Chemical name: 2,2-Bis[4-(4-maleimidophenoxy)phenyl]propane
Synonyms: Bisphenol A bis(4-maleimidophenyl ether), 4,4′-Bis(4-maleimidophenoxy)bisphenol A, N,N’-(4,4′-(Propane-2,2-diyl)bis(4,1-phenylene))bis(oxy)bis(4,1-phenylene) bismaleimide
CAS: 79922-55-7
Molecular weight: 698.73 g/mol
Type: Bisphenol A-based monomeric bismaleimide
Specification / COA:
| Item | Standard | COA |
| Appearance | Yellow solid powder | Yellow solid powder |
| Melting point | 143–170 °C | 147–158 °C |
| Acid value | ≤ 1 KOH mg/g | 0.45 |
| Volatile content | ≤ 1% | 0.28% |
| Purity | ≥ 98.0% | 99.1% |
Usage:
- High-frequency copper-clad laminates (CCL) for 5G and high-speed communications: BMI 4000 is a BPA-backbone bismaleimide monomer widely used as a co-resin in high-frequency CCL formulations for 5G base stations, high-speed server interconnects, and millimetre-wave antenna substrates. Its bisphenol A-derived ether linkages provide lower melt viscosity and improved resin flow compared to DABA-type monomers, facilitating uniform impregnation of glass fabric during laminate pressing. When blended with complementary BMI monomers or oligomers, BMI 4000 contributes to thermoset networks achieving dielectric constant (Dk) below 3.8 and dissipation factor (Df) below 0.007 at 10 GHz, meeting IPC-4101 performance requirements for high-speed multilayer PCB laminates.
- Aerospace structural composites and prepreg systems: BMI 4000 is used as a reactive toughening co-monomer in aerospace-grade bismaleimide prepreg systems, where it is combined with DABA-type BMI (such as BMI 5100) to reduce the brittleness inherent in highly cross-linked monomeric BMI networks. The ether spacer groups in BMI 4000 introduce chain flexibility into the cured thermoset, improving interlaminar fracture toughness (GIc) without significantly compromising the thermal performance — cured laminates maintain glass transition temperatures (Tg) above 250 °C and continuous service capability above 180 °C. Applications include primary aircraft structural panels, engine nacelle liners, and military airframe composite assemblies requiring both thermal resistance and damage tolerance.
- High-temperature adhesives and structural film adhesives: BMI 4000 formulations are used as structural film adhesives for metal-to-composite and composite-to-composite bonding in aerospace hot-zone assemblies. The lower melting point range (147–158 °C actual) relative to DABA-type monomers allows film adhesive processing at reduced cure temperatures while retaining high-temperature service performance. Cured bonds maintain structural integrity at continuous service temperatures exceeding 200 °C, making BMI 4000-based adhesives suitable for aircraft secondary structures, exhaust duct assemblies, and turbine engine proximity components.
- Moulding compounds and encapsulants for high-temperature electronics: BMI 4000 is incorporated into bismaleimide triazine (BT) resin systems and high-temperature transfer moulding compounds for power semiconductor packaging. Its high purity (≥ 99.1% actual) and low acid value (0.45 KOH mg/g) minimise ionic contamination in sensitive electronic packages, contributing to improved insulation resistance and long-term reliability in automotive power modules, industrial motor drives, and aerospace power electronics operating between −55 °C and +200 °C thermal cycling conditions.
Packing: 25 kg kraft paper bags or 500 kg super sacks (FIBC). Store away from moisture and heat; packaging is sealed to preserve shelf life.
Storage: Store in a cool (below 25 °C), dry, well-ventilated area away from heat sources, direct sunlight, and moisture. Keep containers tightly sealed. Recommended shelf life: 12 months from manufacturing date when stored under recommended conditions.
Related Products
Further Reading: BMI 5100: Applications in High-Frequency CCL and Aerospace Composites