main indexes affecting the performance of insulation materials such as FR4 fiberglass sheet

1. Insulation resistance and resistivity

Resistance is the reciprocal of conductance, and resistivity is the resistance per unit volume. The less conductive a material is, the greater its resistance is. And the two are inversely related. For electrical insulating materials like FR4 fiberglass sheet, it is always desirable that the resistivity should be as high as possible.

2. Relative dielectric constant and tangent of dielectric loss angle

Insulation materials like FR4 fiberglass sheet material are used for two purposes: media of mutual insulation and capacitor of electrical network components (energy storage). The former requires relatively small dielectric constant, the latter requires relatively large dielectric constant. Both require small medium loss angle tangent, especially in high frequency and high voltage applications of insulating materials. In order to make the medium loss small, it requires the use of insulating materials with small dielectric loss angle tangent .

3. Breakdown voltage and electrical strength

Under a certain strong electric field, the insulation material like FR4 fiberglass sheet is damaged, and the insulation performance is changed into a conductive state, which is called breakdown. The voltage at the time of breakdown is called the breakdown voltage (dielectric strength). Electrical strength is the quotient of the voltage at the time of breakdown under specified conditions and the distance between the two electrodes to withstand the applied voltage, that is, the breakdown voltage under per unit thickness. For electrical insulating materials like FR4 fiberglass sheet, the higher the breakdown voltage and electrical strength, the better.

4. Tensile strength

Tensile strength is the maximum tensile stress that the specimen bears in the tensile test. It is the most widely used and representative test for the mechanical properties of electrical insulating materials like FR4 fiberglass sheet or G10 material.

5. Fire resistance

Fire resistance is the ability of an insulating material to resist burning when it contacts with a flame or to stop it from burning when it leaves the flame. With the increasing application of insulating materials like FR4 fiberglass sheet or G10 material, it becomes more and more important to improve the flammability of insulating materials through various means. The higher the flammability, the better the safety.

6. Arc resistance

Arc resistance is the ability of an insulating material to withstand arc action along its surface under specified test conditions. In the test, the arc resistance of the insulating material is judged by the time it takes for the conductive layer to form on the surface of the insulating material due to the arc action generated between the two electrodes by ac high voltage and small current. The higher the time value, the better the arc resistance.