What are fr1, fr2, fr3, fr4, fr5 insulation boards, and what are the characteristics of fr4?

FR4 may be the material used more frequently by epoxy board processors now, and is also called imported 3240 epoxy board. In fact, fr4 completely beats 3240 epoxy board in all aspects of performance, but it is also relatively expensive. In addition to fr4, there are actually fr1, fr2, fr3, and fr5. So what do they represent?

 

  1.What do fr1, fr2, fr3, fr4, fr5 stand for?

 

In fact, fr1, fr2, fr3, fr4, and fr5 represent grades, fr1 is the lowest, and fr5 is the highest. However, fr4 is the grade most commonly used on the market, because regardless of the current performance demand and price, More appropriate. Although the fr5 level appears, relatively speaking, the demand for products is not that high.

 

  2.fr4Basic features

 

Vertical layer bending strength A: Normal: E-1/150, 150±5℃≥340Mpa

 

 Parallel layer impact strength (simply supported beam method): ≥230KJ/m

 

 Insulation resistance after water immersion (D-24/23): ≥5.0×108Ω

 

Vertical layer electrical strength (in 90±2℃ transformer oil, plate thickness 1mm): ≥14.2MV/m

 

 Parallel layer breakdown voltage (in 90±2℃ transformer oil): ≥40KV

 

 Relative dielectric constant (50Hz): ≤5.5

 

 Relative dielectric constant (1MHz): ≤5.5

 

Dielectric loss factor (50Hz): ≤0.04

 

Dielectric loss factor (1MHz): ≤0.04

 

 Water absorption (D-24/23, plate thickness 1.6mm): ≤19mg

 

Density: 1.70-1.90g/cm³

 

 Flammability: FV0

 

 

 As can be seen from the above, the biggest feature of fr4 is its excellent flame retardancy and voltage resistance, so many insulating gaskets and transformer room panels now use fr4 boards.