Our Epoxy Glass Fiber Sheet (FR4 / 3240) is a high-performance electrical insulation material made from woven fiberglass cloth impregnated with epoxy resin and cured under high temperature and pressure. FR4 / 3240 sheets provide excellent electrical insulation, high mechanical strength, and stable thermal performance, offering performance comparable to G10 with the added benefit of flame retardancy, and serving as a cost-effective alternative to G11 for most medium to high temperature insulation applications. Due to their balanced electrical, thermal, and mechanical properties, they are widely used in motors, transformers, switchgear, electrical panels, industrial equipment, insulating spacers, supports, structural parts, and PCB fixtures where both insulation reliability and mechanical strength are required.
FR4: Flame-retardant epoxy glass laminate widely used in electrical and electronic insulation applications.
3240: Common Chinese standard epoxy glass laminated sheet, similar in structure and performance to FR4.
G10: Non-flame-retardant epoxy glass laminate with comparable mechanical and electrical properties.
G11: High-temperature epoxy glass laminate designed for more demanding thermal environments.
FR4 / 3240 sheets are commonly selected as a practical alternative to G10 and G11 in most industrial insulation applications.
1. Excellent electrical insulation properties
2. High mechanical strength and rigidity
3. Good thermal resistance and dimensional stability
4. Flame-retardant performance (FR4 grade)
5. Low water absorption and good moisture resistance
6. Good resistance to oils, chemicals, and solvents
7. Easy to machine: cutting, drilling, CNC processing
| Chinese Name | 3240 | 3241 | ||||||
| IEC | EPGC201 | EPGC202 | EPGC203 | EPGC204 | EPGC306 | EPGC308 | 一 | |
| NEMA | – | FR4 | G10 | FR5 | G11 | – | – | |
| Basic Material | Glass fiber cloth | ELectronic grade glss fiber cloth | Glass fiber cloth |
|||||
| Resin | Epoxy | Heat-resistant epxoy resin | Epoxy | |||||
| Color | Nature/Yellow | Nature/Green | Black | |||||
| Test item | Unit | Value | Value | |||||
| Density | g/m³ | 1.8~1.95 | 1.75~1.90 | |||||
| Vertical layer bending strength (nomal) |
MPa | ≥340 | ≥300 | |||||
| Parallel layer impact strength (simply supported beam method) |
KJ/m2 | ≥38 | 250 | |||||
| Vertical layer electrical strength (90℃transformer oil) |
Kv/mm | ≥14.2 | ≥8.0 | |||||
| Parallel layer breakdown voltage(90°℃transformer oil) |
kv | ≥35 | ≥35 | ≥40 | ≥35 | ≥40 | ≥35 | ≥35 |
| Dielectric constant(50Hz) | ≤5.5 | ≤5.5 | ||||||
| Dielectric loss factor(50Hz) | – | ≤0.04 | ≤0.03 | |||||
| Insuation resistance after immersion |
Ω | ≥5.0*1010 | ≥1.0*108 | |||||
| Proof tracking index(PTI) | – | – | ≥200 | 二 | – | |||
| Combustibility | – | V-0 | – | V-0 | – | – | HB40 | |
| Temperature index | 一 | 130 | 130 | 155 | 155 | 155 | 180 | 180 |
| Water absorption(1-20mm thickness) |
mg | 17~73 | 64~193 | |||||
* Electrical insulation parts for motors and transformers
* Switchgear, circuit breakers, and electrical panels
* Insulating spacers, supports, and structural components
* PCB fixtures, test jigs, and electrical tooling
* Industrial mechanical parts requiring insulation and strength
* Applications where G10 or G11 sheets are traditionally used
GBS Die Cut, as adhesive tape supplier, focuses on the research & development, production and sales of various types of adhesive tapes for different industries and has been authorized as golden distributor of many noted brands for so many years, such as Nomex, Formex, Rogers Poron, 3M, Tesa, and so forth.
Transformer insulation papers and flexible laminates are essential materials that ensure dielectric strength, thermal endurance, and mechanical stability in transformers, motors, and other electrical equipment. These materials are widely used
In the medical industry, medical tapes are not just for simple fixation; they play a crucial role in wound care, medical device adhesion, and surgical protection, directly impacting patient comfort
For inquiries about our products or price list, pls leave your email to us and we will be in touch within 24 hours.
