Low Outgassing Adhesives: The Key to Precision Manufacturing in Aerospace and Electronics

In advanced manufacturing sectors like aerospace, semiconductors, and high-end electronics, reliability and precision are non-negotiable. Every component must perform flawlessly under extreme conditions — from vacuum environments in satellites to high-density circuits in smartphones. Among the unsung heroes behind this performance are low outgassing adhesives — specialized bonding materials designed to ensure stability, cleanliness, and longevity.

In this article, we’ll explore what makes low outgassing adhesives unique, why they are essential in modern industries, and how companies like Pacific Adhesive Systems (M) Sdn Bhd are helping manufacturers in Malaysia achieve world-class production standards through advanced adhesive technologies.

What Are Low Outgassing Adhesives?

All adhesives contain volatile compounds that can evaporate or “outgas” over time, especially when exposed to heat or vacuum. These outgassed materials condense on nearby surfaces, forming unwanted films or contaminants. In everyday applications, this is often harmless. But in high-precision environments — such as optical sensors, camera modules, or aerospace components — even microscopic contamination can cause serious malfunctions.

Low outgassing adhesives are specially formulated to release minimal volatile organic compounds (VOCs) during and after curing. Their chemical structures are tightly crosslinked, ensuring that once cured, they remain stable and do not emit gases that could contaminate sensitive parts.

This property makes them indispensable in fields that require ultra-clean environments, such as aerospace, defense, medical technology, and high-performance electronics manufacturing.

Why Outgassing Is a Major Concern

Outgassing may seem like a small issue, but in high-precision manufacturing, it can lead to costly failures or degraded performance.

Common Problems Caused by Outgassing

1. Optical Contamination
   Volatile compounds from adhesives can condense on lenses, mirrors, or sensors, creating hazy deposits that interfere with light transmission or imaging accuracy.

2. Electrical Failures
   Condensed residues may increase surface conductivity, leading to short circuits or signal interference on printed circuit boards (PCBs).

3. Vacuum System Contamination
   In aerospace or semiconductor fabrication, even trace amounts of gas molecules can compromise vacuum integrity, affecting process yields or spacecraft performance.

4. Reduced Bond Strength
   Outgassed components can alter the adhesive’s internal structure, reducing long-term adhesion and mechanical stability.

To prevent these problems, manufacturers specify adhesives that meet strict outgassing standards, such as NASA’s ASTM E595 or ECSS-Q-ST-70-02C, ensuring safe use in vacuum and optical systems.

Key Characteristics of Low Outgassing Adhesives

Low outgassing adhesives combine high purity, chemical stability, and robust mechanical properties. The following characteristics distinguish them from conventional bonding materials:

• Minimal Volatile Release: Designed to emit less than 1% total mass loss (TML) and less than 0.1% collected volatile condensable material (CVCM).

• High Thermal Resistance: Withstands wide temperature ranges from cryogenic conditions up to 200°C or more.

• Excellent Adhesion: Bonds well with metals, ceramics, glass, and engineering plastics.

• Chemical Inertness: Resistant to solvents, fuels, and harsh cleaning agents.

• Dimensional Stability: Maintains bond strength without shrinkage or warping after curing.

• Electrical Insulation: Ideal for encapsulating sensitive electronic circuits.

These properties ensure reliability even in extreme conditions where failure is not an option.

Types of Low Outgassing Adhesives

Different formulations offer unique benefits depending on the application and substrate. The most common categories include:

Epoxy-Based Adhesives

Epoxies are known for their superior mechanical strength and long-term chemical stability. When formulated for low outgassing, they deliver exceptional bonding and thermal resistance.
Typical uses: Optical assemblies, sensors, and space hardware.

Silicone Adhesives

Silicone adhesives remain flexible over a wide temperature range and offer excellent vibration resistance. Their low outgassing grades are often used in optical, aerospace, and thermal interface applications.
Typical uses: Sealing optical housings, thermal insulation, and vibration damping.

UV-Curable Adhesives

UV-curable formulations combine low outgassing performance with fast, on-demand curing. They are especially useful in high-volume electronic or optical production lines.
Typical uses: Bonding display glass, camera modules, and fiber optics.

Polyurethane and Hybrid Systems

For applications requiring a balance between flexibility and strength, low outgassing polyurethane or hybrid adhesives provide good mechanical performance with minimal gas release.
Typical uses: Aerospace interiors, encapsulation, and mechanical assemblies.

Applications in Aerospace Engineering

Aerospace systems demand absolute reliability. Satellites, spacecraft, and aircraft operate under extreme stress — from the vacuum of space to the vibrations of takeoff. Low outgassing adhesives play a vital role in ensuring long-term stability and contamination control.

Key Aerospace Applications

• Satellite Optical Systems: Prevent haze formation on mirrors and sensors.

• Thermal Control Assemblies: Maintain insulation performance without releasing gases that could degrade coatings.

• Electrical Harnesses and Connectors: Provide stable bonding without increasing conductivity or leakage.

• Composite Material Bonding: Used in lightweight structures for vibration resistance and temperature endurance.

NASA and ESA both mandate the use of adhesives that meet outgassing criteria before they are approved for space missions. This ensures that delicate instruments, such as imaging sensors and solar panels, remain pristine throughout their operational lifespan.

Applications in Electronics Manufacturing

In modern electronics, particularly in semiconductors, sensors, and optical devices, contamination is one of the biggest threats to performance. Low outgassing adhesives are now standard in cleanroom production environments.

Typical Electronics Applications

• Encapsulation of Microchips: Protects against moisture and contamination without releasing harmful vapors.

• Bonding Camera Lenses and Optical Sensors: Prevents fogging or film formation that could distort images.

• PCB Assembly: Provides insulation and vibration resistance for surface mount components.

• Display Module Bonding: Maintains clarity and alignment in high-resolution screens.

• Fiber Optic Connectors: Ensures stable light transmission over time without clouding.

In Malaysia’s humid climate, the combination of low outgassing and moisture resistance is particularly valuable, helping local manufacturers maintain international reliability standards.

Testing and Certification Standards

Adhesives used in critical applications must undergo rigorous testing to verify their suitability. The most recognized standard is ASTM E595, developed by NASA to evaluate material outgassing under vacuum conditions.

Key parameters measured include:

• Total Mass Loss (TML): Percentage of mass lost after exposure to high temperature in vacuum.

• Collected Volatile Condensable Material (CVCM): Amount of material that condenses on a cool surface.

• Water Vapor Regain (WVR): Percentage of absorbed water re-evaporated after exposure.

Only adhesives with TML < 1.0% and CVCM < 0.1% pass the NASA low outgassing specification, making them suitable for aerospace and optical applications.

Advantages Over Conventional Adhesives

By using low outgassing materials, manufacturers achieve cleaner production environments, longer component life, and higher precision — all crucial for high-value industries.

The Role of Low Outgassing in Optical and Semiconductor Devices

In optics and semiconductors, contamination control defines product success. Even invisible residues from adhesive vapors can cause:

• Reduced light transmission in laser or imaging systems

• Pixel degradation in camera sensors

• Pattern distortion in lithography equipment

Low outgassing adhesives prevent these microscopic issues by maintaining chemical purity and dimensional stability. Their transparency also makes them suitable for optical bonding where visual clarity is essential.

Choosing the Right Low Outgassing Adhesive

Selecting the right formulation depends on multiple factors such as operating temperature, substrate material, exposure to chemicals, and curing process. Here are key considerations for engineers:

1. Operating Environment – Determine if the application involves vacuum, high humidity, or temperature cycling.

2. Curing Method – Choose between heat-cured, UV-cured, or dual-cure systems based on process needs.

3. Mechanical Requirements – Identify whether flexibility or rigidity is more important.

4. Electrical Properties – For PCBs or semiconductors, ensure high dielectric strength.

5. Transparency and Optical Performance – For optical bonding, use colorless, non-yellowing formulations.

Working with an experienced adhesive supplier helps tailor the product to your specific application.

Pacific Adhesive Systems: Supporting Malaysia’s High-Tech Industries

As Malaysia strengthens its position in the global aerospace and electronics supply chain, local access to advanced adhesive technology is essential. Pacific Adhesive Systems (M) Sdn Bhd is a trusted partner providing world-class bonding solutions, including low outgassing adhesives, UV-curable epoxies, and conformal coatings.

The company supports clients through:

• Expert material selection and customization

• Technical consultation for process optimization

• Compliance with international standards such as NASA ASTM E595

• Reliable supply for industrial and cleanroom applications

By combining global technology with local expertise, Pacific Adhesive Systems enables Malaysian manufacturers to meet demanding performance and certification requirements.

The Future of Low Outgassing Adhesive Technology

As space exploration, 5G communication, and microelectronics continue to evolve, adhesive innovation will play an even larger role. Future low outgassing systems are expected to feature:

• Nanocomposite fillers for improved strength without added mass

• Faster dual-cure mechanisms combining UV and thermal curing

• Environmentally friendly formulations with zero VOC emissions

• Smart adhesives capable of sensing stress or temperature changes

These advancements will further enhance precision, safety, and environmental performance — reinforcing the critical role of adhesives in modern engineering.

Conclusion

Low outgassing adhesives are not just another material choice; they are a technological necessity in precision manufacturing. By preventing contamination, ensuring dimensional stability, and maintaining long-term reliability, they make aerospace missions safer and electronic devices more dependable.

For Malaysian manufacturers looking to compete on a global scale, adopting advanced low outgassing solutions is a strategic investment in quality and innovation. With the expertise of Pacific Adhesive Systems (M) Sdn Bhd, industries can confidently achieve cleaner, more precise, and more sustainable production outcomes.

From satellites orbiting the Earth to microchips powering everyday life, low outgassing adhesives are the silent guardians of performance and precision.