Clean room Silicone and various other adhesives are used for manufacturing and installation of clean rooms.These adhesives must meet stringent requirements to prevent contamination, outgassing, and particle shedding.
A cleanroom is a controlled environment designed to maintain extremely low levels of airborne particles, such as dust, microbes, and chemical vapors. Cleanrooms are essential in industries where tiny contaminants can compromise manufacturing processes or product quality.
Key Characteristics of a Cleanroom
- Controlled Air Quality: Air is filtered through HEPA or ULPA filters to remove particles.
- Positive Pressure: Keeps unfiltered air from entering when doors open.
- Strict Access Control: Personnel wear cleanroom garments (gowns, masks, gloves, etc.).
- Environmental Controls: Regulated temperature, humidity, and airflow.
- Material Restrictions: Only approved tools, clothing, and chemicals are allowed inside to avoid contamination.
Clean rooms are classified based on the number and size of particles permitted per volume of air. The two main classification systems are ISO Cleanroom Standards (ISO 14644-1). This is the most widely used international standard.
| ISO Class | Max particles/m³ ≥ 0.5 µm | Typical Use |
|---|---|---|
| ISO Class 1 | 10 | Semiconductor fabs (extremely critical) |
| ISO Class 2 | 100 | Advanced microelectronics |
| ISO Class 3 | 1,000 | Microchip manufacture |
| ISO Class 4 | 10,000 | Micromechanics |
| ISO Class 5 | 100,000 | Pharmaceutical fill/finish, some surgeries |
| ISO Class 6 | 1,000,000 | Pharmaceutical packaging |
| ISO Class 7 | – | Clean areas for less critical drug manufacturing |
| ISO Class 8 | – | Less stringent medical device assembly |
| ISO Class 9 | – | Ambient room air (typical indoor space) |
Industries That Use Cleanrooms
- Semiconductor & Electronics – Even microscopic dust can ruin microchips.
- Pharmaceuticals – Prevents contamination in drug manufacturing.
- Medical Devices – Ensures sterility and compliance (e.g., for implants).
- Biotech & Life Sciences – For research involving cells, DNA, etc.
- Aerospace & Optics – Needed for high-precision components.
- Food & Beverage (in select cases) – For sterile packaging environments.
Key Requirements for Cleanroom-Compatible Adhesives
- Low Outgassing: Adhesives must not release volatile organic compounds (VOCs) or other gases that could contaminate sensitive environments. (Measured per ASTM E595 or NASA outgassing standards.)
- Low Particle Shedding: Must not shed particulates during curing or over time.
- Chemical Resistance: Tolerant to disinfectants, solvents, or process chemicals.
- Non-Ionic / Low Ionic Content: Especially critical in semiconductor manufacturing to prevent corrosion.
- Sterilization Compatibility: Able to withstand methods like gamma irradiation, autoclaving, or ethylene oxide treatment.
- Cleanroom-Certified Packaging: Some adhesives come in pre-packaged, cleanroom-compatible containers.
Types of Adhesives Commonly Used
| Type | Characteristics | Applications |
|---|---|---|
| Epoxy | High strength, low outgassing, good temperature resistance | Electronics, aerospace, optics |
| Silicone | Flexible, biocompatible, low outgassing | Medical devices, optical assemblies |
| UV-Curable Adhesives | Fast curing under UV light, low VOCs | Optical components, electronics |
| Acrylic | Some low-outgassing variants, good for bonding plastics | Medical devices, displays |
| Polyurethane | Flexible, chemical-resistant | Medical or flexible assemblies (less common in critical cleanrooms) |
Considerations When Choosing an Adhesive
- Substrate compatibility (glass, plastic, metal, etc.)
- Cure method (UV, thermal, ambient)
- Biocompatibility (ISO 10993 or USP Class VI for medical use)
- Application method (manual or automated dispensing)
Summary