BMI 5100 Resin | CAS 105391-33-1 | CCL & Aerospace Bismaleimide

Chemical name: Bis(3-ethyl-5-methyl-4-maleimidophenyl)methane

Synonyms: BMI-5100, DEMI, Methylene bis(3-ethyl-5-methyl-4-maleimidophenyl), 3,3′-dimethyl-5,5′-diethyl-4,4′-diphenylmethane bismaleimide

CAS: 105391-33-1

Molecular formula: C₂₇H₂₆N₂O₄

Molecular weight: 442.51 g/mol

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Specification / COA:

Item	Standard	COA
Appearance	White or light yellow solid powder	White solid powder
Melting point	160–170 °C	164–166 °C
Acid value	≤ 1 KOH mg/g	0.43
Volatile content	≤ 1%	0.19%
Purity	≥ 98.0%	99.00%

Usage:

High-frequency copper-clad laminates (CCL) for 5G and advanced PCB: BMI 5100 is a primary thermoset matrix resin for high-frequency CCL boards used in 5G base stations, millimetre-wave antenna substrates, AI accelerator server boards, and automotive ADAS radar. Its high glass transition temperature (Tg > 260 °C) and low dielectric constant (Dk ≈ 3.2–3.5) with low dissipation factor (Df < 0.010 at 10 GHz) allow signal integrity performance that conventional epoxy laminates cannot achieve. BMI 5100 is commonly co-cured with diallyl bisphenol A (DABA) or blended with VBC-capped PPE oligomers to produce next-generation low-loss laminates.
Aerospace structural composites: BMI 5100 serves as the resin matrix in carbon fibre reinforced polymer (CFRP) composites for aircraft structural components, engine nacelles, and military aerospace assemblies. It processes similarly to epoxy — allowing autoclave and resin transfer moulding (RTM) — while sustaining structural loads at continuous service temperatures of 200–230 °C, where epoxy systems degrade. The addition-cure mechanism produces no volatile by-products, enabling void-free laminates critical for flight-certified structures.
Semiconductor packaging and high-temperature electronics: BMI 5100 formulations are used as encapsulants, underfill resins, and die-attach adhesives in semiconductor packages that experience thermal cycling between −55 °C and +200 °C. Its high Tg ensures dimensional stability and prevents delamination during reflow soldering (peak 260 °C). Applications include power modules, automotive ECUs, and industrial control electronics where long-term reliability under thermal stress is required.
High-temperature structural adhesives: BMI 5100 is formulated into film adhesives and paste adhesives for bonding CFRP-to-metal and CFRP-to-CFRP joints in aerospace, defence, and motorsport applications. The cured adhesive maintains shear strength above 20 MPa after 1,000 hours at 180 °C, making it suitable for hot-zone structures where conventional epoxy adhesives soften and creep.
Specialty coatings and surface treatments: In industrial applications, BMI 5100 is blended into heat-resistant coatings for downhole oil and gas tools, exhaust system components, and chemical processing equipment exposed to aggressive media at elevated temperatures. Its low moisture absorption (< 2 wt%) compared to polyimides provides better electrical insulation retention in humid environments.

Packing: 25 kg kraft paper bags or 1,000 kg super sacks (FIBC). Store away from moisture; packaging is sealed under nitrogen 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.

Further Reading: BMI Resins from China: Grades, Applications, and Price Advantage

Related Products

Further Reading: BMI 5100 Resin: Applications in High-Frequency CCL and Aerospace Composites

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BMI 5100 (CAS 105391-33-1), formally Bis(3-ethyl-5-methyl-4-maleimidophenyl)methane, is a liquid-crystalline bismaleimide monomer that bridges the performance gap between standard epoxy systems and high-cost polyimides. Its maleimide end groups undergo addition polymerisation at 160–180 °C without releasing condensation by-products, enabling void-free laminate and composite structures using conventional epoxy processing equipment. The methylene-linked bis(alkyl-maleimidophenyl) architecture delivers a cured Tg exceeding 260 °C, excellent retention of flexural modulus above 200 °C, and moisture absorption below 2 wt% — properties that make it the resin of choice for high-reliability CCL laminates in 5G infrastructure and for primary aerospace composite structures certified to service at elevated temperatures. Unifarm Chemical supplies BMI 5100 at ≥ 98.0% purity (99.00% typical) with full batch COA and MSDS documentation.