Film adhesive built to win against CTE mismatch
When electronics see real-world thermal swings, coefficient of thermal expansion (CTE) mismatch is the silent killer of bonds. 5020K was engineered with that reality in mind. Its glass-supported epoxy film balances mechanical strength, thermal performance, and electrical insulation—so your packages stay together across thousands of cycles, not just the first few.
Why CTE matters — and how 5020K answers it
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Low CTE regime below Tg – 5020K runs at about 45 ppm/°C below Tg (~109 °C). Keeping your assembly in this range minimizes shear strain, making the adhesive perform like an anchor between dissimilar materials.
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Reinforced with glass fabric – The carrier tempers in-plane growth, delivering dimensionally stable preforms that stay true through lamination and cure.
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Thermally and electrically balanced – With a thermal conductivity around 0.7 W/m·K and a dielectric constant ~4.4 @1 kHz, 5020K gives you thermal path and electrical isolation in one clean step.
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Military-grade reliability – Qualified to MIL-STD-883 Method 5011, proving its pedigree in high-reliability environments.
The CTE playbook
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Know your Tg. At ~109 °C, 5020K transitions into a higher-CTE regime (~270 ppm/°C). If your use case lives below Tg, you’ll keep shear forces low.
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Select your bondline. Standard films run ~4–5 mil thick. Thinner = less differential growth; thicker = more compliance. (side note, NEDC stocks the .005” 5020K-1-005)
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Cutback for stress relief. Preforms with slight edge cutback reduce squeeze-out and help keep stress away from traces, thru holes, and pads.
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Uniform cure pressure. Apply 2–10 psi (or vacuum lamination for large panels) to ensure full wet-out and void-free bonds.
Storage & handling
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Shipments arrive frozen at −40 °C to maximize shelf life.
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Shelf life: ~1 year at −40 °C.
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Work life: ~6 months at room temperature.
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Let material warm to room temperature before opening to avoid condensation on the adhesive surface.
Processing notes
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Cutting: Die-cut preforms are most common for production. Glass support ensures clean edges and stable geometry. For prototyping, sheets can be trimmed with a razor or scissors while keeping release liners in place.
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Placement: Light pre-tack can be developed by warming a substrate to ~40–60 °C before final cure, helping with registration.
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Cure schedule: 1 hr @ 150 °C under continuous pressure (2–10 psi typical).
Spec snapshot
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Form: Glass-supported epoxy film (white)
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Thermal conductivity: ~0.7 W/m·K
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Tg: ~109 °C
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CTE: ~45 ppm/°C below Tg; ~270 ppm/°C above Tg
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Electrical: Volume resistivity ~8×10¹⁴ Ω·cm; dielectric constant ~4.4 @1 kHz
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Thicknesses: Typically ~4–5 mil
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Qualification: MIL-STD-883 Method 5011
Where 5020K wins
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Substrate attach where copper, FR-4, aluminum, and ceramics all meet.
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Electrically insulated thermal paths inside defense, aerospace, and high-rel applications.
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Programs that demand tight dimensional control with die-cuttable preforms.