Difference between acrylic and silicone HumiSeal coatings
Acryl en silicone HumiSeal coatings are two of the most commonly used Conforme coating types in PCB-assemblage, Prototype PCB-assemblage, en SMT-assemblage. While both provide protection against moisture, dust, and contaminants, they differ significantly in performance, flexibility, cost, and application scenarios.

Key difference: material properties
The main distinction lies in their chemical nature:
- Acrylic coatings (AR) → hard, transparent, fast-drying polymers
- Silicone coatings (SR) → soft, rubber-like, highly flexible materials
Acrylic coatings cure into a rigid protective layer, while silicone coatings remain elastic and flexible.
Drying speed and process efficiency
Acrylic coatings are known for their fast drying and easy processing, making them ideal for high-speed SMT-assemblage production lines. They can dry within minutes and are simple to apply.
Silicone coatings typically require longer curing time, especially if moisture curing is involved, which can slow down production throughput.
Flexibility and vibration resistance
This is one of the most important differences:
- Acrylic → relatively rigid, may crack under vibration or thermal cycling
- Silicone → highly flexible, absorbs stress and resists cracking
Silicone coatings are better suited for environments with mechanical stress, vibration, or thermal expansion.
Temperatuurbestendigheid
Acrylic coatings perform well in moderate temperature ranges (typically up to ~120°C).
Silicone coatings offer excellent high and low temperature resistance, often operating from -55°C tot 200°C of hoger, making them ideal for extreme environments.
Chemical and environmental resistance
- Acrylic → good moisture protection, but limited resistance to harsh chemicals
- Silicone → strong resistance to chemicals, humidity, and harsh environments
Silicone coatings are preferred for automotive, aerospace, and outdoor electronics where long-term durability is critical.
Herwerken en repareren
In PCB-assemblage, rework capability is very important:
- Acrylic → easy to remove and repair using common solvents
- Silicone → moeilijker te verwijderen, requires special processes
This makes acrylic coatings highly suitable for Prototype PCB-assemblage, where frequent modifications are needed.
Cost and production considerations
- Acrylic → lower cost + faster processing
- Silicone → higher cost + better performance
For high-volume SMT-assemblage, acrylic is often chosen for cost efficiency, while silicone is used when performance requirements justify the higher cost.
Typische toepassingen
Acrylic HumiSeal coatings (e.g., 1B31):
- Consumentenelektronica
- LED drivers and power supplies
- General-purpose PCB-assemblage
- Prototype PCB-assemblage (easy rework)
Silicone HumiSeal coatings:
- Automobielelektronica
- Aerospace systems
- Outdoor and high-humidity environments
- High-temperature applications
Summary comparison
| Functie | Acrylic Coating | Silicone Coating |
|---|---|---|
| Drying speed | Very fast | Slower |
| Flexibiliteit | Low to moderate | Zeer hoog |
| Temperatuurbestendigheid | Matig | Uitstekend |
| Chemische weerstand | Matig | Hoog |
| Herwerkbaarheid | Easy | Difficult |
| Kosten | Onder | Higher |
| Best use | Standard electronics | Harsh environments |
Definitief inzicht
There is no “one-size-fits-all” choice between acrylic and silicone HumiSeal coatings.
- Kies acrylcoatings voor cost-effective, fast, and rework-friendly solutions in PCB-assemblage en SMT-assemblage
- Kies silicone coatings voor extreme environments, high reliability, and long-term durability
In practice, many manufacturers validate both options during Prototype PCB-assemblage before selecting the most suitable coating for mass production.
Vraag een offerte aan voor conforme coating
Weet u niet zeker welke conformal coating geschikt is voor uw product? Neem vandaag nog contact op met onze experts.
Stuur ons je vereisten en krijg snel antwoord van ons engineeringteam.
✔ 24-uurs respons ✔ Engineering-ondersteuning ✔ Kleine & massaproductie
Shenzhen Tengxinjie Electronics Co, Ltd.


