How to Select a Conformal Coating Material

Knowing how to select a conformal coating material is critical to protecting PCB assemblies against moisture, chemicals, electrical leakage, and long-term reliability risks. This guide compares core chemistries—acrylic, urethane, silicone, epoxy, Parylene—and when to add ProShieldESD for static control.

Illustration of PCB under transparent protective dome with labels Acrylic, Urethane, Silicone, Epoxy, Parylene, and ProShieldESD showing how to select a conformal coating material

At a glance: Match the coating to environment, electrical requirements, application process, reworkability, and compliance.

Key Factors in How to Select a Conformal Coating Material

1) Application Environment

  • Moisture / humidity: Acrylics and silicones perform well.
  • Chemicals / fuels / oils: Urethanes (UR) and epoxies (ER) offer higher resistance.
  • High temperature & thermal cycling: Silicones (SR) excel; Parylene supports wide ranges at thin films.
  • Ultrahigh barrier needs: Parylene (XY) provides exceptional gas and moisture barrier with uniform, pinhole-free films.

2) Electrical Requirements

  • Dielectric strength & leakage control: Select chemistries and thickness to meet creepage/clearance design goals.
  • SIR / Insulation stability: Confirm IPC-CC-830 qualification and your process SIR performance.
  • ESD mitigation: Add ProShieldESD coatings for housings, packaging, or surfaces.

3) Application Process

  • Spray / dip / selective: Acrylics and urethanes are versatile for manual or automated lines.
  • UV-curable: High throughput with rapid cure; mind shadowing and lamp access.
  • Parylene deposition: Vacuum CVD yields conformal, thin, pinhole-free films—ideal for fine pitch or complex geometries.

4) Rework & Repair

  • Easiest: Acrylics (AR) with common strippers.
  • Moderate: Urethanes and silicones—often require specialty solvents and/or mechanical methods.
  • Challenging: Parylene—typically laser ablation, plasma etch, or micro-abrasion.

5) Standards & Compliance

  • IPC-CC-830: Material qualification baseline.
  • UL 746E: Flammability and electrical safety.
  • IEC 60664: Pollution degree & creepage/clearance context.
  • Sector specifics: Parylene is common in medical and aerospace for reliability and biocompatibility.

Comparison Table: How to Select a Conformal Coating Material

Coating Type Strengths Limitations Typical Uses
Acrylic (AR) Easy to apply & remove; good moisture protection; clear Lower chemical resistance; moderate temperature range General electronics, rapid prototyping, rework-heavy builds
Urethane (UR) Excellent chemical/solvent resistance; tough Harder to rework; longer cure; potential yellowing Automotive, industrial, chemical exposure
Silicone (SR) Wide temperature range; flexible; good humidity performance Lower abrasion resistance; more difficult removal Aerospace, power electronics, thermal cycling
Epoxy (ER) High chemical & abrasion resistance; durable Brittle; difficult to rework; potential stress on parts Harsh industrial, chemical environments
Parylene (XY) Superior barrier; ultrathin, uniform, pinhole-free; biocompatible Vacuum process; higher cost; challenging rework Medical, aerospace, fine-pitch/high-reliability electronics
ProShieldESD Conductive polymer for static control; coats surfaces, cases, packaging Not a moisture barrier; complements moisture coatings ESD-sensitive assemblies, workspaces, UXO packaging

Making the Right Choice: How to Select a Conformal Coating Material

  1. Define the environment: humidity, splash/immersion, chemicals, temperature profile, contamination risks.
  2. Set electrical targets: insulation (SIR), dielectric strength, PD/CTI context, ESD strategy.
  3. Choose the process: spray/dip/selective vs Parylene CVD; throughput and masking complexity. See our masking section.
  4. Plan rework/repair: select chemistries compatible with your service model.
  5. Verify compliance: IPC-CC-830/UL 746E requirements and customer sector specifics.

Tip: Use test coupons coated alongside assemblies to verify thickness and properties rather than measuring on populated boards.

Conclusion

When considering how to select a conformal coating material, no single chemistry fits all. Acrylics are versatile and reworkable; urethanes and epoxies offer chemical robustness; silicones tolerate heat and cycling; Parylene delivers unmatched barrier performance. For ESD risks, apply ProShieldESD to surfaces, housings, or packaging alongside your chosen barrier coating.

Need help selecting a coating?
We can specify materials, masking, and process settings for your application—plus ProShieldESD integration for static control.

Why Choose SCH Services?

Partnering with SCH Services means more than just outsourcing — you gain a complete, integrated platform for
Conformal Coating, Parylene & ProShieldESD Solutions, alongside equipment, materials, and training, all backed by decades of hands-on expertise.

  • ✈️ 25+ Years of Expertise – Specialists in coating technologies trusted by aerospace, medical, defence, automotive, and electronics industries worldwide.
  • 🛠️ End-to-End Support – Guidance on coating selection, Parylene grades, masking strategies, application methods, inspection, and ProShieldESD integration.
  • 📈 Scalable Solutions – From small prototype batches to full-scale, high-volume production, SCH delivers flexible capacity that grows with your needs.
  • 🌍 Global Reach – Responsive technical support and supply coverage across Europe, North America, and Asia.
  • ✅ Proven Reliability – A strong reputation built on quality, consistency, and customer satisfaction across services, equipment, and materials.

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