What are the differences between FR4 epoxy sheet and 3240 epoxy sheet?

What is FR4 epoxy sheet?

FR4 epoxy sheet is a common composite material that is widely used in the manufacture of electronic circuit boards. It consists of fiber glass cloth and imported epoxy resin, and has high mechanical properties, dielectric properties, electrical insulation properties. The insulation class is F, and the main colors are white (primary), light green, black and yellow.

What is 3240 epoxy sheet?

3240 epoxy sheet is an insulation material that mainly composed of electrical fiber glass cloth impregnated with epoxy resin and processed through drying and hot pressing. The temperature resistance grade of 3240 epoxy sheet is Class B. Its colors include yellow, red, green, and black. It complies with the standard GB/T1303.1-1998 (natural color). The surface of 3240 epoxy sheet should be smooth, free of bubbles, pits, and wrinkles. But it can have other defects that do not affect its use, such as scratches, indentations, stains, and minor spots. The edges should be neatly cut. And the end faces should be free from delamination and cracks. The thickness of 3240 epoxy sheet is typically 0.5 to 50mm, but 3240 epoxy sheet can also be produced in thicknesses of 50 to 150mm as required.

What is the difference between FR4 epoxy sheet and 3240 epoxy sheet?

The main differences between the 3240 epoxy sheet and the FR4 epoxy sheet are the following:

1. Material composition:

• 3240 epoxy sheet is mainly composed of epoxy resin and phenolic materials and sometimes reinforced with glass fiber cloth. Its standard name is 3240 epoxy phenolic fiber glass cloth laminate.

• FR4 epoxy sheet is mainly based on electronic grade fiberglass cloth and impregnated with epoxy resin, which is a high-performance glass fiber reinforced composite material.

2. Temperature and chemical resistance:

• FR4 epoxy sheet provides better temperature and chemical resistance. So it is suitable for use in higher temperature environments.

• The temperature resistance of 3240 epoxy sheet is relatively poor. It usually has an upper temperature of about 155C.

3. Color and appearance:

• The common color of 3240 epoxy sheet is yellow, while the FR4 epoxy sheet is usually aqua green. And the color of FR4 epoxy sheet is more natural and uniform, like jade texture.

4. Dimensional stability and machinability:

• FR4 epoxy sheet offers better dimensional stability and thickness tolerance control for precision machining.

• The 3240 is slightly inferior in this regard. Especially when the manufacturer adds fillers to reduce costs, its performance can be further reduced.

5. Flame retardant performance:

• FR4 epoxy sheet has good flame retardant performance. It is in line with UL94V-0 flame retardant standard, that is, it can self-extinguish after leaving the fire source.

• 3240 epoxy sheet does not have flame retardant.

6. Density and cost:

• The density of 3240 epoxy sheet is generally not more than 1.9g/cm³, while the density of FR4 epoxy sheet is about 1.85g/cm³. Although the density of FR4 is slightly lower, but it is usually more expensive than 3240 epoxy sheet because of its better performance.

7. Application field

3240 epoxy sheet is widely used in electronic and electrical appliances, communications and other fields with low flame-retardant performance requirements, such as some ordinary electronic equipment, electrical insulation structures, insulation gaskets and so on.

• FR4 epoxy sheets are commonly found in occasions with strict requirements for flame retardant performance, such as high-performance electronic equipment, aerospace equipment, communication equipment, automotive electronics and other fields, as well as circuit boards with high requirements for electrical and mechanical properties.

Ztelec Group is a professional manufacturer of high-quality electrical insulation materials with more than sixty-five years of manufacturing experience. If you need more product information and quotes, please contact us.